After adjusting for age, sex and total energy intake, years of education significantly affect the folate intake . The structural equation model (SEM) shows that the indirect effect of folate intake is statistically significant and strong  in the pathway of education level to depression scale. Our study shows both education and income are significantly associated with depression scales in Japanese workers, and the effort to increase the folate intake may alleviate the harms of social disparities on mental health.The association of socioeconomic status (SES) with nutrient intake attracts public attention worldwide. In the current study, we examined the associations of SES with dietary intake of folate and health outcomes in general Japanese workers. This Japanese occupational cohort consisted off 2266 workers. SES was assessed by a self-administered questionnaire. Intakes of all nutrients were assessed with a validated, brief and self-administered diet history questionnaire (BDHQ). The degree of depressive symptoms was measured by the validated Japanese version of the K6 scale. Multiple linear regression and stratified analysis were used to evaluate the associations of intake with the confounding factors. Path analysis was conducted to describe the impacts of intake on health outcomes. Education levels and household incomes were significantly associated with intake of folate and depression scales ( The association of socioeconomic status (SES) with health outcomes attracts public attention worldwide . Health Several studies of dietary intake showed that folate intake relates to CVD , colorecThe aim of this study is to investigate the associations between SES factors, nutritional intake and health incomes in our occupational cohort, especially to identify the role of nutritional intake in these potential associations. Folate was selected as study object because it is widely used, essential to life and considered relative to many diseases. To our knowledge, this is the first study to evaluate the relations of folate intakes to income and education, as well as depression scales, in Japanese general workers.The present cross-sectional study is a part of the Japanese study of Health, Occupation and Psychosocial factors related Equity (J-HOPE), which was performed to develop and expand research to elucidate mechanisms underlying the social disparity in health and establishment of measures to control over it. It was based on a baseline survey of our occupational cohort study on social class and health, supported by a grant from the Ministry of Education, Culture, Sports, Science and Technology, Japan. A total of 14,534 individuals from 13 independent cohorts enrolled in this study. In the current investigation, employees of a Japanese major manufacturing company  were recruited. Approximately 2500 workers of this company were invited to participate, and 2266 agreed (response rate 90.1%). The protocol and explanation documents of our study were approved by the ethics committee of the University of Tokyo School of Medicine, and written informed consent was obtained from each subject.Age, sex, height, weight, systolic and diastolic blood pressures (SBP and DBP), fasting plasma glucose level (FPG) and serum lipid levels  cholesterol) were measured at health check-ups in all subjects. Body mass index (BMI) was calculated as dividing the weight (in kg) by the square of the height (in meters). The degree of depressive symptoms was measured by the Japanese version of the Kessler’s K6 questionnaire , which cYears of education, annual household income added by income of each family member, and the numbers of family members were assessed by a self-administered questionnaire. Each participant was asked to answer which of the six income grades his/her household income belongs to, defined as: 1, <3.0 million yen/year; 2, 3.0–4.99 million yen/year; 3, 5.0–7.99 million yen/year; 4, 8.0–9.99 million yen/year; 5, 10.0–15.0 million yen/year; 6, >15.0 million yen/year. The midpoint of each grade was calculated . The classification of education subgroups is based on the International Standard Classification of Education (ISCED)  General Conference at its 29th session in November 1997): “Low” education level corresponds to the end of compulsory education, and can also include vocational training after schooling ; “Middle” education level corresponds to at least three years of additional schooling, which includes programs designed to provide access to higher education or leads directly to the labor market ; “High” education level corresponds to a Bachelor’s degree or higher .Dietary habits during the preceding month were assessed with a validated, brief, self-administered diet history questionnaire (BDHQ) . Responses to the BDHQ were checked for completeness and, where necessary, clarified by direct questioning of the subject. The BDHQ is a four-page structured questionnaire that enquires about the consumption frequency of a total of 56 food and beverage items, with specified serving sizes described in terms of the natural portion or the standard weight and volume measurement of servings commonly consumed in general Japanese populations. The BDHQ was developed based on a comprehensive (16-page) version of a validated self-administered diet history questionnaire ,37,38. Tp values represent the relationships between SES factors and intake levels. The association between intake levels of folate and SES factors was examined by multiple linear regression analyses, controlling for age, sex and total energy intakes. The total subjects were stratified into SES subgroups, we calculated age-, sex- and total energy intake-adjusted intake level for folate of each subject, and compared the mean adjusted values between subgroups by using Bonferroni-corrected trend test. Finally, the structural equation modeling (SEM) analysis was performed to estimate the causal relationship between the SES factors and depressive score. The IBM SPSS statistics for Windows version 19.0J  and AMOS 19.0  statistics software packages were used for all statistical analyses. Statistical significance for all analyses was defined as p < 0.05. We aimed to evaluate the relationships between folate intakes and SES factors. Descriptive statistics of clinical characteristics among different education or income groups were compared. Pearson’s correlation coefficients and n = 2266) were 43.4 ± 9.8 years (ranged from 21 to 65 years) and 23.1 ± 3.3 kg/m2 (ranged from 13.8 to 41.8 kg/m2), respectively, which are typical for middle-aged Japanese population. Two hundreds and forty-one of them are women, accounting for 10.6%. 63.6% of the subjects (n = 1442) attained the Japanese RDA of folic acid intake (240 μg/day), and 824 did not.R) were 0.074  and 0.101 , respectively. When the univariate analysis was used, the associations of total energy-adjusted folate intake with SES were also present, and the unadjusted p value for years of education was 0.029, for household income was below 0.001.The correlations of two major SES factors, education and household income, with dietary intakes of folate, were evaluated and the results are present in p < 0.001). After adjusting for age and sex, the differences in SES factors, including years of education, proportion working as managers, and annual household income remained significantly  or income (p for trend <0.001) increased.In a trend test in which SES factors were used as categorized variables, the age-, sex- and total energy intake-adjusted folate intake level of each subject was calculated, and the mean adjusted values were compared between subgroups. There were significant linear increases of the folate intake levels as the education (p < 0.001) were significantly associated with higher intake, but household income was not (p = 0.186). Considering the different dietary habits between genders, we also carried out a separate analysis for male and female subjects. In male subjects accounting for nearly 90% of the total, the results were similar to those of all subjects, education level was significantly associated , but household income was not . As to the women, neither education nor income was associated with folate intake (data not shown). The study may have been underpowered to detect a statistically significant association between folate intakes and education or income among women.We next assessed the effects of SES factors on intake levels by a multiple linear regression model. In this analysis, education level and annual household income were added at the same time, and age, sex and total energy intake were used as confounding factors. The results are shown in p = 0.031), but not with household income. We also investigated whether the SES factors affect the health outcomes. As the results, the incidence of depressive symptoms (proportion of subjects with a K6 score ≥9) was negatively associated with education levels after controlling for age, sex, total energy intake and folate intake , the indirect standardized effect was −0.0056, which calculated by multiplied the coefficient of education on folate intake as 0.07 with that of folate intake on K6 as −0.08. The direct and indirect effect of household income K6 was −0.08 and −0.007  meet the Estimated Average Requirement (EAR) as 320 μg/day, which was calculated for American adults [n = 417) meet the 400 μg of RDA of USA [In the current study, we confirmed that there were statistically significant and linear associations between the dietary intake of folate and SES factors: years of education and household income  in Japann adults , and 18.A of USA  there wep = 0.031, “Low” as the referent group). However, household income levels were not associated with these outcomes. In due consideration of the fact that raising income levels dramatically is quite difficult, education may have a realistic power to relieve the SES effect on health outcomes. Our results in general workers (both men and women) are consistent with them and provided new evidence for the importance of raising the education level in terms of understanding of human health.Markedly, our results show the importance of education. After adjusting for age, sex, total energy intake and folate intake, education level was found to be negatively related to prevalence of depressive symptoms : 0.95 (0.91–1.00), We also found that education levels, but not household incomes, affect the prevalence of depressive symptom. These results are consistent with those reported by several study groups before 2001, in which a clear, graded association between educational attainment and reported depressive symptoms can be seen, demonstrating the consistency of this relationship ,43,44,45However, whether SES factors affect the health outcomes directly or through other factors such as nutritional status, is unknown. In order to assess the role of the nutritional intake in the relationship between SES factors and health outcomes, we carried out a path analysis to detect the direct and indirect impacts of education and household income. In the education-folate intake-depression scale pathway, the direct and indirect impact of education on K6 score were −0.01 and −0.0056, respectively, over a half of the impact was accounted for by the indirect model, suggesting that the folate intake mediates the effects of education level on depression scale a. As to Some limitations of the present study are worth mentioning. First, the cross-sectional nature of the study does not permit the assessment of causality owing to the uncertain temporality of the association. However, it is improbable that a low intake of folate would lead to low income or low education and the reverse causation is almost deniable. Second, our subjects were workers in one large company and not a random sample of Japanese workers, and thus the results may not apply to the general Japanese population. However, the workers were recruited from 22 offices all over Japan (From Hokkaido to Kyushu). So the geographical deviation was reasonably diluted, but it is noteworthy fact that our result is the result of a large company, not a small one. Thirdly, dietary data were obtained from a self-administered semi-quantitative dietary assessment questionnaire . BecauseIn the current study, the results of the structural equation modeling analysis have shown that in the pathway by which education level affects depression scale, the indirect effect mediated by the dietary folate intake was statistically significant, in addition, was considerable large that accounting for 56% of the direct effect. Education and income were strong and independent predictors of folate intake level in Japanese workers in general, and folate intake is an important factor mediating the association between education and depressive symptoms. Because it is difficult to raise one’s education and income level, nutritional interventions, which increase the folate intake, may alleviate the adverse impacts of the social disparity on mental health.


Salmonella Typhi (NARST) infection is increasing worldwide. We are reporting an unusual case of infected haematocolpos presenting as urinary obstruction in a patient with fever of unknown origin (FUO). This case report highlights the importance of quinolone-resistant typhoid fever in the differential diagnosis of any acute febrile illness in countries, like India, where Salmonella infection is endemic.The prevalence of nalidixic acid-resistant  A 12-year old girl with a 10-hour history of dull lower abdominal pain and inability to void was admitted at the emergency of SSK Hospital attached to Lady Hardinge Medical College, New Delhi. She also gave a history of burning micturition for the last two days and of fever for one month. The fever was low-grade, intermittent, arose at any time of the day without chills or notable sweats, was relieved by medication but recurred. The patient had not attained menarche and was not taking any medications other than acetaminophen.9/l . The patient had sterile reports of blood and urine cultures performed within 5 days of the start of fever. On admission, urine and blood cultures were repeated but were found sterile. Thin and thick film examinations of peripheral blood were also negative for malaria. Widal test was performed which showed a titre of 80 against ‘O’ (somatic) antigen and 160 against ‘H’ (flagella) antigen of Salmonella Typhi .Her total leukocyte count was 1.7×10On examination, she was in pain, apyrexic with normal pulse rate and blood pressure. On abdominal examination, tenderness was elicited in the midline of the abdomen between the symphysis pubis and two inches below the umbilicus. A distinct suprapubic mass was felt in this location through the abdominal wall, which was symmetrical, tender, and dull to percussion. Rectal examination showed an excessively tender, large, soft swelling bulging into the anterior rectal wall. Vulval examination revealed a tense bulging membrane of bluish discolouration, and haematocolpos was diagnosed.The patient was catheterized and approximately 500 mL of urine was drained. Hymenectomy with haematocolpos drainage was planned for the patient, and she was admitted for the same.The patient experienced multiple spikes of fever during the hospital stay and was investigated for the same. She was put on empiric treatment with ciprofloxacin 500 mg intravenously given 12-hourly and injection metronidazole 400 mg given 8-hourly. This was initiated to provide coverage for anaerobic bacteria and facultative anaerobic Gram-negative bacteria, which are common pathogens in such closed-cavity infections, particularly of the genitourinary system.Salmonella enterica serotype Typhi was isolated in pure culture from the drained haematocolpos. The isolate was presumptively identified by colony morphology, Gram reaction, motility, and biochemical characteristics as per standard guidelines  in accordance with the Kauffman White scheme. By using Vi phage typing according to the International Federation for Enteric Phage Typing, the strain was classified as Salmonella enterica serotype Typhi Vi deranged phage type. Antimicrobial susceptibility testing was performed by the disc diffusion test for ciprofloxacin (5 µg), ampicillin (10 µg), cotrimoxazole (1.25/23.75 µg), chloramphenicol (30 µg), nalidixic acid (30 µg), and ceftriaxone (30 µg) as per Clinical Laboratory and Standard Institute guidelines of 2011 ((R) AST card. The organism was reported to be sensitive to amoxycillin-clavulanic acid, ticarcillin, piperacillin, cefpodoxime, cefotaxime, ceftizoxime, aztreonam, meropenem, tetracycline, and tigecycline and resistant to nalidixic caid, norfloxacin, and moxifloxacin. The minimum inhibitory concentration (MIC) of nalidixic acid was ≥32 μg/mL; MIC of moxifloxacin was ≥8 μg/mL, and that of norfloxacin was ≥16 μg/mL.There was no remission in the patient's temperature, and ceftriaxone was started parenterally on Day 4 of admission. The patient's condition improved, and she had surgery within 24 hours of the initiation of therapy with ceftriaxone. The haematocolpos was drained, and the blood sample was sent for culture. idelines . The isoSalmonella enterica serotype Typhi and Paratyphi A. Serotype Typhi-related bacteraemia is commonly associated with extra intestinal disease involving liver, spleen, lymph nodes, skin, bones, joints, endocardium, or central nervous system. A review of literature shows that Salmonella enterica serotype Typhi is capable of abscess formation in the spleen, liver, and brain. However, patients with these abscesses had associated bacteraemia. Penetration of the extra-intestinal tissues in isolation is rare (Enteric fever, an invasive infection consisting of bacteraemia with minimal gastrointestinal infection, is caused by  is rare .Salmonella enterica serotype Typhi from haematocolpos blood without systemic bacteraemia is an extremely rare finding. Transient bacteraemia associated with inadvertent self-administration of antimicrobial agents for fever prior to admission could be a possible explanation for the incongruous observation. This is quite possible in the Indian setting where over-the-counter purchase of antibiotics is a common practice.Haematocolpos itself is a very uncommon condition and is usually a consequence of cryptomenorrhoea, in which the formation of menstrual discharge goes on without normal appearance of menstruation . The isoSalmonella enterica serovar Typhi and the therapeutic dilemma faced by the clinicians regarding the empirical use of fluoroquinolones for the treatment of acute febrile illnesses.The isolate in this study was sensitive to most of the antibiotics, except quinolones. This is unusual but can be explained by the fact that resistance to other antibiotics is plasmid-mediated and is independent of the resistance to fluoroquinolones, which is chromosomally mediated . The theSalmonella Typhi from haematocolpos blood without systemic bacteraemia. Also, the susceptibility pattern of the isolated organism highlights the emerging problem of antimicrobial resistance in serovar Typhi and the therapeutic dilemma faced by the clinicians regarding the empirical use of fluoroquinolones.This case report documents the isolation of


Knowledge of normal muscle characteristics is crucial in planning rehabilitation programmes for injured athletes. There is a high incidence of ankle and anterior tibial symptoms in football players, however little is known about the effect of limb dominance on the anterior tibial muscle group (ATMG). The purpose of this study was to assess the effect of limb dominance and sports-specific activity on ATMG thickness in Gaelic footballers and non-football playing controls using ultrasound measurements, and to compare results from transverse and longitudinal scans.Bilateral ultrasound scans were taken to assess the ATMG size in 10 Gaelic footballers and 10 sedentary controls (age range 18-25 yrs), using a previously published protocol. Both transverse and longitudinal images were taken. Muscle thickness measurements were carried out blind to group and side of dominance, using the Image-J programme.Muscle thickness on the dominant leg was significantly greater than the non-dominant leg in the footballers with a mean difference of 7.3%, while there was no significant dominance effect in the controls (p < 0.05). There was no significant difference between the measurements from transverse or longitudinal scans.A significant dominance effect exists in ATMG size in this group of Gaelic footballers, likely attributable to the kicking action involved in the sport. This should be taken into account when rehabilitating footballers with anterior tibial pathology. Ultrasound is a reliable tool to measure ATMG thickness, and measurement may be taken in transverse or longitudinal section. Gaelic football is a high speed field sport played in Ireland and internationally. In common with other field sports involving kicking, physical contact and running, there is a high incidence of ankle and anterior tibial symptoms in Gaelic football players ,2. TheseKnowledge of normal muscle characteristics is crucial in planning rehabilitation programmes for patients with muscle injury, as reduction in muscle size has been reported in injured populations ,4. Real-OSullivan et al  demonstrThe aims of this study are to assess the effect of limb dominance and sports specific activity on ATMG thickness in Gaelic footballers and non-football playing controls using ultrasound measurements, and secondarily to compare results from transverse and longitudinal scans.A convenience sample of 20 healthy subjects  was recruited from a University student population. Information leaflets were provided to volunteers, and subjects were selected based on the inclusion and exclusion criteria below. To be included, footballing subjects had to be over 18 years, be an out-field member of a college-level football team, be playing football for a minimum of 5 years, and have no current or recent (3 month) history of lower limb injury. Goalkeepers were excluded as they would not perform the same amount of kicking as outfield players. Recently injured players were excluded, as recovery may not have been complete. Control subjects were required to be 18 years, and to not engage in any sports or activities that may affect lower limb muscle strength. Written informed consent was obtained from each participant and ethical approval was obtained from the University Research Ethics Committee.Before the testing procedure began, subject characteristics were recorded. These were age, gender, height, weight, leg dominance, frequency of training per week, position of play on the field. Leg dominance was subjectively reported by the footballers, and determined in controls, by asking them to kick a ball that was placed centrally in front of them. with an 8 MHz linear array transducer  was used for measuring both the left and right anterior tibial muscle groups. Measurements were taken in both transverse and longitudinal directions. The testing positioning and procedure used was based on previous research measuring anterior tibial muscle size using real-time ultrasound imaging . SubjectFigure .Ultrasound coupling gel was used over the skin and transducer head. The transducer was held such that the ultrasound beams were aimed at 90 degrees to the muscle borders, by visually ensuring the transducer was held perpendicular to the skin, to ensure a clear image. Controls for contrast, brightness and near and far gain were adjusted to obtain a satisfactory image. Care was taken not to deform the underlying tissues and distort the images by using the minimum pressure required to create a clear image. Transverse measurements were taken by placing the probe perpendicular to the direction of the anterior tibial muscles. Longitudinal measurements were then taken by aligning the probe along the direction of the muscles. Three measurements were taken in each direction in order to reduce error, removing the probe between trials. Linear dimensions of the anterior tibial muscle group have previously been shown to reflect CSA . Scans wThe images were stored and transferred to a computer for measurement. Measurement of muscle thickness was carried out using Image J software . Each image was measured by two examiners. Measurement of anterior to posterior thickness involved placing a vertical line spanning the widest part of the echogenic tissue interface between the muscle belly and the muscle fascia, as seen in Figure p >0.05). Personal data  was compared between groups using independent t-tests. Intraclass correlation coefficients (ICCs) were obtained for inter-tester reliability of the measurement of the scans by the 2 examiners, using the mean thickness obtained by each examiner. Transverse and longitudinal measurements were compared within subjects using paired t-tests, and the association between measures was assessed with Pearsons correlation. A Two-way ANOVA (leg × subject group) was used to examine differences in ATMG thickness between the dominant and non-dominant legs according to group. Significance level was set at p < 0.05.SPSS Version 15.0 software was used for all statistical analysis. All data was found to be normally distributed . Mean age was 21.3 years (range 18-25), and all were right leg dominant. The mean weight and height of controls was 67.1 kg and 172.6 cm respectively, while the mean weight and height of footballers was 72.5 kg and 172.6 cm respectively. Each group contained 5 males and 5 females. There was no significant difference between the groups on any of these variables (p > 0.05), apart from sport-playing history.Intra-class co-efficients for the inter-rater reliability of measurement of the scans by 2 examiners demonstrated excellent reliability with values of 0.997  = 0.986-0.998) and 0.993 (95% CI = 0.984-0.997) for transverse measurements on the dominant and non-dominant sides respectively, and 0.994 (95%CI = 0.985-0.998) and 0.992 (95%CI = 0.981-0.997) for longitudinal measurements on the dominant and non-dominant sides respectively. There was no significant difference between measurements taken using the transverse and longitudinal approaches for either dominant (p = 0.793) or non-dominant legs (p = 0.442), therefore these measurements were collapsed into a single measure obtaining a mean muscle group thickness for each leg of each subject. Further evidence of the close association between measurements in transverse and longitudinal directions can be see in Figure Mean ATMG thickness (± standard deviation) results can be see in Table 3,39 = 8.18; p = 0.007). Examining the data shows that the dominant ATMG was larger only in the footballers, and not in controls. A mean between-leg difference of 0.21 cm was found in the footballers, which can be expressed as the dominant muscle group being 7.3% greater in thickness than the non-dominant muscle group.The results of the two-way ANOVA revealed a significant interaction for the effects of group and leg on ATMG size, showing that the effect of leg dominance differed between the footballers and controls (F The results found in this study highlight some important aspects for consideration in measurement of muscle size in athletes. Inter-rater reliability of scan measurement was high, similar to previous research using ultrasound, which reported high reliability for both linear and CSA measurements between scans and days . MeasureSecondly, this study found that a small, but statistically significant, difference exists in the size of the anterior tibial muscle group in dominant, compared with non-dominant, legs in Gaelic Footballers, representing a 7.3% increase in thickness on the dominant side. This significant side-to-side difference was not seen in age-matched, non-football playing controls and therefore, the difference seen in footballers can be attributed to sports specific performance. This is consistent with previous research on soccer players which found a similar dominance effect in the medial gastrocnemius muscles, where a side-to-side difference of 0.18 cm, equating to an overall difference of 6%, was found . SimilarFootballers also had a significantly larger muscle thickness on their dominant leg, compared to the dominant legs of controls, however no such difference existed in comparison of non-dominant legs between groups. This indicates training-induced hypertrophy of the dominant limb in the footballers. Training, and in particular, resistance training, has been shown to result in altered muscle architecture and muscle producing force  and hencMuscle atrophy following injury has traditionally been measured using measures of limb girth, with atrophy defined as a greater than one centimetre difference between limbs . HoweverThe relationship between muscle size and strength was not assessed in this study. However it would be important to assess the relationship between the size and morphology of this muscle group and muscle performance. The anterior tibial muscle has a fibre type composition ranging from 65% up to 90% type 1 fibres , which mLimitations to this research include small sample size, convenience sample, and possibility of measurement error. Error in scan measurement was reduced by the use of two examiners in measuring each of the scans, and the provision of close training and supervision by a researcher experienced in rehabilitative ultrasound scanning. A sample of convenience was used, however the sample recruited could be considered representative of the Gaelic football playing population. In addition, only one part of the muscle group was measured, and the results may not reflect those that would be obtained using other scanning sites.In conclusion, a side-to-side difference, favouring the dominant leg, exists in the size of the anterior tibial muscle group in Gaelic footballers. This difference is not seen in inactive, age-matched controls and so is likely to be attributable to the action of kicking in the sport. The clinician may take this difference into consideration when treating football players with a lower limb or ankle injury, by using ultrasound scanning to monitor change in muscle dimensions. Future research could examine this dominance effect in other sports and muscle groups, as well as the association between muscle size and strength or performance.The authors declare that they have no competing interests.KM was involved in the design of the study, data collection, data analysis, and drafting of the manuscript. SE was involved in the literature review, design of the study, recruitment, data collection, data analysis and drafting of the manuscript. All authors read and approved the final manuscript.


Count data are often collected in chronic disease research, and sometimes these data have a skewed distribution. The number of unhealthy days reported in the Behavioral Risk Factor Surveillance System (BRFSS) is an example of such data: most respondents report zero days. Studies have either categorized the Healthy Days measure or used linear regression models. We used alternative regression models for these count data and examined the effect on statistical inference.Using responses from participants aged 35 years or older from 12 states that included a homeownership question in their 2009 BRFSS, we compared 5 multivariate regression models — logistic, linear, Poisson, negative binomial, and zero-inflated negative binomial — with respect to 1) how well the modeled data fit the observed data and 2) how model selections affect inferences.Most respondents (66.8%) reported zero mentally unhealthy days. The distribution was highly skewed . Zero-inflated negative binomial regression provided the best-fitting model, followed by negative binomial regression. A significant independent association between homeownership and number of mentally unhealthy days was not found in the logistic, linear, or Poisson regression model but was found in the negative binomial model. The zero-inflated negative binomial model showed that homeowners were 24% more likely than nonowners to have excess zero mentally unhealthy days , but it did not show an association between homeownership and the number of unhealthy days.Our comparison of regression models indicates the importance of examining data distribution and selecting models with appropriate assumptions. Otherwise, statistical inferences might be misleading. Medscape, LLC is pleased to provide online continuing medical education (CME) for this journal article, allowing clinicians the opportunity to earn CME credit.This activity has been planned and implemented in accordance with the Essential Areas and policies of the Accreditation Council for Continuing Medical Education through the joint sponsorship of Medscape, LLC and Preventing Chronic Disease. Medscape, LLC is accredited by the ACCME to provide continuing medical education for physicians.AMA PRA Category 1 Credit(s)™. Physicians should claim only the credit commensurate with the extent of their participation in the activity.Medscape, LLC designates this Journal-based CME activity for a maximum of 1 www.medscape.org/journal/pcd (4) view/print certificate.All other clinicians completing this activity will be issued a certificate of participation. To participate in this journal CME activity: (1) review the learning objectives and author disclosures; (2) study the education content; (3) take the post-test with a 70% minimum passing score and complete the evaluation at Release date: March 27, 2014; Expiration date: March 27, 2015Upon completion of this activity, participants will be able to:Distinguish characteristics of different tools for data analysisAnalyze how data regarding self-reported health can be skewed in the Behavioral Risk Factor Surveillance System (BRFSS) surveyEvaluate results of different evaluation tools on count data from the BRFSS surveyEDITORSPreventing Chronic Disease. Disclosure: Ellen Taratus has disclosed no relevant financial relationships.Ellen Taratus, Editor, CME AUTHORCharles P. Vega, MD, Associate Professor and Residency Director, Department of Family Medicine, University of California, Irvine. Disclosure: Charles P. Vega, MD, has disclosed no relevant financial relationships.AUTHORS AND CREDENTIALSDisclosures: Hong Zhou, Paul Z. Siegel, Rashid S. Njai, Charlotte Kent, Youlian Liao, William W. Thompson, and John Barile have disclosed no relevant financial relationships.Hong Zhou, MS, MPH, Division of Health Informatics and Surveillance, Center for Surveillance, Epidemiology and Laboratory Services, Centers for Disease Control and Prevention, Atlanta, Georgia. Paul Z. Siegel, MD, MPH; Rashid S. Njai, PhD; Charlotte Kent, PhD; and Youlian Liao, MD, National Center for Chronic Disease Prevention and Health Promotion, Centers for Disease Control and Prevention, Atlanta, Georgia. William W. Thompson, PhD, National Center on Birth Defects and Developmental Disabilities, Centers for Disease Control and Prevention, Atlanta, Georgia. John Barile, PhD, Department of Psychology, University of Hawaii at Manoa, Manoa, Hawaii.Researchers of chronic disease often gather data that are measured on a continuum rather than as a “present–absent” or “yes–no” dichotomy. Examples include the following: episodes of a symptom; number of sick days, cigarettes smoked, or alcoholic drinks consumed; measures of health care use, such as number of doctor visits or days of hospitalization; and costs incurred (in dollars). Such measures are referred to as “count” data; that is, the observations can have only nonnegative integer values . Such data are most often gathered during a specified period of time . For some of these measures, most study participants may have a zero count . These data are typically not normally distributed, and the positive skew in their distribution cannot be resolved by data transformation. The Centers for Disease Control and Prevention’s (CDC’s) health-related quality of life (HRQOL) Healthy Days measure  questionnaire includes an HRQOL section composed of 3 questions related to respondents’ healthy days. These questions ask respondents to report the number of days in the previous 30 days when 1) their physical health was not good, 2) their mental health was not good, and 3) poor physical or mental health kept them from doing their usual activities  –6 or morThe second most common method of analyzing the association between various risk factors and the number of reported physically and mentally unhealthy days uses linear regression models and keeps the outcome in its original scale of 0 to 30 days –15. ThesThis study used data from the 12 states that included a question on homeownership in their 2009 BRFSS to examine the independent relationship between homeownership and number of mentally unhealthy days. Studies have shown that homeownership is associated with several health outcomes , but we BRFSS is a state-based system of annual health surveys . Data arwww.cdc.gov/brfss/questionnaires/pdf-ques/2009brfss.pdf.The independent variable for this study was homeownership, based on the following question in the BRFSS: “Do you own or rent your home?” The response options are own, rent, or other arrangement (such as group home or staying with friends or family without paying rent). We classified respondents who rented a home or lived by other arrangement as non-homeowners. The outcome measure was the number of days reported by respondents to the question: “Now thinking about your mental health, which includes stress, depression, and problems with emotions, for how many days during the past 30 days was your mental health not good?” Covariates included age, sex, race/ethnicity, education, household income, marital status, household size, and employment status. The 2009 BRFSS questionnaire is available at There were 68,258 adults aged 18 or older who responded to both the homeownership and mentally unhealthy days questions in the 12 states. We limited the analysis to the 60,113 people aged 35 or older, because those younger than 35 were unlikely to own a home. We excluded 550 (0.9%) people who had missing data for any of these covariates: education, marital status, household size, and employment status. People with missing data on household income  were classified as a separate category (“unknown”) and were not excluded from the analysis. The analyzed sample included 59,563 adults .We first examined the distribution of mentally unhealthy days, including the frequency of zero, mean, median, skew, and variance. We then examined the associations between homeownership and number of mentally unhealthy days by using 5 models:Model 1: Logistic regression. This model has been used in previous HRQOL studies  linear regression. This model also has been used in previous HRQOL studies . Overdispersion, caused by heterogeneity or an excess number of zeros (or both) to some degree is inherent to most Poisson data  in addition to allowing for count data that are skewed and overdispersed. It is a 2-component model, which combines the logistic regression model and the negative binomial model. The first component of the model, logistic regression for excess zeros, predicts the probability of having excess zero unhealthy days. The second component, negative binomial regression for the full range of counts, including random zeros, predicts the frequency of the unhealthy day count  percentage distribution of the number of unhealthy days (from 0 to 30) against the distribution predicted by the model. If the percentage distribution predicted by a model closely matched the observed distribution in the plot, the model was considered a good fit to the data.In the modeling, we simultaneously adjusted for age , sex, race and ethnicity , education level , household income , marital status , household size , employment status . In the univariate analyses, all of these covariates were significantly associated with homeownership and significantly associated with the number of mentally unhealthy days. We considered these covariates as confounders in the relation between homeownership and number of unhealthy days and therefore included them in our multivariate models.We used Stata version 12  to perform all statistical analyses and take into account the complex sampling design of the survey.Among adults aged 35 years or older, about four-fifths (79.3%) owned a home . The meaP = 0.22) between homeownership and having 14 or more mentally unhealthy days in the previous month  and overestimated the percentage in the category 1 to 9 days . The parP < .001), indicating that the data were overdispersed. The likelihood-ratio test was 430,000 (P < .001), suggesting that negative binomial regression is preferred over Poisson regression. The parameter estimate of homeownership was −0.137 in the negative binomial model (P = .04). Negative binomial regression resulted in a better fit of the data than did either linear or Poisson regression . The oveal model  , confirming that the zero-inflated model fit the data better than the non-zero–inflated model. The parameter estimate in the logistic component of the model was 0.216 (P = .003) (P = 0.83) ] ), suggesting no significant association between homeownership and the number of unhealthy days. The zero-inflated negative binomial regression provided a better fit of the data than did negative binomial regression . The z v = .003) ; as suchIn studying the association between homeownership and CDC’s Healthy Days measure as an example, we demonstrated how different models can influence statistical inference — the process of drawing conclusions from empirical data. We did not find an independent association between homeownership and number of mentally unhealthy days by logistic, linear, or Poisson regression models. The negative binomial model showed that homeowners had a moderate but significantly lower number of unhealthy days than non-homeowners. The zero-inflated negative binomial model indicated an association between homeownership and whether individuals reported any mentally unhealthy days but not the number of unhealthy days.We found that a zero-inflated negative binomial model fit the observed number of mentally unhealthy days reported in BRFSS data better than any of the other models we tested. Despite its ability to model count data, Poisson regression did not fully address the problem of overdispersion. Overdispersion may result in misleading inferences about regression parameters . LikewisThe main purpose of this data analysis was not to establish or affirm the “true” relationships between homeownership and number of mentally unhealthy days. We applied various models to BRFSS Healthy Days data as an example to illustrate the importance of appropriate model selection. The study has several limitations. First, it was based on self-reported data from 12 states that elected to include the social context module in its 2009 BRFSS. Second, the survey was conducted through telephone interviews; people without telephones and those who used only cell phones were excluded; these people may be less likely to be homeowners. Third, the BRFSS is a cross-sectional survey: information on the outcome measure  and characteristics  of the respondents were assessed at a single point in time. Hence, determining whether the association of characteristics with outcomes preceded or followed the outcomes was not possible.Any statistical inference requires some assumptions, and incorrect assumptions can invalidate statistical inference . Some reWe believe that when the assumptions of analytic techniques are carefully matched to the nature of the data distribution, the results will be more accurate and compelling. False results can mislead researchers, the public, and policy makers and are potentially detrimental to public health. The selection of data analytic techniques is not a trivial statistical matter. Using appropriate analytic procedures will maximize the accuracy and utility of the findings on factors that are of great importance in clinical, policy, and fiscal decisions.


Aim. This study aimed to analyze blood lipid levels, temporal trend, and age distribution of dyslipidemia in civil aviators in China. Methods. The 305 Chinese aviators were selected randomly and followed up from 2006 to 2011. Their total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C) levels were evaluated annually. Mean values for each parameter by year were compared using a linear mixed-effects model. The temporal trend of borderline high, high, and low status for each index and of overall borderline high, hyperlipidemia, and dyslipidemia by year was tested using a generalized linear mixed model. Results. The aviators' TC , HDL-C , and LDL-C  values differed across years. The prevalence of dyslipidemia , borderline high , and hyperlipidemia  also differed across years. The prevalence rates for hyperlipidemia and dyslipidemia were the highest in the 41–50-year-old and 31–40-year-old groups. Conclusions. Civil aviators in China were in high dyslipidemia and borderline high level and presented with dyslipidemia younger than other Chinese populations. Dyslipidemia is an important risk factor for cardiovascular disease, which is the leading cause of morbidity and mortality worldwide and a major contributor to the global burden of disease –3. With Because of their special working environment, dyslipidemia may be more harmful to aviators than to people in the general populations. Dyslipidemia may lead to aerorelated diseases, such as vertigo, syncope, and flight illusion, which could be dangerous during flight. Indeed, nearly half of grounded aviators are grounded due to cardiovascular disease, a condition which correlates with dyslipidemia . The sudBlood lipid profiles differ across populations, regions, and time periods due, at least in part, to ethnicity factors, working environment, geography, and lifestyle –9. IndeeThe principal aim of this study was to explore blood lipid levels, prevalence, temporal trends, and age distribution of dyslipidemia among civil aviators in China. The resultant data can provide a scientific basis for understanding the current situation of dyslipidemia and for the formulation and implementation of targeted control and prevention measures for civil aviators residing in China.This study was approved by the Ethics Committee of Xi'an Civil Aviation Hospital (Grant no. 200506). All participants provided their written consent to participate in this study.All civil aviators based in China are obligated to receive an annual physical examination between August and October to obtain an aviator-requisite health certificate. A group of 305 were chosen randomly by random sampling from all aviators who received a physical examination in 2006 in an aviation medicine examination center in Xi'an Civil Aviation Hospital. All were male civil aviators, 20–55 years old, and with a cumulative flight time greater than 200 hours. All 305 participants were followed up from 2006 to 2011.2. All data was anonymized before it was provided to the study group.The aviators' annual physical examination results were collected by several aviation medicine examination centers and recorded in China's Civil Aviation Medical Certificate Management System that was hosted in Civil Aviation Administration of China. Each aviation medicine examination center can view and analyze the data of aviators who received physical examination in their hospital. All data used in this study were collected from this system by the aviation medicine examination center in Xi'an Civil Aviation Hospital and represented results collected from 2006 to 2011, including subject height, weight, systolic blood pressure (BP), diastolic BP, pulse, total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C) levels. Body mass index (BMI) was calculated for each subject according to the standard formula: BMI = weight (kg)/[height (m)]Greasy food  was banned for the 3 days before each physical examination. Blood samples were obtained from forearm venipuncture when the civil aviators had an empty stomach in the morning (8:00–10:00 am). The blood samples were centrifuged at 4°C and 3,000 rpm for 10 minutes and the serum was transferred and stored at −20°C for biochemical analyses. TC, TG, HDL-C, and LDL-C were measured enzymatically using the COBAS INTEGRA 400 Plus system and its affiliated reagents from Roche Company (USA). All tests were regular examination items in the civil aviator physical examination.The cut-off points for blood lipid indices were defined according to the criteria set forth in the guidelines for dyslipidemia control in Chinese adults (2007 edition) . TC was P < 0.05. These analyses were performed in SAS 9.2 software.The study populations were categorized into the following four age bands (in years): 21–30, 31–40, 41–50, and 50–60. Subjects were not locked in their original age bands but rather were moved from younger to older age band categories as appropriate with aging over time. The mean and standard deviation (SD) of each blood lipid index were calculated for each year, and then the values were compared based on a linear mixed-effects model. The prevalence of borderline high, high, and low classification for each blood lipid index and of overall borderline high, hyperlipidemia, and dyslipidemia was calculated for age band and year and then analyzed with a generalized linear mixed model. The linear mixed-effects model and generalized linear mixed model were constructed with age as a covariate. Differences and trends were considered significant at The mean age of the 305 subjects studied was 35.52 ± 7.87 in 2006 . Their cumulative flight time at that time ranged from 200 to 25,800 hours, with the mean flight time in 2006 being 10,011.4 hours. The subjects' anthropomorphic, BP, and pulse data are reported in Ps < 0.01) but not on TG. The lowest TC, HDL-C, and LDL-C values were observed in 2007, 2011, and 2007, respectively, and the highest values of these three indices occurred in 2009, 2006, and 2010, respectively (As reported in detail in ectively . As showPs < 0.01). The lowest prevalence rates of overall borderline high, hyperlipidemia, and dyslipidemia were observed in 2011, 2006, and 2006, respectively and the highest values for these three indices occurred in 2006, 2009, and 2009, respectively (The prevalence rates of overall borderline high, hyperlipidemia, and dyslipidemia differed across years (all ectively . From 20ectively . The yeaThe prevalence rates for high TC, hyperlipidemia, and borderline high TC, TG, and LDL-C were the highest in the 41–50-year-old group, and the prevalence rates for high TG, low HDL-C, and dyslipidemia were the highest in the 31–40-year-old group, whereas those for high LDL-C and overall borderline high were the highest in the 51–60-year-old group. The prevalence rates of each index in each age group are reported in The present data indicate that, from 2006 to 2011, the prevalence of high TG and of high LDL-C among civil aviators in China was similar to that in the general population in China as a whole . HoweverThe prevalence of borderline high classifications for the blood lipid indices of civil aviators in China was higher than that of military aviators, whereas the prevalence of high classification for the indices in our cohort was lower than that of military aviators . These dHigh TC and high TG are most prevalent among 45–59-year-old men in China . In thisIt should be noted that the number of civil aviators recruited in this study is less than that of some large-scale surveys on blood lipid levels because our target population is quite small relative to the general population and we focused on a relatively short study time period. And there may be some other causes of dyslipidemia in aviators such as hypothyroidism, renal disease, hepatic disease, and diabetes. Nevertheless, there was sufficient power in this study to demonstrate significant trends in blood lipid levels, prevalence rates, temporal trends, and age of dyslipidemia onset among civil aviators in China. Further study with more civil aviators and a longer follow-up period will provide more insight into the epidemiology of dyslipidemia among civil aviators in China.In conclusion, the prevalence of dyslipidemia, especially the prevalence of the borderline high status of each blood lipid index, was high in this population. Civil aviators in China have a propensity to develop dyslipidemia at a younger age than the general population in China and military aviators. There is a need to step up dyslipidemia control and prevention efforts and to adjust public health resource allocation more effectively for the benefit of civil aviators in China.


At the end of the study, there was a significant decrease in triglyceride  and a significant increase in HDL  levels in the carnitine group. Decrease in total cholesterol  and increase in hemoglobin  concentrations in the carnitine group were not significant. There was no statistically significant changes in LDL in any group (P > 0.05). Erythropoietin dose was significantly decreased in both the carnitine  and the placebo group . No improvement was observed in QOL scores of two groups. In ESRD patients under maintenance hemodialysis, oral L-carnitine supplementation may reduce triglyceride and cholesterol and increase HDL and hemoglobin and subsequently reduce needed erythropoietin dose without effect on QOL.In patients on maintenance hemodialysis several factors reduce the body stored carnitine which could lead to dyslipidemia, anemia, and general health in these patients. We evaluated the effect of oral L-carnitine supplementation on lipid profiles, anemia, and quality of life (QOL) in hemodialysis patients. In a randomized, double-blinded, placebo-controlled trial, end-stage renal disease (ESRD) patients on hemodialysis received either L-carnitine 1 g/d ( The prevalence and incidence of chronic kidney diseases (CKDs) is increasing all over the world and in Iran as well . In spitDyslipidemia is commonly observed in ESRD patients, which is one of the major underlying causes of development and progression of atherosclerosis in this group of patients. Almost 40% of patients on continuous hemodialysis have some types of dyslipidemia, and most of them are affected by hyperlipidemia type IV and decreased high-density lipoprotein (HDL) plasma level . DevelopSince the kidney is one of the main sites of carnitine synthesis, endogenous carnitine production is significantly reduced after the kidney parenchymal damage . MoreoveSeveral studies have been conducted on the effects of carnitine supplement administration on dyslipidemia, skeletal muscle function, cardiac function, and anemia in patients under continuous hemodialysis. The effect of carnitine supplementation on dyslipidemia has been remained unknown . In addiConsidering the possible role of carnitine deficiency in development of dyslipidemia in ESRD and contrary findings of previous studies in this respect, this study was carried out to determine the effect of oral L-carnitine supplement on lipid profile, anemia, and life quality of dyslipidemic ESRD patients under continuous hemodialysis.β-blockers, glucocorticoids, or lipid-lowering agents during the previous eight weeks were not enrolled. Furthermore, patients with liver dysfunction, hypothyroidism, chronic infectious diseases such as hepatitis, active source of infection or inflammatory diseases, or history of seizure and known cases of any brain mass according to medical history were not included. Sampling was performed with convenient nonrandomized method from among the patients referred to the dialysis ward of the hospitals. Considering the study power of 80%, type one error of 5%, and at least 5 mg/dL increase in HDL concentration, according to the previous studies [http://www.clinicaltrial.org/  (NCT01278693), and all patients signed a fully informed written consent before including to the study.This randomized, placebo-controlled, double-blinded, clinical trial was carried out on dyslipidemic ESRD patients under continuous hemodialysis in Noor and Al-Zahra University Hospitals in Isfahan, Iran. The inclusion criteria were the age range of 18–75 years, history of at least 12 weeks of hemodialysis, three times a week and each session almost 4 hours, and serum TG or total cholesterol concentration >200 mg/dL or serum HDL concentration <40 mg/dL at the beginning of the study. The patients were not included into the study if they were on carnitine supplement or any drug that interacts with carnitine, that is, anticoagulant medication or those lowering the seizure threshold  in the last month. Patients on other drugs influencing lipid metabolism, such as Eligible patients were assigned to either carnitine or placebo groups based on the random number table, generated by random allocation software . The patDemographic characteristics, including age, sex, body mass index (BMI), the underlying cause of ESRD, and duration of dialysis were recorded at the beginning of the study. Moreover, total cholesterol, HDL, low-density lipoprotein (LDL), TG, and hemoglobin (Hb) serum concentrations, as well as the received erythropoietin dose was recorded at the onset of the study and 8 and 16 weeks after the beginning of the intervention. To assess the QOL of patients, we used the Short-Form Health Survey (SF-36)  questiont-test. For evaluation of variable changes in the two groups, we used repeated measures and paired t-test. Multivariate analysis was done for controlling covariate factors. The data was analyzed using SPSS software, version 16.0 . The P value less than 0.05 considered statistically significant.To compare baseline and demographical characteristics of the participants between the two groups, we used chi-square and independent sample P = 0.383). We omitted two extra value cases of obesity in carnitine group, and analysis was repeated again but there were not significant changes in final result comparing to the previous analysis.Twenty-seven patients were entered into each group. In the carnitine group, three patients were excluded; one underwent kidney transplantation, one died because of myocardial infarction, and one was not willing to continue the study. Thus, we analyzed the information of 24 patients in the carnitine group and 27 patients in the placebo group. As it is reported in P = 0.204; Hb: P = 1.84). The changes in lipid profile, Hb, and received dose of erythropoietin are shown in P = 0.001), while it was increased in the placebo group . Decrease in cholesterol level in the carnitine group was not statistically significant , and there was no significant change in the placebo group as well . The HDL concentration in the carnitine group increased significantly by 3.7 ± 2.8 mg/dL (P < 0.001), but it did not change significantly in the placebo group (P = 0.185). The LDL concentration, however, did not change in any group . According to repeated measure analysis, the changes in Hb level was not statistically significant in the carnitine group (P = 0.081), but with paired t-test, there was a significant increase in Hb level after the study (P = 0.037). No significant change was observed in Hb level in the placebo group (P = 0.145). The required dose of erythropoietin significantly decreased in both groups, by a greater amount of decrease in the carnitine group .Of total, 5 patient in carnitine group and 6 patients in placebo group had high triglyceride (TG), high cholesterol, and low HDL levels. There was no difference between baseline TG and Hb levels in 2 groups . Score of the physical health domain decreased in the carnitine group (P = 0.033), and score of the mental health domain decreased in the placebo group (<0.001).The changes of overall scores of QOL and its physical and mental subscales in the two groups are presented in t = 6.2, P < 0.001), receiving carnitine , and female gender  significantly predicted decrease in TG level after study. For decrease in cholesterol level after study, baseline cholesterol level  and duration of hemodialysis  were predictors, but receiving carnitine did not significantly predict changes in cholesterol level . Baseline HDL level , BMI , male gender , and receiving carnitine  were predictors of increase in the HDL level after study. Only duration of hemodialysis was a predictor for lower LDL level after study  and receiving carnitine was not associated to changes in LDL level .Considering differences between the two groups in BMI and baseline lipid profiles, we conducted multivariate analysis to determine the effect of carnitine on each of the lipid profile components controlling by age, sex, BMI, duration of hemodialysis, and baseline level of the related variable. According to the results, baseline level of TG  comparing to placebo after each dialysis session for 12 weeks. But there was no significant effect on QOL. It is of note that length of study was less than our trial. Also the route, interval, and dose of prescription were different from our study. In addition they used specific inclusion criteria containing intradialytic hypotension, muscle cramping, lack of energy, muscle weakness or myopathy, cardiomyopathy, or lack of responsiveness to erythropoietin. The considered criteria are important direct consequences and comorbidities in patients with ESRD on chronic hemodialysis that can influence on QOL . In anotIt should be considered that L-carnitine has some anti-inflammatory effect that can influence on our results. In a study by Savica et al., maintenance hemodialysis patients were assigned to receive intravenous injections of L-carnitine 20 mg/kg comparing to placebo thrice weekly at the end of each hemodialysis treatment for 6 months. The carnitine-treated group showed a statistically significant decrease in serum C-reactive protein and increase in serum albumin and transferrin, blood Hb, and body mass index. They reported that in hemodialysis patients, L-carnitine therapy may suppress inflammation, particularly among those patients with C-reactive protein ≥3 mg/dL, and may improve protein-energy nutritional status [Our study has some limitations. The randomization was not effective to match patients in both groups in the case of BMI and lipid profile. Furthermore, because of the small sample size, a precise multivariate analysis to evaluate the predictive factors of response to treatment was not possible. Some possible contributory factors such as folate and iron were not measured.In dyslipidemic ESRD patients under continuous hemodialysis, oral L-carnitine supplementation can decrease TG and increase HDL levels, without significant effects on cholesterol or LDL levels. In spite of the observed positive effects of oral L-carnitine on lipid profile and anemia, it did not have a positive effect on the patients' QOL in our study. Complementary studies with larger sample size, longer follow up, and evaluation of other important treatment outcomes such as cardiopulmonary function and the kidney disease specific QOL are necessary.


Field studies have shown that native, parasitic plants grow vigorously on invasive plants and can cause more damage to invasive plants than native plants. However, no empirical test has been conducted and the mechanism is still unknown. We conducted a completely randomized greenhouse experiment using 3 congeneric pairs of exotic, invasive and native, non-invasive herbaceous plant species to quantify the damage caused by parasitic plants to hosts and its correlation with the hosts' growth rate and resource use efficiency. The biomass of the parasitic plants on exotic, invasive hosts was significantly higher than on congeneric native, non-invasive hosts. Parasites caused more damage to exotic, invasive hosts than to congeneric, native, non-invasive hosts. The damage caused by parasites to hosts was significantly positively correlated with the biomass of parasitic plants. The damage of parasites to hosts was significantly positively correlated with the relative growth rate and the resource use efficiency of its host plants. It may be the mechanism by which parasitic plants grow more vigorously on invasive hosts and cause more damage to exotic, invasive hosts than to native, non-invasive hosts. These results suggest a potential biological control effect of native, parasitic plants on invasive species by reducing the dominance of invasive species in the invaded community. Invasive plants threaten human economic interests as well as the natural functioning of ecosystems and are thus a subject of active research within ecology Biological control  has received much attention Cassytha filiformis plants were used to control the invasive plant, Bidens pilosaCuscuta campestris, Cuscuta australis and Cassytha pubescens, all parasitic species, have been considered as potential biological control agents for invasive plants Cuscuta australis exhibited more vigorous growth and a higher level of reproduction on invasive Mikania micrantha and Wedelia trilobata than on native plants Cassytha pubescens on the growth of invasive Cytisus scoparius plant was greater than the effect on native Leptospermum myrsinoidesParasitic plants commonly occur in many natural and semi-natural ecosystems in the world, where they play key roles in determining community structure and function and are considered keystone species Hosts with high growth rates would provide more susceptible tissue to parasites. Hosts with high resource use efficiency and high nutrient contents, such as legumes, are preferred hosts for parasitic plants Bidens pilosa and B. bipinnata are annual branching herbs belonging to the family Asteraceae. B. pilosa is native to tropical America and has spread widely in throughout China B. bipinnata is native to China and is widely distributed throughout the country We tested the effect of parasitic plants on their host plants. Three exotic, invasive plants and their corresponding congeneric native, non-invasive species were used. Plant species were selected based on their ability to germinate, their shared biological traits and similar size. Solidago canadensis and S. decurrens are perennial herbs belonging to the family Asteraceae. S. canadensis is native to North America and was introduced into China in 1935. It rapidly spread in South-East China, such as Zhejiang, Jiangsu, Jiangxi, Anhui, Hubei Province. It is often found in abandoned fields and along roadway. And S. decurrens is endemic to the southern China, such as Zhejiang, Jiangsu, Anhui and Guangdong Province Ipomoea cairica and I. batatas are perennial vines belonging to the family Convolvulaceae. I. cairica is native to East Africa I. batatas is one of the world's most important food crops and is widely planted in China. The majority of the world production of I. batatas occurs in China Cuscuta chinensis (Convolvulaceae) is an annual parasitic plant native to China that attacks more than 100 wild and cultivated species C. chinensis were purchased from the Chinese Herb Market (www.zgycsc.com). To cultivate the parasite, we used soybean as a temporary host plant for C. chinensis. Soybean seeds were purchased from Linhai City Vegetable & Seed Co., Ltd. . We sowed uniform, healthy soybean seeds in farmland soil on May 20, 2008. When the soybean seedlings were approximately 10-cm tall, we sowed the seeds of C. chinensis in the soil around the soybean seedlings. C. chinensis successfully established on soybean after germination.We conducted a greenhouse experiment at Taizhou University  in Linhai City, Zhejiang Province, China. Seeds of native parasitic Pots that were 30 cm in diameter and 30-cm deep were filled with yellow, clay soil from a field in Linhai City . Vegetation and litter were removed from the soil. The soil was mixed with sand in a 1∶1 ratio, with a final pH of 6.84±0.17, an organic matter content of 10.36±1.40 g/kg, an available nitrogen content of 27.90±8.08 mg/kg, an available phosphorus content of 31.88±9.34 mg/kg and an available potassium content of 42.20±3.35 mg/kg.Bidens pilosa and B. bipinnata were geminated from seeds. Seeds of the invasive plant B. Pilosa, and the native plant B. bipinnata, were collected near the Sanfeng temple  on October 6, 2008. This is an open location owned by the government in Linhai City. The vegetation in this location is very common and no endangered or protected species are located here. On June 10, 2009, we sowed the seeds of B. pilosa and B. Bipinnata in trays containing sand for germination in a greenhouse. Two weeks later, 5-cm tall seedlings were transplanted into pots in a greenhouse.Solidago canadensis and S. decurrens were propagated using direct transplantation of the seedlings collected from Taizhou City and Xianju County, respectively, in Zhejinag Province, China. The sites are located in an open, abandoned field and no specific permits were required for the described field studies. On June 25, 2009, intact, approximately 10-cm tall seedlings were collected with soil and moved immediately to the greenhouse. On the same day, the soil was carefully removed from the roots of the seedlings and transplanted into pots. The pots were set up in the greenhouse with shade to avoid excess transpiration. Sufficient water was irrigated in the pots every day, and three days after planting, shading was removed and the healthy seedlings were selected for future experiments.Ipomoea cairica and I. batatas were propagated using cuttings. I. cairica plants were kindly provided by Dr. Zhao from Zhaoqing College in Guangdong Province. I. batatas plants were collected from Linhai City in Zhejiang Province . Both of them were successfully transplanted in the greenhouse before the experiment. On June 20, 2009, sharp pruning shears were used for cutting, after being sterilized with 70% ethanol. The upper parts of the healthy, disease-free plants were selected for cutting. Ten centimeter long cuttings were taken, and the remaining leaves were cut in half to reduce water loss. While maintaining the vertical orientation of the stems, we inserted the cuttings (one-third of their length) into pots containing soil into a greenhouse.C. chinensis were cut into small pieces (15-cm long) and were twined onto the stems of both the invasive and the native hosts for infection. Six replicates were used for each treatment; a total of 72 pots were used in the experiment. The pots were randomly set up in the greenhouse and irrigated with tap water twice daily. The plants were fertilized with 1/4 Hoagland's nutrient solution On July 20, 2009, 15-cm tall plants were selected for a completely randomized designed experiment. For factor parasitism, one case of parasitism and a control (without parasitism) were used. The stems of C. chinensis was separated from its host and dried for at least 72 h at 70°C to determine the total parasite biomass. Harvested host plants were separated into shoots and roots. Leaves were scanned using an Epson Perfection 1670 Photo Scanner , and leaf area was measured with the WinFOLIA leaf area analysis system . Roots were washed and collected on a sieve with a 0.5 mm mesh screen, and an extra sieve (0.2 mm mesh) was placed at the outflow of the system to ensure that no fine root material was lost At the beginning of the experiment (t1), six plants were harvested and separated into shoots and roots to obtain the original biomass (W1) and dried for at least 72 h at 70°C. On September 20, 2009 (t2), after two months of growth, the plants were harvested. In our study, the growth rate was reported as the relative growth rate (RGR) of the hosts, which was calculated according to the modified method by González-Santana Both leaves and fine roots are ephemeral and function primarily in resource acquisition The strength of the parasitic plant damage to host plants was quantified by the deleterious effect (DE) that the parasites had on the host. The DE of parasites on a host was measured as the loss of fitness due to a given parasite infection. The DE was calculated as the difference in total biomass between parasitized plants and the mean total biomass of the control plants, standardized to the mean biomass of the control plants To quantify the plastic responses of RGR, SLA, SFRL and SFRSA to parasites, the parasitism responses (PR) of these indices were also calculated as the difference in traits between parasitised plants and the mean of the control plants, standardised to the mean control plant levels, according to the following formula: PR = (parasitised-control)/control p<0.05 was considered significant.A one-way analysis of variance (ANOVA) was used to analyze the effects of parasitism on plant species traits. A mixed-model, nested two-way ANOVA was used to analyze the effect of plant origin (invasive or native) and species (nested with origin) on the PR of host plants. Plant origin was used as a fixed factor, and species (nested with origin) was used as a random factor. A mixed-model nested three-way ANOVA was used to analyze the effects of parasitism (present or absent), plant origin and species (nested with origin) on host plant traits. Plant origin and parasitism were used as fixed factors, and species (nested with origin) was used as a random factor. Pearson correlation analysis was conducted to determine the relationship between the DE of parasites to their hosts and parasite biomass, as well as the growth rate and resource use efficiency of the hosts. SPSS (version 16.0) was used for all analyses, and B. pilosa, S. canadensis and I. cairica) than congeneric, native, non-invasive species . Species (nested with origin) had a significant effect on parasite biomass  and the DE of parasites to hosts . The DE of parasites to hosts was significantly negatively correlated with the parasite biomass , indicating that parasites growing more vigorously would have a greater impact on host plants.Parasites had significantly larger biomass  and causB. pilosa , native B. bipinnata  and invasive S. canadensis   . Speciesp<0.001)  and the The DE of parasites to hosts was significantly negatively correlated with the mean parasite-free host RGR and positively correlated with the PR of host RGR; however, no significant correlation was observed between parasite DE to hosts and the RGR of hosts with parasites , indicatF4,30 = 152.275, 11.708, and 13.820, p<0.001, Parasitism significantly increased the SLA, SFRL and SFRSA of hosts . SpeciesThe DE of parasites to hosts was significantly negatively correlated with the SLA, SFRL and SFRSA of hosts with or without parasites. In addition, the DE of parasites to hosts was also negatively correlated with the PR of the SLA, SFRL and SFRSA of hosts , indicatC. chinensis, caused significantly more damage to exotic, invasive hosts than to congeneric native, non-invasive hosts. Our result is also supported by field studies reported by Yu et al., in which the parasitic plant, C. australis, exhibited more vigorous growth and higher reproduction on invasive plants (Mikania micrantha and Wedelia trilobata) than on native plants Cassytha pubescens, on the growth of invasive Cytisus scoparius was greater than the impact on a co-occurring native plant, Leptospermum myrsinoides in the field The results revealed in this study confirmed our original hypothesis that the parasitic plant, Pennings and Callaway compared the interactions between parasitic plants and their hosts with the interactions between herbivores and plants and found that parasitic plants paralleled the host preferences of herbivores by reducing host biomass, altering host allocation patterns, modifying plant community structure and dynamics, and mediating interactions between host plants and other organisms C. chinensis, to host plants was significantly positively correlated with the relative growth rate and the resource use efficiency of the hosts, indicating that the higher the RGR and resource use efficiency of the hosts, the more parasite damage there is to the hosts. It has been implied that the fact that exotic, invasive plants exhibit rapid growth, high levels of reproduction, and efficient resource capture and nutrient cycling contributes to their invasiveness C. australis was enhanced by the vigorous growth and high nutrient content of exotic, invasive hosts Our results directly demonstrated that the damage of the parasitic plant In addition, we also found that the parasite damage to hosts was significantly positively correlated with the plastic responses of SLA, SFRL, and SFRSA, whereas parasite damage was negatively correlated with the plastic responses of the RGR of parasitized hosts. In this study, parasitism significantly increased the SLA, SFRL and SFRSA of hosts, which can help hosts gain more resources to compensate for the biomass loss after damage, although the RGR of hosts was significantly inhibited by parasitism. The greater the host resource use efficiency, which was enhanced by parasitism, and the more the host growth was inhibited by parasitism, the greater the damage caused by parasitic plants to their hosts. Plants are highly plastic, and individuals within a species may vary by orders of magnitude in size, growth rate, allocation to different organs, reproduction, and chemical constituency C. campestris could suppress the invasive plant Mikania micrantha, and contribute to native community recovery Alternanthera philoxeroides was naturally infected and suppressed by the parasitic plant, C. austrails, which facilitated the recovery of its native community Cassytha pubescens occurred at high densities on invasive plants and caused more damage to invasive species than to native species In a field survey of the effect of a biological control experiment, artificial, introduced parasitic


Mechanical ventilation (MV) is considered a predisposing factor for increased intra-abdominal pressure (IAP), especially when positive end-expiratory pressure (PEEP) is applied or in the presence of auto-PEEP. So far, no prospective data exists on the effect of MV on IAP. The study aims to look on the effects of MV on IAP in a group of critically ill patients with no other risk factors for intra-abdominal hypertension (IAH).An observational multicenter study was conducted on a total of 100 patients divided into two groups: 50 patients without MV and 50 patients with MV. All patients were admitted to the intensive care units of the Medical and Surgical Research Centre, the Carlos J. Finlay Hospital, the Julio Trigo University Hospital, and the Calixto García Hospital, in Havana, Cuba between July 2000 and December 2004. The IAP was measured twice daily on admission using a standard transurethral technique. IAH was considered if IAP was greater than 12 mmHg. Correlations were made between IAP and body mass index (BMI), diagnostic category, gender, age, and ventilatory parameters.p < 0.0001). This difference was maintained regardless of gender, age, BMI, and diagnosis. The use of MV and BMI were independent predictors for IAH for the whole population, while male gender, assisted ventilation mode, and the use of PEEP were independent factors associated with IAH in patients on MV.The mean IAP in patients on MV was 6.7 ± 4.1 mmHg and significantly higher than in patients without MV (3.6 ± 2.4 mmHg, In this study, MV was identified as an independent predisposing factor for the development of IAH. Critically ill patients, which are on MV, present with higher IAP values on admission and should be monitored very closely, especially if PEEP is applied, even when they have no other apparent risk factors for IAH. As stated in the consensus report from 2004, in the critically ill patient, intra-abdominal pressure (IAP) is frequently elevated above the patient's normal baseline IAP level which is approximately 5 to 7 mmHg in critically ill adults . Many faOn the other hand, the effects of IAP on the respiratory system have been well studied . Increasper se.The situation turns more complicated when the patient at risk for IAH is being mechanically ventilated because under analgosedation and/or muscle relaxation, the typical signs and symptoms of complications such as abscesses or intra-abdominal fluid collections, hematomas, or even diffuse peritonitis could be masked. These conditions, that can be very deleterious through the well-known effects of IAH on hemodynamics, respiratory and renal function, hepatosplanchnic perfusion and, therefore, for the whole body ,6,7 coulThe aim of the present study is to look on the effects of MV on baseline IAP values in critically ill patients. To the best of our knowledge, this has not been studied before. So far, no prospective data is available on the effect of MV on IAP although this situation is of special importance for intensive care unit (ICU) patients.An observational multicenter and prospective study was conducted including a total of 100 critically ill patients without apparent risk factors for IAH other than the use of MV. The patients were admitted at the ICUs of the Medical and Surgical Research Centre, the Carlos J. Finlay Hospital, the Julio Trigo University Hospital, and the Calixto García Hospital between July 2000 and December 2004.Patients of both genders were consecutively included according to feasibility criteria (the availability of resources for the measurement and the presence of the investigator in charge of the measurements). After their inclusion, the patients were separated into two groups: 50 critically ill patients were mechanically ventilated and 50 critically ill patients were not mechanically ventilated.The criteria for the selection of the sample were established as follows:Inclusion criteria include:• patients with no abdominal medical or surgical pathology for the last 3 months or during the first 24 h before entry and• patients that had a vesical catheter already in place, without signs of urinary tract infection or urologic sepsis.Exclusion criteria (to avoid other factors related to IAH) were as follows:• patients with abdominal surgery or with suspicion of a surgical abdomen, abdominal distension, ascites, present or recent pregnancy, and abdominal or pelvic trauma and• patients who were administered a volume of fluids higher than 5 l of crystalloids or colloids in the preceding 24 h.The recruited patients were distributed in each of the five pre-established age groups . In relation with the diagnosis, the patients were also separated into two major categories, medical and surgical; the latter was divided into elective, emergency (E), and trauma (T) patients. The indications for MV in the medical patients were categorized as follows: respiratory failure (RF), cerebrovascular problems with diminished mental status (GCS<8), acute myocardial infarction (AMI), metabolic disorders (MD), congestive heart failure (CHF), and others; in the surgical group, the elective patients corresponded to cardiovascular surgery (CVS) and neurosurgery (NS).2O) was added to the urinary drainage system  and recalculated in millimeter mercury using the conversion factor (1 cmH2O = 0.74 mmHg). The two IAP values obtained in each patient were averaged, and the results were entered in a database. The total number of measurements was 200. As stated by the consensus, IAH was considered when the measured IAP values exceeded 12 mmHg [The IAP was measured in each patient according to Cheatham and Safcsak's technique , but insm Figure . Two meaFour ventilation modes were used: controlled mechanical ventilation (CMV), assisted/controlled ventilation (ACV), pressure support ventilation (PSV), and continuous positive airway pressure (CPAP). The patients were sedated to obtain a Ramsay score of 4 to 5 when receiving mechanical controlled ventilation and a Ramsay score of 2 to 3 in the ACV mode and PSV. Patients on CPAP ventilation were sedated only if necessary. No relaxing agents were used.t' test was used to evaluate the differences of means in two samples, and the Mann-Whitney U test was used to evaluate the differences of means in two independent samples and non-normality assumption. The Kruskal-Wallis test was used to compare more than two means. The chi-square test with Yates' correction for continuity or Fisher's exact test was used wherever appropriate in order to identify the differences between categorical variables. Pearson correlation test was also applied to find out any association between ventilation parameters and IAP.The Statistical Package for Social Sciences  was used in order to organize, validate, and analyze the collected data. Indicators of central tendency and dispersion: medians, means, standard deviations, and 95% confidence intervals (CI) were estimated for quantitative variables, while frequencies and percentages were used for qualitative variables. Two-sample paired 'A multiple linear regression model was applied for the whole patient population to assess the independent influence of age, gender, body mass index (BMI), and MV on IAP. With the ventilated group, a multiple linear regression model was applied for assessing the independent influence of age, gender, BMI, PEEP, minute volume, and PSV mode on IAP.p value of <0.05 was considered to be significant for all the statistical tests. Tables and figures were constructed in order to present the most relevant findings. The primary endpoint in the study was the effect of MV on IAP values.A The protocol was approved by the local ethics committees, and informed consent was provided by patients or next of kin before the study inclusion. The IAP measurements had no interference with other diagnostic or therapeutic procedures, according to the Council for International Organizations of Medical Sciences recommendations  and HelsOne hundred patients were included in this study. The general characteristics are shown in Table p < 0.0001) in the ventilated patients (6.7 ± 4.1 mmHg) compared to the non-ventilated patients (3.5 ± 2.4 mmHg), and concordantly, the abdominal perfusion pressure  was lower in the ventilated patients (85.3 ± 21.7 mmHg). IAH was present in only six ventilated patients (12% in the MV group and 6% for the whole group). As can be seen, the proportions of medical and surgical patients were similar. The majority (66%) of the surgical patients was elective (31/47).The IAP was significantly higher (p = 0.087). ICU mortality was higher in ventilated patients compared to the non-ventilated ones (p < 0.0001).The ICU stay was not significantly longer in the ventilated group compared to the non-ventilated patients (p < 0.0001).Table According to gender, the IAP values were higher in males regardless of the use of MV or not. The IAP values in ventilated patients were always higher Figure . With rep < 0.001) as well as in surgical ones (p = 0.029) undergoing MV. Among the surgical patients, the elective patients had the most important differences.According to the major diagnostic categories Figure , the IAPp = 0.015 and p = 0.04, respectively). Figure According to the indications for MV, some of the subgroups influenced the IAP values, as can be seen in Figures p = 0.018).In general, ventilation parameters were similar through the different ventilation modes Table , but as p < 0.05), BMI (p < 0.05), and MV (<0.001) were independently related with IAP, but not the age (p = 0.495) (Table p < 0.05), PEEP (p < 0.05), and PSV (<0.001) were independently related to IAP, but not the age (p = 0.740), BMI (p = 0.061) and minute volume (p = 0.950) (Table p = 0.022) , male gender (5) Table . Multiplge p = 0.40, BMI (2) Table .In this study population, we observed that IAP was affected by MV, leading to higher IAP values, and this difference was also observed throughout the subsequent analysis performed in relation to gender, age, and diagnostic category. Moreover, the multiple linear regression showed that MV was an independent and predicting factor for the development of IAH in this cohort of critically ill patients. Our results support previous suggestions that artificial ventilation can exert a direct influence on the IAP due to increased intrathoracic pressures that are then transmitted to the abdomen ,2,7.In relation to gender, males had the higher IAP values, and this difference was observed also in the ventilated patients. This is an interesting observation that has only been reported in few studies previously. Sugerman et al.  found siThe BMI was also independently associated with IAH. This relation has been reported previously in non-critically ill patients by Sanchez et al.  and NoblAmong the ventilation parameters, only PEEP correlated significantly with IAP, albeit the fact that the PEEP levels observed were not so high in this study. Moreover, PEEP was the most important factor in relation to the development of IAH in the multiple regression analysis (for the whole population and in the group of patients on MV).2O but is more pronounced when PEEP levels are raised to 15 to 20 cmH2O. As Verzilli et al. stated the effects of PEEP on IAP values were such that they would increase the IAH grading, especially in patients with hypovolemia or high baseline IAP [A review of the literature shows different results with regard to the relation between PEEP and IAP. For example, Sussman, the first to study this relation, could not find any relation between PEEP and IAP , while oline IAP , suggestAlthough in the ventilated patients we could not find any statistical differences with regard to the influence of the mode of ventilation on IAP, there were no IAH patients included in the ACV and CPAP modes. The multiple linear regression analysis showed that PSV was strongly associated with IAH. Although higher intrathoracic pressures can be observed or expected in controlled MV, in comparison to other ventilation modes, the use of sedation could result in improved static compliance hence lowering the IAP. While putting patients on PSV, ACV and CPAP could result in higher IAP values in view of the absence of sedation. We speculate that some unknown factors could have influenced our results. Maybe the random distribution of the patients and the small sample size of patients in ACV and CPAP modes can also explain these differences.Some factors like body position, zero reference position, or interobserver variability did not influence our results -22 as thThis study has some limitations. First, although the measurement technique was standardized and applied by the same person to avoid interobserver variability, the amount of instilled saline into the bladder was 100 ml, higher than the recommended, and this could have resulted in overestimation of the IAP values. At the time when the study was conducted, it was common practice to use 100 to 200 ml of saline as priming solution. Nowadays, it is well known that large instillation volumes may cause overestimation of IAP as demonstrated by several investigators -27.Second, a measurement bias is possible because all values were obtained in centimeters of water and recalculated to be expressed in millimeter mercury. Third, the selected casemix had of course an impact on the results. Our study is clearly different from previously performed studies since patients with abdominal surgical problems and those who received fluid overload  were excluded. As a result, the measurement of IAP was not used to evaluate the risk of IAH. That explains the relatively low prevalence of IAH in contrast with the previous reports ,23,28-30To our knowledge, this is the first multicenter observational study looking at the effect of MV on baseline IAP values in critically ill patients with no other apparent risk factors for IAH. Our results support the consensus definition statement  with regThis study also confirms that PEEP is a predisposing factor for the development of IAH in a selected group of ventilated patients. No matter the cause, IAH is always deleterious and should be diagnosed and treated in time. Consequently, IAP should be followed-up carefully in the critically ill population, even when they have no other apparent risk of IAH, and especially if MV is applied.ACV: assisted/controlled ventilation; AMI: acute myocardial infarction; APACHE: Acute Physiology and Chronic Health Evaluation; BMI: body mass index; CHF: congestive heart failure; CI: confidence interval; CMV: controlled mechanical ventilation; CPAP: continuous positive airway pressure: CVS: cardiovascular surgery; DC: dynamic compliance; E: emergency; IAH: intra-abdominal hypertension; IAP: intra-abdominal pressure; ICU: intensive care unit; MD: metabolic disorders; MV: mechanical ventilation; NS: neurosurgery; PEEP: positive end-expiratory pressure; Ppeak: peak pressure; Pplateau: plateau pressure; PSV: pressure support ventilation; RF: respiratory failure; RR: respiratory rate; SC: static compliance; T: trauma; Vmin: minute volume; Vt: tidal volume.The authors declare that they have no competing interests.CSM was involved in the design, collection, analysis, and interpretation of data and drafted the manuscript. TTB revised meticulously the database and made a new statistical analysis. TTB also collaborated in the interpretation of data and finally made a critical revision of the manuscript. All authors read and approved the final manuscript.