African Americans suffer from disproportionately high rates of hypertension and cardiovascular disease. Psychosocial stress, lifestyle and telomere dysfunction contribute to the pathogenesis of hypertension and cardiovascular disease. This study evaluated effects of stress reduction and lifestyle modification on blood pressure, telomerase gene expression and lifestyle factors in African Americans.hTERT and hTR) and clinic blood pressure. Secondary outcomes included lifestyle-related factors. Data were analyzed for within-group and between-group changes.Forty-eight African American men and women with stage I hypertension who participated in a larger randomized controlled trial volunteered for this substudy. These subjects participated in either stress reduction with the Transcendental Meditation technique and a basic health education course (SR) or an extensive health education program (EHE) for 16 weeks. Primary outcomes were telomerase gene expression  and hTERT mRNA levels . However, no statistically significant between-group changes were observed. Both groups showed reductions in systolic BP. Adjusted changes were SR = -5.7 mm Hg, p< 0.01; EHE = -9.0 mm Hg, p < 0.001 with no statistically significant difference between group difference. There was a significant reduction in diastolic BP in the EHE group  but not in SR ; the between-group difference was significant (p = 0.04). The EHE group showed a greater number of changes in lifestyle behaviors.Both groups showed increases in the two measures of telomerase gene expression, In this pilot trial, both stress reduction  and extensive health education groups demonstrated increased telomerase gene expression and reduced BP. The association between increased telomerase gene expression and reduced BP observed in this high-risk population suggest hypotheses that telomerase gene expression may either be a biomarker for reduced BP or a mechanism by which stress reduction and lifestyle modification reduces BP.NCT00681200ClinicalTrials.gov  Hypertension is a major risk factor for cardiovascular disease (CVD) ,2 There Amongst a range of proposed mechanisms, telomere dysfunction is emerging as a potential pathophysiological mechanism for hypertension and CVD ,10,11,12In parallel, high psychosocial stress has been causally associated with low telomerase and shorter telomere length . The mecMeta-analyses of randomized controlled trials of stress reduction with the Transcendental Meditation (TM) technique report reduced blood pressure in African American and white subjects ,18,19. PTherefore, the overall objective was to conduct a pilot study to compare effects of a stress reduction-based program to an extensive health education for hypertension on telomerase gene expression, blood pressure, lifestyle and behavioral risk factors in a sample of African American hypertensive men and women.hTR, hTERT and clinic blood pressure. Secondary outcomes were psychosocial stress factors, dietary intake, body mass index, physical activity and telomere length.This study was part of a larger randomized controlled trial on physiological mechanisms of stress reduction and lifestyle modification for hypertension in African Americans. In the parent trial, 152 African American men and women with stage I hypertension were randomly assigned to a Transcendental Meditation-based program plus health education program  or an extensive health education (EHE) program. As shown in the patient flow diagram , 48 of tThe clinical site was Howard University Medical Center, Washington, DC. The study coordinating center was Maharishi University of Management Research Institute (MUMRI) in Maharishi Vedic City, Iowa. The institutional review boards of Howard University and Maharishi University of Management reviewed and approved the protocols in December 2007, December 2009, and April 2010. Subjects provided written informed consent twice. The first consent was for participation in the parent trial and the second consent was for participation in the telomere biology substudy study. Randomization of subjects into the study arms began in April 2008; data collection was completed in March 2012. There was a brief administrative delay for registration on ClinicalTrials.gov which occurred in May 2008. The overall trial was monitored by an independent data and safety monitoring board.Eligibility criteria included: age ≥ 40 years, male or female, stage I hypertension (SBP 140–159 mm Hg and /or DBP 90–99 mm Hg). Subjects who were taking two or more antihypertensive medications or sympatholytic medications i.e., beta blocker, alpha blocker, central adrenergic agent, ACE inhibitor were excluded.  Subjects who had a history of major psychiatric disorders, dementia or substance abuse disorder, or any life threatening illness were excluded.Subjects were recruited from Howard University Hospital clinics and through local media. Potential subjects who had a history of stage I hypertension but who were taking excluded antihypertensive medications were offered the opportunity to taper off these medications to determine if they were eligible according to BP criteria.After baseline measurements in the parent trial, subjects were randomly allocated to the SR or EHE programs with stratification for antihypertensive medication status. There were three strata: no medication, diuretic only, or non-diuretic antihypertensive medication. Randomization was performed by the study biostatistician using computer generated random sequence. The study biostatistician concealed the allocation schedule and conveyed the assignments to the study coordinator. Investigators, data collectors and data management staff were blinded to group assignment. Intervention groups met separately to minimize contamination. This was a single blind protocol recommended for behavioral intervention trials . SubjectResting clinic blood pressure was measured in a standardized protocol by trained and certified observers using a Dinamap DPC 120X automated BP device . BP was measured three times at one-minute intervals in the seated position . The firVenipuncture blood draws of 20 mL per subject at baseline and at posttest were taken by a trained phlebotomist at the Howard University General Research Center (GRC). Blood was collected in red labeled serum tubes without additives and frozen at -70° C on site. When all blood data was collected, frozen blood tubes were shipped on dry ice from Howard University in Washington, DC to the MUM Molecular Biology Laboratory in Fairfield, Iowa.A total of 96 frozen blood clot samples (50–100 mg) were lysed in vials with 1mL of TRIZOL reagent . Homogenization was performed using a mortar and pestle, which was thoroughly washed first with RNAase ZAP solution , and then with DEPC treated water . The samples were then incubated at room temperature for 5–10 min. The homogenate was centrifuged at 12,000 g for 15 min at 4°C and the supernatant transferred to a new micro centrifuge tube. Next, 0.2 mL chloroform was added to the supernatant and after thorough vortexing, incubated at room temperature for 5–15 min. After centrifugation at 12,000 g for 15 min at 4°C, the upper aqueous phase was carefully removed, and transferred to new vials.The RNA was precipitated with 0.5 mL isopropyl alcohol per 1mL of TRIZOL reagent and incubated at room temperature for 10 min. After centrifugation at 12,000 g for 8 min at 4°C the pellet was washed 2 times with 1 mL of 75% ethanol. The RNA pellet was dried at room temperature and re-suspended in 80 μL of the RNA storage solution .In order to remove DNA, 50 μL of RNA sample was treated with 5μL 10x turbo reaction buffer and incubated at 37°C for 30 min. 5 μL of the DNase inactivation reagent were added and centrifuged at 10,000 x g for 3 min. 40 μL were removed and used for further analysis.The purity of RNA was assessed by comparing light absorption at 260 nm versus 280 nm, and the integrity of RNA was verified by electrophoresis in 1% agarose gels, staining with ethidium bromide, and observation of well-defined 28S and 18S rRNA bands using the Gel Doc 1000/2000 image analysis system .hTR), which serves as a template for telomeric DNA synthesis; the other is a catalytic protein (hTERT) with reverse transcriptase activity. Cells with elevated telomerase activity show delayed senescence and cellular aging [Telomerase is an RNA-dependent DNA polymerase that synthesizes telomeric DNA sequences. Activity of this enzyme is recognized almost universally as contributing to cellular proliferative potential . Telomerar aging ,23.hTR, hTERT) was determined by measurement of the levels of hTR and hTERT mRNA by the quantitative real time reverse transcriptase polymerase chain reaction (RT-PCR)  in order to obtain shorter PCR products.Telomerase gene expression  contained 12.5μL of 2x Quantifast RT PCR Mix , 0.5 μL of 50x ROX dye solution, 1.25 μL of 20x primer-probe mix, 0.25μL of reverse transcriptase (RT) mix (QIAGEN OneStep RT-PCR Enzyme Mix), 0.5μL of RNase free water, 10 μL of template RNA or universal RNA (50 ng). The thermal cycling profile consisted of 20 min reverse transcription at 50°C, 5 min PCR initial activation step, at 95°C; 15 sec denaturation at 95°C, 15 sec annealing/extension at 60°C. Forty cycles of denaturation and annealing/extension were carried out.hTERT and hTR mRNAs was carried out, using as internal reference amplification of the endogenous GAPDH mRNA. Nuclease free water was used as negative control, and universal RNA  was used as positive control. Relative quantification measures the levels of the target gene mRNAs (hTR and hTERT) relative to the level of GAPDH mRNA.To normalize for differences in the amount of total RNA added to each reaction, relative quantification of the An exploratory analysis of telomere length change was performed using the Bio-Rad MyiQ Single Color Real-Time PCR Detection System. Telomere primer pair telg and telc and scg albumin primers were synthesized by Integrated DNA technologies, USA . The finThe thermal cycling profile consisted of Stage 1: 15 min at 95°C; Stage 2: 2 cycles of 15 sec at 94°C, 15 sec at 49°C; and Stage 3: 32 cycles of 15 sec at 94°C, 10 sec at 62°C, 15 sec at 74°C with signal acquisition, 10 sec at 84°C, 15 s at 88°C with signal acquisition. The 74°C reads provided the Ct values for the amplification of the telomere template ; the 88°C reads provided the Ct values for the amplification of the scg template . Relative mean telomere length, or T/S ratio, was measured according to the protocol of Cawthon . Relativ2. Dietary patterns were assessed with the Block Dietary Food Consumption Questionnaire [BMI was calculated as weight/heightionnaire . The Angionnaire . A modifionnaire .The two interventions were matched for time, attention and other nonspecific factors. The stress reduction (SR) methods were the Transcendental Meditation (TM) technique. The TM technique was chosen as the stress reduction intervention for this study because of its standardization, reproducibility and previously demonstrated effects on physiological correlates of stress ,30,31. TThe extensive health education (EHE) intervention actively taught JNC VII recommendations for lifestyle modification for hypertension . The lift tests for independent variables. Outcome data were assessed for within-group and between-group differences. Normality of distribution was tested by skewness and kurtosis. Normally distributed outcome data were tested for within-group differences by dependent t test and for between-group differences by analysis of covariance (ANCOVA) using baseline level as a covariate as well as variables on which there were significant baseline differences between the groups. Non-normally distributed data were tested for within-group differences by Wilcoxon matched pair test and for between-group differences by Kruskal Wallis ANOVA test. Statistical analyses were performed using SPSS software, Windows version 14.0 . All tests were two-tailed. Analyses were conducted according to the intention-to-treat principle.Baseline characteristics were compared with The baseline characteristics of each group are shown in The groups were generally well matched; however, there were significant baseline differences in diastolic BP. When the baseline characteristics of the 48 subjects in this substudy were compared to the 104 subjects in the parent study, the results were generally similar except that the substudy group had a greater percentage of males  and a lower average BMI  data in .The telomerase gene expression results showed significant within-group changes in both the SR and EHE groups  Figs 2  2 and 3.hTR, increased in both groups (p < .001 for SR and p < .001 for EHE). The catalytic component of telomerase, hTERT, increased in both the SR group (p = 0.055) and the EHE group (p = 0.002). There were no significant differences between the groups in hTERT or hTR gene expression.The functional RNA component of telomerase, p < 0.01; EHE = -9.0 mm Hg, p< 0.001).As shown in p = 0.42; EHE = -5.3 mm Hg, p <0.001). The between-group difference in diastolic BP change was significant (p = 0.04). A sensitivity analysis that included baseline age and physical activity in an ANCOVA yielded essentially the same results as the ANCOVA above with baseline BP as the covariate.There was no significant difference between groups in systolic BP reduction. For diastolic BP, the adjusted changes were: SR = -1.2 mm Hg, The SR group showed significant within-group reductions in dietary intake of sodium and protein. The EHE group reported significant within-group reductions in dietary intake of sodium, protein, carbohydrate, total calories, total fat, oleic acid and linoleic acid. There were no significant between-group differences in these lifestyle factors.p value = 0.61 and EHE group = -0.02 ± 0.5 relative units; p value = 0.84; between group p value = 0.39).There were no significant within or between-group changes in telomere length  and practice of the Transcendental Meditation technique are effective in lowering high BP with average changes in this range ,40,41,42Both groups reported changes in lifestyle factors related to BP, including lower levels of self-reported sodium intake (300–600 mg/day) and protein (12–14 g/day); however the extensive health education group showed a greater number of dietary changes including reduced intakes of calories, carbohydrate, and fat than the stress reduction group. It may be that EHE group was motivated for more extensive dietary modifications due to active reinforcement of lifestyle change through the additional program of motivational videos, field trips and social support groups.Many studies have found that African Americans patients are on average sensitive to the blood pressure-lowering effects of sodium intake . DependihTR and hTERT. There were similar changes in both intervention groups. Telomerase RNA (hTR) along with telomerase reverse transcriptase protein (hTERT) is combined in vitro to reconstitute telomere synthesis. Hence, both these are necessary for telomere synthesis and are determinants of telomere length [hTERT in telomere maintenance, tissue culture studies have demonstrated that introducing exogenous hTERT into primary cells results in the induction of telomere maintenance and escape of cells from senescence [hTERT has also been shown to protect cells from stress-induced apoptosis and necrosis, thereby delaying cellular senescence and cell death [hTR component is also considered an essential requirement for telomere maintenance and telomerase activity in normal tissues and disease [Concurrently, the SR and EHE groups each showed within-group increases in expression of the telomerase genes, e length . To suppnescence ,50. Intrll death . The hTR disease .Clinical associations have been observed between low telomerase levels, short telomere length and hypertension. It has been hypothesized that telomere biology may play a pathophysiological role in the development of hypertension ,13,52,53et al.[et al [Several previous studies have examined the relationship between telomerase, telomere length, BP and cardiovascular hemodynamics—although these did not include antihypertensive interventions. Findinget al. showed tet al.. In anotet al.. A studyl.[et al  found inet al. conducted a pilot trial with 39 dementia caregivers using meditation or a relaxation music control for eight weeks. Their results suggested increased telomerase activity in peripheral blood mononuclear cells (PBMC) in the experimental group compared to controls [et al. studied the effects of relaxation on genome-wide gene expression in a general population sample, but did not report hTR or hTERT RNA levels [Many studies have found that chronic psychosocial stress is associated with decreased telomerase activity ,57,58. Lcontrols . In anotcontrols . Dusek eA levels . In addiIn practical clinical settings, concerns have been raised about compliance with lifestyle modification interventions ,63,64. FThere are several limitations of the present study. The first was the lack of an inactive control group. To address this limitation, future research might use a three-arm design, including an inactive or placebo control group. On the other hand, the current pilot trial may be considered a comparative effectiveness study of two clinical programs, both of which have been recommended for consideration in the treatment of hypertension ,42,46,66hTERT and hTR gene expression within each of the two lifestyle modification groups, the results indicated that there were no significant differences between the two groups studied. A larger sample size would generate the statistical power needed to either confirm or disprove these findings.Another limitation was the relatively small sample size of 48. Although there were significant increases in There were no statistically significant differences in telomere length within or between groups. Telomere length is usually not sensitive to short-term interventions, such as the 16 weeks in the present study, but may require a year or more for detectable changes to be observed . Thus, aWe also did not find significant changes for anger expression either between or within groups. Recent meta-analysis of psychological effects of the Transcendental Meditation technique have reported reductions in anxiety ,70 and aIn this study, we have used whole blood samples to determine the telomerase activity. One of the risks of using whole blood samples is that the proportions of different types of white blood cells, in particular T cells and B cells, among subjects. It is known that these cell types vary in telomere length. Therefore, if the cell-type composition varies from subject to subject, it could affect the levels of measured telomerase  Various The larger parent trial was a randomized controlled trial. However, this ancillary study comprised volunteers from each group after they had been randomized. Therefore, this pilot trial was not a randomized trial, although its sample was drawn from an RCT. The experimental design may be considered a quasi-randomized trial . Future In conclusion, this pilot trial compared a stress reduction program based on the Transcendental Meditation technique to an extensive health education intervention in African American patients with stage I hypertension. Both interventions demonstrated increased telomerase gene expression and reduced BP. The results suggest molecular biomarkers or mechanisms of these two lifestyle modification approaches in the treatment of hypertension.S1 CONSORT Checklist(DOC)Click here for additional data file.S1 Protocol(DOCX)Click here for additional data file.S1 Table(DOCX)Click here for additional data file.


Our results do not demonstrate that airborne CB exposure increases all-cause or cardiac disease mortality.Epidemiological studies have demonstrated associations between airborne environmental particle exposure and cardiac disease and mortality; however, few have examined such effects from poorly soluble particles of low toxicity such as manufactured carbon black (CB) particles in the work place. We combined standardised mortality ratio (SMR) and Cox proportional hazards results from cohort studies of US, UK and German CB production workers. Under a common protocol, we analysed mortality from all causes, heart disease (HD), ischemic heart disease (IHD) and acute myocardial infarction (AMI). Fixed and random effects (RE) meta-regression models were fit for employment duration, and for overall cumulative and lugged quantitative CB exposure estimates. Full cohort meta-SMRs (RE) were 1.01  0.79–1.29) for HD; 1.02 (95% CI 0.80–1.30) for IHD, and 1.08 (95% CI 0.74–1.59) for AMI mortality. For all three outcomes, meta-SMRs were heterogeneous, increased with time since first and time since last exposure, and peaked after 25–29 or 10–14 years, respectively. Meta-Cox coefficients showed no association with lugged duration of exposure. A small but imprecise increased AMI mortality risk was suggested for cumulative exposure (RE-hazards ratio (HR) = 1.10 per 100 mg/m Further research should explore the optimal methods of air pollution reduction and document the effects of this on the incidence of cardiovascular disease and related mortality in order to pressurize policy makers to intensify efforts required for effective legislation on air pollution reduction” [Epidemiological studies of exposure to airborne environmental particulates have reported associations with a variety of cardiovascular effects including myocardial infarction (MI) and ischemic heart disease (IHD) ,2,3. Theduction” .2.5 and cardiovascular effectsTogether, the collective evidence from epidemiologic, controlled human exposure, and toxicological studies is sufficient to conclude that a causal relationship exists between short-term exposures to PM” and “2.5 and cardiovascular effectsTaken together, the evidence from epidemiologic and toxicological studies is sufficient to conclude that a causal relationship exists between long-term exposures to PM” [The United States Environmental Protection Agency (US EPA) also considers the association to be causal: “effects” . 3 for PM2.5 and a three-year annual average of 12 μg/m3. The US EPA also regulates PM10 at 150 μg/m3 (24 h) [10 concentration averages must not exceed 50 μg/m3 on more than 35 days per year [3, including those from monitoring stations near heavy automobile traffic. Low emission zones (LEZs)—areas or roads where the most polluting vehicles are restricted—have been introduced in many European cities to help meet these standards. The established associations between environmental particulate exposure and cardiac diseases and mortality served as drivers for these regulations, although the effectiveness of these measures to reduce exposures or disease has yet to be demonstrated [Regulatory actions to reduce ambient particulate emissions, especially from road traffic and fossil fueled power plants, have been promulgated. For example, the US EPA implemented a 24-h limit of 35 μg/m3 (24 h) . Similarper year , and annnstrated . 3) of air contrast sharply with occupational exposure limits for airborne particulates, which are typically orders of magnitude higher, i.e., in the milligrams per m3 range. Notwithstanding the consistency of environmental studies demonstrating associations between particles and risk of heart diseases in the general population, studies of occupational cohorts—often at exposure levels 2–3 orders of magnitude greater than environmental concentrations—have shown small and inconsistent risks, at most [The environmental exposure limits for airborne particulate matter (PM) in units of micrograms per cubic meter . Unlike rubber manufacturing, carbon black production does not lead to mixed dust exposures and, thus, no speciation analysis is indicated. Since CB is nearly 99% pure carbon, this study offers an important research opportunity to (1) study cardiovascular disease mortality risks associated with respiratory exposure to poorly soluble particles of low toxicity; and (2) contrast findings with those of environmental studies, in which exposures are to complex mixtures of various particulates and gaseous compounds. To enhance the statistical power of our evaluation, as well as to abide by laws prohibiting the re-use and/or sharing of the individual study data, we performed meta-analyses of standardised mortality ratios (SMRs) and Cox proportional hazards results from the three studies. Our meta-analysis included 6634 workers from the US, 1147 from the UK and 1535 from Germany. This represents the largest study of CB workers, many of whom were occupationally exposed to relatively high historical concentrations of CB no longer found in these workplaces. To explore possible associations between airborne particle exposures and risk of heart diseases, we examined mortality from HD, IHD and AMI in three established cohorts of carbon black (CB) production workers in the United States (US) ,15, Unitet al. [We combined mortality findings from three cohorts of CB production workers. Table 6 in Dell et al.  providedet al. [et al. [The US cohort was described in Dell et al.  and Dell [et al. . Men andet al. [3. Total dust measurements were converted to inhalable dust measurements using an empirical factor of 2.97:1  derived by Kerr et al. [3-years were used as the exposure metrics in the meta-analyses.Individual work histories were collected and exposure assessment was performed as described in Dell et al. . More thr et al. . Facilitet al. [et al. [3 was estimated for 12 job categories and for 5- or 10-year calendar periods. Data for plant 4 were also used to estimate exposures for Plants 2, 3, and 5. Working conditions at these four plants were considered to be similar but different from plant 1. Time-dependent individual exposure estimates were derived for each plant: duration of exposure to CB in years; and cumulative exposure to inhalable CB in mg/m3-years. Study materials were anonymised some years ago, and now include no information on names, addresses, or National Health Service (NHS) numbers.The UK cohort was described in Sorahan et al.  and Soraet al. . Male ma [et al.  describeet al. [et al. [et al. [et al. [et al. [et al. [et al. [3. Validation of exposure estimates was not possible. Interpolation and extrapolation were performed to all years under study to derive time-dependent individual exposure variables: duration of exposure to CB in years and cumulative exposure to  CB in unit-years.The German cohort was defined in Wellmann et al. , Morfeld [et al.  and Morf [et al. . Further [et al. , Morfeld [et al. , Morfeld [et al. , and Mor [et al. . Male ma [et al.  and Morf [et al.  describe [et al. . The corUsing meta-analytical approaches, we combined the results from the three industrial cohorts available on CB production workers, as described below, to evaluate the relationship between CB exposure and mortality from all causes and from HD, specifically MI and IHD.The associations between quantified CB exposure, including duration of exposure, and mortality from all causes and MI and IHD were analyzed in each cohort separately at their respective institutes  using a common standardized protocol. Cohort-specific effect estimates then were combined and analyzed (by author Peter Morfeld) using meta-analyses. A pooled analysis of all cohort data was not possible due to data transfer and privacy restrictions noted above. The cohorts, upon which our analyses were based, were all assessed and approved by an institutional review board (IRB) in the USA and by data protection officers in Germany and the UK, respectively. Since the current meta-analysis involved assessment of aggregate data from previously published studies and not new individual data, no additional IRB assessments were deemed necessary. The USA study was approved by the ENVIRON Institutional Review Board (USDHHS/OHRP/IRB No. 1265 FWA No. 00006387) for project “Exposure Reconstruction and Updated Mortality Analysis for the US industrywide Carbon Black Mortality Cohort Study”.et al. [et al. [Our meta-analysis is similar to that used by Raaschou-Nielsen et al.  to carry [et al.  for a joWe calculated SMRs  and 95% confidence intervals (95% CIs) for the following International Classification of Disease (ICD) groups in each cohort: all-cause mortality ; HD ; IHD ; and AMI (ICD-9 410 and ICD-10 I21).SMR analyses based on underlying cause of death were calculated using national rates  stratified by 5 year-intervals of age and calendar time. Person years were censored at age 85 years such that no contributions were made to expected or observed numbers past this age.etc. SMRs were additionally stratified by time since cessation of exposure (abbreviated as “tsce” and defined as period since leaving employment) <1 year, 1–4 years, 5–9 years, 10–14 years, 15–19 years, etc. The first category (<1 year) included in-service deaths. SMRs and 95% CIs based on a Poisson distribution were calculated for the full and inception cohorts stratified by time since first exposure (abbreviated as “tsfe” and defined as period from hire) <5 years, 5–9 years, 10–14 years, 15–19 years, Time-dependent Cox proportional hazards regression models  ,32 were Cox analyses were performed for all three full cohorts  on the following underlying causes of death: IHD  and AMI (ICD-9 410 and ICD-10 I21). Duration of exposure and cumulative exposure were treated as time-dependent variables in continuous form. In addition, because the cardiovascular effects of exposure to particles are more likely associated with recent than more distant past exposure ,27. For 3-years or unit-years).Time-dependent cumulative exposures also were evaluated as categorical variables. Unmodified exposures were categorized into <20, 20–49, 50–99, ≥100 whereas exposures lugged by 10 years were categorized into <5, 5–9, 10–19, ≥20  in the German cohort. No smoking data were available for the US and UK cohorts. Year of birth was categorized by decade indicators in models with categorized cumulative exposure.Adjustment was done with three sets or combinations of covariables: year of birth (continuous) in the US, UK and German cohorts; year of birth (continuous) and plant group indicator in the US  and UK cohorts ; and year of birth (continuous) and smoking status ; Z scores (Z = coefficient/standard error of coefficient); and AIC (Akaike Information Criterion) [We report coefficients with 95% CIs for duration of exposure to CB (per 10-years) and for cumulative exposure to inhalable CB dust (per 100 mg/miterion) . AICs (Aiterion) .2 and Cochran’s Q with phet [2 is the percentage of variation attributable to heterogeneity, Cochran’s Q is a heterogeneity chi2-statistic (chi2het) related to I2, phet is the heterogeneity p-value belonging to Q (null hypothesis = homogeneity).Results from the three cohorts were combined to increase statistical power and summarized using meta-analyses to assess the impact of differences in SMRs and Cox relative risk (hazard ratio) estimates across cohorts . Fixed eith phet . I2 is tIn addition, we performed random effects (RE) meta-analyses. These analyses do not assume homogeneity and take into account potential variability of SMR parameters and Cox relative risk parameters, accepting the potential heterogeneity of populations . We used Stata 13  and the i.e., hazard ratios) with 95% CIs as meta-effect estimates and measures of heterogeneity.We report FE and RE combined SMR estimates with 95% CIs, FE and RE combined Cox relative risk estimates . We evaluated “tsfe” and “tsce” as continuous time variables defined by the arithmetic mean of SMR time periods. The basic model included a constant, study indicators, and the time variable. We extended this basic structure to an interaction model with constant, study indicators, time, and time × study indicators . In addition, we estimated pstudy from the basic model, the two-sided p-value for differences among the offsets (study indicators). Also, we calculated pinteract from the interaction model, the two-sided p-value for heterogeneity of trends . We report meta-effect estimates (meta-trend estimates) from the basic model: meta-SMR per 10 years of exposure with 95% CIs and the two-sided 3-years  with those based on estimated unit-years (Germany). The score Z (=coefficient/standard error of coefficient) avoids problems associated with non-comparable units. However, it does not directly measure the association between exposure and effect, but a standardized effect. The standardized effect can be used to estimate p-values of effect and heterogeneity, and the scores are not affected by the unit problem, but cannot be interpreted in terms of risk.Cumulative exposure regression coefficients  and their standard errors rely on the study-specific exposure assessment. We expect heterogeneity across studies. In particular, it is problematic to combine effect estimates based on cumulative exposures estimated as mg/met al. [observed can be interpreted as realizations of random Gaussian variables with mean 0 and variance 1, i.e., Z–N . If there are k independent studies the sum of Zs across studies is a Gaussian variable with mean 0 and variance k, i.e., Ʃ Z–N . Because the studies differ in power, we weight the Zs by the relative number of expected cases based on national rates used in SMR analyses, i.e., weights are w = expected/(Ʃ expected). It follows that the sum of weighted Zs, Ʃ w × Z, is a Gaussian variable M with M–N . M = Ʃ w × Z is a weighted mean of Zs, i.e., the meta-Z. It could be argued that power differences in Z scores have already been taken into account by the standard deviation of the coefficient. Thus, we calculated unweighted meta-Z scores additionally.We complemented the FE and RE meta-analyses on Cox coefficients with FE meta-analyses on Cox model Z scores as follows  distributions of M, appropriately evaluated at the observed mean of weighted Zs. Accordingly, we calculated a heterogeneity p-value, phet, based on the sum of the quadratic deviations of the observed weighted Zs from the observed weighted mean. We used the reverse cumulative (upper tail) distribution of a chi2-variable with k − 1 degrees of freedom.We calculated a 2-sided Twelve tables are presented: eight addressing results of the SMR analyses and four addressing results of the Cox models. The joint mortality study analysis is based on 869 total observed deaths from HD , includi2 was greater than 85% for all endpoints studied in the full cohort SMR analyses . This finding is mainly caused by consistently lower SMRs in the US study. The heterogeneity I2 was always greater than 50% when evaluating the inception cohorts  for overall mortality, 1.01  for HD, 1.02  for IHD, and 1.08  for AMI . When thInception cohort RE-Meta-SMRs were 1.11  for overall mortality, 1.06  for HD, 1.06  for IHD, and 1.13  for AMI (data not shown in Tables). When we restricted the mortality follow-up to 1979–2011 in the US inception cohort we got the following RE-Meta-SMRs: 1.12  for overall mortality, 1.08  for HD, 1.08  for IHD, and 1.18  for AMI .peff = 0.28. Heterogeneity, however, was pronounced with I2 = 79%, chi2het = 9.4, and phet < 0.01. FE analyses do not reveal other patterns although FE-SMRs are almost always lower than RE-SMRs. Notably, there is no statistically elevated SMR in any of the analyses performed on the four endpoints of interest. Any excesses are small and more pronounced for mortality from AMI within the inception cohorts. Nevertheless, the highest meta-estimate was obtained from the RE analysis on mortality from AMI in the inception cohorts when restricting the follow-up in the US component, and was not statistically significant : meta-SMWe observed only marginal differences between SMRs based on national rates or state rates . Furthermore, restricting the follow-up period in the US study to the period 1979–2011 did not lead to any remarkable changes in the meta-SMRs.p = 0.015, 95% CI 3%, 29%). The differences between offsets (study indicators) were significant in this model (pstudy = 0.0029) as could be expected from the finding of heterogeneity in SMRs for overall mortality between studies. Interestingly, the estimated upward trend showed no heterogeneity between study components (pinteract = 0.21). This finding of a homogeneous trend of SMRs across time since first exposure after adjustment for different baseline risks was confirmed in analyses of all combinations of endpoints and study groups. In contrast to the trends for overall mortality, none of the upward trends in mortality from HD, IHD, and AMI achieved statistical significance.p = 0.044, 95% CI 1%–38%). Heterogeneity was obvious for the offset of the regression model (pstudy = 0.037) but there was no indication of heterogeneity in the trend estimate (pinteract = 0.72).The upward trends were no longer significant in HD mortality if the US follow-up was restricted to the period 1979–2011 or if incidence cohorts were analyzed. The meta-regressions on time since cessation of exposures suggested similar increases in meta-SMRs as described for time since first exposure. e.g., for the data on HD mortality of the full cohorts, as shown in pstudy > 0.2) and trends (pinteract > 0.7) in any of these models. Meta-SMRs up to 1.43 were found in analyses of AMI mortality in the period of 25 to 29 years after first exposure .As an example, we report in p-values of effect from meta-Z scores in full cohort analyses on mortality from IHD were consistent with results from fixed and random effect models on coefficients. Both procedures marked the same analyses as statistically significant. p-values of heterogeneity were somewhat more pronounced  in meta-Z score analyses. This difference was no longer observed when follow-up was restricted to 1979–2011 in the US component . Full cohort analyses of AMI showed p-values of effect from meta-Z scores that were consistent with results from fixed and random effects analyses on coefficients. p-values of heterogeneity were very close. Results did not change after follow-up was restricted in the US component. Thus, meta-Z score analyses are helpful secondary statistics to measure significance of effects and heterogeneity. They can be applied reliably even if the definition and/or units of exposure variables differ across studies as it is the case in this meta-analysis when cumulative exposures from the three studies are evaluated simultaneously. When we calculated meta-Z scores without weighting by number of expected cases we obtained essentially the same values. For comparison to results, e.g., on full cohorts as reported in p-values for cumulative exposure models with adjustment for plant were p = 0.08, phet = 0.27 (no lugging), p = 0.36, phet = 0.87 (lug = 5 years), and p = 0.57, phet = 0.90 (lug = 10 years).Results from Z score meta-analyses were similar to those from RE and FE coefficient analyses if the exposure variable is duration of exposure, which was expected because there are no differences in units and this exposure variable is similar across studies. In addition, we detected no heterogeneity in RE and FE analyses of coefficients. Thus, it is of interest to explore whether results from both kinds of analyses coincide. Indeed, Cox model results for categorized cumulative exposure and mortality from AMI are presented in Lugging exposures by 10 years  led to b3-years when adjusting for plant. Fitting continuous exposure models in each cohort with no lugging, lug of 5 years or lug of 10 years, respectively, yielded trend coefficients for cumulative exposure that never achieved statistical significance and varied in sign, most likely reflecting random variation (data not shown). Only the US study showed a significant association with AMI  restrictp = 0.09 or 0.11 after adjustment for plant. Analyses demonstrated that all trend estimates were rather homogeneous across the three studies (phet > 0.1). Meta-hazard ratios for mortality from AMI are reported in p = 0.15) supported the finding of no significant excess. We note that no excess relative risks were indicated in lugged analyses. Heterogeneity was not demonstrated in any of the analyses (phet > 0.35).Findings were similar in incidence cohorts and when restricting the US mortality follow-up period to 1979–2011 . After lugging no increase of relative risks across cumulative exposure was found regardless of adjusting for plant. Overall, regression model findings and meta-results on mortality from IHD were similar to those from AMI (data not shown). FE and RE analyses of IHD mortality in the full cohorts resulted in a meta-hazard ratio of 1.02 per 100 mg/m3-years; 95% CI 0.92–1.31), but no increase was seen when recent exposure was considered. Inception cohort analyses were not different from the full cohort results. Full cohort RE Meta-SMRs were 1.01  for HD, 1.02  for IHD, and 1.08  for AMI. For all three cardiac outcomes, meta-SMRs were heterogeneous, increased with tsfe and tsce and peaked after 25–29 or 10–14 years, respectively. Meta-Cox coefficients showed no association with lugged or unlugged duration of exposure. Some homogeneous but non-significant increase in the hazard ratio (HR) for AMI mortality was found for cumulative exposure  of all-cause, cardiovascular disease, IHD, heart failure, and cerebrovascular disease mortality were 1.24 (95% CI 1.22–1.27), 1.23 (95% CI 1.19–1.26), 1.37 (95% CI 1.28–1.47), 1.11 (95% CI 1.05–1.17), and 1.23 (95% CI1.18–1.28), respectively [3) derived by Hoek and colleagues in their review and meta-analysis of studies of long-term air pollution exposure and cardiac and respiratory disease mortality [The reported associations between airborne environmental particle exposures and cardiovascular disease and mortality risk have raised public health concern regarding the adequacy of existing environmental regulation of airborne particle pollution. That airborne particles are ubiquitous and that low concentrations have been associated with significant increases in cardiovascular disease and mortality risk in environmental studies underscores the importance of more fully understanding those specific aspects of particle exposures that contribute to disease risk, and subsequently, what can be done to effectively reduce risk and improve public health. For example, 39,054 inhabitants of four Chinese cities were followed for all-cause mortality and for mortality from specific cardiovascular diseases from 1998 to 2009. For each 10 μg/mortality . At the et al. [Complicating the translation of these findings into public health regulations is the fact that airborne particles vary considerably in their physical, chemical and electrostatic properties. They also occur in the environment in a wide range of circumstances, and can change rapidly due to local anthropogenic activity as well as natural forces, such as weather patterns, dust storms and volcanic action. Particles contributing to ambient air pollution vary in size distribution and chemical composition, and are present with other non-particle constituents of air pollution. Among particulate air pollutants are carbon-based compounds, sometimes characterized as “soot” or “black carbon”. As Long et al.  explaineet al. [et al. [et al. [Numerous studies of occupational exposures to airborne particulate matter and risks of cardiovascular disease or mortality have been published. The earliest of these were presented in a narrative review by Sjögren , and moret al. . Fang et [et al.  conducte [et al.  p. 1784– [et al. .et al. [et al. [et al. [In addition to the studies included in the meta-analysis by Fang et al. , we iden [et al.  followed [et al.  conducte [et al. . A cohor [et al. . 2.5 was associated with IHD [More recent studies include a review of medical insurance claims of nearly 12,000 US aluminum workers, which showed that recent occupational exposure to PMwith IHD . In a cowith IHD . 3-years. A study of over 42,000 Chinese workers exposed to crystalline silica included 2846 deaths due to various forms of HD [A cohort of over 74,000 Chinese workers from metal mines and pottery factories was evaluated for mortality risks . A statims of HD . No incrms of HD .A cohort of all manual workers in the Swedish national census of 1980 was identified with information on demographic data and occupation . ExposurAmong over 265,000 textile workers in Shanghai, no increase in IHD was found; however, mildly elevated risks in ischemic and hemorrhagic stroke were observed .3-years. Risk was also associated with coal dust rank. The authors were unable to adjust for silica exposure and referred to an earlier study of silica-exposed workers in which an increased risk of IHD was observed [Risk of IHD among a cohort of nearly 9000 US coal miners was increased with increasing levels of exposure . Statistobserved .10 and PM2.5 fractions are used in environmental settings  whereas inhalable, thoracic, and alveolar (respirable) fractions are used in occupational settings . The PM10 dust fraction is defined to have a mass sampling distribution with a median effectiveness at an aerodynamic particle diameter of about 10 μm  and it is very similar to the thoracic dust fraction . The PM2.5 dust fraction has no direct counterpart among the dust fractions used in occupational settings. It is similar, however, to the alveolar fraction, although with a tendency to underestimate the latter . We note that often misleading definitions of the PM10 and PM2.5 fractions are presented as if these fractions cover all and only particles with diameters below 10 μm or below 2.5 μm, respectively . Thu. Thu10 a2.5, the hazard ratio was 1.21 (95% CI 0.87–1.69) per 5 μg/m3 and for PM10, 1.22 (95% CI 0.91–1.63) per 10 μg/m3” [On the other hand, some very large recent studies of particulate exposures have not demonstrated clear risks for cardiovascular diseases. For example, within the multicenter European Study of Cohorts for Air Pollution Effects (ESCAPE), long-term exposure to air pollutants and risk of various cardiovascular diseases (CVD) mortality was investigated . The stu0 μg/m3” .i.e., workers must be reasonably healthy to seek employment and continue employment, whereas the general population includes all individuals, including sick and disabled people [Another difference between environmental  and occupational (workforce-based) studies may be related to the healthy worker effect, d people ,67,68. Pd people . Although today airborne CB dust exposures in the workplace are relatively low and well controlled, historical levels are known to have been quite high, especially in certain production and handling areas . Previous evaluations of cardiovascular disease risks among CB manufacturing workers have been limited by methodological shortcomings and incomplete reporting of non-cancer health effects including cardiovascular effects by quantified exposure categories ,71.et al. [Animal studies have the distinct advantage of being able to control or precisely characterize the composition of the administered exposures, and to observe subtle pathological changes in sacrificed animals. However, while cardiovascular effects can be observed following respiratory exposure to CB, animal studies have not elucidated the mechanism for these effects. One study demonstrated significant inflammatory and other effects in mouse lung and liver following installation of Printex 90, a specific CB product  . A furthet al. , exploreet al. [Kim et al.  intratraThese studies, and other studies in which rodents receive single or repeated intratracheal instillations of CB, must be interpreted with caution. First, the particle doses are quite massive compared to the “normal” doses that humans might receive through either environmental of occupation exposure. Second―and most importantly―the means of delivering the dose are unphysiological. Intratracheal instillation causes a bolus effect, as often evidenced by acute lung inflammatory effects and thus may elicit corresponding unphysiological responses which may mask or overwhelm subtle true cardiovascular physiological perturbations, possibly related to cardiovascular dysfunction and particle exposure. Ultimately, even where effects can be seen in animal models, problems of extrapolation―across species as well as in terms of exposure levels―are difficult to overcome .et al. [In a recent review of human and mouse investigations, Saber et al.  have proet al.  had prevThe current evaluation of cardiovascular disease mortality risks among defined cohorts of industrial CB production workers helps fill a critical void, as it is the first such study to combine quantitative CB exposures with HD, IHD and MI mortality risks. The context for this study―the three established and long-followed cohorts of CB workers in the UK, Germany and the US―presents some distinct advantages in evaluating the risks of these diseases potentially associated with occupational exposure to substantial concentrations of relatively pure CB particles of known particle size distribution and free from other concomitant, including gaseous exposures. The exposures are reasonably well documented and characterized and CB studies may be helpful in pinpointing whether cardiovascular disease risks are associated with occupational CB exposure, and by extension, possibly other particles of low toxicity.Results from each of the individual cohort studies are presented separately, however, some―especially those from the UK and Germany―were based on relatively small numbers. Therefore, the meta-analysis procedures used in this study to combine cohort-specific results derived according to a common protocol greatly enhanced statistical power, thus improving our ability to identify even small associations. This study essentially included all cohort studies of industrial CB workers published to date, and therefore has the greatest potential for identifying cardiovascular disease mortality risks associated with occupational CB exposure. The availability of reasonably detailed employment histories and exposure assessment efforts in each of the three constituent cohorts allowed quantitative evaluation of risk of cardiovascular mortality by standardized individual CB exposure estimates. Although results did not suggest any, this approach might have allowed identification of exposure thresholds for cardiovascular mortality risks.i.e., SMR analyses). These differences are reflected in the heterogeneity measures obtained in the meta-SMR analyses, and were especially strong in the category of all-cause mortality. On the other hand, the Cox analyses compared risks among more highly exposed workers with relatively unexposed workers from the same cohorts , which avoids some problems associated with comparing disease or mortality risks among workers with those of the general population. Although the individual study findings previously published highlighted some potential differences in mortality patterns  across cohorts, the methods used here largely confirmed that any differences tend to be seen only with respect to “external” referent comparisons , however, no direct evidence of this is available.Intensive epidemiological research into risk factors for heart diseases has identified a number of potential causes of these diseases. Delfino et al.  summarizet al. ,81,82, get al. , social et al. , diet [8et al. ,86,87,88et al. ,90,91,92et al. ,94,95,96et al. , styreneet al. , ambientet al. , and shiet al. ,103,104.S cohort , there wRegardless of the various analytical approaches attempted, results based on meta-analyses of these three cohorts demonstrated no convincing evidence of a relationship between quantitative occupational CB exposure and cardiovascular disease mortality risk―including specific evaluations of all HD, IHD and MI mortality. Analyses included meta-SMRs, which address the research question of whether the occupational cohort exhibits greater mortality rates due to these diseases than expected from an appropriate referent population , as well as Cox analyses, which compare exposed workers with the unexposed/least exposed workers. Because observations that “reductions in PM levels are associated with decreases in cardiovascular mortality within a time frame as short as a few years” , we addiet al. [Our results, which contrast with those of many environmental and occupational studies of various particles and mixtures , suggest that exposure to relatively pure CB may not contribute to increased cardiovascular risk. This again raises the question of whether the chemical composition of particulate pollution might play a greater role in cardiovascular disease development than the quantity or size distribution. Although Landen et al.  observedet al. . This miVarious mechanisms have been proposed for particle induced cardiovascular effects including systemic inflammation ,105,106.et al. [i.e., ultrafine particles) or particle constituents  into the systemic circulation. Newby et al. [et al. [2 exposure and fatal MI; similar results were not observed with non-fatal MI. This suggests that air pollution might particularly aggravate disease progression caused by other factors leading to mortality in those most compromised [Brook et al.  proposedy et al.  describe [et al.  identifipromised .et al. [et al. accounts for why excess deaths occur in people indoors and why “similar serious effects are not seen in industrial workers exposed to much higher concentrations of dust measured by weight” [Inflammatory markers have been increased in relation to particle exposure as manifested by elevations in Interleukin (IL)-6 . Miller et al.  have proet al. , which a weight” . et al. study [3, in comparison to US guidelines of 3.5 mg/m3  and far lower carbon black dust concentrations reported in US and European production plants [In a study of 81 CB workers in China, a statistically significant association was shown between exposure to CB and serum levels of the inflammatory mediators . Multiple logistic regression analyses showed an association between CB exposure and increases in cytokines after adjusting for age, BMI, smoking, and drinking habits. The authors noted that their study was the “first to provide persuasive evidence for CB-induced pro inflammatory cytokines in human beings” . Similarl. study . Averagen plants . Thus, wet al. [Based on the evolving body of evidence regarding inhalable particles and cardiovascular disease risks, including the primary findings of this study, more attention should be paid to the combination of physical and chemical properties of particulate air pollutants, as well as the context in which people are exposed. Our results suggest that occupational exposure to substantial airborne concentrations of commercially produced pure CB particles is not associated with increased risk of cardiovascular disease, IHD or MI mortality. Because the physical-chemical characteristics of occupational exposure to carbon black may be different from that of other particulate exposures , these Epidemiological studies have demonstrated associations between environmental particle exposure and cardiac disease and mortality; however, few have examined such effects from pure carbon such as manufactured CB particles. We combined SMR and Cox proportional hazards results from cohort studies of US, UK and German CB production workers, particularly for IHD and AMI. Results from each of the individual cohort studies are presented separately, some―especially those from the UK and Germany―were based on relatively small numbers. Therefore, the meta-analysis procedures used in this study to combine cohort-specific results derived according to a common protocol greatly enhanced statistical power, thus improving our ability to identify even small associations. This study essentially included all cohort studies of industrial CB workers published to date, and therefore has the greatest potential for identifying cardiovascular disease mortality risks associated with occupational CB exposure. The availability of reasonably detailed employment histories and exposure assessment efforts in each of the three constituent cohorts allowed quantitative evaluation of risk of cardiovascular mortality by standardized individual CB exposure estimates. Although results did not suggest any, this approach might have allowed identification of exposure thresholds for cardiovascular mortality risks.Meta-SMRs were unexceptional. Meta-Cox coefficients showed no association with lugged or unlugged duration of exposure. Our results do not demonstrate that CB exposure increases cardiac disease mortality. Based on the evolving body of evidence regarding inhalable particles and cardiovascular disease risks, more attention should be paid to the combination of physical and chemical properties of particulate air pollutants, as well as the context in which people are exposed.


During this period, ET over land has increased significantly (p < 0.01), caused by increases in Et and Ei, which are partially counteracted by Es decreasing. These contrasting trends are primarily driven by increases in vegetation leaf area index, dominated by greening. The overall increase in Et over land is about twofold of the decrease in Es. These opposing trends are not simulated by most Coupled Model Intercomparison Project phase 5 (CMIP5) models, and highlight the importance of realistically representing vegetation changes in earth system models for predicting future changes in the energy and water cycle.Evapotranspiration (ET) is the process by which liquid water becomes water vapor and energetically this accounts for much of incoming solar radiation. If this ET did not occur temperatures would be higher, so understanding ET trends is crucial to predict future temperatures. Recent studies have reported prolonged declines in ET in recent decades, although these declines may relate to climate variability. Here, we used a well-validated diagnostic model to estimate daily ET during 1981–2012, and its three components: transpiration from vegetation (E Terrestrial ET is a key component of the energy and water cycles over global land2t, Es and Ei) to these global trends remains unknown. ET components can respond differently to changes in environmental conditions and/or vegetation. For example, while Et is dependent on plant phenology and water-use efficiency, Es is mostly driven by the atmospheric demand for vapour, the availability of water in the soil, and the amount of vegetation above the soil, and Ei by the occurrence of rainfall and the characteristics of the vegetation stand.Recent studies have focused on ET trends in last several decades, and have attributed the ET trends to regional droughtt is a major component of ET, the global ratio of Et to ET remains uncertain101011131416Several studies report the partitioning of global land surface ET, mainly using global land models8i/P ratio in homogeneous forests; (vi) evaluation of Es in extreme climates; and (vii) model inter-comparison. This assessment includes five validations, being (i) to (v), and two evaluations, (vi) to (vii); all are outlined below in-turn.The PML estimated ET and its partitioning are comprehensively assessed from point to global scale, including: (i) catchment precipitation (P) and streamflow (Q) data; (ii) eddy-covariance flux tower data; (iii) satellite-derived soil moisture; (iv) field experiments of ET partitioning; (v) comparing annual E2) catchments across the world . This indicates a good performance of the annual ET simulations. In addition, PML-estimated ET trend compares reasonably well to the catchment annual P–Q trend for 46 large unregulated catchments  distributed across North America, Europe, South America and Australia (R2 = 0.40). It is noted that the catchment annual P–Q trend may have noticeable errors in some catchments due to the influence of catchment storage changes.First, over a long-term catchment water balance, ‘observed’ mean annual ET is the difference between the observed catchment mean annual P–Q. The PML estimated ET compares well with long-term water-balance ET observations from 643 largely unregulated large  and wet (R2 = 0.77 and Bias = −5.3%) climatic conditions, demonstrating that the PML model performs equally well in both dry and wet conditions.Second, at monthly scale, the estimated ET is compared to eddy-covariance flux measurements in 95 flux towers widely spread , yieldin = −6.0% . To tests series estimated by the PML model shows good agreement with the TRMM  soil moisture estimates , with R2 = 0.71 , MTE (p < 0.01) and GLEAM (p < 0.1) models, respectively.Seventh, the ET estimates from the PML model are also compared to other two diagnostic models MTE, 9 land Overall, these seven assessments, including five point to regional validations and two global evaluations, give confidence on the ET components used in our analysis.−1  (−1); in good agreement with previous estimates based on similar study periods123t accounts for ~65% of ET (350.4 ± 54.7 mm year−1), Es for ~25% (133.9 ± 15.0 mm year−1) and Ei for ~10% (53.7 ± 5.5 mm year−1). These estimates fall within the broad range of variability reported by studies based on isotopes81920t and Ei are larger   or ~67% e larger ; whereastributor .2 year−2, representing only ~6.2% of the P variance , despite the Et being more than double Es. This is because some vegetation, especially trees, has access to deep soil water for Et, and have developed deep roots in response to P variability22s responding directly to the P variability. As a result, global variance in Es is comparable to that in Et, as Es is a larger component of ET in regions with a high inter-annual variability in P, like Australia or South AfricaAveraged across the global land surface, the inter-annual variance of ET is 1907 ± 147 mmvariance . The grep < 0.01), i.e. in the same direction as previous estimatest (0.72 ± 0.23 mm year−2) and in Ei (0.14 ± 0.07 mm year−2), which are partly counter-balanced by a significant but smaller negative trend in Es (–0.32 ± 0.07 mm year−2)  in ET is positive (981–2012  year−2) . Strong  year−2) , mainly ar−2) (t . Negativ2) (t (s . Decrease Sahelt .t and negative trend in Es is mostly explained by the increase in leaf area index (LAI) (2 fertilization27s29The contrasting positive trend in Eex (LAI) . This int   variability is dominated by inter-annual climate variability(and ET)  and the  America . In thesAmerica 6. Furthert, 25% Es and 10% Ei. Although Et is larger than Es, their inter-annual variability is similar, because the variability in Et is buffered by vegetation and soil moisture storage. The Es has high inter-annual variability reflecting the high inter-annual variability of P. Regionally, the ET variability is dominated by Et and Ei in densely vegetated and wet regions, and by Es in sparsely vegetated and arid regions.Using the well-validated diagnostic PML model, we estimated that global ET is comprised of 65% E−2) of the trends in four other global ET products1633t trend of 0.72 mm year−2, which is partially counteracted by a negative Es trend of 0.32 mm year−2. These contrasting trends are primarily driven by the increasing trend in vegetation LAI.The PML model showed positive trend in ET consistent with, and close to, the median  if the CO2 influence on vegetation water use efficiency is taken into account, but the PML result will still show the strong opposing trends in Et and Es.There is a limitation in the PML model in that it does not directly account for the impact of enhanced COt and Es  a more direct ET response to P in the CMIP5 models thereby implying an insufficient accounting of the vegetation and soil moisture buffering on ET in the CMIP5 models ; and , estimated from the accumulated precipitation over the previous monthA, the available energy absorbed by the surface (net absorbed radiation minus soil heat flux), is partitioned using LAI into canopy absorption (Ac) and soil absorption (As). Ei is modelled using an adapted version of the widely adopted Gash rainfall interception model, and assumes that the ratio between the wet canopy evaporation rate and the rainfall rate does not vary between stormswhere gsx) to calculate Et in PML. The gsx was estimated for each land cover type using the trial-and-error method by comparing (1) modelled mean annual ET with water balance ET observations , and (2) modelled monthly ET with in situ flux tower ET measurements.There is only one-free parameter, the maximum stomatal conductance , the PML model is further constrained by the classic Budyko framework, the Fu hydroclimatic modelMeteorological forcings from 1981 to 2012 used to drive the PML model include daily precipitation, air temperature, vapour pressure, shortwave downward radiation, longwave downward radiation and wind speed. The forcings were obtained from two widely used datasets: the Princeton Global Forcing (PGF) data14Rlo. Static land cover for 16 land cover types based on the International Geosphere-Biosphere Program (IGBP) Data, generated using 2000–2001 MODIS data, were obtained from the Oak Ridge National Laboratory Distributed Active Archive CenterVegetation forcing data were obtained as follows. LAI data from 1981 to 2011 were obtained from Boston University (BU) datasethttp://www.meridianworlddata.com/) and (iii) National Land and Water Resources Audit of Australia (http://www.nlwra.gov.au/). Daily streamflow data for the selected catchments was obtained from four sources: (i) the Global Runoff Data Centre ; (ii) the Water Information Research and Development Alliance between CSIRO and Australian Bureau of MeteorologyValidation datasets include catchment streamflow, fluxnet eddy covariance ET and over land microwave soil moisture. A total of 643 largely unregulated catchments with a widespread geographic distribution were selected to evaluate model performance at the mean annual scale. To exclude regulated catchments, major dam locations were obtained from three sources: (i) International Commission of Large DamsA total of 95 fluxnet towers were selected to evaluate model performance at monthly scale. Data for the 93 towers were obtained from the LaThuile FLUXNET dataset. An additional two sites were obtained, one from the OzFlux and another from AmeriFlux. The selected sites span a wide range of climate regimes, covering a total of 11 vegetation typesPML at 0.50° spatial resolution  against ETflux representing ET from a radius of tens to hundreds of metres .Each flux site meets the following criteria: (1) mostly homogeneous land cover at 1 km radius from the flux tower (checked with Google Earth); (2) daily energy balance closure of more than 75%; and (3) more than 2 years of daily data (during days with no precipitation) available. Note here that our evaluation compares the ETAnnual variation of ET and its components was validated against that of observed soil moisture in sparsely-vegetated regions. The observed soil moisture data were obtained from the radiometer Microwave Instrument on board NASA’s Tropical Rainfall Measuring Mission (TRMM) that started providing passive microwave observations at 10.7 GHz (X-band) and eight higher frequencies including the 37 GHz (Ka) band from December 1997. The observations can be assimilated in a microwave radiation transfer model to infer soil moisture, soil and canopy temperature and vegetation optical depth. We used the top soil moisture retrieved from the Land Parameter Retrieval ModelThe PML model simulations used two forcing datasets (PGF and WFDEI). Four simulations were run as follows: (1)PML + PGF; (2) PML + WFDEI; (3) PML + PGF (detrended LAI); (4) PML + WFDEM (detrended LAI).Simulations 1–2 were carried out using observed LAI time series, and simulations 3–4 were carried out by repeating the simulations 1–2 but using detrended LAI . The difference between simulations 1–2 and simulations 3–4 is used to quantify the impacts of LAI change on trends and variability in ET and its components.t, Es and Ei components, and expressed as Annual variance in ET at each grid cell was partitioned into EHow to cite this article: Zhang, Y. et al. Multi-decadal trends in global terrestrial evapotranspiration and its components. Sci. Rep. 6, 19124; doi: 10.1038/srep19124 (2016).


The aim of this study was to investigate the prevalence of osteoporosis in rheumatoid arthritis (RA) patients and to analyze the risk factors in these patients using the KORean Observational study Network for Arthritis (KORONA) database.Among the RA patients in the KORONA who were recruited between July 2009 and December 2011, postmenopausal women with bone mineral density (BMD) results within one year from the time of KORONA enrollment were included in this study. The baseline characteristics of patients in three groups, defined by BMD results, were compared. The BMD measurement rates and prevalence of osteoporosis in the study patients were calculated in accordance with age and gender subgroups. Multivariable logistic regression analysis was used to explore the association between osteoporosis and demographics and disease-related risk factors.p = 0.004) and wrist (p = 0.042). Advanced age , lower body mass index , longer disease duration , higher cumulative glucocorticoid dose , and higher Health Assessment Questionnaire score  were independent risk factors for osteoporosis.Of 1322 postmenopausal woman patients with RA in whom BMD was measured within one year of study enrollment, 619 patients (46.8 %) were in the osteoporosis group (T-score ≤ −2.5 SD). RA patients with osteoporosis had a higher frequency of previous fractures than those in other groups, especially fractures of the femur (A large percentage (90.8 %) of RA patients enrolled in the KORONA cohort had osteoporosis and osteopenia. Nevertheless, BMD measurement rates in this population remained low, despite high risk groups of fractures. Osteoporosis is a well-known extra-articular complication in patients with rheumatoid arthritis (RA) . It is mThe prevalence of osteoporosis in RA patients is reported to be approximately twice that in the general population . The freThe risk factors for osteoporosis and osteoporotic fractures in RA patients are age, disability, low body mass index (BMI), previous non-vertebral fracture, long-standing disease, and glucocorticoids. In particular, regardless of additional risk factors, patients taking glucocorticoids should be screened for osteoporosis. Although awareness of osteoporosis by healthcare professionals has increased in recent years, it remains underdiagnosed and undertreated .The increased risk of osteoporosis in RA patients is well reported , 2 and mThus, the aims of this study were to investigate the prevalence of osteoporosis in RA patients and to analyze the risk factors in these patients using the KORean Observational study Network for Arthritis (KORONA) database , a largeKORONA was established in July 2009 by the Clinical Research Center for Rheumatoid Arthritis and funded by the Ministry of Health and Affairs, South Korea. RA patients over the age of 18 who satisfied the 1987 American College of Rheumatology (ACR) classification criteria for RA  were recAll participants in this research completed an initial questionnaire to establish their demographic profile, medical history, and disease-specific outcomes. Disease activity was evaluated by physicians, and joint assessments were made by rheumatologists or well-trained health professionals. These evaluations, together with laboratory test results, prescription information (glucocorticoids—current and cumulative doses), and patient self-evaluation , were incorporated into the KORONA database.Laboratory data to identify the characteristics of RA (anti-cyclic-citrullinated protein antibody (ACPA) and rheumatoid factor (RF)) were obtained, and disease activity was monitored using erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP). Disease Activity Score 28 using erythrocyte sedimentation rate (DAS28-ESR) and Health Assessment Questionnaire (HAQ) results were used to assess health-related outcomes. The DAS28-ESR index combines information regarding the number of swollen and tender joints, as well as a measure of general health and acute phase response (ESR) . The HAQOnly patients with BMD data available within one year from the time of recruitment were included in this study. BMD measurements were carried out with Hologic QDR  and GE Lunar Prodigy  systems, using the manufacturers’ standard scan and positioning protocols. Trained technicians at each center performed the scanning according to a standardized protocol. Each center followed the manufacturers’ procedures to check the stability and accuracy of their equipment using regular measurements of European phantom. However, no cross-calibration was performed on any of the systems. The reference BMD values use Korean data provided by the manufacturers.Diagnoses of osteopenia and osteoporosis were made using calculations based on the World Health Organization (WHO) T-score criteria (−1.0 to −2.5 SD and ≤ −2.5 SD) . In addiBaseline characteristics were compared among three patient groups  defined according to BMD results Table . Chi-squp < 0.001). Disease duration in the study population was 12.1 ± 9.9 years (mean). The RA patients with osteoporosis were older (p < 0.001) and had longer disease duration (p < 0.001), lower BMI (p < 0.001), and higher cumulative dosage of glucocorticoid (p < 0.001) than the patients in the other groups. The osteoporosis patients also had a higher frequency of previous fractures than the patients in the other groups, especially fractures of the femur (p = 0.004) and wrist (p = 0.042). HAQ scores (median and interquartile range) were significantly higher [1.0 (1.1)] in the osteoporosis patients than in the osteopenia patients [0.8 (0.9)] and the normal patients [0.6 (0.9)] (p < 0.001). Disease activity-related factors such as DAS28-ESR (p = 0.120), ESR (p = 0.240), CRP (p = 0.058), current smoking (p = 0.300), and alcohol intake (p = 0.067) did not differ among the three groups.The demographic and clinical features of the RA patients are presented in Table n = 285, 46.0 %) , 582 (44.0 %), and 121 (9.1 %) patients were in the osteoporosis, osteopenia, and normal groups, respectively. The number of osteoporosis patients in the 60–69 years age group was the highest , of the RA patients in the database with at least a one-year follow up, 45 % reported dual-energy X-ray absorptiometry (DXA) data upon study entry. Furthermore, of the 2717 RA patients with at least a one-year follow up without reported DXA data at enrollment in the CORRONA study, 297 (11 %) patients reported undergoing DXA during the first year of follow up . AlthougRisk factors for developing osteoporosis in patients with RA include not only the use of glucocorticoids, high disability scores, low body weight, and age, but also RF status; the frequency of osteoporosis and reduced bone mass is higher in RF (+) patients. In our study, older age (≥70 years), low BMI <25), longer disease duration ≥10 years), higher HAQ score, and higher cumulative glucocorticoid dose were significantly associated with osteoporosis. RF, ACPA, and the use of glucocorticoids were not significantly associated with osteoporosis  in Korea. The numerous centers, both physician-derived and patient-derived outcomes, well controlled data, and use of a “real-world” cohort are the strengths of the study . This stWe found that older age (≥70 years), low BMI (<25), longer disease duration (≥10 years), higher HAQ score, and higher cumulative glucocorticoid dose were significantly associated with osteoporosis. These findings were not markedly different from those of previous studies. A large percentage (90.8 %) of RA patients enrolled in the KORONA cohort had osteoporosis and osteopenia. BMD measurement rates in this population remain low, despite being a high-risk group for osteoporotic fractures.


Perceived stress, immature defense style, depression and anxiety and negative life events all are known to be associated with eating disorders. The present study aimed to investigate the relationships between these factors and their relative strength of association with eating disorder symptoms over time.This research was embedded in a longitudinal study of adult women with varying levels of eating disorder symptoms and who were initially recruited from tertiary educational institutions in two Australian states. Four years from initial recruitment, 371 participants completed the Eating Disorder Examination- Questionnaire (EDE-Q) for eating disorder symptoms.Kessler-10 Psychological Distress Scale (K-10) as a measure of depression and anxiety, a Life Events Checklist as a measure of previous exposure to potentially traumatic events, the Defense Style Questionnaire (DSQ) and the Perceived Stress Scale (PSS) to determine perceived stress. One year later, in year 5, 295 (878.7%) completed follow-up assessments including the EDE-Q. The questionnaires were completed online or returned via reply paid post.s) >0.18, p < 0.01) and at one year follow-up . In multivariate linear regression modeling adjusted for age and year 4 global EDE-Q scores, perceived stress and psychological distress scores were significantly associated with year 5 global EDE-Q scores (p = 0.046 and <0.001 respectively).All four independent factors were found to correlate significantly with the global EDE-Q score in cross-sectional analyses (all Spearman rho (rPsychological distress, and to a lesser degree perceived stress had the strongest association with eating disorder symptoms over time The findings support further investigation of interventions to reduce distress and perceived stress in adult females with disordered eating. Three main eating disorders are defined in the DSM-5  of the universities involved and University of Western Sydney as lead HREC . All participants completed written informed consent and there were no children requiring consent from a parent or guardian.The EDE-Q is a 36-item self-report questionnaire focusing on the previous 28 days ) was used because of non-normality of some data. Multivariate linear regression analyses were conducted to determine the strength of association of perceived stress, psychological distress, life event number in preceding year and level of immature defense style (independent variables) on concurrent (year 4) global EDE-Q scores adjusting for age and 12-month (year 5) global EDE-Q scores (dependant variables) adjusting for year 4 EDE-Q scores and age. A significance level of < 0.05 was employed for all tests. Analyses were conducted using the SPSS for Windows version 20.Data were inspected for normality. The Spearman ranked correlations test (Spearman rho (rOf the 371 participants (46.7% of first year respondents) who completed the four year follow up survey, 19.1% were currently studying, 68.5% were employed, 49.3% were married or living as married, 34.5% had children, the highest level of education of majority of respondents (55.1%) was a bachelor’s degree and the majority lived with a partner/husband (49.7%). Other features of the sample are found in Table Two hundred and ninety-five individuals completed both the year four and fifth year survey. Twenty percent of these were currently studying, 66.5% were employed, 51.6% were married or living as married, 33.2% had children. The highest level of education of majority of respondents was a bachelor level degree (55.3%), and the majority lived with a partner or husband (52.2%).s = 0.18), levels of perceived stress (rs = 0.33), psychological distress (rs =0.37) and immature defense style (rs = 0.23) all correlated positively with global EDE-Q scores in the concurrent year (p ≤ 0.001) and with each other (see Table s = 0.15), levels of perceived stress (rs = 0.36), psychological distress (rs =0.40) and immature defense style (rs = 0.25) all also correlated positively with global EDE-Q 12-months later (p ≤ 0.05)  and 78.7% response rate of individuals followed over both years of the study, and the longitudinal design and the use of validated instruments supports the integrity of this study’s findings. Two important limitations of this study are that the participants were from a convenience sample and were women only, the latter of which makes it difficult to apply the findings to men. Another limitation of the study is the low response rate (46.7%) of participants from initial recruitment to the fourth year with the consequence that the present sample was more representative of those with higher levels of eating disorder symptoms, although not general psychological distress.Research to further investigate the findings of the present study includes more formal meditational and moderational analyses of perceived stress, psychological distress and related features such as psychological immaturity and stressful life events over time. In addition, it would be relevant to test the specific effect of interventions that aim to reducing depression and anxiety or psychological distress on eating disorder symptoms.Higher levels of perceived stress, higher levels of psychological distress, immature defense style and more frequent life events all significantly correlated with eating disorder symptoms. Psychological distress and perceived stress had the strongest independent associations with eating disorder symptoms over time.


Tramadol is a centrally acting analgesic prescribed off-label for the treatment of premature ejaculation (PE). However, tramadol may cause addiction and difficulty in breathing and the beneficial effect of tramadol in PE is yet not supported by a high level of evidence. The purpose of this study was to systematically review the evidence from randomised controlled trials (RCT) for tramadol in the management of PE.We searched bibliographic databases including MEDLINE to August 2014 for RCTs. The primary outcome was intra-vaginal ejaculatory latency time (IELT). Methodological quality of RCTs was assessed. Between-group differences in IELT and other outcomes were pooled across RCTs in a meta-analysis. Statistical and clinical between-trial heterogeneity was assessed.A total of eight RCTs that evaluated tramadol against a comparator were included. The majority of RCTs were of unclear methodological quality due to limited reporting. Pooled evidence , suggests that tramadol is significantly more effective than placebo at increasing IELT over eight to 12 weeks (p = 0.0007). However, a high level of statistical heterogeneity is evident (I-squared = 74%). Single RCT evidence indicates that tramadol is significantly more effective than paroxetine taken on-demand, sildenafil, lidocaine gel, or behavioural therapy on IELT in men with PE. Tramadol is associated with significantly more adverse events including: erectile dysfunction, constipation, nausea, headache, somnolence, dry mouth, dizziness, pruritus, and vomiting, than placebo or behavioural therapy over eight to 12 weeks of treatment. However, addiction problems or breathing difficulties reported by patients for PE is not assessed in the current evidence base.Tramadol appears effective in the treatment of PE. However, these findings should be interpreted with caution given the observed levels of between-trial heterogeneity and the reporting quality of the available evidence. The variability across placebo-controlled trials in terms of the tramadol dose evaluated and the treatment duration does not permit any assessment of a safe and effective minimum daily dose. The long-term effects and side effects, including addiction potential, for men with PE have not been evaluated in the current evidence base.CRD42013005289.The review is registered on PROSPERO 2013:The online version of this article (doi:10.1186/1471-2490-15-6) contains supplementary material, which is available to authorized users. Premature ejaculation (PE) is commonly defined by a short ejaculatory latency, a perceived lack of ejaculatory control; both related to self-efficacy; and distress and interpersonal difficulty . PE can The treatment of PE should attempt to alleviate concern about the condition as well as increase sexual satisfaction for the patient and the partner . Availabhttp://www.crd.york.ac.uk/PROSPERO/display_record.asp?ID=CRD42013005289.The aim of this study was to systematically review the evidence base for tramadol in the management of PE, by summarising evidence from randomised controlled trials (RCTs) and reporting a mean difference meta-analysis of RCT IELT data. The review addressed the question “in men with premature ejaculation, what is the clinical effectiveness of tramadol as compared with a non-active comparators or other treatments, evaluated in randomised controlled trials”. The review is registered on PROSPERO 2013:CRD42013005289. Available from The review was undertaken in accordance with the general principles recommended in the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement .The following databases were searched from inception to 5 August 2014 for published and unpublished research evidence: MEDLINE; Embase; Cumulative Index to Nursing and Allied Health Literature (CINAHL); The Cochrane Library including the Cochrane Systematic Reviews Database (CDSR), Cochrane Controlled Trials Register (CCRT), Database of Abstracts of Reviews of Effects (DARE) and the Health Technology Assessment (HTA) database; ISI Web of Science (WoS), including Science Citation Index, and the Conference Proceedings Citation Index-Science. Full search terms are reported elsewhere . The U.SSearches were screened for potentially relevant studies by one reviewer and a subset checked by a second reviewer (and a check for consistency undertaken). Full texts were screened by two reviewers. Details of studies identified for inclusion were extracted using a data extraction sheet.RCTs in adult men with PE that evaluated tramadol were eligible for inclusion. Randomised crossover design studies were excluded to avoid double counting of participants in the meta-analysis. Theses and dissertations were not included. Non-English publications were included where sufficient data could be extracted from an English-language abstract or tables.The primary outcome was intra-vaginal ejaculatory latency time (IELT). Other outcomes included sexual satisfaction, control over ejaculation, relationship satisfaction, self-esteem, quality of life, treatment acceptability and adverse events.One reviewer performed data extraction of each included study. All numerical data were then checked by a second reviewer.Methodological quality of RCTs was assessed using the Cochrane Collaboration risk of bias assessment criteria . We clasvs. placebo) were pooled across trials in a pairwise meta-analysis using Cochrane RevMan software (version 5.2) . Contintatistic ) was 40%The project was not primary research involving humans or animals but was a secondary analysis of human subject data available in the public domain.The searches identified 2,331 citations (as part of a wider project assessing a variety of treatments for PE ). Of theDetails of the included RCTs, the comparator(s), outcomes assessed and the risk of bias assessment are detailed in Table The majority of RCTs were considered at overall unclear risk of bias mainly due to lack of reporting of information to inform the risk of bias assessment. Three RCTs were described as single-blind and were considered at high risk of performance bias –17. One RCT details of the treatments, efficacy and safety outcomes, and the risk of bias assessment are presented in Table Tramadol was prescribed across all RCTs, on-demand one to four hours prior to sexual intercourse. Prescribed doses varied and range from 25 mg , 20 to 1IELT was assessed by all of the included RCTs Table . Where rIELT as a mean outcome with a variance estimate was available for all but two RCTs , 23. OneTramadol vs. placebo: Meta-analysis of mean IELT change (minutes) at 8 or 12 week follow-up, based on -four RCT study group comparisons from -three RCTs (n = 721), displayed high heterogeneity (I2 = 74%). The pooled mean difference (MD) in IELT was 1.24 minutes, favouring tramadol [MD (random effects) 95% confidence interval [CI], 0.52 to 1.95; p = 0.009]. The between-group difference in end of study values at four weeks based on one RCT (n = 56) was 4.50 minutes , in favour of tramadol. The forest plot for these analyses is presented in Figure Significant improvements on measures of the Premature Ejaculation Profile (PEP)  with tramadol compared with placebo were reported by one RCT  Signific2 = 0%). The pooled relative risk (RR) across five RCTs (583 participants) was 2.27 [RR (fixed effect) 95% confidence interval [CI], 1.45 to 3.57; p = 0.0004] in favour of placebo (lower risk). The forest plot for this analysis is presented in Figure Where reported, adverse events associated with tramadol included: erectile dysfunction, constipation, nausea, headache, somnolence, dry mouth, dizziness, pruritus (itching), and vomiting. Meta-analysis of numbers experiencing adverse events at 8 or 12 week follow-up displayed low heterogeneity (ITramadol vs. paroxetine (SSRI): The between-group difference in geometric mean IELT (minutes) at 6 weeks, based on one RCT (n = 70) comparing tramadol with paroxetine taken daily, was −0.83 . The between-group difference in end of study mean IELT (minutes) at four weeks based on one RCT (n = 57) was 2.74 (95% CI 1.91 to 3.57); p < 0.00001, in favour of tramadol compared with paroxetine taken on-demand : The between-group difference in end of study mean IELT (minutes) at four weeks based on one RCT (n = 59) was 2.01 (95% CI 1.21 to 2.87); p < 0.00001, in favour of tramadol  at 12 weeks, based on one RCT (n = 72), was 1.65, significantly favouring tramadol combined with behavioural therapy . The forest plot for this analysis is presented in Figure Tramadol vs. lidocaine gel: The between-group difference in end of study mean IELT (minutes) at four weeks based on one RCT (n = 59) was 1.21 (95% CI 0.23 to 2.17); p = 0.02, in favour of tramadol  evaluated three different doses of tramadol. The between-group differences in mean IELT (minutes) at 24 weeks were: 10.65 in favour of tramadol 50 mg vs. 25 mg ; 23.32 in favour of tramadol 100 mg vs. 25 mg ; and 13.06 in favour of tramadol 100 mg vs. 50 mg . The forest plot for this analysis is presented in Figure Pooled evidence across four RCT study groups (721 participants), suggests that tramadol is significantly more effective than placebo at increasing IELT over eight to 12 weeks. However, a high level of between-trial statistical heterogeneity is evident. The largest between-group effect size (3.52 min) was notable for one RCT . Three cThe placebo-controlled RCTs prescribed tramadol doses from 25 mg to 89 mg. Reporting of the methodological quality across these RCTs was limited. Blinded outcome assessment was not reported by any of the RCTs, which may have contributed to detection bias. Allocation concealment was not reported by five of RCTs, which may have contributed to selection bias , 20–22. The evidence from one RCT (70 participants) suggests that there is no difference in IELT between tramadol taken two to three hours prior to sexual intercourse and paroxetine daily . ConversSingle RCT evidence also suggests that tramadol is significantly more effective than sildenafil, lidocaine gel, or behavioural therapy on IELT in men with PE. However, reporting of the methodological quality is limited in terms of concealment of group allocation and blinding of the outcome assessment across all RCTs included by this review.Various assessment methods in terms of ejaculation control, patient/partners sexual satisfaction, anxiety and other patient-reported outcomes have been used across RCTs to measure the effectiveness of tramadol. Across placebo-controlled RCTs, tramadol was reported as significantly more effective than placebo for various patient-reported outcomes. Pooled evidence across trials (817 participants) suggests that tramadol is associated with significantly more adverse events including: erectile dysfunction, constipation, nausea, headache, somnolence, dry mouth, dizziness, pruritus (itching), and vomiting, than placebo or behavioural therapy over eight to 12 weeks of treatment. Addiction to tramadol by patients treated with tramadol for PE was not assessed in the current evidence base. Likewise, patient acceptability of treatment was not reported. However, one RCT reported 100% follow-up of all patients prescribed 25 mg, 50 mg or 100 mg of tramadol over 24 weeks . All paret al., daily use of clomipramine (off-label use), ‘on demand’ topical local anaesthetic agents (off-label use) and ‘on demand’ tramadol (off-label use) . Given tTramadol appears more effective than placebo or behavioural therapy in the treatment of PE. However, these findings should be interpreted with caution given the observed levels of between-study heterogeneity and the methodological quality of the available evidence.MEDLINE search strategy.(DOCX 13 KB)Additional file 1: