The effects of temperature on behavior change and mental health have previously been explored, but the association between temperature and crime is less well understood, especially in developing countries. Single-city-level data were used to evaluate the association between the short-term effects of temperature on crime events in urban Hanoi, Vietnam. We used quasi-Poisson regression models to investigate the linear effects and distributed lag non-linear models to investigate the non-linear association between daily temperature and daily crime events from 2013 to 2019. There were 3884 crime events, including 1083 violent crimes and 2801 non-violent crimes during the 7-year study period. For both linear and non-linear effects, there were positive associations between an increase in daily temperature and crime, and the greatest effects were observed on the first day of exposure (lag 0). For linear effects, we estimated that each 5 °C increase in daily mean temperature was associated with a 9.9% , 6.8% , and 7.5%  increase in the risk of violent, non-violent, and total crime, respectively. For non-linear effects, however, the crime risk plateaued at 30 °C and decreased at higher exposures, which presented an inverted U-shape response with a large statistical uncertainty. Ambient temperature is linked to several human health effects, including communicable and non-communicable diseases, and behavior changes. Whereas a large body of the epidemiologic literature describes the relationship of temperature with mortality, morbidity, and hospitalization ,2, fewerLittle research has been conducted in developing countries to examine the effects of temperature on crime, and no study has been conducted in Vietnam. Gates et al. found an increase in homicides for each 1 °C in maximum temperature in South Africa . HoweverRelated to this problem is the larger issue of climate change, which poses significant public health concerns, threatening humanity through the perpetuation of adverse environmental consequences, such as extreme weather events, and wildfires, and increased temperature . AccordiTo the best of our knowledge, no study has evaluated the association between temperature and crime events in Hanoi, Vietnam. Vietnam is a Southeast Asian nation, a region at high risk for climate change-related hazards like rising temperature . Our invWe conducted an ecological study to estimate the short-term association between temperature and the risk of criminal behavior in urban Hanoi, Vietnam. We collected data on daily temperatures and crime events from 2013 to 2019. We considered two types of crime, violent and non-violent crime, and three temperature measures, daily minimum temperature, daily mean temperature, and daily maximum temperature.2 and an estimated density of 2239 people/km2 (https://www.gso.gov.vn/dan-so/ accessed on 6 June 2022). Over ten years the annual population growth has been approximately 4.4% in urban areas, compared to 0.72% in rural areas. Hanoi is divided into 30 districts, including 12 urban districts, one district-leveled town, and 17 rural districts. There are four seasons in Hanoi, Spring (Feb–April), Summer (May–July), Fall (Aug–Oct), and Winter (Nov–Jan), with the lowest temperature in January and the highest temperature in June or July [Hanoi is the capital of Vietnam and is in a sub-tropical climate region. Based on the Annual National Population and Household Report 2019, Hanoi covered an area of 3358 kmThe study outcome was daily reported crime counts. All criminal activities were coded with the Vietnamese Criminal Code (No 100/2015/QH13). We obtained crime data from 1 January 2013 to 31 December 2019 based on daily reports in the PC02 Department, Police Headquarters Hanoi.The PC02 Department reported six common types of crime representing violent behavior that might physically harm an individual through injury, force, or threat of injury, and three common types of crime representing non-violent behavior that is directed at an individual’s property. The six violent crime types included murder/manslaughter, rape, assault, lewd and being lascivious behavior with a child under 16, kidnapping, and robbery. Robbery was in the violent crime group because it is defined as “Any person who uses violence, the threat of immediate violence, or commits other acts that render another person unable to resist to obtain his/her property”. Three non-violent crimes were: larceny, burglary, and fraud. Other non-violent crimes that are not directed at individuals, such as drug-related and prostitution, were not included in this study because those types of crime were not reported and managed by the PC02 Department.Each type of daily criminal activity is reported by the local District Police Office and aggregated by Police Headquarters Hanoi using paper reports. The reports include the name of the criminal, age, type of crime, time, date, and location where the crime was committed. For the purposes of this study, only the date, time, location, and type of crime were ascertained. Information on age, sex, personal characteristics, or identifying information were not allowed to be collected for this study in accordance with Vietnamese national security protocols.http://www.epidata.dk/ accessed on 25 December 2021). A 10 percent random sample of the data was checked to ensure the validity of the data entry process; this determined a 99% accuracy rate.A total of 1826 paper reports were collected from 2013 to 2019. The assistance of police department personnel was obtained to enter data from paper reports using an Epidata Software v4.6.0.2 (2.5), and relative humidity (R.H.).The Hanoi Environment and Natural Resource Department and Vietnam Environment Administration maintains 11 weather station monitors, including three stationary monitors and eight mobile monitors, that report hourly atmospheric data, including temperature, fine particulate matter (PMhttps://www.gso.gov.vn/en/homepage/ accessed on 15 January 2022) and a previous study [Estimates of daily environmental measures based on hourly data were calculated in several steps. First, we identified daily minimum, maximum, and mean temperature based on the hourly temperature data of each air monitor. Illogical measurements and outliners were removed. In each air monitor, we removed all days with daily maximum temperatures below daily minimum temperature, while removing all values under 5 °C for daily minimum temperature, over 44 °C for daily maximum temperature, and under 7 °C or over 40 °C for daily mean temperature. These cutpoints were based on the lowest and highest value of temperature measurements in Hanoi reported in the General Statistics Office of Vietnam  as time-variant confounders of crime. Holiday was a binary indicator for whether a day was classified as holiday or non-holiday. Holiday included all Vietnamese public holidays, including New Year’s Eve, Lunar New Year’s Event, Labor Day, Independence Day, and the preceding Friday or following Monday if a holiday fell on a Saturday or Sunday, respectively. (https://www.officeholidays.com/countries/vietnam/2020 accessed on 6 April 2021). Daily PM2.5 (μg/m3) and R.H. (%) represents the average of daily mean measurement of the 11 station monitors.This study considered day of the week, holidays, season, year, and additional atmospheric conditions . The results were reported as the percent increase in the relative risk (RRI) of a crime occurrence for each 5 °C increase in daily minimum temperature, mean temperature and maximum temperature, separately. The interpretation of the RRI can be considered the percent relative effect and is directly derived from the relative risk. Reporting an RRI allows for a change in risk that may be lower in magnitude, but still statistically significant, to be more easily interpreted. This is calculated as the (Relative Risk −1) × 100 .2.5. Model 4 was adjusted for day of week, holiday status, daily relative humidity and daily PM2.5. We estimated the RRI at seven individual lag day models, from 0 to 7 days, to identify the delayed effects of temperature and crime counts. All models were also fit separately for each temperature measurement and crime outcome: violent crime, non-violent crime, and the combination of violent and non-violent crime.The primary model (Model 1) was adjusted for day of week and holiday status. Model 2 was adjusted for day of week, holiday status and daily relative humidity. Model 3 was adjusted for day of week, holiday status and daily PMst percentile of daily mean temperature for the entire 7 years to demonstrate the change in risk from a low-temperature exposure point. The minimum recorded temperature was not selected to reduce the effects of extreme outliers in the final model.Distributed lag non-linear models (DLNM) were fit to estimate the relative risk of each 1 °C increase in daily temperature and each type of crime. A natural cubic spline with 4 degrees of freedom and 7 lag days for temperature was applied in the DLNM. The modelling framework can describe non-linear relationships both in the day of exposure and lags . The modAnalyses were performed using R Software analysis, version 4.0.5, R Foundation for Statistical Computing  relying on the dlnm package for statistical assessments We evaluated the sensitivity of the models to different elements: (1) estimating the linear effects of temperature and crime using separated models stratified by holiday status (holiday and non-holiday) and weekend status (weekend and weekday), (2) applying times series analysis adjusted for a time component to control for seasonal and long-term trends using natural cubic spline with 3, 5, 7 and 9 degrees of freedom per year for linear effects.We identified 3884 total crimes, including 1083 violent crimes and 2801 non-violent crimes across 2556 data days from 1 January 2013 through 31 December 2019. Crime incidence changed seasonally with more crime occurring in Spring , with highest risk in violent crime , followed by all crime types  and non-violent crime  . The criIn our non-linear distributed lag model, we observed an increase in the risk of violent crime, non-violent crime, and total crime with increased daily mean temperature until around 30 °C, at which point the risk begins to decline in an inverted U-shape response . At a daCrime counts in Hanoi were characterized by relatively few events per day without a sharp seasonal pattern observed. We tested the sensitivity of our model to two temporal smoothers: the year and season variable and a natural cubic spline model for time . It was In this study we observed an association between a short-term increase in daily temperature and an increased risk of violent and non-violent crime in Hanoi, Vietnam. The greatest effect was observed on the day of exposure, and the association between crime and mean temperature was non-linear, with an increased risk up to 30 °C, which then decreased at higher temperatures, supporting previous research in other populations . Our resUrban Hanoi offers a unique population to explore temperature–crime associations. Hanoi is in northern Vietnam which has a sub-tropical climate with four seasons per year. This differs from cities in the southern regions of Vietnam, such as Ho Chi Minh city, where two seasons are characterized as dry or rainy. Therefore, the temperature–crime associations in Hanoi may differ from Ho Chi Minh city, as well as cities in the Americas, Africa, and Europe. Hanoi is the second-largest city in Vietnam and has experienced rapid growth through urbanization in the last two decades. Hanoi’s urban structure and boundary were expanded in 2008, and policies have strongly promoted population density and social development . MoreoveThere is an increased interest in whether the rising temperatures could affect criminal behavior ,6,17,18.A limitation of single-city analyses is that they cannot be generalized to larger geographic regions due to the different social, demographic and climate factors. Our study was conducted in Hanoi, located in the north of Vietnam, so it may not be generalizable to elsewhere in the country. However, the results from a single-city study can raise the public’s awareness of climate change at the local level.This study contributed evidence of a potential linear and non-linear temperature-crime association. For linear effects, we observed an increase in crime risk for each 5 °C increase in temperature, in line with other single-city studies in South Africa and Maryland. The non-linear effect of daily mean temperature showed an inverted U-shaped response with a downward deflection at a very high temperature. This can be explained by the Social Escape or Avoidance Theory and the Negative Affect Escape Model ,20, and We used three temperature measures to estimate temperature–crime associations. Daily minimum, mean and maximum temperature show similar associations and trends, but the precision varied across five models when adjusted for various confounding factors. Several studies have used one or two temperature measurements to examine the effects of temperature on crime, such as minimum and maximum daily temperature or only mean daily temperature ,21,22. DSeveral limitations need to be acknowledged in this study. First, individual-level information about people who commit crimes was not obtainable due to policy use restrictions on the available data. Thus, we were not able to examine differences in risk by age, gender, or other factors. However, our study investigated the risks in a single population where the underlying distribution of demographic factors is unlikely to change across short time durations, so these factors would be unlikely to confound the population-level results. Second, the original data reported to the Hanoi Police Department were recorded on a paper report, which was then abstracted to an electronic record. This process poses a risk of errors during the data-entry process, but we believe that these were minimized by the data-entry verification processes established in the abstraction process. Third, many crimes are underreported for various reasons, so the absolute crime burden is not known. Additionally, some crimes, such as drug use and prostitution, were not reported by the PC02 Department with other violent/non-violent crime types. The extent to which this underreporting is related to temperature is unknown, and there may be some selection bias that could not be accounted for in our analyses. Fourth, this study was limited to seven years, which, in concert with the relatively low rate of crime in Hanoi, resulted in a small number of crime events compared to other studies, thus limiting the precision of our estimates. The small number of events limited our ability to adjust for the time variable because under- or over-smoothed estimations may occur based on the chosen number of degrees of freedom per year ,24. AddiThe observed association between temperature and crime may be of particular concern in the context of climate change, especially in low- and middle-income countries. To the best of our knowledge, this study is the first study in Vietnam to examine the relationship between short-term temperatures and criminal behavior. Our findings from both linear and non-linear models support the hypothesis that temperature influences criminal behavior. We expect that our results may be valuable for local police planning and social services in urban Hanoi, Vietnam. Our results indicate that additional investigations that including other regions of Vietnam are warranted.


This descriptive study aimed to determine the prevalence of metabolic syndrome (MetS) and its components among Chinese children and adolescents aged 7–17 from 2016–2017 according to the Cook’s criteria modified for age on the basis of the National Cholesterol Education Program-Adult Treatment Panel III (NCEP-ATP III) and to evaluate the associations between the factors of interest  of MetS and its components, using data from the China National Nutrition and Health Survey of Children and Lactating Mothers from 2016–2017. A total of 54,269 school-aged children and adolescents were ultimately included in this study. Anthropometric measurements and laboratory examinations of the subjects and their relevant information were also collected. A multivariate logistic regression analysis model was applied to analyze the relationships between relevant factors associated with MetS and its components. In the present study, the prevalence of MetS in children and adolescents was 5.98%. Among the five components of MetS, elevated blood pressure (BP) and abdominal obesity were the most prevalent (39.52% and 17.30%), and 58.36% of the subjects had at least one of these components. In the multivariate logistic regression, an overweight condition, obesity and hyperuricemia were positively correlated with the incidence of MetS and all five components. There was also a positive association observed between vitamin A and the risk of MetS and some components of MetS ) and vitamin A was negatively associated with the risk of low high-density lipoprotein cholesterol (HDL-C). Subjects with vitamin D inadequacy had a higher risk of MetS  and four of its components, excepting elevated FBG (fast blood glucose). Vitamin D deficiency was positively associated with MetS  and all five of its components. Well-designed, large-scale prospective studies are also needed in the future. Metabolic syndrome (MetS) has become one of the major public health challenges worldwide and is characterized by the combination of abdominal obesity, elevated blood pressure (BP), high triglycerides (TG), elevated fast blood glucose (FBG) and low high-density lipoprotein cholesterol (HDL-C) . The criUria acid is a final product of purine nucleotides and is formed by the liver and mainly excreted by the kidneys in human metabolism . HyperurVitamin A is a lipid-soluble vitamin which plays important roles in the vision, the immune system and cell protection , and it Similarly, serum vitamin D is another fat-soluble molecule, mainly synthesized in the skin following exposure to UV-B radiation from sunlight or from the diet . The funIn this study, data from the China National Nutrition and Health Survey of Children and Lactating Mothers from 2016–2017 were used to calculate the prevalence of MetS and its components and explore its possible correlates in order to provide evidence for the prevention and control of the disease. We also compared the corresponding indicators between subjects with and without MetS and its components to identify differences.Data were obtained from the China National Nutrition and Health Survey of Children and Lactating Mothers from 2016–2017. A complex, multistage, stratified cluster random sampling method was carried out to create a representative sample of 31 provinces, autonomous regions and municipalities. The first, including a total of 275 survey sites were, randomly selected. The second, including two townships/subdistricts, were randomly picked from every survey site. The third, two communities/villages were randomly selected from each township/subdistrict. At least 280 children and adolescents aged 6–18 were selected from schools in each survey site, with an equal number of males and females. In this study, after excluding participants who were unable to provide important information, such as total anthropometric measurement data and blood laboratory tests information, and participants who had unreasonable data, a total of 54,269 participants aged 7–17 were included.The data collection and measurements were conducted by the trained investigators. Basic demographic information, such as age, sex, living area and other information, was collected using the standardized questionnaires provided by the China Center for Disease Control and Prevention (the China CDC) project group.The anthropometric measurements included height, weight, waist circumference (WC), systolic blood pressure (SBP), diastolic blood pressure (DBP) of the participants. Height and weight were measured without shoes or coats on. Height was measured to the nearest 0.1 cm with a stadiometer (TZG) while the participants were standing in an upright position. Weight was measured to the nearest 0.1 kg using an electric scale . BMI was calculated by dividing the body weight (kg) by the square of the height (m). The WC measurement was performed at the midpoint between the bottom of the rib cage and the top of the iliac crest twice using a soft tape. After guaranteeing that the error between the two measurements was less than 2 cm, the investigators then recorded the average value. After resting quietly for 5 min, the SBP and DBP were measured three times at one-minute intervals by an electronic sphygmomanometer  with an accuracy to 1 mmHg, and the mean of the SBP and DBP was recorded for further analysis. The measurements strictly followed the relevant standard protocols .Laboratory examinations: 6 mL fasting venous blood samples of participants were obtained in the morning and used for the testing indicators. Triglyceride (TG) and high-density lipoprotein cholesterol (HDL-C) were tested using enzyme colorimetry . Fast blood glucose (FBG) was measured using the glucokinase method . Vitamin A was tested by high-performance liquid chromatography (HPLC). Vitamin D was tested by high-performance liquid chromatography-mass spectrometry (HPLC-MS/MS). Serum uric acid was measured using colorimetry .This study was approved by the ethical committee of the National Institute for Nutrition and Health of Chinese Center for Disease Control and Prevention, and the ethical approval number was 201614. All participants gave signed informed consent before the study, provided either by themselves or their guardians.The living area was categorized into urban and rural areas. The nutritional status  of the participants was identified by the sex- and age-specific BMI cut-off values for Chinese school-age children and adolescents ,26. To aGiven that the Cook’s criteria  modified(1)Abdominal obesity: WC ≥ age- and sex-specific 90th percentile, determined by the cut-off points for Chinese children and adolescents ;(2)Elevated blood pressure: SBP or DBP ≥ 90th percentile for age, sex and height ;(3)High triglycerides: serum TG ≥ 1.24 mmol/L;(4)Low HDL-C: HDL-C ≤ 1.03 mmol/L;(5)Elevated fast blood glucose: FBG ≥ 6.1 mmol/L.According to the Cook’s criteria, participants meeting at least 3 of the following 5 criteria were defined as having the MetS:Hyperuricemia was defined in this study according to the threshold of the serum uric acid value ≥357 µmol/L, in line with previous studies .Vitamin A sufficiency, inadequacy and deficiency were defined according to serum retinol levels of more than 0.3 µg/mL and 0.2–0.3 µg/mL, and less than 0.2 µg/mL, respectively . Vitaminp values < 0.05 were considered to be statistically significant.All analyses were conducted with SAS software . The continuous data were displayed as the median  in view of non-normality. The categorical data were reported as numbers and percentages. The continuous variables were compared using the Wilcoxon rank-sum test between subgroups. The chi-square test was used to compare the distributions of different characteristics between subgroups. The Cochran–Armitage trend test was used to test the increasing/decreasing trends between subgroups. The prevalence of MetS, its risk factors and its components were calculated. Multivariate logistic regression analysis was used to explore the related factors of MetS and its components. The odds ratios (ORs) and 95% confidence intervals (CIs) were presented. Two-sided A total of 54,269 children and adolescents aged 7–17 were included in this study. The basic demographic, anthropometric and clinical characteristics of the research population are presented in n = 934) were higher than those without elevated FBG. Compared with subjects without elevated BP, subjects with elevated BP  had higher BMI, weight, WC, SBP, DBP, FBG, TG, serum uric acid and vitamin A values, but lower age and height values. Subjects with low HDL-C (n = 6285) were found to have higher age, BMI, height, weight, WC, SBP, DBP, TG and serum uric acid and had lower values of HDL-C and vitamin D than those without low HDL-C. No difference was found in the values of HDL-C between the subjects with and without elevated BP, and in values of vitamin A between the subjects with and without low HDL-C. Moreover, it is noted that subjects with elevated FBG had higher HDL-C levels, and subjects with low HDL-C had lower FBG levels in the fasting venous blood tests.As presented in The results regarding the prevalence of MetS and one or more of its risk factors are shown in p < 0.05).It was noted that the prevalence of subjects with at least one risk factor of MetS in China was up to 58.36% in this sample. A total of 21.01% had two or more risk factors and 1.19% had four or more risk factors. With age, BMI, increased vitamin A and decreased vitamin D, the prevalence of one or more of the risk factors of MetS also increased . However, females had a lower risk of elevated FBG  and low HDL-C . Compared with subjects living in urban areas, living in a rural area was positively associated with MetS, elevated BP, high TG and low HDL-C, and was negatively associated with abdominal obesity and elevated FBG. Subjects in the pubertal and post-pubertal stages had an increased risk of having MetS, abdominal obesity, elevated FBG, high TG and low HDL-C, and a decreased risk of having elevated BP. Overweight condition, obesity and hyperuricemia were positively correlated with the incidence of MetS and all five of its components.To further characterize the risk and protective factors of MetS and its components, a multivariate logistic regression was performed, and the corresponding results are presented in Furthermore, we found that subjects with vitamin A inadequacy had a lower risk of having MetS, abdominal obesity, elevated BP and high TG, and had a higher risk of having low HDL-C than those with vitamin A sufficiency. Vitamin A deficiency was negatively correlated with MetS, abdominal obesity and high TG, and was positively correlated with elevated FBG and low HDL-C. Subjects with vitamin D inadequacy had a higher risk of having MetS and four of its components, excepting elevated FBG. Vitamin D deficiency was positively associated with MetS and all five of its components.In the present study, we reported the prevalence of MetS and its components in Chinese children and adolescents aged 7–17 using the Cook’s criteria modified for age on the basis of the NCEP-ATP III. Additionally, we explored the associations between the corresponding factors of MetS and its components using a large-scale cross-sectional study.In our study, the prevalence of MetS was 5.98% among Chinese children and adolescents aged 7–17 from 2016–2017. Compared with the previous value of 3.37% also defined by Cook’s criteria in 2009 , the prep < 0.05), and the prevalence was up to 41.48% in the prepubertal subjects. The logistic regression indicated that age was negatively associated with the incidence of elevated BP among children and adolescents aged 7–17.We divided participants into three age-based subgroups to reflect the prepubertal, pubertal and post-pubertal stages, respectively, because the data for the Tanner stage were not available. With age, the prevalence of MetS and its components was increased. The OR of the incidence of MetS was increased among subjects who were in the pubertal  or post-pubertal  stage. We speculated that this trend could be correlated with the IR that occurs at the beginning of puberty . Howeverp < 0.05). This trend could be reasonably explained by the fact that an overweight condition or obesity entails more visceral fat in the body, which has been shown to be an important trigger that can activate most of the pathways of MetS, such as chronic inflammation, hormonal activation and IR [In addition, it was revealed that overweight or obese children and adolescents had a higher prevalence of MetS and its components than normal-weight subjects, which is in line with the previous studies ,40,41. Tn and IR .p < 0.05), the values of which were similar to previous studies [The prevalence of hyperuricemia was 29.18% among Chinese children and adolescents aged 7–17. Hyperuricemia is associated with Western diets or lifestyles ; thus, t studies ,27,44 bu studies . The rel studies . In fact studies . Our stu studies . We coulp < 0.05), and the prevalence of one or more risk factors increased with decreased the vitamin D, which was also the case for the five components of MetS. Moreover, our study reported that vitamin D deficiency (<12 ng/mL) was a possible risk factor of the incidence of MetS and all its components . Subjects with vitamin D inadequacy (12–20 ng/mL) had a high risk of having MetS, abdominal obesity, elevated BP, high TG and low HDL-C. Our results were similar to those of certain previous studies [Biochemical analysis of vitamin D is an accurate way of assessing vitamin status, and it can reflect the real nutritional status of vitamin D from diet intake and skin synthesis . The prequacy 12– ng/mL ha studies  but inco studies . A dose– studies . Two pat studies . Many cl studies  observed studies . It is nSimilarly, serum vitamin A levels can reflect the intake of vitamin A from diet . In our It is clear that the adverse associations among the risk factors of MetS begin in childhood and the prevalence of MetS has been increasing; therefore, it is necessary to suggest interventions and treatments as soon as possible. Given that overweight and obese subjects had a higher risk of having MetS and all 5 components, lifestyle intervention must be the most effective measure, including dietary and physical activity. Multiple studies have shown that greater adherence to the Mediterranean diet  and the This study had some limitations. Firstly, this study had a cross-sectional design, despite the use of a large-scale population, preventing us from forming conclusions about cause–effect relationships. A longitudinal, prospective study design is needed in the future. Secondly, we did not take into consideration dietary factors and other unmeasured potential confounding influences, such as lifestyle habits and environmental factors. In addition, the data for the insulin resistance (IR) and Tanner stage were not available for all participants in the database, and these factors are closely related with MetS. These factors should be taken into account in further studies. Nevertheless, our study still had some strengths. Using the scientific sampling method and rigorous quality control measures, a large-scale regional population was included in this research. Moreover, our study had some innovations, such as exploring the associations of serum vitamin A, vitamin D and hyperuricemia with MetS and its components among children and adolescents aged 7–17. To our knowledge, our study was first to report on the combined effects of vitamin A, vitamin D and hyperuricemia on MetS and its components among Chinese children and adolescents at the national level.In summary, our study calculated the prevalence of MetS and its components in Chinese children and adolescents aged 7–17 at the national level, and we explored the correlates. The associations of living area, age, nutritional status, hyperuricemia, vitamin A and vitamin D with MetS and its components were observed after adjustment for sex. Among these factors, overweight condition, obesity and hyperuricemia had positive relationships with the incidence of MetS and all five components. Vitamin A inadequacy (0.2–0.3 µg/mL) was positively associated with low HDL-C and was negatively associated with MetS, abdominal obesity, elevated BP and high TG. Vitamin A deficiency (<0.2 µg/mL) was positively associated with low HDL-C and elevated FBG, and was negatively associated with MetS, abdominal obesity and high TG. Vitamin D inadequacy (12–20 ng/mL) was positively associated with MetS, abdominal obesity, elevated BP, high TG and low-HDL-C. Vitamin D deficiency (<12 ng/mL) had a positive relationship with MetS and all of its five components. These findings shed light on the relevant disease prevention and control methods. Further large-scale longitudinal investigations are still needed to elucidate the potential pathophysiological mechanisms and correlates of MetS in China.


Teacher burnout is affected by personal and social factors. COVID-19 has greatly impacted teachers' physical and mental health, which could aggravate teacher burnout.Based on the JD-R model, this study aims to investigate the relationship between teacher professional identity (TPI) and job burnout during the COVID-19 pandemic, and examine the moderating roles of perceived organizational support (POS) and psychological resilience (PR) in these relationships among primary and secondary school teachers in China.A total of 3,147 primary and secondary school teachers participated in this study.Work engagement played a mediating role in the relationship between professional identity and burnout; when the POS and PR scores were high, the predictive coefficient of TPI on burnout was the largest.This study tested the mechanism underlying the relationship between TPI and burnout, and explored the protective factors of burnout.This study supports the applicability of the JD-R model during COVID-19 and provides ideas for teachers to reduce burnout. Burnout refers to emotional exhaustion, a low sense of achievement, and a depersonalized state of psychological stress caused by an individual's inability to cope effectively with work pressure in their occupational field , 2. ThisTeacher professional identity (TPI) is defined as the beliefs, values, and commitments that an individual holds toward being a teacher , 17. SomWork engagement (WE) is a positive, well-rounded, work-related emotional state characterized by energy, dedication, and focus . ResearcRegarding the relationship between PI and burnout, some researchers believe that WE is an independent concept that is negatively associated with burnout. It involves the way a person devotes more time and energy to complete their tasks , 33. ThePerceived Organizational Support (POS) refers to whether individuals feel that the organization values their contributions, whether individuals are content with the attention they provide to the organization, and whether the organization, in this case, schools, cares about the basic interests of employees . OrganizNo previous study has examined the relationship between TPI, POS, and WE. However, Social Exchange Theory (SET) can provide a perspective. SET suggests that employees are willing to provide their best  to their organization when they receive corresponding respect from the organization . FurtherPsychological resilience (PR) is an individual's ability to bounce back in the face of adversity, trauma, tragedy, or stress. It is a vital personal psychological resource in today's fast-paced, high-stress, and unpredictable work environment . PreviouPrevious studies have shown that teachers' PI, WE, POS, and PR have positive effects on preventing or reducing the level of teacher burnout –55. HoweThe JD-R model could be the theoretical basis of this study to explain teacher burnout. The JD-R model mainly assumes that job burnout is caused by an imbalance between job demands and resources and that many job resources can compensate for the impact of high job demands on job burnout . Job resBased on the JD-R model theory, we propose a theoretical model. We expect that our results will not only support this theory but also extend it. The JD-R model posits that resources could help individuals prevent or reduce their level of burnout. Resources can be divided into personal, organizational, and other resources. Although the JD-R model posits that resources are significant for preventing burnout, it does not consider the effects of different levels of resources , especially when they interact with one another. In our study, we considered the effects of personal resources  and organizational resources , which might differ from those of previous studies.In summary, this study aimed to explore the mechanisms underlying the relationship between TPI and burnout. Based on these theories and empirical evidence, we propose the following hypotheses:Hypothesis 1: WE mediates the relationship between TPI and burnout.Hypothesis 2: POS moderates the relationship between TPI and work engagement.Hypothesis 3: PR moderates the relationship between WE and teacher burnout.The model is shown in This study was approved by the Ethics Committee of Zhejiang Normal University and performed in accordance with the Declaration of Helsinki and APA ethical standards. The survey was conducted over 3 months, from June to September 2021. Simple sampling was used, and 3,500 in-service teachers in a city in Zhejiang Province participated in this study. After excluding 353 questionnaires with incomplete responses, 3,147 valid questionnaires were included. There were 927 females and 2,220 males, with an average age of 39 years and a standard deviation of 8.74 years old. The average number of years of teaching was 17.90 years. Among the 3,147 valid questionnaires, 2,040 (64.82%) were pre-and primary school teachers, and 1,107 (35.18%) were secondary school teachers. A total of 2,856 (90.75%) teachers majored in teaching, and 291 (9.25%) majored in a non-teaching program.Teacher burnout was measured using the Professional Quality of Life Scale designed by Stamm . This scTPI was assessed using the Teachers' Professional Identity Scale by Wei et al. . The scaWE was measured using the Utrecht Work Engagement Scale (UWES) by Schaufeli and Bakker , which cPOS was measured using the Perceived Organizational Support Scale designed by Eisenberger et al. . The scaPR was assessed using the Psychological Capital Questionnaire designed by Zhang  for primvia the Credamo platform. Second, the data were collated, and finally imported and analyzed using SPSS 21.0  Descriptive statistics and correlation analyses were performed on the main variables. (2) The SPSS PROCESS macro was used for mediation and moderation analysis with 5,000 bootstrapped samples. (3) Model 4 (PROCESS macro) was used to examine the mediating effect of job engagement between teachers' PI and job burnout. (4) Model 1 was used to examine the moderating effects of POS and resilience on teachers' PI and job engagement, as well as job engagement and burnout. (5) Model 21 was used to moderate the mediation analysis. A 95% CI was reported in our study. The CI in the Results section represents the 95% CI.Since the data collected by the questionnaire in this study were all from teachers' self-reports, there may be common methodological deviations. In this study, the Harman single-factor test was used as a statistical control. The results showed that the eigenvalues of 14 factors were >1, and the explanatory power of the first factor was 37.41%, which was less than the critical value of 40%, indicating that there were no serious problems resulting from common method bias in this study.r = −0.55, p < 0.01), WE , POS , and PR . TPI was positively related to WE , POS , and PR . Furthermore, the results found that WE was positively correlated with POS  and PR . These results indicate that TPI, WE, POS, and PR may be regarded as protective factors in reducing the level of burnout. The results are shown in The descriptive statistics are presented in B = 0.06, SE = 0.03, CI = , p < 0.05]. Further simple slope analysis showed that compared to the low POS (M-1SD), the predictive coefficient of TPI on WE increased from 0.74  to 0.83  when the POS score was high (M + 1 SD). As for the moderating role of PR, the results showed a significant interaction effect of WE and PR on burnout . Further simple slope analysis showed that compared to the low PR (M – 1 SD), the predictive coefficient of WE on burnout increased from 0.34  to 0.41  when the PR score was high (M + 1 SD).The results of the moderation effects of POS and PR after controlling for gender and age are shown in p < 0.001; M-Y: B = −0.33, CI = , p < 0.001; X-Y: B = −0.16, CI = , p < 0.001]. The results showed that POS played a moderating role in the relationship between TPI and WE, and PR played a moderating role in the relationship between WE and burnout. Further simple slope analysis showed that when the scores of POS and PR were high, the predictive coefficient of TPI on burnout through WE was −0.31; when the scores of POS and PR were low, the predictive coefficient of TPI on burnout was −0.22. This result indicated that when the POS and PR scores were high, the predictive effect of TPI on burnout through WE was the largest. The direct effect of TPI on burnout was −0.19. Thus, the indirect effect of WE accounted for 62.0% of the total effect.The results of the moderated mediation analysis, after controlling for gender and age, are shown in Based on the JD-R model, this study explored the mediating role of WE in the relationship between TPI and burnout among Chinese primary and secondary school teachers and examined the moderating roles of POS and PR. This study reveals that when POS and PR are high, the predictive effect of TPI on burnout is greatest through WE. On the one hand, the organizational level should strengthen the affirmation of teachers' work so that teachers have a more positive attitude toward their work. On the other hand, it is necessary to provide full support to teachers to increase their positive psychological emotions, thereby reducing job burnout caused by long-term online teaching.According to the Pearson correlation results, the correlation between the three variables was significant at the 0.01 level. Specifically, the correlation coefficient between burnout and TPI was −0.55, that between burnout and WE was −0.67, and that between TPI and WE was 0.63. This result is consistent with previous research findings, that is, TPI had a negative effect on burnout , and TPIp < 0.001) in the relationship between TPI and burnout, supporting H1. This result is consistent with the findings of a study conducted by Zhang et al. on health inspectors. Their research found that PI not only directly affects burnout but also reduces the likelihood of burnout through WE . Based on these two reasons, we believe that we did not test the JD-R model, but support it to a certain extent through relevant data analysis.In this study, teachers' PI, POS, and PR were all work resources that played a protective role in the occurrence of teacher burnout. Regarding the mediating role of WE, previous studies have shown that burnout is closely related to WE, and WE is positively correlated with teachers' PI. Moreover, previous research has found that burnout is negatively related to other work resources, such as self-efficacy , empathyFrom the perspective of social organization and personal psychological resources, the following suggestions are made. First, to increase perceived social support, there is a need to organize training sessions for school administrators to strengthen their understanding of online teaching principles and quality monitoring. Teachers are also encouraged to engage in online teaching. Online teaching during the pandemic is not only a disadvantage but also increases the ability of teachers to teach online. Therefore, teachers should engage in online teaching with a positive attitude. Moreover, to alleviate burnout, support from external work resources such as POS can be strengthened to ensure the normality of online teaching. In summary, schools should strive to improve the service capabilities of their teaching environment, such as ensuring that teachers reorganize teaching equipment during the teaching process and that the teaching environment is comfortable. This will result in a better teaching platform and provide necessary support tools for teaching and learning. At the same time, schools need to build a teacher professional development community to support teachers in reducing professional burnout under the conditions of long-term online teaching.This study has some limitations. First, the data we collected was purely correlational, collected at a single time point, and with no experimental manipulation or random assignment, which resulted in difficulties in inferring the causal relationship. Meanwhile, one drawback of cross-sectional data that was used to test mediation effects was that it was a lack of control for prior levels of variables. Thus, the results of mediation and moderation analysis should be interpreted with caution, which refers to the causalities implicitly implied by the arrows in the mediation model and that all evidence for causation comes from either the theoretical reasoning or the existing empirical findings. Future research could adopt an experimental design or longitudinal design to test the causal relationship between these variables. Second, the large sample size of this study did not apply nationwide. The study was conducted only in Zhejiang province. Future researchers could consider other variations, such as teachers at different levels (preschool and high school teachers). Furthermore, this study can be replicated in other provinces in China. Third, our research only explored the effect of job resources on burnout, ignoring the effect of job demands on burnout, which resulted in difficulties in testing the JD-R model. Future research could simultaneously consider the influence of job demands and resources on burnout.Based on the JD-R model, this study examined several protective factors that can help reduce burnout among teachers at the organizational and individual levels. These findings suggest that WE mediates the relationship between TPI and burnout. POS moderated the relationship between TPI and WE, while PR moderated the relationship between WE and burnout. Moreover, this study provides suggestions that can help overcome the problem of burnout among primary and secondary school teachers in China during the COVID-19 pandemic. It is worth noting that, although most schools have already started online teaching, it is unclear whether online teaching will still be part of daily teaching after the pandemic. However, online teaching is an important direction for future college education reform, and this study aims to provide an organizational reference for the development of online teaching in the future.The raw data supporting the conclusions of this article will be made available by the authors, without undue reservation.The studies involving human participants were reviewed and approved by the Ethics Committee of Zhejiang Normal University. The patients/participants provided their written informed consent to participate in this study.YL and BS: conceptualization. YL and QZ: methodology. BS and WL: validation. YL and QZ: resources. YL: writing—original draft preparation and funding acquisition. YL and MA: writing—review and editing. QZ and WL: supervision. BS: project administration. All authors contributed to the article and approved the submitted version.


Photobiomodulation is a novel technique to reduce pain following different surgeries and treatments. This study aimed to investigate the effect of photobiomodulation on pain control after clinical crown lengthening procedures. Twenty patients were included and randomly assigned to two groups in this single-blind randomized clinical trial. The patients had been referred to the Periodontics Department, Tabriz Faculty of Dentistry, for crown lengthening surgery. In the laser group, diode laser therapy with a wavelength of 860 nm and a power of 100 mW was applied immediately after the surgery on the surgery day and three and seven days after the surgery. In the control group, the laser was turned off, and passive radiation was applied to the area as the test group for 30 seconds per session in non-contact mode. The pain was assessed by a visual analog scale (VAS) questionnaire on the study timelines. Data were analyzed with SPSS 20 using ANOVA and post hoc Tukey tests. Twenty patients were included in each study group, where the pain was relieved significantly over time. On the first (5.50±1.18) and seventh (1.8±0.42) days, the pain intensity was similar in the test and control groups. However, on the third day, the laser group (2.90±0.74) experienced a significantly lower pain intensity than the control group (4.0±0.67). Photobiomodulation relieved pain after clinical crown lengthening surgeries. The indications of this surgery are subgingival decay or broad decay that shortens the tooth length, fractures, and premature eruption of the anatomical tooth crown. Various techniques such as gingivectomy, undisplaced flap with/without bone surgery, apical resected flap with/without bone resection, and forced eruption with/without fiberotomy have been proposed for crown lengthening procedures. Selecting the technique depends on various factors like esthetics, crown-to-root ratio, root morphology, furcation and tooth location, and reconstruction possibility. Crown lengthening procedures have become an essential part of aesthetics, as they are widely used to enhance the esthetics and restorations in the esthetic area.The crown lengthening surgery is a technique to expose more tooth surfaces for esthetic or reconstruction purposes through lowering the gingival or bone tissue apically. A part of the patient’s pain and discomfort is associated with his mental status before the surgery and expectations. This also depends on the surgery duration, which can intensify the patient’s stress and anxiety, leading to more severe pain.Compared to bone surgeries, pure mucogingival procedures result in more pain. The technical differences between the procedures with varying exposure levels of bone connective tissue can lead to differences in postoperative pain intensities. Wide surgeries are associated with more pain than less invasive surgeries.Photobiomodulation (PBM) has been applied in dentistry for various purposes, including wound treatment, aphthous stomatitis, mucositis, nerve regeneration, postherpetic neuralgia (PHN), synovitis, arthritis, temporomandibular joint pathologies, acute abscesses, peripheral granuloma, chronic orofacial pains, and bone regeneration. The analgesic effects of PBM are due to stimulating the synthesis of androgenic endorphins like beta-endorphin, reducing cytokines, and inflammatory enzymes, pain threshold shift, morphological changes in neurons, reduced mitochondrion membrane potential, and blocking the fast axon flow, leading to the neural pathway blockage. Its inflammatory impact occurs because of the increased activity of phagocytes, number and diameter of lymphatic vessels, and decreased vessel permeability and micro-capillaries blood circulation, and decreased edemas. Concerning the importance of pain relief in crown lengthening surgery, this study investigated the impact of PBM on pain intensity after clinical crown lengthening procedures.Previous studies investigated the impact of PBM on the gingival regeneration after gingivectomy procedures, concluding that such laser therapy can enhance wound healing after gingivectomy.This single-blind clinical trial was registered in the Iranian Center of Randomized Controlled Trials with an IRCT code of 20180114038364N1 and confirmed by the Ethics Committee of Tabriz University of Medical Sciences (IR.TBZMED.REC.1398.1299). Twenty patients referring to the Department of Periodontics, Tabriz Faculty of Dentistry, for crown lengthening surgery, who met the inclusion and exclusion criteria, were selected.Patients aged 1860 with no systemic disease were randomly assigned to two groups (n=10). The flap technique was used for crown lengthening surgeries, and all the surgeries were performed by a skilled surgeon by observing all surgery principles. The patients were blinded to the intervention type.2 immediately after the surgery on the surgery day and three and seven days after surgery. For the control group, the laser was turned off, and passive irradiation was carried out on the given area. Patients in both groups were visited on the first, third, and seventh days. The laser irradiation duration was 30 seconds per session. All the laser therapy processes were carried out by meeting the laser safety guidelines.The test group was treated by the photobiomodulation with GaAlAs laser  in non-contact mode with a wavelength of 860 nm, a power of 100 mW, and an energy density of 3 J/cmThe patient’s pain status was assessed by the visual analog scale (VAS) questionnaire up to the seventh day after the surgery. Painkillers were prescribed for all the patients for one week .In this study, 20 patients were studied in two groups: control and intervention. The frequency of males and females in the laser  and control groups  was the same. In addition, the mean age in the control group was 31.2±5.4, with no significant difference from the laser group.The results showed that on the first day, pain intensity in both the control (6.2±0.79) and intervention (5.50±1.18) groups was similar. On the third day, pain intensity in the intervention group (2.90±0.74) was significantly lower than the control group (4.0±0.67). On the seventh day, the control group (2.0±0.67) experienced the same level of intensity as the laser group (1.8±0.42). Based on the Friedman test, the pain intensity decreased significantly over time in both groups .The mean use of painkillers on the first, third, and seventh days was the same in both the control and intervention groups, with no significant difference . AccordiIn this study, pain intensity in both the control and laser groups had a significantly decreasing trend until the seventh day after surgery. It was also the same on the first and seventh days for both groups. However, on the third day, the pain intensity in the laser group was significantly lower than in the control group. The number of painkillers taken was similar in both groups. On the seventh day, 80% of patients in both groups took no painkillers. pain intensity in the periodontal flap surgery on the second, third, fourth, fifth, sixth, and seventh days after surgery was lower in the laser group. Furthermore, these patients took fewer painkillers during these days, consistent with the present study since we observed significant pain relief on the third day.In a study by Heidari et al, reported that the low-level laser could be effective in pain relief by reducing the biochemical markers, oxidative stress, and edema, which itself depends on the dose (effective dose range from 0.3 to 19 J/cm2 with a mean dose of 7.5 J/cm2). Furthermore, they reported that the analgesic impact of low-level laser is higher when it is irradiated with high density in the first 72 hours after surgery, which should continue with lower doses to accelerate regeneration. Studies by Lingamaneniet al and Kohale et al revealed that laser therapy could enhance wound healing after gingivectomy. Each researcher applied a different laser (InGaAsP) and obtained the same results.In a systematic review, Bjordal et al Regarding the various stages of wound healing, photobiomodulation seems to be more effective in the fibroblastic phase of wound healing, including excessive fibroblast activity, angiogenesis, and epithelial proliferation. Effects of photobiomodulation on the fibroblast, including increased proliferation, increased growth factor secretion, and conversion into myofibroblasts, have already been observed in previous studies.Wound healing is a complicated and dynamic process with three overlapping phases. The first phase, or inflammatory phase, begins with tissue injury. The second phase, or the fibroblastic phase, includes the production of tropocollagen and collagen by fibroblasts. The final phase or remodeling lasts from months to years. In this stage, the irregular collagen fibers are removed and replaced by highly regular new fibers. reported pain relief by photobiomodulation in treating radiotherapy-induced mucositis in patients with maxillofacial cancers. Aras et al showed the impact of laser on reducing trismus and inflammation resulting from the impacted wisdom tooth surgery. Lioubavina-Hack et al presented a report on the effect of laser therapy on reducing the initial level of periodontal pathogens. Mechanisms of treatment by photobiomodulation are sophisticated, but they are necessarily dependent on the absorption of special visible red and near-to-infrared wavelengths in the photoreceptors of sub-cellular elements, particularly the electron transport chain (respiratory) in mitochondria. Photobiomodulation is a red or infrared light that stimulates the proliferation of fibroblasts through non-thermal effects. The possible mechanisms involved in pain relief are the stability of neural cell membrane, increased cell regeneration system, and increased ATP production. However, a study showed that this treatment method has no significant impact. In this regard, Heidari et al reported that laser photobiomodulation (PBM) has no impact on reducing free gingival graft (FGG). A low number of studied patients is among the reasons for differences in the results. Small size leads to the lack of reasonable certainty in the results. Age and gender are also among the variables affecting pain.Numerous studies have reported the impact of lasers on pain relief or wound regeneration. Carvalho et al2 immediately after surgery and on days 3 and 7 after surgery, as an adjunct, had limited effect on pain relief after clinical crown lengthening surgeries.Photobiomodulation (with GaAlAs laser) with a wavelength of 860 nm, a power of 100 mW, and an energy density of 3 J/cmMF and MS planned the study. Data collection was carried out by SR. Statistical analyses and interpretation of data were carried out by RCH, MGH, and SR. The manuscript was prepared by RCH and MGH and revised by MS. All the authors have read and approved the final manuscript for submission.The study protocol was approved by the Ethics Committee on Medical Research, Tabriz University of Medical Sciences.The authors declare that they have no competing interests regarding authorship and/or publication of this paper.


This meta-analysis comprehensively evaluated the association between hypertensive disorders in pregnancy (HDP) and the risk of developing chronic hypertension and the associations between specific types of HDP, including preeclampsia (PE) and gestational hypertension (GH), and the risk of developing chronic hypertension.Systematic review and meta-analysis.The PubMed, Embase and Cochrane Library databases were searched from inception to August 20, 2021.Depending on heterogeneity, the combined odds ratio (OR) of the 95% confidence interval (CI) was obtained with a random-effects or fixed-effects model. We used meta-regression analysis to explore the sources of heterogeneity. We analyzed the OR value after adjusting for age and BMI at recruitment, prepregnancy BMI, age at first delivery, and other factors. Additionally, we evaluated the results of the subgroup analysis by the year of publication , study design, sample size , region  and NOS score .Our systematic review and meta-analysis comprehensively explored the relationships between HDP, GH, and PE and chronic hypertension. Twenty-one articles that included 634,293 patients were included. The results of this systematic review and meta-analysis suggested that women with a history of HDP are almost 3.6 times more likely to develop chronic hypertension than those without a history of HDP, women with a history of GH are almost 6.2 times more likely to develop chronic hypertension than those without a history of GH, and women with a history of PE are almost 3.2 times more likely to develop chronic hypertension than those without a history of PE. In addition, we further calculated the probability of developing chronic hypertension among patients with HDP or PE after adjusting for age and BMI at recruitment, prepregnancy BMI, age at first delivery, and other factors. The results suggested that women with a history of HDP are almost 2.47 times more likely to develop chronic hypertension than those without a history of HDP and that women with a history of PE are almost 3.78 times more likely to develop chronic hypertension than those without a history of PE. People in Asian countries are more likely to develop chronic hypertension after HDP or PE, while American people are not at high relative risk.These findings suggest that HDP, GH, and PE increase the likelihood of developing chronic hypertension. After adjustment for age and BMI at recruitment, prepregnancy BMI, age at first delivery, and other factors, patients with HDP or PE were still more likely to develop chronic hypertension. HDP may be a risk factor for chronic hypertension, independent of other risk factors. GH and PE, as types of HDP, may also be risk factors for chronic hypertension.www.ClinicalTrials.gov], identifier [CRD42021238599].[ Hypertension is one of the most common conditions that occur during pregnancy and the main cause of maternal death . Ten perStudies have shown that women with preeclampsia have a higher risk of developing chronic hypertension. Indeed, comprehensive data show that 20% of women with eclampsia develop hypertension within 15 years . HoweverThis systematic review and meta-analysis assessed recent reports to explore the association between HDP and chronic hypertension and evaluate the associations between specific types of HDP, including preeclampsia (PE), and gestational hypertension (GH), and the risk of developing chronic hypertension. We analyzed both crude and adjusted OR values to better determine the relationships between the variables and the stability of the results. We also conducted subgroup analysis by country and year to analyze the relationship between HDP and chronic hypertension.This systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines .This review was based on a prior design recommended by a systematic review and meta-analysis. The PubMed, EMBASE, and Cochrane Library databases were searched electronically in August 2021 using a combination of terms, keywords and word variants related to the medical subject headings (MeSH) “hypertension, pregnancy,” “preeclampsia,” “eclampsia” and “hypertension.” We used Endnote x9 to remove duplicate articles and then browsed the titles and summaries to exclude unrelated articles. Reviews, meta-analyses, articles lacking relevant data, letters and abstracts were excluded. There were no time or language restrictions. The reference lists of relevant articles and comments were manually searched for additional reports. The study was registered in the Prospero database (Registration number: CRD42021238599).The main outcome was the incidence rate of chronic hypertension in patients with HDP or with the specific types PE and GH. We included case–control studies and cohort studies that provided data on how many patients developed hypertension several years after delivery. The research period of the different studies varied: the span was large, and the time period ranged from 1 to 30 years. Hypertension was defined as a systolic blood pressure (SBP) ≥ 140 mmHg and/or a diastolic blood pressure (DBP) ≥ 90 mmHg occurring more than once in a clinical environment. The use of antihypertensive drugs and lower thresholds for defining hypertension were also included in the diagnostic criteria. When data were available, only patients affected by HDP, PE, and GH were considered in the analysis. We excluded studies in which chronic hypertension was present before pregnancy or before 20 weeks of gestation. If a study included patients with chronic hypertension, we considered only the articles that provided the number of patients with chronic hypertension. In addition, we did not include articles about the incidence rate of postpartum hypertension within 1 year of delivery.Two researchers, Xu and Wang, independently performed all abstract screenings. The two researchers retrieved and independently evaluated the full texts of potentially eligible studies. Any inconsistencies or differences were discussed with a third reviewer, and a consensus was reached. Several articles were translated into languages other than English to determine whether they were suitable for inclusion. The reviewers extracted data on the study characteristics and results, especially the author, year, location, study type, population size, and reported results. If multiple studies with the same endpoint were published for the same cohort, the report containing the most comprehensive population information was used to avoid population overlap.The quality of the included studies was assessed using the Newcastle–Ottawa Scale (NOS) for cohort and case–control studies, which was developed by Schokker et al. to assess the quality of non-randomized studies . With th2 ≥ 50%. Otherwise, we used a random-effects model. Sensitivity analysis was used to explore the robustness of the included literature. Publication bias was assessed by funnel plots and linear regression equations. If the funnel plot was obviously asymmetric, we further used the trim-and-fill method to adjust the data. In addition, meta-regression analysis was performed based on the publication year, NOS score, status, sample size, and study design to explore the sources of heterogeneity. All analyses were conducted via R version 3.6. The critical value for statistical significance was set as P < 0.05.We constructed forest plots to obtain pooled ORs and 95% CIs. We applied a fixed-effects model to calculate the combined effect estimate if ITo obtain relevant literature, we searched the PubMed, Embase and Cochrane Library databases from inception to August 20, 2021. A total of 57,194 studies were obtained . After rThe 21 studies included in this systematic review and meta-analysis varied in study design, year of publication, NOS score, country, and sample size. All studies were observational; 12 were described as cohort studies, eight as case–control studies and one as a cross-sectional study. The publication dates of these articles ranged from 2000 to 2021. Among these articles, the study areas included Europe for seven studies, North and South America for nine studies, and other regions for five studies. The smallest sample size was 28 , and theI2 = 96% (P< 0.01), so we chose to use a random-effects model. The overall combined effect showed that HDP patients had a higher risk of developing chronic hypertension than healthy controls . We also calculated the GH and PE results and chose to use random-effects models . Women with GH or PE were at higher risk of developing chronic hypertension than healthy controls  (As shown in 52–6.70) .Some articles reported adjusted OR values for age and BMI at recruitment, prepregnancy BMI, age at first delivery and other factors. We further evaluated the associations between HDP, GH, and PE and chronic hypertension based on the adjusted OR values.I2 = 90%, OR = 3.78, 95% CI 2.05–6.98)  , and the05–6.98) .P = 0.4639) and PE (P = 0.5380) had no publication bias . Other factors showed no significant effect on the heterogeneity in the HDP group. The publication year and study design may be the sources of heterogeneity for the experimental results. None of the factors showed a significant effect on the heterogeneity in the PE group , study design, region , sample size  and NOS score  to further evaluate the correlations between HDP, GH, and PE and the risk of chronic hypertension. The subgroup analyses showed some inconsistencies; some of them seemed reasonable, while others did not.I2 = 49%) was found for the risk of developing postpartum hypertension among women with a history of HDP. According to the subgroup analysis, the risk of chronic hypertension in patients with HDP increased for different continents, but there were differences among the continents (P = 0.03). The increased risk in North and South America was the lowest , and the risk in Europe was the highest , while the risk in Asia was similar to the overall assessment     . Accordi62–7.16) . Grouped62–7.16) . Accordi94–9.33) .I2 = 97%), and women with a history of PE had a greater risk of developing postpartum hypertension than women without PE. The increased risks in the Americas and Europe were similar to the overall risk , while the risk of developing chronic hypertension in Asia was significantly increased     . Accordi21–9.53) . Grouped21–9.53) . The OR 21–9.53) . Accordi7, 7.45) .Our systematic review and meta-analysis comprehensively explored the associations of HDP, GH, and PE with chronic hypertension. We included 21 articles with a total of 634,293 patients. The results of this systematic review and meta-analysis suggested that women with a history of HDP are almost 3.6 times more likely to develop chronic hypertension than those without a history of HDP, women with a history of GH are almost 6.2 times more likely to develop chronic hypertension than those without a history of GH, and women with a history of PE are almost 3.2 times more likely to develop chronic hypertension than those without a history of PE. In addition, we further calculated the probability of developing chronic hypertension among patients with HDP or PE after adjusting for age and BMI at recruitment, prepregnancy BMI, age at first delivery and other factors. The results suggested that women with a history of HDP were almost 2.47 times more likely to develop chronic hypertension than those without a history of HDP and that women with a history of PE were almost 3.78 times more likely to develop chronic hypertension than those without a history of PE . The aboOur systematic review illustrates the risk of developing chronic hypertension among pregnant women with HDP, GH and PE. Although the evidence linking pregnancy-induced hypertension with the development of hypertension has been recognized, there are still many outstanding problems in a number of specific aspects .In 2007, a systematic review and meta-analysis showed that preeclampsia patients had more than three times the risk of developing hypertension  than those without preeclampsia; the follow-up time was adjusted to 14.1 years . SubsequThe advantage of our study is that a large number of articles were selected, and the sample size was large. We not only studied the possibility of HDP leading to chronic hypertension but also accounted for the relevant data on various types of HDP and finally chose to analyze the large amount of relevant data for PE and GH. We also performed subgroup analysis  to analyze the sources of heterogeneity and the probability of developing chronic hypertension in each subgroup. In addition, we further calculated the probability of developing chronic hypertension for patients with HDP or PE after adjusting for age and BMI at recruitment, prepregnancy BMI, age at first delivery and other factors. In general, we carried out statistical analysis on all aspects of the obtained data that could be analyzed.However, there are still some limitations of this study, which need further study. There are few studies with high scores. The ages of patients with HDP and chronic hypertension were not statistically analyzed because the data were seriously lacking, which may be the reason for the high heterogeneity. The published literature is insufficient to determine the best screening period for postpartum detection of hypertension. We could not determine an observation age or follow-up period to limit the screening of the articles. The heterogeneity of the population and hypertension definitions and the failure to obtain sufficient details make the results of the meta-analysis misleading, and they could not be adjusted using statistical tests.HDP, GH, and PE increase the likelihood that patients will develop chronic hypertension. After adjustment for age and BMI at recruitment, prepregnancy BMI, age at first delivery and other factors, patients with HDP or PE were still more likely to develop chronic hypertension. HDP, GH, and PE may be risk factors for chronic hypertension, independent of other risk factors.The original contributions presented in this study are included in the article/supplementary material, further inquiries can be directed to the corresponding author/s.JX, TL, and YW: study design, data extraction, statistical analysis, and manuscript writing. LX, ZM, WL, and KX: study design, data extraction, and verification. CH and HD: study design, statistical analysis, manuscript editing and reviewing, and funding. All authors contributed to the article and approved the submitted version.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.


Cardiac rehabilitation (CR) barriers are well-understood in high-resource settings. However, they are under-studied in low-resource settings, where access is even poorer and the context is significantly different, including two-tiered healthcare systems and greater socioeconomic challenges.To investigate differences in characteristics of patients attending publicly versus privately funded CR and their barriers to adherence.Observational, cross-sectional study in public and private CR programs offered in Brazil.Patients who had been attending CR for ≥ 3 months were recruited from one publicly and one privately funded CR program. They completed assessments regarding sociodemographic and clinical characteristics and the CR Barriers Scale.From the public program, 74 patients were recruited, and from the private, 100. Participants in the public program had significantly lower educational attainment (P < 0.001) and lower socioeconomic status (P < 0.001). Participants in the private program had more cognitive impairment (P = 0.015), and in the public program more anxiety (P = 0.001) and depressive symptoms (P = 0.008) than their counterparts. Total barriers among public CR participants were significantly higher than those among private CR participants , as were scores on 3 out of 5 subscales, namely: comorbidities/functional status (P = 0.027), perceived need (P < 0.001) and access (P = 0.012).Publicly funded programs need to be tailored to meet their patients’ requirements, through consideration of educational and psychosocial matters, and be amenable to mitigation of patient barriers relating to presence of comorbidities and poorer health status. However, barriers in lower-resource settings have not been well-studied. A recent review identified only 13 studies globally,11 and there are also few studies in South America12 or Brazil to date.16 This is problematic, given the different contexts in these settings. Firstly, patients would be more socioeconomically disadvantaged, and hence face different barriers. Secondly, healthcare systems are more often two-tier.17 So, for example, half of CR programs in Brazil are solely publicly-funded (53.3%), a third privately-funded, and the remainder a mixture.18 It has been established that CR funding sources affect program characteristics, such as scale, healthcare providers on the team and component comprehensiveness.17 However, to our knowledge, it has yet to be investigated how barriers might differ for patients accessing privately and publicly-funded programs in any country worldwide.19The reasons for underuse of CR have been well-characterized in high-resource settings20 and offering privately funded programs may enable greater availability, the CR community needs to consider the inequities that this might raise.Therefore, the objectives of this study were to compare: (1) the sociodemographic and clinical characteristics of patients accessing publicly versus privately funded CR programs; and (2) multi-level barriers to adherence in each of these types of programs. While the world needs more CR,This was an observational cross-sectional study. Participants signed an informed consent statement. The local ethics committee approved all procedures on June 28, 2018 (CAAE number: 88504718.0.0000.5402).A convenience sample was recruited between March and August 2019. Participants in the public or private CR programs offered in the city of Presidente Prudente, São Paulo, Brazil, were approached with a view to inviting them to take part in this study and undergo assessments. These assessments were administered by physiotherapists who were not part of the programs.The publicly funded CR program for this study is offered by the Cardiology Division of the Center for Studies and Attendance in Physiotherapy and Rehabilitation, School of Technology and Sciences, Universidade Estadual Paulista (UNESP), Presidente Prudente, São Paulo, Brazil. The CR program is funded by the Brazilian National Health System and is delivered through the physiotherapy program. The program is indefinite in length (i.e. phase II and maintenance).21 Most patients who use the private program have a health plan, for which they pay a monthly fee. This health plan covers 36 sessions, after which it is necessary to request coverage of further sessions if the doctor perceives more are required. When the patient does not have a health plan, they pay out-of-pocket monthly (R$ 390.00).The privately funded CR program is offered through the city's Heart Institute. The program is funded by the patient or through medical health insurance .To start either program, patients require a written medical referral. The public program offers sessions three times/week, while the private program offers two to three per week, depending on the patient. In both programs, exercises are performed in groups; the public program serves on average 18 patients/session and the private one, 12 patients/session. With regard to staffing, in the private program, care is delivered by physiotherapy cardiology specialists; in the public program, care is provided by physiotherapy students supervised by professors.The programs are primarily centered on structured exercises, and the exercise prescriptions are quite consistent between programs: they are based on heart rate reserve, and are re-evaluated each month. Exercises in the public program are done on treadmills and stationary bikes. In the private program, there are also resistance exercises. In addition, in the public program, there are group educational lectures and patients are provided with written materials. In the private program, there is informal counselling regarding risk factor control during the one-to-one sessions only.The inclusion criteria were that the participants needed to be aged over 18 years, with a diagnosis of cardiovascular disease or with cardiovascular risk factors (as per the program inclusion criteria), and needed to have been in the CR program for ≥ 3 months (frequency of attendance was not considered). There were no exclusion criteria.https://sgrace.info.yorku.ca/cr-barriers-scale/crbs-instructions-and-languages-translations/).The independent variable of interest was CR program funding type (public or private), which was coded based on the program attended. For objective one, the participants’ sociodemographic characteristics  and clinical characteristics  were first assessed. The participants then completed psychometrically-validated scales assessing factors that are known to impact CR access and which may be particularly important in lower-resource settings, along with the CR Barriers Scale  was administered. This asks about education level, family income, possession of certain items (e.g. number of televisions) and services offered in patients’ homes.23 was used. The test scores were adjusted based on level of education24 and categorized based on the presence of any cognitive impairment (e.g. participants who had four years of education and scored less than 25 were considered at least mildly cognitively impaired).To evaluate cognitive function, the psychometrically validated Brazilian-Portuguese version of the Mini-Mental State Examination (MMSE)25 was administered.To quantify mental health symptoms, the psychometrically validated Brazilian-Portuguese version of the Hospital Anxiety and Depression Scale (HADS)13 This assesses patient perceptions of 21 barriers at the healthcare system, healthcare provider and patient levels on a scale from 1 (“strongly disagree”) to 5 (“strongly agree”). Higher scores indicate higher barriers to CR adherence.26 A total mean score is computed, and there are five subscales: comorbidities/functional status, perceived need, personal/family issues, travel/work conflicts and access.Lastly, CR barriers were assessed in relation to the second objective. The psychometrically validated Brazilian-Portuguese version of the Cardiac Rehabilitation Barriers Scale (CRBS) was administered.To investigate differences in patient characteristics and barriers between participants attending public versus private programs, Fisher's exact tests or independent-sample t tests were used , as appropriate. Statistical significance was set at 5%. The analyses were performed using the IBM Statistical Package for the Social Sciences (SPSS) software, version 22.0 .During the period of this study, 178 patients were approached, of whom 174 (97.75%) participated; 57.5% were from the private program. The sample characteristics are shown in With regard to sociodemographic characteristics, the participants in the public program had significantly lower educational attainment and lower socioeconomic status (plus a trend regarding work status). With regard to clinical characteristics, the participants in the private program had more cognitive impairment, and in the public program more anxiety and depressive symptoms than their counterparts. Participants were in the public program for significantly longer durations than those in the private program. Moreover, the total barriers were higher, the longer the participants were in the program .As shown in As also shown in 11 In many of these countries, the healthcare systems are two-tier. It is known that there may be differences in program quality, and that there are significant differences in cost according to funding source,17 yet to our knowledge there has been no investigation of how this impacts patients. In this study, we began to investigate differences in the nature of patients accessing these programs, and how their barriers to adherence might differ, and indeed some important differences emerged.There have been few studies on CR barriers outside of Western, high-income settings.27It was promising to observe fewer differences than expected, in the characteristics of those accessing a publicly funded program rather than a privately funded program. For instance, there were no differences with regard to sex, age or diagnostic indication. As expected, the chief differences were socioeconomic, which are likely to explain the differences in mental health as well as cognition.28 They would also want to ensure that they have staff who can assess and treat mental health issues, or have a close relationship with a referral source that does not have a long waitlist. Private programs could serve as important settings where patients who need more staff time could safely receive CR. If so, staff would need to have specialized training to successfully work with these patient groups.The differences in the nature of patients accessing public or private programs, if replicated, hold implications for program delivery. Public programs would need to consider the health literacy of their patients, and tailor their educational programming accordingly.32 Overall, the barriers were low, which was consistent with other CRBS studies in enrollees.33 This was to be expected, given the sample was composed of patients who had already completed ≥ 3 months of CR. Still, the patients accessing public programs did report significantly more barriers to adherence than did their counterparts in private programs. Socioeconomic differences in the cohorts do seem to explain the differences; for example, factors such as transportation costs, distance, time constraints and not getting support from healthcare providers to attend were more strongly endorsed by patients in the public than in the private system. Efforts to tackle the social determinants of health continue to be needed.The top barriers observed here were consistent with those reported in other studies, in Brazil, South America and beyond.34 This study was also limited to participants who had been able to access CR and had adhered to the program for ≥ 3 months. Arguably these participants were among the few who had been able to successfully access and adhere to CR, even in a low-resource setting. In future studies, the barriers among participants should be investigated at the time of diagnosis ,18 as well as very early in their program. Lastly, the sample size was modest, and this was the first study examining these differences. Therefore, replication is warranted prior to implementing any changes based on these preliminary findings.Caution is warranted when interpreting these results. Their generalizability is limited, particularly given that we sampled from only one public and one private program. Moreover, the programs were of long duration, compared with other programs internationally.In summary, as expected, but for the first time, we have shown that within a two-tier healthcare system in a lower-resource setting, patients accessing publicly funded CR programs are of significantly lower socioeconomic status and have poorer mental health and cognitive ability than those accessing privately funded programs. Publicly funded programs will need to tailor their delivery to meet the needs of their patients through educational and psychosocial programming. While referral and time conflicts remain key barriers in these settings, once patients do access CR, the barriers are greater for those in publicly funded programs than in privately funded ones, particularly with regard to comorbidities/functional status, perceived need and access.