Mediation of metabolic syndrome in the association between long-term exposure to particulate matter and incident cardiovascular disease: Evidence from a population-based cohort in Chengdu.

BACKGROUND: Particulate matter (PM) exposure has been linked with cardiovascular disease (CVD) and metabolic syndrome (MetS), the latter characterized by concurrent multiple metabolic disorders. As a result, the mechanisms assumption from PM to CVD through MetS have emerged, thus requiring further epidemiological evidence. This cohort study aimed to assess whether MetS mediates the associations of PM with CVD risk. METHODS: This study included 14,195 participants from the Chengdu cohort of the China Multi-Ethnic Cohort (CMEC) study in 2018. The primary outcome of incident CVD diagnoses was identified using matched hospital records from the Health Information Center of Sichuan Province. Residence-specific levels of PM with aerodynamic diameters of ≤ 1 µm (PM1), ≤ 2.5 µm (PM2.5), and ≤ 10 µm (PM10) were estimated by spatiotemporal models. Causal mediation analyses were applied to evaluate the indirect effect of MetS. RESULTS: Increased exposure levels to PM were significantly associated with MetS and CVD. Mediation analyses indicated that the associations between PM exposure and CVD were mediated by MetS, with the proportion of multiple mediations being 19.3%, 12.1%, and 13.5% for PM1, PM2.5, and PM10, respectively. Further moderated mediation analyses suggested that male, overweight individuals, alcohol drinkers, and those suffering from indoor air pollution may experience more significant adverse effects from PM exposure on CVD via MetS than others. CONCLUSIONS: Our findings suggest that MetS partially mediates the association between long-term exposure to PM and CVD. These mediation effects appear to be amplified by demographic characteristics and unhealthy lifestyles.

The association between chemical constituents of ambient fine particulate matter and obesity in adults: A large population-based cohort study.

OBJECTIVES: Current evidence demonstrated that ambient fine particulate matter with an aerodynamic diameter ≤2.5 µm (PM2.5) and its constituents may be obesogenic in children, but evidence from adults is lacking. Our aim was to characterize the association between PM2.5 and its constituents and obesity in adults. METHODS: We included 68,914 participants from the China Multi-Ethnic Cohort (CMEC) baseline survey. Three-year average concentrations of PM2.5 and its constituents were evaluated by linking pollutant estimates to the geocoded residential addresses. Obesity was defined as body mass index (BMI) ≥ 28 kg/m2. Logistic regression was used to examine the relationship between PM2.5 and its constituents and obesity. We performed weighed quantile sum (WQS) regression to get the overall effect of PM2.5 and its constituents and the relative contribution of each constituent. RESULTS: Per-SD increase in PM2.5 (odds ratio [OR] = 1.43, 95% confidence interval [CI]: 1.37-1.49), black carbon (BC) (1.42, 1.36-1.48), ammonium (1.43, 1.37-1.49), nitrate (1.44, 1.38-1.50), organic matter (OM) (1.45, 1.39-1.51), sulfate (1.42, 1.35-1.48), and soil particles (SOIL) (1.31, 1.27-1.36) were positively associated with obesity, and SS (0.60, 0.55-0.65) was negatively associated with obesity. The overall effect (OR = 1.34, 95% CI: 1.29-1.41) of the PM2.5 and its constituents was positively associated with obesity, and ammonium made the most contribution to this relationship. Participants who were older, female, never smoked, lived in urban areas, had lower income or higher levels of physical activity were more significantly adversely affected by PM2.5, BC, ammonium, nitrate, OM, sulfate and SOIL compared to other individuals. CONCLUSION: Our study revealed that PM2.5 constituents except SS were positively associated with obesity, and ammonium played the most important role. These findings provided new evidence for public health interventions, especially the precise prevention and control of obesity.

Long-term exposure to ambient PM2.5 constituents is associated with dyslipidemia in Chinese adults.

BACKGROUND: Ambient particulate matter with aerodynamic diameter ≤ 2.5 µm (PM2.5) consists of various toxic constituents. However, the health effect of PM2.5 may differ depending on its constituents, but the joint effect of PM2.5 constituents remains incompletely understood. OBJECTIVE: Our goal was to evaluate the joint effect of long-term PM2.5 constituent exposures on dyslipidemia and identify the most hazardous chemical constituent. METHODS: This study included 67,015 participants from the China Multi-Ethnic Cohort study. The average yearly levels of PM2.5 constituents for all individuals at their residences were assessed through satellite remote sensing and chemical transport modeling. Dyslipidemia was defined as one or more following abnormal blood lipid concentrations: total cholesterol (TC) ≥ 6.22 mmol/L, triglycerides (TG) ≥ 2.26 mmol/L, high-density lipoprotein cholesterol (HDL-C) < 1.04 mmol/L, and low-density lipoprotein cholesterol (LDL-C) ≥ 4.14 mmol/L. The logistic regression model was utilized to examine the single effect of PM2.5 constituents on dyslipidemia, while the weighted quantile sum regression model for the joint effect. RESULTS: The odds ratio with a 95 % confidence interval for dyslipidemia positively related to per-SD increase in the three-year average was 1.29 (1.20-1.38) for PM2.5 mass, 1.25 (1.17-1.34) for black carbon, 1.24 (1.16-1.33) for ammonium, 1.33 (1.24-1.43) for nitrate, 1.34 (1.25-1.44) for organic matter, 1.15 (1.08-1.23) for sulfate, 1.30 (1.22-1.38) for soil particles, and 1.12 (1.05-1.92) for sea salt. Stronger associations were observed in individuals < 65 years of age, males, and those with low physical activity. Joint exposure to PM2.5 constituents was positively related to dyslipidemia (OR: 1.09, 95 %CI: 1.05-1.14). Nitrate was identified as the constituent with the largest weight (weighted at 0.387). CONCLUSIONS: Long-term exposure to PM2.5 constituents poses a significant risk to dyslipidemia and nitrate might be the most responsible for the risk. These findings indicate that reducing PM2.5 constituent exposures, especially nitrate, could be beneficial to alleviate the burden of disease attributed to PM2.5-related dyslipidemia.

Ambient PM2.5 and its components associated with 10-year atherosclerotic cardiovascular disease risk in Chinese adults.

BACKGROUND: Exposure to particulate matter with aerodynamic diameters less than 2.5 µm (PM2.5) may increase the risk of 10-year atherosclerotic cardiovascular disease (ASCVD) risk. While PM2.5 is comprised of various components, the evidence on the correlation of its components with 10-year ASCVD risk and which component contributes most remains limited. METHODS: Data were derived from the baseline assessments of China Multi-Ethnic Cohort (CMEC). In total, 69,722 individuals aged 35-74 years were included into this study. The annual average concentration of PM2.5 and its components (black carbon, ammonium, nitrate, sulfate, organic matter, soil particles, and sea salt) were estimated by satellite remote sensing and chemical transport models. The ASCVD risk of individuals was calculated by the equations from the China-PAR Project (prediction for ASCVD risk in China). The relationship between single exposure to PM2.5 and its components and predicted 10-year ASCVD risk was assessed using the logistic regression model. The effect of joint exposure was estimated, and the most significant contributor was identified using the weighted quantile sum approach. RESULTS: Totally 69,722 participants were included, of which 95.8 % and 4.2 % had low and high 10-year ASCVD risk, respectively. Per standard deviation increases in the 3-year average concentration of PM2.5 mass (odds ratio [OR] 1.23, 95 % confidence interval [CI]: 1.12-1.35), black carbon (1.21, 1.11-1.33), ammonium (1.21, 1.10-1.32), nitrate (1.25, 1.14-1.38), organic matter (1.29, 1.18-1.42), sulfate (1.17, 1.07-1.28), and soil particles (1.15, 1.04-1.26) were related to high 10-year ASCVD risk. The overall effect (1.19, 1.11-1.28) of the PM2.5 components was positively associated with 10-year ASCVD risk, and organic matter had the most contribution to this relationship. Female participants were more significantly impacted by PM2.5, black carbon, ammonium, nitrate, organic matter, sulfate, and soil particles compared to others. CONCLUSION: Long-term exposure to PM2.5 mass, black carbon, ammonium, nitrate, organic matter, sulfate, and soil particles were positively associated with high 10-year ASCVD risk, while sea salt exhibited a protective effect. Moreover, the organic matter might take primary responsibility for the relationship between PM2.5 and 10-year ASCVD risk. Females were more susceptible to the adverse effect.

Bayesian borrowing from historical control data in a vaccine efficacy trial.

In the context of vaccine efficacy trial where the incidence rate is very low and a very large sample size is usually expected, incorporating historical data into a new trial is extremely attractive to reduce sample size and increase estimation precision. Nevertheless, for some infectious diseases, seasonal change in incidence rates poses a huge challenge in borrowing historical data and a critical question is how to properly take advantage of historical data borrowing with acceptable tolerance to between-trials heterogeneity commonly from seasonal disease transmission. In this article, we extend a probability-based power prior which determines the amount of information to be borrowed based on the agreement between the historical and current data, to make it applicable for either a single or multiple historical trials available, with constraint on the amount of historical information to be borrowed. Simulations are conducted to compare the performance of the proposed method with other methods including modified power prior (MPP), meta-analytic-predictive (MAP) prior and the commensurate prior methods. Furthermore, we illustrate the application of the proposed method for trial design in a practical setting.

Extending the two-stage single arm phase II clinical trial design to the delayed response scenario.

Two-stage single arm designs are widely used in phase II clinical trials with binary endpoints. The trial may be stopped early due to insufficient positive responses in the first stage. There may be some enrolled subjects who have yet to respond by the end of the first stage, and their data are ignored if the first stage results in rejection of the trial. It is possible that the result after the first stage is rejection by a slim margin, while the results of pipeline subjects are quite positive. In this case, combining the data from the two sources may provide a valuable opportunity to rescue a promising treatment that was mistakenly rejected. We propose a novel double-check design to take advantage of the pipeline subjects' data to establish a rescue criterion based on two-stage design. When the rescue criterion is met, the decision to reject the trial at the end of the first stage can be reversed, allowing the trial to continue. A derivation based on a binomial distribution shows that the double-check strategy can strictly preserve the type I error rate. Further examination shows that the strategy can provide a slight increase in overall power and a substantial increase in conditional power when the proportion of positive response at the end of the first stage is at the margin. The extra rescue opportunity's cost is pretty low, only a slight increasing in the expected sample size.

[Ethnic differences in influencing factors of caregivers' first complementary food addition behavior in western rural areas].

OBJECTIVE: To investigate the status quo and influencing factors of the first-time complementary food addition behavior of caregivers in the multi-ethnic background in the western rural areas. METHODS: In 2019, a multi-stage stratified cluster random sampling was used to selecting research subjects in western rural areas. A structured questionnaire was designed by ourselves with literature review and expert consultation method, and information such as sociodemographic characteristics, feeding knowledge, and complementary food addition of 1290 caregivers and infants were collected, ordered multi-classification Logistic regression was used to analyze the influencing factors of the first complementary food addition behavior of the Han nationality and the minority nationality. RESULTS: In the western rural areas, only 8.22% of the caregivers had better behavior of first complementary food addition, and 16.31% of the caregivers in the Han group had a good behavior of first complementary food addition. In the minority population, only 3.64% of infant caregivers had a good behavior of first complementary food addition. In Han, parents, as caregivers, had better first complementary food addition behavior than grandparents(OR=1.7829, 95% CI 1.1651-2.7283). Among ethnic minorities, education(OR=1.753, 95%CI 1.190-2.581), family fixed assets(OR=3.870, 95%CI 1.959-7.645)and feeding knowledge(OR=3.396, 95%CI 2.749-4.195) were the promoting factors for the first complementary food addition behavior. CONCLUSION: In western rural areas, caregivers' behavior of adding complementary food for the first time is generally poor.

[Association of Dietary Diversity with Growth and Development of Children in Multi-ethnic Rural Areas of Sichuan Province].

Objective To understand the growth and dietary diversity status of children in multi-ethnic areas of Sichuan province,and to explore the associations of dietary diversity with growth and development indicators. Methods Children of 18-36 months old and their primary caregivers were selected with multi-stage cluster random sampling method from rural areas of Han,Tibetan,and Yi ethnic groups in Sichuan province. The sociodemographic information of children and their caregivers was collected using self-designed questionnaire.The dietary diversity score(DDS)was calculated according to the criteria in the Guidelines for Measuring Household and Individual Dietary Diversity released by the Food and Agriculture Organization of the United Nations.The body height(length)and body weight of each child were measured by standard equipment for anthropological measurement,and the height for age Z score(HAZ),weight for age Z score(WAZ),and weight for height Z score(WHZ) were calculated.Multivariate linear regression was performed to analyze the relationship between dietary diversity and growth indicators of children. Results A total of 1092 children were enrolled in this study,and the prevalence of stunting(HAZ<-2),underweight(WAZ<-2),and wasting(WHZ<-2)was 21.1%,4.9%,and 2.5%,respectively.The children had the mean DDS of 4.8±1.7,and 45.3% of children had poor dietary diversity(DDS≤4).The children of Han ethnic group(5.8±1.4)had higher DDS than those of Tibetan ethnic group(4.9±1.6)and Yi ethnic group(3.9±1.6)(P<0.001).The results of multivariate linear regression indicated that DDS was positively correlated with HAZ(ß=0.206,95%CI=0.158-0.254,P<0.001)after adjustment of sex,age,birth weight,preterm birth,and parental body height.After further adjustment of family fixed assets,ethnic group,caregiver's type,and caregiver's education background,the correlation between DDS and HAZ remained significant(ß=0.077,95%CI=0.026-0.128, P=0.003). Conclusions The children in the multi-ethnic rural areas of Sichuan province showed troublesome growth and development status and low dietary diversity,which were conspicuously different between ethnic groups,especially in the rural areas of Yi ethnic group.The dietary diversity was positively associated with HAZ.It is recommended to carry out nutrition and health education according to the local dietary characteristics and thus improve the growth and development of children in multi-ethnic rural areas in Sichuan.

Spatiotemporal assessment of health burden and economic losses attributable to short-term exposure to ground-level ozone during 2015-2018 in China.

BACKGROUND: Ground-level ozone (O3) pollution is currently the one of the severe environmental problems in China. Although existing studies have quantified the O3-related health impact and economic loss, few have focused on the acute health effects of short-term exposure to O3 and have been limited to a single temporal and spatial dimension. METHODS: Based on the O3 concentration obtained from ground monitoring networks in 334 Chinese cities in 2015-2018, this study used a two-stage exposure parameter weighted Log-linear exposure-response function to estimate the cause-specific mortality for short-term exposure to O3. RESULTS: The value of statistical life (VSL) method that were used to calculate the economic loss at the city-level. Our results show that in China, the national all-cause mortality attributed to O3 was 0.27(95% CI: 0.14-0.55) to 0.39 (95% CI: 0.20-0.67) million across 2015-2018. The estimated economic loss caused by O3 was 387.76 (95% CI: 195.99-904.50) to 594.08 (95% CI: 303.34-1140.65) billion CNY, accounting for 0.52 to 0.69% of total reported GDP. Overall, the O3 attributed health and economic burden has begun to decline in China since 2017. However, highly polluted areas still face severe burden, and undeveloped areas suffer from high GDP losses. CONCLUSIONS: There are substantial health impacts and economic losses related to short-term O3 exposure in China. The government should pay attention to the emerging ozone pollution, and continue to strengthen the intervention in traditional priority areas while solving the pollution problem in non-priority areas.

Effects of effort-reward imbalance, job satisfaction, and work engagement on self-rated health among healthcare workers.

BACKGROUND: Healthcare workers, who protect and improve the health of individuals, are critical to the success of health systems and achieving national and global health goals. To respond effectively to the healthcare needs of populations, healthcare workers themselves must be in a good state of health. However, healthcare workers face various psychosocial pressures, including having to work night shifts, long working hours, demands of patient care, medical disputes, workplace violence, and emotional distress due to poor interactions with patients and colleagues, and poor promotion prospects. Constant exposure to these psychosocial hazards adversely impacts healthcare workers' health. Consequently, this study aimed to examine the influence of effort-reward imbalance, job satisfaction, and work engagement on self-rated health of healthcare workers. The results would be conducive to providing policy guidance to improve the health of healthcare workers. METHODS: We analysed the data of 1327 participants from The Chinese Sixth National Health and Services Survey in Sichuan Province that was conducted from August 2018 to October 2018. Structural equation modelling was used to test the hypothesized relationships among the variables. RESULTS: Only 40.1% of healthcare workers rated their health as 'relatively good' or 'good'. Effort-reward imbalance had a significant negative correlation with self-rated health (ß = - 0.053, 95% CI [- 0.163, - 0.001]). The associations of effort-reward imbalance and work engagement with self-rated health were both mediated by job satisfaction (95% CI [- 0.150, - 0.050] and [0.011, 0.022]), and work engagement mediated the relationship between effort-reward imbalance and self-rated health (95% CI [- 0.064, - 0.008]). CONCLUSION: In order to improve the health of healthcare workers, administrators should balance effort and reward and provide opportunities for career development and training. In addition, health managers should help healthcare workers realize the significance and value of their work and keep them actively devoted to their work through incentive mechanisms.

Regional-level risk factors for severe hand-foot-and-mouth disease: an ecological study from mainland China.

BACKGROUND: Severe hand-foot-and-mouth disease (HFMD) is a life-threatening contagious disease among young children and infants. Although enterovirus A71 has been well acknowledged to be the dominant cause of severe HFMD, there still remain other unidentified risk factors for severe HFMD. Previous studies mainly focused on identifying the individual-level risk factors from a clinical perspective, while rare studies aimed to clarify the association between regional-level risk factors and severe HFMD, which may be more important from a public health perspective. METHODS: We retrieved the clinical HFMD counts between 2008 and 2014 from the Chinese Center for Disease Control and Prevention, which were used to calculated the case-severity rate in 143 prefectural-level cities in mainland China. For each of those 143 cities, we further obtained city-specific characteristics from the China City Statistical Yearbook (social and economic variables) and the national meteorological monitoring system (meteorological variables). A Poisson regression model was then used to estimate the associations between city-specific characteristics (reduced by the principal component analysis to avoid multicollinearity) and the case-severity rate of HFMD. The above analysis was further stratified by age and gender to examine potential modifying effects and vulnerable sub-populations. RESULTS: We found that the case-severity rate of HFMD varied dramatically between cities, ranging from 0 to 8.09%. Cities with high case-severity rates were mainly clustered in Central China. By relating the case-severity rate to city-specific characteristics, we found that both the principal component characterized by a high level of social and economic development (RR = 0.823, 95%CI 0.739, 0.916) and another that characterized by warm and humid climate (RR = 0.771, 95%CI 0.619, 0.960) were negatively associated with the case-severity rate of HFMD. These estimations were consistent across age and gender sub-populations. CONCLUSION: Except for the type of infected pathogen, the case-severity rate of HFMD was closely related to city development and meteorological factor. These findings suggest that social and environmental factors may also play an important role in the progress of severe HFMD.

Spatio-temporal analysis of socio-economic characteristics for pulmonary tuberculosis in Sichuan province of China, 2006-2015.

BACKGROUND: The disease burden caused by pulmonary tuberculosis (TB) in Sichuan province still persisted at a high level, and large spatial variances were presented across regional distribution disparities. The socio-economic factors were suspected to affect the population of TB notification, we aimed to describe TB case notification rate (CNR) and identify which factors influence TB epidemic are necessary for the prevention and control of the disease in Sichuan province. METHODS: A retrospective cross-sectional study and an ecological spatial analysis was conducted to quantify the presence and location of spatial clusters of TB by the Moran's I index and examined these patterns with socio-economic risk factors by hierarchical Bayesian spatio-temporal model. RESULTS: A total of 630,009 pulmonary TB cases were notified from 2006 to 2015 in 181 counties of Sichuan province. The CNR decreased year by year since 2007, from 88.70 to 61.37 per 100,000 persons. The spatial heterogeneities of CNR were observed during the study periods. Global Moran's I index varied from 0.23 to 0.44 with all P-value < 0.001. The Bayesian spatio-temporal model with parametric spatio-temporal interactions was chosen as the best model according to the minimum of Deviance Information Criterion (DIC)(19,379.01), and in which the quadratic form of time was taken. The proportion of age group and education year were all associated with CNR after adjusting the spatial effect, temporal effect and spatio-temporal interactions. TB CNR increased by 10.2% [95% credible interval (CI): 6.7-13.7%] for every 1-standard-deviation increase in proportion of age group and decreased by 23% (95% CI: 13.7-32.7%) for every 1-standard-deviation increase in education year. CONCLUSIONS: There were spatial clusters of TB notification rate in Sichuan province from 2006 to 2015, and heavy TB burden was mainly attributed to aging and low socioeconomic status including poor education. Thus, it is more important to pay more attention to the elderly population and improve socioeconomic status including promoting education level in Sichuan province to reduce the TB burden.

Estimating health burden and economic loss attributable to short-term exposure to multiple air pollutants in China.

Existing studies focused on the evaluation of health burden of long-term exposure to air pollutants, whereas limited information is available on short-term exposure, particularly in China. Air pollutant concentrations in 338 Chinese cities in 2017 were used to estimate the air pollutants related health burden which was defined as premature mortalities from all-cause, cardiovascular and respiratory disease as well as hospital admissions for cardiovascular and respiratory disease. Log-linear model was used as the exposure-response function to estimate the health burden attributable to each air pollutant. The value of statistical life and cost of illness methods were used to estimate economic loss of the premature mortalities and hospital admissions, respectively. The national all-cause premature mortalities attributable to all air pollutants was 1.35 million, accounting for 17.2% of reported deaths in China in 2017. Among all-cause premature mortality, contributions of PM2.5, PM2.5-10, NO2, SO2, O3 and CO were11.1%, 5.2%, 28.9%, 9.6%, 23.0%, and 22.2%, respectively. The national cardiovascular and respiratory premature mortalities were 0.77 and 0.21 million, respectively. About 7.8 million cardiovascular and respiratory disease hospital admissions were attributed to short-term exposure to all air pollutants. The economic loss of the overall health burden (premature mortality and hospital admissions) was 2065.54 billion Yuan, which was equivalent to 2.5% of the national GDP in 2017. The health burden and economic loss attributable to short-term exposure to ambient air pollutant are substantial in China. It suggested that the adverse health effects attributable to short-term exposure to air pollutant should not be neglected in China. In order to reduce the health impact of air pollution, each city should develop air pollution prevention and control measures based on existing scientific evidence.

Money boys in Chengdu, China: migration, entrepreneurial precarity and health service access.

This qualitative study highlights the complex interplay between the social and structural conditions in Chengdu, China that shape the possibilities and vulnerabilities of money boys' sexual health. Within the context of China's liberalised market economy, we explore (1) how money boys' enter the sex trade market and navigate their sexual networks; (2) how their lives are enmeshed in fields of sexual desire, stigma and coercion; and (3) how the illicit and stigmatising nature of their work poses barriers to health service access. Findings reveal how the sex trade market and clinic are precarious spaces in which entrepreneurial ethics of the self and stigma-related coercive relations simultaneously enable and constrain money boys' sexual freedom and safer sex practices. By understanding this entrepreneurial precarity through the co-articulation of clinical and organisational work spaces, public health and social service providers can have a stronger sense of how various vulnerabilities configure to affect safer sex practices.

Uptake of maternal care and childhood immunization among ethnic minority and Han populations in Sichuan province: a study based on the 2003, 2008 and 2013 health service surveys.

BACKGROUND: China has made remarkable progress in maternal and child health (MCH) over the last thirty years, but socio-economic inequalities persist. Ethnicity has become an important determinant of poor MCH outcomes, but little rigorous analytical work has been done in this area. To understand the socio-economic factors that explain ethnic variation in uptake of MCH care, we report the findings from an analysis in Sichuan province. METHODS: We linked data from the 2003, 2008 and 2013 National Health Service Surveys in Sichuan Province. The ethnic disparities in uptake of maternal care (completing 5 antenatal visits, giving birth in hospital and receiving a caesarean section) and childhood immunization (Bacillus Calmette Guerin (BCG), three doses of diphtheria (DPT) and measles immunization) were examined by geographical (Han district/county vs. ethnic minority county) and individual-based (Han women/children vs. ethnic minority women/children) comparisons. We also examined variation by distance to township and county hospitals, women's education, parity and age using weighted multilevel Poisson regressions with random intercept at district/county level. RESULTS: Ethnic inequalities in maternal care were marked, both at the geographical (district/county) and the individual level. The % of births in hospital was 90.7% among women in Han districts, compared to 83.3% among women living in Han counties (crude RR 0.93; 95% CI 0.75-1.15), 53.8% among Han women living in ethnic minority counties (crude RR 0.57; 95% CI 0.36-0.93), and 13.5% among ethnic minority women living in ethnic minority counties (crude RR 0.18; 95% CI 0.06-0.57). Adjusting the analysis for survey year, education, parity and distance to county level hospital weakened the association between geographical/individual ethnicity and uptake of maternity care, but associations remained remarkably strong. Coverage of childhood immunization was much higher than uptake of maternity care, and inequalities by ethnicity were much less pronounced. CONCLUSION: Lessons can be learned from China's successful immunization programme to further reduce inequalities in access to maternity care among ethnic minority populations in remote areas. Bringing the services closer to the women's homes and strengthening health promotion from the township to the village level may encourage more women to seek antenatal care and give birth in hospital.

Associations between perceived barriers and benefits of using HIV pre-exposure prophylaxis and medication adherence among men who have sex with men in Western China.

BACKGROUND: To investigate the associations between the perceived barriers and benefits of using HIV pre-exposure prophylaxis medication, including worries about the side effects, disliking taking drugs, perceived burden of taking medication, positive expectations as to the efficacy of the drugs, favourable doctor-patient relationships, and medication adherence among men who have sex with men (MSM) to provide a target for improving medication adherence and reducing HIV infection among MSM. METHODS: MSM were recruited in western China from April 2013 to October 2014, administered oral tenofovir (TDF) daily and followed up every 12 weeks for 2 years. At each follow-up, the medication rate was calculated based on the self-reported number of missed doses over 2 weeks, and then, the medication adherence was evaluated. The barriers and benefits perceived during medication were obtained by a self-administered questionnaire, and their effects on medication adherence were analysed by linear mixed models. RESULTS: A total of 411 participants were enrolled in this study, and 1561 follow-up observation points were obtained. The average medication rate was 0.62 ± 0.37, and the medication rate increased with longer follow-up (P < 0.05). The medication rate was higher among MSM who were divorced (compared to those who were unmarried, P < 0.0001). MSM with more positive expectations as to the efficacy of the drugs showed higher rates of medication (P < 0.0001), while those who were more worried about side effects had a lower medication rate (P = 0.0208). In contrast, the dislike of taking the drugs and the burden perceived during medication had no effects on the actual medication rate of taking TDF (P > 0.05). CONCLUSION: How to obtain and maintain high medication adherence among MSM is the key to the PrEP intervention strategy for effective reduction of HIV infection. For MSM in China, we should deepen their understanding of the effectiveness and safety of PrEP and increase their confidence in PrEP, thereby improving their medication adherence. TRIAL REGISTRATION: ChiCTR-TRC-13003849 . Registered on 24/06/2013.

[Validity of the Inpatient Satisfaction Questionnaire].

OBJECTIVE: To assess the validity of the self-designed inpatient satisfaction questionnaire using Structural Equation Model (SEM). METHODS: The questionnaire survey was conducted in a tertiary hospital in Sichuan in April 2016,with participants selected through a systematical sampling approach. The structural validity of the inpatient satisfaction questionnaire was assessed using SEM. The statistical analyses were performed using Lisrel8.70. RESULTS: About 98.5% of returned questionnaires were valid for data analyses,which resulted in a total sample of 2562. A good model fit was achieved: df=8.36,root mean square error of appoximation (RMSEA)=0.054,root mean square residual (RMR)=0.021,goodness-of-fit index (GFI)=0.93,adjusted GFI (AGFI)=0.91,com-parative fit index (CFI)=0.98,non-normed fit index (NNFI)=0.98,parsimony GFI(PGFI) =0.74. Factor loadings on exogenous latent variables ranged from 0.59 to 0.94,with 0.52-0.87 AVE. CONCLUSION: The questionnaire has a good construct validity,which can be used for evaluating inpatient satisfaction in tertiary hospitals.

A cross-national comparison of violence among young men in China and the UK: psychiatric and cultural explanations.

PURPOSE: Public health psychiatry has a key role in violence prevention. Cross-national comparisons of violence and associated psychiatric morbidity can indicate targets for preventive interventions. METHOD: Data on young adult men in households, 18-34 years, were drawn from the Second Men's Modern Lifestyles survey in Great Britain (n = 2046) and from a corresponding survey in Chengdu, China (n = 4132), using a translated questionnaire. Binary logistic regression models were carried out to estimate the cross-national differences for different types of violence and to identify explanatory variables. RESULTS: Chinese men were less likely to report violence in the past 5 years (AOR 0.59, 95% CI 0.48-0.72, P < 0.001). All levels of violence were lower among Chinese men except intimate partner violence (AOR 2.43, 95% CI 1.65-3.59, P < 0.001) and a higher proportion of Chinese men were only violent towards their partners (AOR 7.90, 95% CI 3.27-19.07, P < 0.001). CONCLUSIONS: Cross-national differences were explained by British men's reports of early violence persisting into adulthood, confidence in fighting ability, perception that violence is acceptable behaviour, and experience of violent victimization. More British men screened positive for antisocial personality disorder and substance misuse. Attitudes which condone violence and a serious problem of alcohol-related, male-on-male violence are key targets for preventive interventions among British men. The higher prevalence of life course-persistent antisocial behaviour among British men is of concern and requires further investigation. Higher prevalence of intimate partner violence among Chinese men reflects patriarchal approaches to conflict resolution and confirms an important public health problem in China which requires further cross-national investigation.

[A Cross-sectional Study of Hepatitis B Virus Infection in Mianyang, Sichuan Province].

OBJECTIVES: To determine the prevalence and distribution of hepatitis B virus (HBV) infection in Mianyang. METHODS: Data were extracted from the 12th five-year National Science and Technology Major Projects-Integrated Prevention and Control of Major Infectious Diseases in Mianyang. A two-level logistic regression model was established to determine factors associated with HBV infection. RESULTS: About 4.91% of people in Mianyang were HBsAg positive, which increased with age. HBV infection showed aggregation at townships. Governmental spending ≥¥1 000 000 on public health was a protective factor in the regression model; whereas, age, male gender, medical workers, absent from HBV vaccination, more than 80 g/d alcohol consumption were risk factors of HBV infection. CONCLUSIONS: Mianyang had medium level of HBV infections. But high HBV prevalence can be found in some townships. The known behavior risk factors all exist in Mianyang, which can serve as a screening tool for identifying high risk populations.

[Identifying Factors Associated with Visits to Doctors using a Multilevel Zero-inflated Poisson Model].

OBJECTIVE: To determine factors influencing patient visits to doctors using a multilevel zero-inflated Poisson model with count data with excessive zero. METHODS: The data in relation to rural health services collected in Sichuan Province as part of the Fifth National Health Service Survey (2013) were used in this study. A multilevel random intercept zero-inflated Poisson model was established to identify factors associated with visits to doctors in two weeks. RESULTS: The logistic regression showed that gender, age and presence of chronic diseases were the main factors associated with the likelihood of visiting doctors in two weeks. The Poisson regression revealed that travel time to the nearest medical facility, ethnicity, marital status and educational attainment were associated with numbers of visits to doctors in two weeks. CONCLUSION: Rural residents with a high level of education, unmarried, and living close to medical facility are more likely to visit doctors than others. The multilevel zero-inflated Poisson model can be used for analyzing data with zero extra.