Roles of Social Capital in the Association Between Internalized Homophobia and Condomless Sex Among Men Who Have Sex With Men in Southwest China: A Four-Way Decomposition

Objectives: This study examined whether social capital (SC) mediated the association between internalized homophobia (IH) and condomless sex among men who have sex with men (MSM), with the interaction of SC and IH considered.Methods: A cross-sectional study was conducted between November 2018 and April 2019 in Sichuan Province, China. A total of 540 participants were recruited to investigate their IH, SC, and condomless sex. A four-way decomposition of causal mediation analysis was used to test SC’s roles in the association between IH and condomless sex.Results: Condomless sex was prevalent (46.7%) among the participants, which was significantly associated with IH [odds ratio (OR) = 1.70] and SC (OR = 0.55). A direct effect [excess risk ratio (RR = 0.32)] and an indirect effect (excess RR = 0.16) of SC were found to be significant in the association between IH and condomless sex. Heterogeneities in effects were observed when taking the SC’s domains (e.g., individual and family-based SC) as mediators. SC’s effects were significant only in the homosexual subgroup.Conclusion: IH-based intervention with consideration of SC can be tailored to MSM to decrease condomless sex and curb the spread of HIV, especially for the homosexual subgroup

Association of PM2.5 chemical constituents with general, abdominal and visceral obesity and mediation roles of physical activity

Abstract Background The association between exposure to PM2.5 chemical constituents and obesity remains to be elucidated, as most studies have used a single measure of obesity. This study aimed to investigate the associations of exposure to PM2.5 chemical constituents with general, abdominal, and visceral obesity, and the mediation effect of physical activity (PA) in the associations. Methods Based on a total of 49,819 adults from the baseline of the Yunnan Behavior and Disease Surveillance cohort (YBDS) in southern China in 2021, we used multiple linear regression, weighted quantile sum regression, and quantile regression to estimate independent and joint effects of PM2.5 chemical constituents on elevated BMI, waist circumference (WC) and visceral adiposity index (VAI) and whether these effects changed in quantiles. Mediation analysis was used to examine whether physical activity acts as a mediator in these pathways. Results Per IQR μg/m3 increase in all PM2.5 chemical constituents was significantly associated with the elevated BMI (β [95% CI]: 0.170 [0.127, 0.214]), WC (0.316 [0.217, 0.415]) and VAI (0.102 [0.075, 0.129]), with the largest weights from OM (53.89, 81.67, and 89.82%, respectively). The effects of PM2.5 chemical constituents on obesity showed an overall upward trend from quantiles 1–4 of BMI, WC, and VAI, especially with a rapid upward trend from the sixth decile of VAI. Reduced PA mediated 3.16, 7.08, and 3.78% of the associations between PM2.5 chemical constituents and elevated BMI, WC, and VAI, respectively. Conclusions Exposure to PM2.5 chemical constituents, especially OM, was significantly associated with increased risks for obesity in adults. The effects of associations increased with obesity severity, with PA playing a mediation role. </jats:sec

Development and validation of an age-sex-ethnicity-specific metabolic syndrome score in the Chinese adults

Abstract Metabolic syndrome (MetS) is characterized by metabolic dysfunctions and could predict future risk for cardiovascular diseases (CVDs). However, the traditionally defined dichotomous MetS neither reflected MetS severity nor considered demographic variations. Here we develop a continuous, age-sex-ethnicity-specific MetS score based on continuous measures of the five metabolic dysfunctions (waist circumference [WC], triglycerides [TG], high-density lipoprotein cholesterol [HDL-C], mean arterial pressure [MAP], and fasting blood glucose [FBG]). We find that the weights of metabolic dysfunctions in the score vary across age-sex-ethnicity-specific subgroups, with higher weights for TG, HDL-C, and WC. Each unit increase in the score is associated with increased risks for hyperlipidemia, diabetes, and hypertension, and elevated levels of HbA1c, cholesterol, body mass index, and serum uric acid. The score shows high sensitivity and accuracy for detecting CVD-related risk factors and is validated in different geographical regions. Our study would advance early identification of CVD risks and, more broadly, preventive medicine and sustainable development goals