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.

Residential greenness associated with decreased risk of metabolic- dysfunction-associated fatty liver disease: Evidence from a large population-based epidemiological study.

BACKGROUND: Numerous studies have shown that residential greenness positively correlates with enhanced health. Metabolic dysfunction-associated fatty liver disease (MAFLD) affects about a quarter of the population while lacking specific treatments. Given that the association between green space and MAFLD is still unknown, we explored the association between residential greenness and MAFLD as well as the potential mechanisms based on the baseline survey of the China Multi-Ethnic Cohort (CMEC). METHODS: Residential greenness was expressed as normalized difference vegetation index (NDVI) and enhanced vegetation index (EVI). MAFLD was assessed through hepatic steatosis, the presence of overweight/obesity, type 2 diabetes mellitus, and evidence of metabolic dysregulation. We used logistic regression to examine the association between NDVI/EVI and the prevalence of MAFLD. Moreover, we utilized causal mediation analyses to explore the role of physical activity and ambient particulate matters (PM1, PM2.5, and PM10) on the association between residential greenness and MAFLD. RESULTS: We included 72,368 participants from the CMEC and found that residential greenness was negatively associated with the prevalence of MAFLD. For an interquartile range (IQR) increase in NDVI500 m and EVI500 m, the odds ratio (OR) of MAFLD were 0.78 (95 %CI: 0.75, 0.81) and 0.81 (95 %CI: 0.78, 0.84), respectively. Greater association between residential greenness and MAFLD was observed among males. Air pollutants and physical activity could mediate a partial effect (8.5-22.9 %) of residential greenness on MAFLD. CONCLUSION: Higher residential greenness was associated with decreased risk of MAFLD. Moreover, the association was greater among males. The protective effects of residential greenness may be achieved by mitigating the hazardous effects of air pollutants and encouraging physical activity.

Association of Daytime Napping with chronic diseases among Tibetan people in China: a cross-sectional study.

BACKGROUND: Obesity, diabetes, and hypertension, as three of the most prevalent chronic diseases, remain a daunting health challenge. However, to our knowledge, no study has made a thorough examination of the association between the three chronic diseases and daytime napping, a widely accepted behavior in many countries. This is especially necessary among Tibetan populations, whose lifestyles and health outcomes may be unique, yet patterns of chronic diseases and napping are under-examined. Thus, we sought to explore the aforementioned association in the Tibetan population of China. METHODS: A total of 2902 participants aged 45-79 in 2019 were included. Multivariate logistic regressions were conducted in 2020. The sex disparity was examined through interaction and stratified analyses. RESULTS: Hypertension (40.7%) was more prevalent than obesity (20.2%) and diabetes (21.6%). Comparing to non-nappers, those who napped were more likely to have any conditions (OR = 1.30, 95% CI = 1.04-1.62 for 1-59 min/day group and OR = 1.40, 95% CI = 1.10-1.80 for ≥60 min/day group). Participants who had 1-59 min/day of napping were more likely to develop obesity (OR = 1.37, 95% CI = 1.07-1.75), and ≥ 60 min/day of napping was associated with diabetes (OR = 1.33, 95% CI = 1.01-1.74). The interactions between napping and sex were not statistically significant in the models. CONCLUSIONS: The study revealed napping was unfavorably associated with obesity, diabetes, and any conditions in Tibetan people living on the Tibetan Plateau. Future interventions regarding the three chronic diseases may pay more attention to napping. TRIAL REGISTRATION: Not applicable.

Dietary patterns and cardiometabolic risks in diverse less-developed ethnic minority regions: results from the China Multi-Ethnic Cohort (CMEC) Study.

Background In Western developed countries, food-based dietary patterns have been associated with the risk of cardiometabolic diseases, but little is known about such associations in less developed ethnic minority regions (LEMRs), where the cardiometabolic disease burden is growing rapidly and food patterns differ substantially. Methods Between May 2018 and September 2019, we recruited 99556 participants aged 30-79 years from the China Multi-Ethnic Cohort (CMEC) Study. We measured habitual dietary intake with validated food frequency questionnaire (FFQ) and then calculated dietary pattern scores for two of the most studied a priori dietary patterns, i.e., Dietary Approaches to Stop Hypertension (DASH) and alternative Mediterranean (aMED) style diets, and three a posteriori dietary patterns. Four cardiometabolic risks, including hypertension, diabetes, dyslipidaemia and metabolic syndrome (MetS), were newly diagnosed by medical examination and blood tests. We estimated adjusted odds ratios (OR) relating various dietary pattern scores to cardiometabolic risks using marginal structural models under the guidance of directed acyclic graphs. For the above associations, we further calculated the proportion mediated by overweight (PM) using regression-based mediation analysis for better public health implications. Findings The final study sample consisted of 68834 participants. Among them, we newly diagnosed 12803 hypertension, 3527 diabetes, 16342 hyperlipidaemia, and 8198 MetS cases. Overall, all 5 dietary patterns showed considerable associations with risks of hypertension and MetS. Comparing the highest with the lowest quintiles, the DASH score showed the strongest inverse associations with risks of hypertension (OR=0.74, 95% CI:0.70-0.79; PM=10%) and MetS (OR=0.79, 95% CI:0.74-0.85; PM=35%); conversely, scores of the localized a posteriori Yunnan-Guizhou plateau dietary pattern in LEMRs showed the strongest positive associations with risks of hypertension (OR=1.44, 95% CI:1.35-1.52; PM=10%) and MetS (OR=1.35, 95% CI:1.26-1.46; PM=33%), with all P values for trend <0.001. These associations were consistent in various subgroups defined by sex, age, smoking and physical activity, but with magnitudes that differed substantially across different ethnic regions and urbanicity. By investigating the single-component effects of dietary patterns, the dairy intake component contributed a major proportion to the beneficial effects of DASH (41.9% for hypertension and 100.5% for MetS). Interpretation Substantial socioeconomic status and ethnic disparities in diet quality and related cardiometabolic risks were seen in LEMRs, with hypertension being the top diet-related cardiometabolic risk. Our findings support that DASH provides superior dietary guidance compared to aMED for reducing cardiometabolic risks in LEMRs. In particular, the dairy intake encouraged by DASH may produce considerable beneficial effects. Funding This study was funded by the National Key R&D Program of China; full funding sources listed in the acknowledgements.

Dietary Pattern and Long-Term Effects of Particulate Matter on Blood Pressure: A Large Cross-Sectional Study in Chinese Adults.

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Determinants of self-rated health among an older Tibetan population in a Chinese plateau area: analysis based on the conceptual framework for determinants of health.

BACKGROUND: Self-rated health (SRH) has been frequently used in population health surveys. However, most of these studies only focus on specific factors that might directly affect SRH, so only partial or confounding information about the determinants of SRH is potentially obtained. Conducted in an older Tibetan population in a Chinese plateau area, the aim of our study is to assess interrelationships between various factors affecting SRH based on the conceptual framework for determinants of health. METHODS: Between May 2018 and September 2019, 2707 Tibetans aged 50 years or older were recruited as part of the China Multi-Ethnic Cohort Study (CMEC) from the Chengguan District of Lhasa city in Tibet. The information included SRH and variables based on the conceptual framework for determinants of health (i.e., socioeconomic status, health behaviors, physical health, mental health, and chronic diseases). Structural equation modeling (SEM) was used to estimate the direct and indirect effects of multiple factors in the conceptual framework. RESULTS: Among all participants, 5.54% rated their health excellent, 51.16% very good, 33.58% good, 9.12% fairly poor and 0.59% poor. Physical health (ß = - 0.23, P <  0.001), health behaviors (ß = - 0.44, P <  0.001), socioeconomic status (ß = - 0.29, P <  0.001), chronic diseases (ß = - 0.32, P <  0.001) and gender (ß = 0.19, P <  0.001) were directly associated with SRH. Socioeconomic status, physical health and gender affected SRH both directly and indirectly. In addition, there are potential complete mediator effects in which age and mental health affect SRH through mediators, such as physical health, health behaviors and chronic diseases. CONCLUSIONS: The findings suggested that interventions targeting behavioral changes, health and chronic disease management should be attached to improve SRH among older populations in plateau areas without ignoring gender and socioeconomic disparities.