The relationship between cooking fuel use and sex hormone levels: A cross-sectional study and Mendelian randomization study.

PURPOSE: The aim of this study was to investigate the effect of solid fuel use on serum sex hormone levels. Furthermore, the effects of improved kitchen ventilation and duration of cooking time on the relationship between solid fuel use and serum sex hormone levels will be further explored. METHODS: In this cross-sectional study, 5386 individuals were recruited. Gender and menopausal status modified associations between solid fuel type and serum sex hormone levels was investigated through generalized linear models and further analyzed by improving kitchen ventilation and length of cooking time on the relationship between solid fuel use and serum sex hormone levels. To identify the causal association, mendelian randomization of two-sample was performed. RESULTS: In observational analyses, for ln-17-hydroxyprogesterone, ln-testosterone, and ln-androstenedione among premenopausal women, the estimated ß and 95 % CI of sex hormone levels for the effect of solid fuel users was -0.337 (-0.657, -0.017), -0.233 (-0.47, 0.005), and - 0.240 (-0.452, -0.028) respectively, and - 0.150 (-0.296, -0.004) in ln-progesterone among postmenopausal women. It was found that combining solid fuels with long cooking periods or no ventilation more effectively reduced testosterone and androstenedione in premenopausal women. We further found the adverse effects of using solid fuel on progesterone, testosterone, and androstenedione levels were enhanced with the increases of PM1, PM2.5, PM10, and NO2. Corresponding genetic, the causal risk effect of solid fuel were - 0.056 (-0.513, 0.4) and 0.026 (-3.495, 3.547) for testosterone levels and sex hormone binding globulin, respectively. CONCLUSION: Using gas or solid fuel was negatively related to sex hormone levels. A combination of using solid fuels, cooking for a long time, or cooking without ventilation had a stronger effect on sex hormone levels. However, genetic evidence did not support causality for the associations. WHAT IS ALREADY KNOWN ON THIS TOPIC?: The mechanisms underlying these associations household air pollution (HAP) from incomplete combustion of such fuels and occurrence of chronic diseases remained obscure. Recent years, extensive evidences from animal as well as human researches have suggested that progestogen and androgen hormones are involved in the development of diabetes, hypertension, and cardiovascular disease, which indicated that changes in serum progestogen and androgen hormones levels might play a role in these pathological mechanisms. However, limited evidence exists examining the effect of HAP from solid fuel use on serum sex hormone levels.

Gender-specific associations between mixture of polycyclic aromatic hydrocarbons and telomere length.

Evidence shows the relationships of individual environmental PAHs by their urinary metabolites with relative telomere length (RTL), which may be affected by biological gender differences. Since plasma parent PAHs are not metabolized, it may reflect human exposure to PAHs more realistically in daily life. Thus, exploring joint associations between plasma parent PAHs and RTL is urgent, which may identify the major contributor to its adverse effect. In this study, 2577 participants were obtained from the Henan Rural Cohort. The level of PAHs in blood samples was detected by gas chromatography coupled with tandem mass spectrometry. RTL in blood samples was detected by quantitative polymerase chain reaction. Generalized linear models or quantile g-computation were performed to evaluate the associations between the individual or a mixture of PAHs and RTL. Results from generalized linear models showed that each unit increment in BghiP value corresponded to a 0.098 (95%CI: 0.067, 0.129) increment in RTL for men; each unit increment in BaP, BghiP and Flu value corresponded to a 0.041 (95%CI: 0.014, 0.068), 0.081 (95%CI: 0.055, 0.107) and 0.016 (95%CI: 0.005, 0.027) increment in RTL for women. Results from quantile-g computation revealed that each one-quantile increment in the mixture of 10 PAHs corresponded to a 0.057 (95%CI: 0.021, 0.094) and 0.047 (95%CI: 0.003, 0.091) increment in RTL values of women and men, but these associations were mainly ascribed to three PAHs for women (BaP, Flu and BghiP) and men (BaP, BghiP and Pyr), respectively. Similar results were found in smoking men and cooking women without smoking. Our study found that exposure to 10 PAHs mixture was positively associated with RTL across gender, mainly attributed to Flu, BaP and BghiP, implicating that gender-specific associations may be ascribed to tobacco and cooking smoke pollution. The findings provided clues for effective measures to control PAHs pollutants-related aging disease.Clinical trial registration The Henan Rural Cohort Study has been registered at the Chinese Clinical Trial Register (Registration number: ChiCTR-OOC-15006699). Date of registration: 06 July 2015. http://www.chictr.org.cn/showproj.aspx?proj=11375 .

Associations between healthy lifestyle score and health-related quality of life among Chinese rural adults: variations in age, sex, education level, and income.

PURPOSE: This study aimed to investigate the associations between overall lifestyles and HRQoL, as well as the variations in age, sex, education level, and income. METHODS: A total of 23,402 participants from the Henan rural cohort were included. The healthy lifestyle score (HLS) consists of five lifestyle factors: smoking, alcohol drinking, physical activity, diet, and body mass index. HRQoL was assessed by the EQ-5D-5L questionnaire. The general linear model and Tobit regression model were utilized to assess the associations of HLS with visual analogue score (VAS) and utility index. RESULTS: Compared with participants with an HLS of 0-2, the corresponding regression coefficients (ß) and 95% confidence intervals (CI) of participants with an HLS of 3, 4, and 5 for VAS score were 1.09 (0.59, 1.59), 1.92 (1.38, 2.46), and 2.60 (1.83, 3.37); the corresponding ß and 95% CI for utility index were 0.02 (0.01, 0.03), 0.05 (0.03, 0.06), and 0.06 (0.04, 0.07). Notably, these positive associations were greater among the elderly, female, and those with lower education level and average monthly income (p for interaction < 0.05). For instance, the corresponding ß and 95% CI of individuals with an HLS of 5 for utility index in average monthly income < 500 RMB, 500-999 RMB, and ≥ 1000 RMB groups were 0.08 (0.05, 0.11), 0.06 (0.03, 0.09), and 0.02 (- 0.00, 0.05). CONCLUSION: Engaging in healthier lifestyle habits was associated with a higher level of HRQoL, especially in the elderly, females, and those with low education level and average monthly income.