ObjectiveAn ongoing debate surrounds the relationship between body composition and pubertal timing, in particular for boys. This cross-sectional study aimed to investigate the association of body composition with pubertal timing among children and adolescents.MethodsA total of 1,493 boys and 1,261 girls who entered puberty were enrolled in Guangzhou, China. Tanner stages were evaluated by examination of breast development for girls and testicular volume for boys. Fat mass (FM) and fat-free mass (FFM) were determined by bioelectrical impedance analysis. Parameters for body composition were transformed into age-and gender-specific Z-scores. The association of body composition with pubertal timing was examined using multinomial logistic regression with inverse probability weighting (IPW) based on the propensity score.ResultsFor boys, IPW analysis showed Z-scores of body fat percentage (BF%) and FM index (FMI) were negatively associated with early puberty (OR = 0.75, 95% CI = 0.64–0.87; OR = 0.74, 95% CI = 0.63–0.88). As for girls, in contrast to boys, positive associations were seen between BF% and FMI with early puberty (OR = 1.39, 95% CI = 1.19–1.64; OR = 1.59, 95% CI = 1.33–1.90). With respect to appendicular skeletal muscle mass index (ASMI), there was a positive association with early puberty and a negative one with late puberty in boys (OR = 1.26, 95% CI = 1.07–1.49; OR = 0.82, 95% CI = 0.69–0.99).ConclusionThere is a positive association of FM with early puberty for girls while negative for boys. FFM yields a positive association with early puberty and a negative one with late puberty in boys, but not in girls. Our findings highlight the gender differences in the connection between body composition and pubertal onset.

We hypothesized that exposure to polluting fuels for cooking was associated with abnormality of glucose metabolism and diabetes mellitus (DM) in south urban China. 3414 residents were surveyed in 14 urban areas of Guangdong Province in 2018. We recorded polluting fuels for cooking exposure, different DM status (DM, prediabetes), fasting blood glucose (FBG), oral glucose tolerance test (OGTT), glycated hemoglobin (HbA 1c ), and other covariates by using a structured questionnaire. We conducted logistic regression model and multivariate linear regression model based on propensityscore method (inverse probability of weighting) to examine the effect of polluting fuels for cooking exposure on DM and glucose metabolism. Exposure to polluting fuels for cooking was associated with DM (odds ratio: 2.57, 95% confidence interval:1.71 to 3.86) and prediabetes (odds ratio: 1.98, 95% confidence interval: 1.52 to 2.58) in both the adjusted and unadjusted models (all p < 0.05). Exposure to polluting fuels for cooking was significantly associated with an increase of FBG (β: 0.30 mmol/L, 95% confidence interval: 0.22 to 0.38 mmol/L). Sensitivity analysis showed that the results were not substantially changed. There was an increased risk of DM, prediabetes and high levels of FBG, OGTT, and HbA 1c among participants aged ≥ 40 years with exposure to polluting fuels for cooking. We demonstrated that exposure to polluting fuels for cooking was associated with higher levels of FBG, which contributed to the increased risk of DM and prediabetes in middle-aged elderly Chinese population living in urban areas.

Objectives: We sought to investigate the effects of occupational exposure to vapors, gases, dust and fumes (VGDF) on chronic bronchitis and lung function impairment. Methods: We conducted chronic obstructive pulmonary disease surveillance in six cities of south China between 2014 and 2019. We recorded the diagnosis of chronic bronchitis, respiratory symptoms, occupational exposure to VGDF and other covariates by using a structured questionnaire. Logistic regression and multivariate linear regression model were adopted for analysis. Results: A total of 7418 and 5249 participants were included. Cough (OR: 1.60, 95%CI: 1.22 to 2.08) and phlegm (OR: 1.49, 95%CI: 1.19 to 1.85) correlated significantly with the exposure to dust. There was an increased risk of cough (OR: 1.53, 95%CI: 1.11 to 2.07) for occupational exposure to gas/vapor/fume. Dual exposure to dust and gas/vapor/fume was associated with a significantly increased risk of chronic bronchitis (OR: 1.74, 95%CI: 1.20 to 2.52), as well as cough (OR: 1.43, 95%CI: 1.15 to 1.79) and phlegm (OR: 1.49, 95%CI: 1.24 to 1.79). Gas/vapor/fume was associated with the reduced ratio of forced expiratory volume in one second and forced vital capacity (FEV1/FVC) (β: -1.05, 95%CI: -1.85 to -0.26) and maximal mid-expiratory flow(MMEF) (β: -0.15, 95%CI: -0.23 to -0.07). Dual exposure to dust and gas/vapor/fume was significantly associated with decreased FEV1/FVC (β: -0.74, 95%CI: -1.28 to -0.20) and MMEF (β: -0.06, 95%CI: -0.12 to -0.01) . Results of sensitivity analysis did not materially change. Conclusions: VGDF exposure was associated with chronic bronchitis, respiratory symptoms and impaired lung function, suggesting that VGDF contribute to the pathogenesis and progression of COPD.