Bisphenol A (BPA), an exogenous endocrine-disrupting chemical, has been shown to alter DNA methylation. However, little information is available about the effect of BPA exposure on DNA hydroxymethylation in humans. The objective of the present study was to examine whether BPA exposure was associated with DNA hydroxymethylation in human semen samples. We measured urine BPA levels and LINE-1 hydroxymethylation in 158 male factory workers selected from an occupational cohort study conducted in China between 2004 and 2008. Among them, there were 72 male workers with occupational BPA exposure (BPA-exposed group) and 86 male workers without occupational BPA exposure (unexposed group). Multivariate linear regression models were used to examine the association of exposure to BPA with LINE-1 hydroxymethylation. LINE-1 was more highly hydroxymethylated in the BPA-exposed group than in the unexposed group (median 12.97% vs. 9.68%, respectively; p < 0.05), after adjusting for the potential confounders. The medians of 5-hydroxymethylcytosine (5hmC) generally increased with increasing urine BPA levels: 8.79%, 12.16%, 11.53%, and 13.45%, for undetected BPA and corresponding tertiles for the detected BPA, respectively. After analysis using data at individual level, our findings indicated that BPA exposure was associated with alterations of sperm LINE-1 hydroxymethylation, which might have implications for understanding the mechanisms underlying BPA-induced adverse effects on male reproductive function.

China is experiencing a sizeable rural-urban flow, which may influence the health of internal migrant youth deeply. Disadvantages in the city are highly likely to contribute to health issues among the young internal migrant population. The current qualitative study is to explore how internal migrant young people view the health issues they face, and the services and opportunities they could seek in their host community. Data were collected from 90 internal migrant youth aged between 15 and 19 years old and 20 adult service providers who worked with them in a community of Shanghai, where the population of internal migrants was relatively large. Four types of qualitative research methods were used, including key informant interviews with adults, in-depth interviews with adolescents, a photovoice activity with adolescents and community mapping & focus group discussions with adolescents. Guided by the ecological systems framework and the acculturation theory, thematic analysis was conducted using ATLAS.Ti 7.0 software. While younger migrants had a limited understanding of health, elder migrant youths were more sensitive to societal and political factors related to their health. Mental health and health risk behaviors such as smoking, violence and premarital unsafe sex were thought as major health issues. Internal migrant youths rarely seek health information and services initiatively from formal sources. They believed their health concerns weren’t as pressing as the pressure coming from the high cost of living, the experience of being unfairly treated and the lack of opportunities. Participants also cited lack of family and social support, lack of awareness and supportive policies to get access to community and public services as impacting health factors. The study’s findings provide the insight to the social contexts which influence the health experience, health seeking behaviors, and city adaptation of young internal migrants in their host community. This research stresses the importance of understanding social networks and structural barriers faced by migrant youth in vulnerable environments. A multidimensional social support is essential for internal migrant youth facing present and potential health risks.

Animal studies suggest that bisphenol A (BPA) may perturb pubertal development in females. However, evidence from human studies is limited. This was a cross-sectional study to investigate the association between BPA exposure and pubertal development in school-aged girls. A total of 655 girls aged 9–18 years were selected from three schools in Shanghai, from May to June 2011. We collected one single spot urine sample from each girl. Urine BPA concentrations were measured by modified high-performance liquid chromatography and categorized according to LOD and the median of those above LOD. Pubertal development status was assessed by using Tanner staging, and age at menarche was collected as a milestone for mid-puberty. Modified Poisson regression was used to estimate adjusted prevalence ratios (PRs) and 95% confidence intervals (CIs). After adjustment for potential confounders, girls with detected BPA were more likely to have delayed menarche, a mid-puberty event, compared with girls with undetectable BPA; the prevalence ratios (PR) were 0.73 (0.56, 0.95) for those with moderate BPA(LOD-median) and 0.72 (0.52, 0.99) for those with high BPA(>median), respectively. Girls aged 9–12 years with detected BPA were more likely to have reached pubic hair stage 2, the indicator of pubarche; while among girls aged >15 years, those with detected BPA were less likely to have reached pubic hair stage 5, the late stage of pubic hair development. BPA exposure was associated with alterations in the timing of pubertal development. Results in the present study should be interpreted with caution because of its cross-sectional nature and the limited sample size in each age group.

Studies have reported that prenatal exposure to fine particulate matter (PM_2.5) might be associated with adverse birth outcomes in offspring. However, evidence with regard to the effects of prenatal exposure to PM_2.5 and, especially, its main chemical constituents on offspring's weight in childhood is limited and inconsistent. The present study aimed to examine associations of prenatal exposure to PM_2.5 total mass and its chemical constituents in each trimester with children's weight from birth to 6 years of age using data from Shanghai-Minhang Birth Cohort Study. A total of 1,084 mother-infant pairs were included with both PM_2.5 exposure data and at least one measurement of weight and height. Weight-for-Length (WLZ), BMI-for-Age (BMIz), and Weight-for-Age (WAZ) z-scores were generated according to the World Health Organization guidelines. Exposure to PM_2.5 total mass and its chemical constituents [organic carbon (OC), black carbon (BC), ammonium (NH₄⁺), nitrate (NO₃^-), sulfate (SO₄^2-), and soil dust (SOIL)] during pregnancy was estimated from a satellite based modelling framework. We used multiple informant model to estimate the associations of trimester-specific PM_2.5 total mass and its specific constituents concentrations with WLZ/BMIz and WAZ of offspring at birth and 1, 4, and 6 years of age. In multiple informant model, we observed consistent patterns of associations between exposure to PM_2.5 total mass, OC, BC, NH₄⁺, NO₃^-, and SO₄^2- during the 2^nd and 3^rd trimesters and decreased WLZ/BMIz and WAZ at 1, 4, and 6 years of age in boys. We observed associations between prenatal exposure to PM_2.5 total mass, NH₄⁺, and NO₃^- during the 1^st and 2^nd trimesters and increased WLZ/BMIz and WAZ in girls at birth. However, there were null associations at 1 and 4 years of age and inverse associations at 6 years of age. Prenatal exposure to PM_2.5 total mass and its main chemical constituents was associated with decreased weight in boys from 1 to 6 years of age, with increased weight at birth and decreased weight at 6 years of age in girls. Our findings suggest that prenatal exposure to PM_2.5 and its chemical constituents may have a lasting effect on offspring's weight in childhood.