Exposure to herbicides mixtures in relation to type 2 diabetes mellitus among Chinese rural population: Results from different statistical models.

BACKGROUND: Although it has been reported that herbicides exposure is related to adverse outcomes, available evidence on the associations of quantitatively measured herbicides with type 2 diabetes mellitus (T2DM) and prediabetes is still scant. Furthermore, the effects of herbicides mixtures on T2DM and prediabetes remain unclear among the Chinese rural population. AIMS: To assess the associations of plasma herbicides with T2DM and prediabetes among the Chinese rural population. METHODS: A total of 2626 participants were enrolled from the Henan Rural Cohort Study. Plasma herbicides were measured with gas chromatography coupled to triple quadrupole tandem mass spectrometry. Generalized linear regression analysis was employed to assess the associations of a single herbicide with T2DM, prediabetes, as well as indicators of glucose metabolism. In addition, the quantile g-computation and environmental risk score (ERS) structured by adaptive elastic net (AENET), and Bayesian kernel machine regression (BKMR) were used to estimate the effects of herbicides mixtures on T2DM and prediabetes. RESULTS: After adjusting for covariates, positive associations of atrazine, ametryn, and oxadiazon with the increased odds of T2DM were obtained. As for prediabetes, each 1-fold increase in ln-transformed oxadiazon was related to 8.4% (95% confidence interval (CI): 1.033, 1.138) higher odds of prediabetes. In addition, several herbicides were significantly related to fasting plasma glucose, fasting insulin, and HOMA2-IR (false discovery rates adjusted P value < 0.05). Furthermore, the quantile g-computation analysis showed that one quartile increase in multiple herbicides was associated with T2DM (OR (odds ratio): 1.099, 95%CI: 1.043, 1.158), and oxadiazon was assigned the largest positive weight, followed by atrazine. In addition, the ERS calculated by the selected herbicides from AENET were found to be associated with T2DM and prediabetes, and the corresponding ORs and 95%CIs were 1.133 (1.108, 1.159) and 1.065 (1.016, 1.116), respectively. The BKMR analysis indicated a positive association between mixtures of herbicides exposure and the risk of T2DM. CONCLUSIONS: Exposure to mixtures of herbicides was associated with an increased risk of T2DM among Chinese rural population, indicating that the impact of herbicides exposure on diabetes should be paid attention to and measures should be taken to avoid herbicides mixtures exposure.

Predictors of thallium exposure and its relation with preterm birth.

Thallium (Tl) is a well-recognized hazardous toxic heavy metal that has been reported to have embryotoxicity and fetotoxicity. However, little is known about its association with preterm birth (PTB) in humans. We aimed to evaluate the predictors of Tl exposure and assessed its relation with PTB. The study population included 7173 mother-infant pairs from a birth cohort in Wuhan, China. Predictors of Tl concentrations were explored using linear regression analyses, and associations of Tl exposure with risk of PTB or gestational age at birth were estimated using logistic regression or generalized linear models. The geometric mean and median values of urinary Tl concentrations were 0.28 µg/L (0.55 µg/g creatinine) and 0.29 µg/L (0.53 µg/g creatinine). We found that maternal urinary Tl concentrations varied by gestational weight gain, educational attainment, multivitamin and iron supplementations. Women with Tl concentrations higher than 0.80 µg/g creatinine were at higher risk of giving birth prematurely versus those with Tl concentrations lower than 0.36 µg/g creatinine [adjusted odds ratio (95% confidence interval (CI)): 1.55 (1.05, 2.27)], and the association was more pronounced in PTB with premature rupture of membranes (PROM) rather than in PTB without PROM. About 3-fold increase in creatinine-corrected Tl concentrations were associated with 0.99-day decrease in gestational length (95% CI: -1.36, -0.63). This is the first report on the associations between maternal Tl exposure and the risk of PTB.

Pancreatic impairment and Igf2 hypermethylation induced by developmental exposure to bisphenol A can be counteracted by maternal folate supplementation.

Increasing evidence indicates that bisphenol A (BPA), a widely manufactured environmental pollutant, can induce changes in DNA methylation paatterns, which is a potential mechanism linking this environmental exposure to disease development. We investigated the influence of developmental exposure to BPA on pancreatic DNA methylation patterns and whether maternal folate supplementation can modify the epigenetic status and pancreatic impairment induced by BPA. Our results showed that maternal dietary folate supplementation in rats exposed to BPA counteracted the observed BPA-induced pancreatic impairments in the offspring, which included disrupted insulin secretion and glucose intolerance, and impaired morphology and ultrastructure of ß cells. Moreover, these pancreatic dysfunctions were shown to be associated with low expression and DNA hypermethylation of insulin-like growth factor-2 (Igf2) in islets induced by exposure to BPA during the developmental period. Importantly, maternal dietary folate supplementation was demonstrated to negate this Igf2 DNA hypermethylation in the offspring, which was consistent with the upregulation of Igf2 expression. Overall, our results suggest that early developmental exposure to BPA alters the DNA methylation of Igf2, that these altered methylation patterns are associated with impaired ß-cell function in the offspring and that these effects can be counteracted by maternal folate supplementation. Copyright © 2017 John Wiley & Sons, Ltd.