Multiple mediation effects on association between prenatal triclosan exposure and birth outcomes.

BACKGROUND: Triclosan is a broad-spectrum antimicrobial, and was thought to affect intrauterine development, but the mechanism remains unclear. OBJECTIVE: To explore the association between prenatal triclosan exposure and birth outcomes. METHODS: Based on 726 mother-child pairs from the Sheyang Mini Birth Cohort Study (SMBCS), we used the available (published) data of triclosan in maternal urines, the hormones including thyroid-related hormones, gonadal hormones in cord blood, and adipokines, trimethylamine-N-oxide (TMAO) and its precursors in cord blood to explore possible health effects of triclosan on birth outcomes through assessing different hormones and parameters, using Bayesian mediation analysis. RESULTS: Maternal triclosan exposure was associated with ponderal index (ß = 0.317) and head circumference (ß = -0.172) in generalized linear models. In Bayesian mediation analysis of PI model, estradiol (ß = 0.806) and trimethylamine (TMA, ß = 0.164) showed positive mediation effects, while total thyroxine (TT4, ß = -0.302), leptin (ß = -2.023) and TMAO (ß = -0.110) showed negative mediation effects. As for model of head circumference, positive mediation effects were observed in free thyroxine (FT4, ß = 0.493), TMA (ß = 0.178), and TMAO (ß = 0.683), negative mediation effects were observed in TT4 (ß = -0.231), testosterone (ß = -0.331), estradiol (ß = -1.153), leptin (ß = -2.361), choline (ß = -0.169), betaine (ß = -0.104), acetyl-L-carnitine (ß = -0.773). CONCLUSION: The results indicated triclosan can affect intrauterine growth by interfering thyroid-related hormones, gonadal hormones, adipokines, TMAO and its precursors.

Carbamate pesticides exposure and delayed physical development at the age of seven: Evidence from the SMBCS study.

BACKGROUND: Carbamate pesticides are widely used in agriculture and cause widespread human exposure. The health effect of carbamates on physical development remains unclear. The current study aimed to explore the carbamate's health effect on physical development. METHODS: Prenatal, 3-year-old, 7-year-old urinary carbofuranphenol concentration was measured by gas chromatography tandem mass spectrometry and adjusted by creatinine. Anthropometric indices were measured by standard method and z-score standardized. Generalized linear models (GLM) were using to assess associations between exposure measurements and anthropometric indices. The generalized estimate equation (GEE) was applied to analyze the association between multiperiod exposure and anthropometric indices, and time-interaction terms were used to exam health effect consistency of exposure in each period. Gender-stratified analysis were conducted according to results of gender-interaction terms to identify gender-specific effects. RESULTS: The gender-interaction term of prenatal exposure with height z-score was significant (ß = -0.057; 95% CI: -0.113, -0.001; p = 0.045). The 3-year-old carbofuranphenol level showed negative associations with weight z-score (ß = -0.019; 95% CI: -0.038, -0.000; p = 0.040), height z-score (ß = -0.015; 95% CI: -0.028, -0.001; p = 0.026), chest circumference (ß = -0.086; 95% CI: -0.171, -0.001; p = 0.046), and waist circumference (ß = -0.128; 95% CI: -0.230, -0.026; p = 0.014). No statistically significant trend was found for prenatal and 7-year-old carbofuranphenol levels. In GEEs, carbofuranphenol level was negatively associated with weight z-score (ß = -0.103; 95% CI: -0.195, -0.011; p = 0.027), height z-score (ß = -0.087; 95% CI: -0.152, -0.022; p = 0.008), and chest circumference (ß = -0.472; 95% CI: -0.918, -0.026; p = 0.037). Boy's height z-score was inversely associated with carbamate exposure (ß = -0.140; 95% CI: -0.227, -0.053; p = 0.001). CONCLUSIONS: Prenatal and postnatal carbamate exposure may affect physical developmental process.

Prenatal exposure to mixture of heavy metals, pesticides and phenols and IQ in children at 7 years of age: The SMBCS study.

OBJECTIVE: Prenatal exposure to heavy metals, pesticides and phenols has been suggested to interfere with neurodevelopment, but the neurotoxicity of their mixtures is still unclear. We aimed to elucidate the associations of maternal urinary concentrations of selected chemical mixtures with intelligence quotient (IQ) in children. METHODS: Maternal urinary concentrations of selected heavy metals, pesticide metabolites, and phenols were quantified in pregnant women who participated in the Sheyang Mini Birth Cohort Study (SMBCS) from June 2009 to January 2010. At age 7 years, child's IQ score was assessed using the Chinese version of Wechsler Intelligence Scale for Children (C-WISC) by trained pediatricians. Generalized linear regression models (GLM), Bayesian kernel machine regression (BKMR) models and elastic net regression (ENR) models were used to assess the associations of urinary concentrations individual chemicals and their mixtures with IQ scores of the 7-year-old children. RESULTS: Of 326 mother-child pairs, single-chemical models indicated that prenatal urinary concentrations of lead (Pb) and bisphenol A (BPA) were significantly negatively associated with full intelligence quotient (FIQ) among children aged 7 years [ß = -2.31, 95% confidence interval (CI): -4.13, -0.48; p = 0.013, sex interaction p-value = 0.076; ß = -1.18, 95% CI: -2.21, -0.15; p = 0.025; sex interaction p-value = 0.296, for Pb and BPA, respectively]. Stratified analysis by sex indicated that the associations were only statistically significant in boys. In multi-chemical BKMR and ENR models, statistically significant inverse association was found between prenatal urinary Pb level and boy's FIQ scores at 7 years. Furthermore, BKMR analysis indicated that the overall mixture was associated with decreases in boy's IQ when all the chemicals' concentrations were at their 75th percentiles or higher, compared to at their 50th percentiles. ENR models revealed that maternal urinary Pb levels were statistically significantly associated with lower FIQ scores (ß = -2.20, 95% CI: -4.20, -0.20; p = 0.031). CONCLUSIONS: Prenatal exposure to selected chemical mixtures may affect intellectual performance at 7 years of age, particularly in boys. Pb and BPA were suspected as primary chemicals associated with child neurodevelopment.