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 (beta = 0.317) and head circumference (beta =-0.172) in generalized linear models. In Bayesian mediation analysis of PI model, estradiol (beta = 0.806) and trimethylamine (TMA, beta = 0.164) showed positive mediation effects, while total thyroxine (TT4, beta =-0.302), leptin (beta =-2.023) and TMAO (beta =-0.110) showed negative mediation effects. As for model of head circumference, positive mediation effects were observed in free thyroxine (FT4, beta = 0.493), TMA (beta = 0.178), and TMAO (beta = 0.683), negative mediation effects were observed in TT4 (beta =-0.231), testosterone (beta =-0.331), estradiol (beta =-1.153), leptin (beta =-2.361), choline (beta =-0.169), betaine (beta =-0.104), acetyl-L-carnitine (beta =-0.773).Conclusion: The results indicated triclosan can affect intrauterine growth by interfering thyroid-related hor-mones, gonadal hormones, adipokines, TMAO and its precursors.