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