2018 Study Highlights
- We measured triclosan levels 3 times during gestation and 3 times during childhood
- We measured thyroid function during pregnancy and at delivery and age 3 years
- Triclosan levels during pregnancy were not associated with maternal thyroid levels
- Triclosan levels at delivery were associated with reduced neonatal thyroxine levels
- Triclosan levels at age 1 year were associated with higher child thyroxine levels
Triclosan, an antimicrobial agent used in some consumer products, reduces endogenous thyroid hormone concentrations in rodents. Despite ubiquitous triclosan exposure and the importance of thyroid hormones for normal fetal development, few human studies have examined the impact of triclosan exposure on maternal, neonatal, or child thyroid hormones.
In the HOME Study, a prospective cohort from Cincinnati, OH, we measured urinary triclosan concentrations up to three times in pregnant women between 16 weeks and delivery, and up to three times in children between age 1–3 years. We quantified serum concentrations of thyroid stimulating hormone and total and free thyroxine and triiodothyronine in mothers at 16-weeks gestation (n = 202), neonates at delivery (n = 274), and children at age 3 years (n = 153). We estimated covariate-adjusted differences in thyroid hormones with a 10-fold increase in triclosan using linear regression and multiple informants models.
Triclosan was not associated with thyroid hormones during pregnancy. We observed a few associations of triclosan concentrations with thyroid hormone concentrations in neonates at delivery and children at age 3 years. Higher gestational triclosan, particularly around the time of delivery, was associated with lower cord serum total thyroxine (β: 0.3 μg/dL; 95% CI: − 0.6, − 0.0). Childhood triclosan, particularly at age 1 year, was positively associated with total thyroxine at age 3 years (β: 0.7 μg/dL; 95% CI: 0.3, 1.2).
Our findings suggest that triclosan exposure may influence some features of neonatal and early child thyroid function. Given the large number of comparisons we made, these findings should be replicated in other cohorts.