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Associations of early life urinary triclosan concentrations with maternal, neonatal, and child thyroid hormone levels.

ABSTRACT: BACKGROUND: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. METHODS:In the HOME Study, a prospective cohort from Cincinnati, OH, we measured urinary triclosan concentrations up to three times in pregnant women between 16weeks and delivery, and up to three times in children between age 1-3years. 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 3years (n=153). We estimated covariate-adjusted differences in thyroid hormones with a 10-fold increase in triclosan using linear regression and multiple informants models. RESULTS: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 3years. Higher gestational triclosan, particularly around the time of delivery, was associated with lower cord serum total thyroxine (?: 0.3?g/dL; 95% CI: -0.6, -0.0). Childhood triclosan, particularly at age 1year, was positively associated with total thyroxine at age 3years (?: 0.7?g/dL; 95% CI: 0.3, 1.2). CONCLUSION: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.

SUBMITTER: Braun JM

PROVIDER: S-EPMC5970023 | biostudies-literature | 2018 May

REPOSITORIES: biostudies-literature

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Associations of early life urinary triclosan concentrations with maternal, neonatal, and child thyroid hormone levels.

Braun Joseph M JM Chen Aimin A Hoofnagle Andrew A Papandonatos George D GD Jackson-Browne Medina M Hauser Russ R Romano Megan E ME Karagas Margaret R MR Yolton Kimberly K Thomas Zoeller R R Lanphear Bruce P BP

Hormones and behavior 20171206

<h4>Background</h4>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.<h4>Methods</h4>In the HOME Study, a prospective cohort from Cincinnati, OH, we measured urinary triclosan concentrations up to thre ...[more]

PMID: 29154791

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Project description:BACKGROUND:Phthalates, endocrine-disrupting chemicals that are commonly found in consumer products, may adversely affect thyroid hormones, but findings from prior epidemiologic studies are inconsistent. OBJECTIVES:In a prospective cohort study, we investigated whether maternal urinary phthalate metabolite concentrations and phthalate mixtures measured during pregnancy were associated with thyroid hormones among pregnant women and newborns. METHODS:We measured nine phthalate metabolites [monoethyl phthalate (MEP), mono-n-butyl phthalate, mono-isobutyl phthalate, monobenzyl phthalate (MBzP), and four monoesthers of di(2-ethylhexyl) phthalate] in urine collected at approximately 16 and 26 weeks' gestation among women in the Health Outcomes and Measures of the Environment Study (2003-2006, Cincinnati, Ohio). Thyroid stimulating hormone (TSH) and free and total thyroxine and triiodothyronine were measured in maternal serum at 16 weeks' gestation (n?=?202) and cord serum at delivery (n?=?276). We used multivariable linear regression to assess associations between individual urinary phthalate metabolites and concentrations of maternal or cord serum thyroid hormones. We used weighted quantile sum regression (WQS) to create a phthalate index describing combined concentrations of phthalate metabolites and to investigate associations of the phthalate index with individual thyroid hormones. RESULTS:With each 10-fold increase in 16-week maternal urinary MEP, maternal serum total thyroxine (TT4) decreased by 0.52??g/dL (95% CI: -1.01, -0.03). For each 10-fold increase in average (16- and 26-week) maternal urinary MBzP, cord serum TSH decreased by 19% (95% CI: -33.1, -1.9). Among mothers, the phthalate index was inversely associated with maternal serum TT4 (WQS beta?=?-0.60; 95% CI: -1.01, -0.18). Among newborns, the phthalate index was inversely associated with both cord serum TSH (WQS beta?=?-0.11; 95% CI: -0.20, -0.03) and TT4 (WQS beta?=?-0.53; 95% CI: -0.90, -0.16). CONCLUSION:Our results suggest that co-exposure to multiple phthalates was inversely associated with certain thyroid hormones (TT4 in pregnant women and newborns, and TSH in newborns) in this birth cohort. These findings highlight the need to study chemical mixtures in environmental epidemiology.

Project description:BACKGROUND:Maintaining thyroid homeostasis during pregnancy is essential for normal fetal growth and development. Growing evidence suggests that phthalates interfere with normal thyroid function. Few human studies have investigated the degree to which phthalates may affect thyroid hormone levels in particularly susceptible populations such as pregnant women. OBJECTIVES:We examined the associations between repeated measures of urinary phthalate metabolites and plasma thyroid hormone levels in samples collected at up to four time points per subject in pregnancy. Additionally, we investigated the potential windows of susceptibility to thyroid hormone disturbances related to study visit of sample collection. METHODS:Data were obtained from pregnant women (n = 439) participating in a nested case-control study of preterm birth with 116 cases and 323 controls. We measured 9 phthalate metabolite concentrations in urine samples collected at up to four study visits per subject during pregnancy (median = 10, 18, 26, and 35 weeks of gestation, respectively). We also measured a panel of thyroid function markers in plasma collected at the same four time points per subject during pregnancy. RESULTS:Although our results were generally null, in repeated measures analyses we observed that phthalate metabolites were largely inversely associated with thyrotropin and positively associated with free and total thyroid hormones. Cross-sectional analyses by study visit revealed that the magnitude and/or direction of these relationships varied by timing of exposure during gestation. CONCLUSIONS:These results support previous reports showing the potential for environmental phthalate exposure to alter circulating levels of thyroid hormones in pregnant women. Citation: Johns LE, Ferguson KK, McElrath TF, Mukherjee B, Meeker JD. 2016. Associations between repeated measures of maternal urinary phthalate metabolites and thyroid hormone parameters during pregnancy. Environ Health Perspect 124:1808-1815;?http://dx.doi.org/10.1289/EHP170.

Dataset Information

Associations of early life urinary triclosan concentrations with maternal, neonatal, and child thyroid hormone levels.

Publications

Associations of early life urinary triclosan concentrations with maternal, neonatal, and child thyroid hormone levels.

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