Developmental triclosan exposure decreases maternal, fetal, and early neonatal thyroxine: A dynamic and kinetic evaluation of a putative mode-of-action

Paul, Katie B.; Hedge, Joan M.; Bansal, Ruby; Zoeller, R. Thomas; Peter, Robert; DeVito, Michael J.; Crofton, Kevin M.

doi:10.1016/j.tox.2012.05.023

Cited by 109 publications

(88 citation statements)

References 76 publications

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“…Although 3 human studies measured thyroid hormones, only one quantified exposure (urinary triclosan from NHANES) 30 , while in the other 2 of these studies, the exposure was use of toothpaste containing triclosan, and was not measured 44, 63 .…”

Section: Resultsmentioning

confidence: 99%

Application of the Navigation Guide systematic review methodology to the evidence for developmental and reproductive toxicity of triclosan

Johnson

Koustas

Vesterinen

et al. 2016

Environment International

128

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Background There are reports of developmental and reproductive health effects associated with the widely used biocide triclosan. Objective Apply the Navigation Guide systematic review methodology to answer the question: Does exposure to triclosan have adverse effects on human development or reproduction? Methods We applied the first 3 steps of the Navigation Guide methodology: 1) Specify a study question, 2) Select the evidence, and 3) Rate quality and strength of the evidence. We developed a protocol, conducted a comprehensive search of the literature, and identified relevant studies using pre-specified criteria. We assessed the number and type of all relevant studies. We evaluated each included study for risk of bias and rated the quality and strength of the evidence for the selected outcomes. We conducted a meta-analysis on a subset of suitable data. Results We found 4,282 potentially relevant records, and 81 records met our inclusion criteria. Of the more than 100 endpoints identified by our search, we focused our evaluation on hormone concentration outcomes, which had the largest human and non-human mammalian data set. Three human studies and 8 studies conducted in rats reported thyroxine levels as outcomes. The rat data were amenable to meta-analysis. Because only one of the human thyroxine studies quantified exposure, we did not conduct a meta-analysis of the human data. Through meta-analysis of the data for rats, we estimated for prenatal exposure a 0.09% (95% CI: −0.20, 0.02) reduction in thyroxine concentration per mg triclosan/kg-bw in fetal and young rats compared to control. For postnatal exposure we estimated a 0.31% (95% CI: −0.38, −0.23) reduction in thyroxine per mg triclosan/kg-bw, also compared to control. Overall we found low to moderate risk of bias across the human studies and moderate to high risk of bias across the non-human studies, and assigned a “moderate/low” quality rating to the body of evidence for human thyroid hormone alterations and a “moderate” quality rating to the body of evidence for non-human thyroid hormone alterations. Conclusion Based on this application of the Navigation Guide systematic review methodology, we concluded that there was “sufficient” non-human evidence and “inadequate” human evidence of an association between triclosan exposure and thyroxine concentrations, and consequently, triclosan is “possibly toxic” to reproductive and developmental health. Thyroid hormone disruption is an upstream indicator of developmental toxicity. Additional endpoints may be identified as being of equal or greater concern as other data are developed or evaluated.

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Section: Resultsmentioning

confidence: 99%

Application of the Navigation Guide systematic review methodology to the evidence for developmental and reproductive toxicity of triclosan

Johnson

Koustas

Vesterinen

et al. 2016

Environment International

128

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“…27 In animals, triclosan disturbed the homeostasis of thyroid hormones, which are required for fetal normal growth and brain development. 28,29 In humans, to our knowledge, no study has investigated the effects of triclosan exposure on thyroid hormone levels during pregnancy.…”

Section: Discussionmentioning

confidence: 99%

Prenatal Exposure to Phenols and Growth in Boys

et al. 2014

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Background Phenols interact with nuclear receptors implicated in growth and adipogenesis regulation. Only a few studies have explored their effects on growth in humans. Objectives We studied the associations of maternal exposure to phenols during pregnancy with prenatal and postnatal growth of male newborns. Methods Within a cohort of women recruited during pregnancy, we selected 520 mother–son pairs and quantified 9 phenols in spot urine samples collected during pregnancy. We used ultrasonography during pregnancy, together with birth measurements, to assess fetal growth. We modeled individual postnatal growth trajectories from repeated measures of weight and height in the first 3 years of life. Results Triclosan concentration was negatively associated with growth parameters measured at the third ultrasound examination but not earlier in pregnancy. At birth, this phenol tended to be negatively associated with head circumference (−1.2 mm for an interquartile range [IQR] increase in ln-transformed triclosan concentration [95% confidence interval = −2.6 to 0.3]) but not with weight or height. Parabens were positively associated with weight at birth. This positive association remained for 3 years for methylparaben (β = 193 g [−4 to 389]) for an IQR increase in ln-transformed concentrations. Conclusion We relied on only 1 spot urine sample to assess exposure; because of the high variability in phenol urinary concentrations reported during pregnancy, using only 1 sample may result in exposure misclassification, in particular for bisphenol A. Our study suggested associations between prenatal exposure to parabens and triclosan and prenatal or early postnatal growth.

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“…TCS markedly lowered maternal T4 levels in rat dams during gestation and lactation as well as in neonatal rats following perinatal exposures (100, 101). Based on its thyroid-disrupting properties, TCS is thought to be a potential developmental neurotoxicant because maternal hypothyroxinemia has been linked to impaired cognitive and motor function in children.…”

Section: Biological and Physiological Effects Of Tcs In Experimental mentioning

confidence: 97%

Triclosan: A Widespread Environmental Toxicant with Many Biological Effects

Yueh

Tukey²

2016

Annu. Rev. Pharmacol. Toxicol.

257

153

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Triclosan (TCS) is a broad-spectrum antimicrobial agent that has been added to personal care products, including hand soaps and cosmetics, and impregnated in numerous different materials ranging from athletic clothing to food packaging. The constant disposal of TCS into the sewage system is creating a major environmental and public health hazard. Owing to its chemical properties of bioaccumulation and resistance to degradation, TCS is widely detected in various environmental compartments in concentrations ranging from nanograms to micrograms per liter. Epidemiology studies indicate that significant levels of TCS are detected in body fluids in all human age groups. We document here the emerging evidence—from in vitro and in vivo animal studies and environmental toxicology studies—demonstrating that TCS exerts adverse effects on different biological systems through various modes of action. Considering the fact that humans are simultaneously exposed to TCS and many TCS-like chemicals, we speculate that TCS-induced adverse effects may be relevant to human health.

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Developmental triclosan exposure decreases maternal, fetal, and early neonatal thyroxine: A dynamic and kinetic evaluation of a putative mode-of-action

Cited by 109 publications

References 76 publications

Application of the Navigation Guide systematic review methodology to the evidence for developmental and reproductive toxicity of triclosan

Application of the Navigation Guide systematic review methodology to the evidence for developmental and reproductive toxicity of triclosan

Prenatal Exposure to Phenols and Growth in Boys

Triclosan: A Widespread Environmental Toxicant with Many Biological Effects

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