Characterization of phthalate exposure in relation to serum thyroid and growth hormones, and estimated daily intake levels in children exposed to phthalate-tainted products: A longitudinal cohort study

Po-Chin Huang; Wei-Hsiang Chang; Ming-Tsang Wu; Mei-Lien Chen; I-Jen Wang; Shu-Fang Shih; Chao A Hsiung; Kai-Wei Liao

doi:10.1016/j.envpol.2020.114648

Characterization of phthalate exposure in relation to serum thyroid and growth hormones, and estimated daily intake levels in children exposed to phthalate-tainted products: A longitudinal cohort study

Environ Pollut. 2020 Sep:264:114648. doi: 10.1016/j.envpol.2020.114648. Epub 2020 Apr 24.

Authors

Po-Chin Huang¹, Wei-Hsiang Chang², Ming-Tsang Wu³, Mei-Lien Chen⁴, I-Jen Wang⁵, Shu-Fang Shih⁶, Chao A Hsiung⁷, Kai-Wei Liao⁸

Affiliations

¹ National Institute of Environmental Health Sciences, National Health Research Institutes, Miaoli, Taiwan; Department of Medical Research, China Medical University Hospital, China Medical University, Taichung, Taiwan; Research Center for Environmental Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan; Department of Safety, Health and Environmental Engineering, National United University, Miaoli, Taiwan.
² Research Center of Environmental Trace Toxic Substances, National Cheng Kung University, Tainan, Taiwan; Department of Food Safety & Hygiene and Risk Management, National Cheng Kung University, Tainan, Taiwan.
³ Research Center for Environmental Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan; Department of Public Health, College of Health Sciences, Kaohsiung Medical University, Kaohsiung, Taiwan.
⁴ Institute of Environmental and Occupational Health Sciences, College of Medicine, National Yang Ming University, Taipei, Taiwan.
⁵ National Institute of Environmental Health Sciences, National Health Research Institutes, Miaoli, Taiwan; Institute of Environmental and Occupational Health Sciences, College of Medicine, National Yang Ming University, Taipei, Taiwan; Department of Pediatrics, Taipei Hospital, Ministry of Health and Welfare, Taipei, Taiwan; College of Public Health, China Medical University, Taichung, Taiwan.
⁶ Department of Health Management and Policy, University of Michigan School of Public Health, Ann Arbor, MI, United States.
⁷ Institute of Population Health Sciences, National Health Research Institutes, Miaoli, Taiwan. Electronic address: hsiung@nhri.edu.tw.
⁸ School of Food Safety, College of Nutrition, Taipei Medical University, Taipei, Taiwan. Electronic address: kaiwei.liao@tmu.edu.tw.

PMID: 32380394
DOI: 10.1016/j.envpol.2020.114648

Abstract

Background: No information is available on the long-term effects on thyroid and growth hormones of children exposed to phthalate-tainted products, despite the infamous 2011 Taiwan phthalate episode. We investigated estimated daily intake levels and their long-term effects on serum thyroid and growth hormone levels in children.

Methods: We recruited 166 children (2-18 years old) in three visits who provided specimens and filled out a questionnaire from the Risk Assessment of Phthalate Incident in Taiwan (RAPIT) project study from 2012 to 2016. Morning spot urine samples were analyzed for nine phthalate metabolites. Serum thyroid (triiodothyronine [T₃], thyroxine [T₄], and free T₄) and growth hormone (insulin-like growth factor-1 [IGF-1] and its binding protein 3 [IGF-BP3]) levels were measured. A generalized estimating equation model was used to evaluate associations between phthalate metabolite levels and children's thyroid and growth hormone levels.

Results: The median metabolite levels of monomethyl phthalate (MMP), Σdibutyl phthalate (DBP), and Σdi-(2-ethylhexyl) phthalate (DEHP) at visits 1, 2, and 3 were 6.59, 10.5, and 21.0 ng/mL, 0.15, 0.24, and 0.20 nmol/mL, and 0.15, 0.17, and 0.12 nmol/mL, respectively. After adjusting for potential confounding factors, we found that levels of urinary MMP were negatively associated with T₃ (β = -0.013, p = 0.047), T₄ (β = -0.016, p = 0.006), free T₄ (β = -0.012, p = 0.002), and IGF-BP3 (β = -0.025, p = 0.003). Urinary mono-ethyl phthalate (MEP) was negatively associated with IGF-1 (β = -0.027, p = 0.029) and IGF-BP3 (β = -0.016, p = 0.018). In addition, serum free T₄ was positively associated with urinary mono-2-ethyl-5-hydroxy hexyl phthalate (MEHHP) (β = 0.016, p = 0.043), mono-2-ethyl-5-oxohexyl phthalate (MEOHP) (β = 0.015, p = 0.024), and ΣDEHPm (β = 0.019, p = 0.020).

Conclusions: Our findings support the hypothesis that specific phthalates disturb the hemostasis of thyroid and growth hormone levels in children exposed to phthalate-tainted products.

Keywords: Children; Insulin-like growth factor; Phthalate metabolites; Thyroid hormones.

MeSH terms

Adolescent
Child
Child, Preschool
Diethylhexyl Phthalate*
Environmental Exposure / analysis
Growth Hormone
Humans
Longitudinal Studies
Phthalic Acids*
Taiwan
Thyroid Gland

Substances

Phthalic Acids
phthalic acid
Growth Hormone
Diethylhexyl Phthalate