| 摘要: | BACKGROUND: Previous epidemiologic and toxicological studies provide some inconsistent evidence that exposure to phthalates may affect thyroid function and growth hormone homeostasis. OBJECTIVE: To assess the relations between exposure to phthalates and indicators of thyroid function and growth hormone homeostasis disturbances both among adults and minors. METHODS: We conducted a population-based cross-sectional study of 279 Taiwanese adults (>/=18 years old) and 79 minors (<18 years old) in 2013. Exposure assessment was based on urinary biomarkers, 11 phthalate metabolites measured by using online liquid chromatography/tandem mass spectrometry. Indicators of thyroid function included serum levels of thyroxine (T4), free T4, triiodothyronine, thyroid-stimulating hormone, and thyroxine-binding globulin (TBG). Growth hormone homeostasis was measured as the serum levels of insulin-like growth factor 1 (IGF-1) and insulin-like growth factor binding protein 3 (IGFBP3). We applied multivariate linear regression models to examine these associations after adjusting for covariates. RESULTS: Among adults, serum T4 levels were negatively associated with urinary mono-(2-ethyl-5-hydroxyhexyl) phthalate (beta=-0.028, P=0.043) and the sum of urinary di-(2-ethylhexyl) phthalate (DEHP) metabolite (beta=-0.045, P=0.017) levels. Free T4 levels were negatively associated with urinary mono-ethylhexyl phthalate (MEHP) (beta=-0.013, P=0.042) and mono-(2-ethyl-5-oxohexyl) phthalate (beta=-0.030, P=0.003) levels, but positively associated with urinary monoethyl phthalate (beta=0.014, P=0.037) after adjustment for age, BMI, gender, urinary creatinine levels, and TBG levels. Postive associations between urinary MEHP levels and IGF-1 levels (beta=0.033, P=0.006) were observed. Among minors, free T4 was positively associated with urinary mono benzyl phthalate levels (beta=0.044, P=0.001), and IGF-1 levels were negatively associated with the sum of urinary DEHP metabolite levels (beta=-0.166, P=0.041) after adjustment for significant covariance and IGFBP3. CONCLUSIONS: Our results are consistent with the hypothesis that exposure to phthalates influences thyroid function and growth hormone homeostasis. |
