Associations between urinary phthalate metabolites and bisphenol A levels, and serum thyroid hormones among the Korean adult population - Korean National Environmental Health Survey (KoNEHS) 2012-2014.
BACKGROUND
Phthalates and bisphenol A (BPA) have been used extensively in many consumer products, resulting in widespread exposure in the general population. Studies have suggested associations between exposure to phthalates and BPA, and serum thyroid hormone levels, but confirmation on larger human populations is warranted.


METHODS
Data obtained from nationally representative Korean adults (n=6003) recruited for the second round of the Korean National Environmental Health Survey (KoNEHS), 2012-2014, were employed. Three di-(2-ethylhexyl) phthalate (DEHP) metabolites, along with benzyl-butyl phthalate (BBzP) and di-butyl phthalate (DBP) metabolites, and BPA were measured in subjects' urine. Thyroxine (T4), total triiodothyronine (T3), and thyroid-stimulating hormone (TSH) were measured in serum. The associations between urinary phthalates or BPA and thyroid hormone levels were determined.


RESULTS
Urinary phthalate metabolites were generally associated with lowered total T4 or T3, or increased TSH levels in serum. Interquartile range (IQR) increases of mono-(2-ethyl-5-oxohexyl) phthalate (MEOHP), and mono-(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP) were associated with a 3.7% increase of TSH, and a 1.7% decrease of total T4 levels, respectively. When grouped by sex, urinary MEHHP levels were inversely associated with T4 only among males. Among females, mono-benzyl phthalate (MBzP) and mono-n-butyl phthalate (MnBP) levels were inversely associated with TSH and T3, respectively. In addition, negative association between BPA and TSH was observed.


CONCLUSIONS
Several phthalates and BPA exposures were associated with altered circulatory thyroid hormone levels among general Korean adult population. Considering the importance of thyroid hormones, public health implications of such alteration warrant further studies.
Environmental Health Research Division, National Institute of Environmental Research, Ministry of Environment, Incheon, South Korea.
Choonghee
C
Park
Environmental Health Research Division, National Institute of Environmental Research, Ministry of Environment, Incheon, South Korea.
Wookhee
W
Choi
Environmental Health Research Division, National Institute of Environmental Research, Ministry of Environment, Incheon, South Korea.
Moonyoung
M
Hwang
Environmental Health Research Division, National Institute of Environmental Research, Ministry of Environment, Incheon, South Korea.
Youngmee
Y
Lee
Environmental Health Research Division, National Institute of Environmental Research, Ministry of Environment, Incheon, South Korea.
Suejin
S
Kim
Environmental Health Research Division, National Institute of Environmental Research, Ministry of Environment, Incheon, South Korea.
Seungdo
S
Yu
Department of Environmental Health Sciences, Graduate School of Public Health, Seoul National University, Seoul, South Korea.
Inae
I
Lee
Department of Environmental Health Sciences, Graduate School of Public Health, Seoul National University, Seoul, South Korea.
Domyung
D
Paek
Department of Environmental Health Sciences, Graduate School of Public Health, Seoul National University, Seoul, South Korea. Electronic address: kyungho@snu.ac.kr.
Kyungho
K
Choi
D000328:Adult; D001559:Benzhydryl Compounds / Q000652:urine*; D004781:Environmental Exposure; D004785:Environmental Pollutants / Q000652:urine*; D005260:Female; D006801:Humans; D008297:Male; D010636:Phenols / Q000652:urine*; D010795:Phthalic Acids / Q000652:urine*; D056910:Republic of Korea; D011795:Surveys and Questionnaires; D013963:Thyroid Hormones / Q000097:blood*; D000098826:Bisphenol A Compounds
D001559:Benzhydryl Compounds; D004785:Environmental Pollutants; D010636:Phenols; D010795:Phthalic Acids; D013963:Thyroid Hormones; C032279:phthalic acid; C006780:bisphenol A; D000098826:Bisphenol A Compounds
Bisphenol A; Human biomonitoring; Korean National Environmental Health Survey; Phthalate; Thyroid hormone