Association between urinary phthalate metabolites and obesity in adult Korean population: Korean National Environmental Health Survey (KoNEHS), 2012–2014

ABSTRACT

BACKGROUND: Phthalate is a chemical that is commonly used as a plasticizer in processing plastic products and as a solvent in personal care products. Although previous experimental studies have reported that phthalate metabolites are associated with obesity, epidemiological study results have been inconsistent and insufficient. The objective of the present study was to investigate the association between urinary phthalate metabolites and obesity in adult Korean population. METHODS: The present study selected 4,752 Korean adults aged 19 years or older from the 2012–2014 Korean National Environmental Health Survey data. The concentrations of urinary di-(2-ethyl-5-carboxypentyl) phthalate (DEHP) metabolites—i.e., mono-(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP), mono-(2-ethyl-5-oxohexyl) phthalate (MEOHP) and mono-(2-ethyl-5-carboxypentyl) phthalate—mono-benzyl phthalate (MBzP) and mono-n-butyl phthalate (MnBP) were adjusted using the urinary creatinine. We used logistic regression analysis to investigate the association between urinary phthalate metabolite concentration and body mass index (BMI) with respect to sex and age. RESULTS: Among women, urinary MEHHP and DEHP concentrations were found to have statistically significantly positive associations with obesity (Q4 versus Q1; odds ratio (OR) 1.72, 95% confidence interval (CI) 1.19–2.49 for MEHHP and OR 1.52, 95% CI 1.04–2.21 for DEHP). Among men, urinary MnBP concentration was found to have statistically significantly negative association with obesity (Q4 versus Q1; OR 0.71, 95% CI 0.50–0.99). In the analysis stratified by sex and age, women aged ≥ 50 years showed statistically significantly positive associations between the concentrations of urinary DEHP metabolites, DEHP, MBzP, and obesity (Q4 versus Q1; OR 1.94, 95% CI 1.28–2.94 for MEHHP, OR 1.88, 95% CI 1.21–2.94 for MEOHP, OR 2.04, 95% CI 1.31–3.18 for DEHP, and Q3 versus Q1; OR 1.45, 95% CI 1.02–2.05 for MBzP). Meanwhile, men aged ≥ 50 years showed no significant associations between urinary phthalate concentrations and obesity. CONCLUSIONS: In the present study, we found differences in the associations between urinary phthalate metabolites and BMI according to sex and age. However, because the present study was cross-sectional in nature, additional support through prospective studies is needed to estimate the causal associations.