Background: Childhood obesity is a major health concern. Exposure to environmental chemicals may play a role in childhood obesity.
Objective and hypotheses: We investigated whether urinary phthalate metabolite concentrations was associated with overweight or obese status in 4-year-old children.
Method: Forty-hundred thirteen children born as term, appropriate-for-gestational-age infants (226 males) were included in this study. BMI was calculated based on height and weight at the visit. Children were classified into lean (n=366) and overweight or obese (n=47, ≧85th BMI percentile). Birth weight, parental BMI, breastfeeding, daily calorie intake, and weekly exercise hours were investigated. Urinary mono-(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP), mono-(2-ethyl-t-oxohexyl) phthalate (MEOHP), and mono-n-butyl phthalate (MnBP) were measured at ages 4. Urinary phthalate metabolites were ln-transformed (ln-MEHHP, ln-MEOHP, and ln-MnBP) for statistical analysis.
Results: The proportion of overweight or obese children was higher in girls than boys (15.5% vs 8.0%, P<0.05). Overweight or obese children showed lower hours of weekly exercise (P=0.03), and higher concentrations of MEHHP (mean 78.0 vs 62.7, P=0.034) and MEOHP (mean 58.8 vs 48.3, P=0.044) than lean children, respectively. No significant differences in birth weight, paternal obesity, exclusive-breastfeeding, daily calorie intake, and levels of ln-MnBP were found between the two groups. No interaction of sex on the relationship between urinary phthalates and overweight or obesity was found. In multivariable models after adjusting for sex, birth weight, weekly exercise hours (including significant covariates in univariate analysis), each ln unit increase in MEHHP and MEOHP was associated with increased odds of overweight or obesity (OR=1.95 for MEHHP and 2.04 for MEOHP, P<0.05 for both). After additional adjustment for exclusive breastfeeding, parental obesity, parental college graduate, and daily calorie intake (including all previously well-known covariates), each ln unit increase in MEHHP and MEOHP was significantly associated with increased odds of overweight or obesity (P<0.05 for both).
Conclusion: This study suggests positive relationships between urinary concentrations of MEHHP and MEOHP and overweight or obese status in 4-year-old children, even after adjusting for genetic and environmental confounders.
10 Sep 2016 - 12 Sep 2016