Modification of the Association by Sex Between the Prenatal Exposure to Di(2-Ethylhexyl) Phthalate and Fat Percentage in a Cohort of Mexicans Schoolchildren

Introduction Children’s overweight and obesity are global public health problems, children with obesity have grater obesity risk as adults, thus leading to develop cardiometabolic diseases. Previous studies have found positive and significant associations between the exposure to phthalates and body mass index and body composition. Objective To evaluate the modification of the association by sex between DEHP exposure during pregnancy and the percentage of body fat in a cohort of Mexican schoolchildren. Material and methods The sample was comprised by children which had previously participated in a POSGRAD longitudinal study. A subsample of 190 mother–children binomials were included. Mothers’ DEHP concentrations and its metabolites had been measured in the second trimester of pregnancy: Mono-2-ethylhexyl phthalate (MEHP), Mono-2-ethyl-5-carboxypentyl phthalate (MECPP), Mono-2-ethyl-5-hidroxyhexyl phthalate (MEHHP), and Mono-2-ethyl-5-oxohexyl phthalate (MEOHP). The children’s adipose mass was measured at age 8, 9, and 10. Longitudinal data were analyzed using the mixed effects linear regression model, with intercept and random slope, adjusted by important confounders and stratified by sex. Results We found a differentiated effect by sex, the exposure to DEHP during pregnancy significantly increases the adipose mass in boys. The average increase was 0.058% ( p = 0.02) for every 1% variation in MECPP; 0.047% ( p = 0.04) in MEHHP; 0.051% ( p = 0.03) in MEOHP, and 0.066% ( p = 0.007) in MECPP. Conclusions The results suggest an effect differentiated by sex; with boys being the main ones affected by the prenatal exposure to phthalates. However, we cannot rule out effects in girls.