Association of di-2-ethylhexyl phthalate exposure with gut microbiota diversity and obesity in Chinese children: a cross-sectional study

The association of di-2-ethylhexyl phthalate (DEHP) exposure with childhood obesity and with gut microbiota diversity remains poorly understood. This study aimed to investigate the independent and joint associations of DEHP exposure and gut microbiota diversity with obesity in Chinese children. We analyzed data from 1252 children aged 9–11 years enrolled in the Childhood Obesity and New Environmental Factors (CONEF) cohort. Urinary DEHP metabolites (MEHP, MEHHP, and MEOHP) were quantified using HPLC–MS/MS. Gut microbial communities were profiled via 16 S rRNA gene sequencing in a subpopulation ( n = 288). Logistic regression was used to assess associations. The prevalence of obesity was 13.3%. DEHP exposure was near universal. After full adjustment, children in the highest quartile (Q4) of DEHP exposure had higher odds of obesity than those in Q1 (OR: 1.69; 95% CI 1.03, 2.78). lnMEOHP, lnMEHHP, and lnΣDEHP levels were positively associated with F/B ratio ( p < 0.05) before Benjamini–Hochberg correction for multiple testing. Higher α-diversity was associated with lower odds of obesity ( p < 0.05). In the joint analysis, compared with the low DEHP exposure/high-index group, odds of obesity were approximately threefold higher in high-exposure/low-index group for observed species (OR: 3.04; 95% CI 1.07, 8.62), ACE (OR: 3.03; 95% CI 1.08, 8.52) and Chao1 (OR: 2.84; 95% CI 1.00, 8.07). However, multiplicative interaction was not significant for any index ( p for interaction > 0.05). DEHP exposure was associated with modestly increased odds of obesity in Chinese children, but not with any index of gut microbial diversity, and the inverse association between microbial richness and obesity was independent of exposure.