Associations of Phthalate Exposure With Adiposity and Metabolic Syndrome in US Adolescents and Adults, NHANES 2013 to 2018.

Context: Phthalates are ubiquitous endocrine-disrupting chemicals and suspected obesogens. However, the associations with fat distribution and associated cardiometabolic complications remain unclear.

Objective: We examined the associations between phthalate exposure, body fat (total and distribution patterns), and metabolic syndrome (MetS) among US adolescents and adults.

Methods: We analyzed cross-sectional data from 829 adolescents and 3905 adults in the 2013 to 2018 National Health and Nutrition Examination Survey. Total percentage body fat (%BF), visceral adipose tissue (VAT) mass, and android to gynoid (A/G) ratio were determined using dual-energy x-ray absorptiometry. Associations between molar sums of low molecular weight (∑LMW), high molecular weight (∑HMW), and di(2-ethylhexyl) phthalate (∑DEHP) metabolites, and adiposity indicators and MetS were analyzed with multivariable linear and logistic regressions. Models included sex interaction terms, were stratified by age group, and adjusted for relevant covariates.

Results: ∑HMW and ∑DEHP exposures were positively associated with %BF in males, and all phthalate groups were associated with greater VAT mass and A/G ratio in adolescent males. Five-fold increases in ∑HMW and ∑DEHP metabolites were associated with 21.7% (95% CI, 10.5-33.9) and 18.0% (95% CI, 7.72-29.2) greater VAT mass among adolescent males, respectively. Sex modified the relationship between ∑HMW exposure and A/G ratio among adolescents (interaction P value = .0185). Phthalates were not associated with odds of MetS. When assessing individual MetS components, phthalates were associated with hyperglycemia in adult males.

Conclusion: Greater exposure to phthalates was associated with greater %BF in all males, and with fat distribution in adolescent males; however, phthalates were not linked to MetS.