Urinary bisphenol-A, phthalate metabolites and body composition in US adults, NHANES 1999-2006.

BACKGROUND: Exposure to bisphenol-A (BPA) and phthalates is highly prevalent. Prior studies have not assessed associations between urinary levels of BPA and phthalate metabolites and body composition. METHODS: National Health and Nutrition Examination Survey (NHANES) data from 1999 to 2006 on adults aged ≥20 were analyzed by linear regression for associations between urinary BPA, monoethyl phthalate, monobutyl phthalate (MBP), monoethylhexyl phthalate (MEHP), and monobenzyl phthalate (MBzP) and lean mass, fat mass, and percent body fat. RESULTS: BPA and phthalate metabolites were not independently associated with fat mass or percent body fat. Significant inverse associations were observed with lean mass, with the strongest association observed for BPA in men (mean lean mass 1.39 kg lower for quartile 4 vs. quartile 1, p trend = 0.02). CONCLUSIONS: BPA and some phthalates could have important, negative effects on muscle and may affect conditions related to deficits in lean mass, though additional research is needed.