Urinary concentrations of total and free bisphenol A and daily intake estimation in northern Mexican women

Bisphenol A (BPA) is a component of polycarbonates used to manufacture plastic reusable bottles and miscellaneous containers; it is a constituent of epoxy resins used for the internal coating of beverage cans. Humans are mainly exposed by ingesting contaminated food and beverages. Experimental and human studies reported diverse health problems associated with BPA. Our objectives were to measure free (FBPA) and total (TBPA) urinary levels, to estimate daily BPA intake, and to investigate sources of exposure in northern Mexican women. This study is a secondary cross-sectional analysis in controls (n = 201) participating in a population-based case-control study. BPA was extracted from urine using the Micro-QuEChERS method and determined by gas chromatography/mass spectrometry. FBPA was detected in 88% of participants (geometric mean: 6.66; range: < LOD-48.83 ng/ml) whereas TBPA was detected in 98.5% (20.13; < LOD-37.15 ng/ml). TBPA estimated intake was 0.199 (0.007-4.26 μg/kg/bw/day), lower than the current American and Canadian tolerable daily intakes (TDI) of 50 and 25, respectively, but higher than the recently proposed TDIs by the European (0.0002 μg/kgbw/day) and German (0.2 μg/kgbw/day) authorities. Women having lower FBPA levels presented lower energy consumption, whereas those with higher TBPA concentrations were younger, had higher BMI, and higher energy intake. TBPA was positively associated with the estimated intake of sugar-sweetened beverages (SSB) but significantly negatively associated with cow's milk. The urinary concentrations of FBPA and TBPA indicated that women were widely exposed to BPA since their values were in the upper part of the range reported in other regions.