Relationship of urinary bisphenol A concentration to risk for prevalent type 2 diabetes in Chinese adults: a cross-sectional analysis.

Greater bisphenol A exposure has been shown to be associated with a higher risk for self-reported adverse health outcomes, including diabetes. To examine the association between bisphenol A exposure and type 2 diabetes in adults. Cross-sectional study. Songnan, Baoshan District, Shanghai, China. 3423 local residents aged 40 years or older who were enrolled from 27 June 2008 to 10 August 2009. Urinary concentrations of bisphenol A from morning spot urine samples (exposure) and fasting plasma glucose concentration, plasma glucose concentration 2 hours after an oral glucose tolerance test, and serum insulin concentration (outcomes). Median age of the participants was 59.0 years (interquartile range, 53.0 to 68.7 years), 40% were men, and 1087 had type 2 diabetes. The median urinary bisphenol A level was 0.81 ng/mL (interquartile range, 0.47 to 1.43 ng/mL). Clinical characteristics differed between participants with normal glucose regulation and those with impaired glucose regulation and by bisphenol A quartile, but in multivariable analyses, there was no clear association between bisphenol A levels and type 2 diabetes. The adjusted odds ratio (OR) of type 2 diabetes was slightly increased for participants in the second bisphenol A quartile (0.48 to 0.81 ng/mL) (adjusted OR, 1.30 [95% CI, 1.03 to 1.64]) and the fourth quartile (>1.43 ng/mL) (adjusted OR, 1.37 [CI, 1.08 to 1.74]) but not the third quartile (0.82 to 1.43 ng/mL) (adjusted OR, 1.09 [CI, 0.86 to 1.39]), and a test of the trend of the association was not statistically significant. The cross-sectional study design and nonrandom sample of participants limit the conclusions that can be drawn. Many patients in the study already had diabetes, successful treatment of which could have obscured apparent associations. Dietary variables were not measured; however, this is necessary in observational studies of bisphenol A and diabetes because the presence of the chemical in the body may reflect consumption of sugared drinks in plastic bottles. These findings do not confirm a previously reported association between urinary bisphenol A levels and self-reported type 2 diabetes.