Association of bisphenol A exposure with overweight in the elderly: a panel study

Bisphenol A (BPA) is an ubiquitous chemical, which is an endocrine disruptor. Recent epidemiological studies have suggested a relationship between BPA exposure and body weight. However, most of these studies were cross-sectional and not on elderly people. We conducted a panel study with repeated measurements to evaluate the relationship between BPA and overweight in elderly people. A total of 560 elderly participants aged ≥60 years were recruited in Seoul from 2008 to 2010. Urinary BPA levels and body mass index (BMI, kg/m(2)) were measured at every visit. We defined a BMI ≥25 as overweight and examined the relations between urinary BPA and BMI or overweight. Repeated measures analysis was performed after adjusting for age, sex, low-density lipoprotein cholesterol levels, alcohol consumption, regular exercise, total calorie intake, fatty acid intake, urinary cotinine levels, and the status of diabetes mellitus. The geometric mean of BPA was 0.67 μg/g creatinine. The odds ratio (OR) of overweight was 1.17 (95 % confidence interval [CI] 1.04-1.32) per interquartile range increase of log-transformed BPA. When stratified based on sex, we observed a significant association in women (OR 1.25; 95 % CI 1.09-1.45) but not in men (OR 0.97; 95 % CI 0.77-1.22). The ORs of overweight increased with quartiles of BPA in women (quartile 2 vs 1: OR 1.54; 95 % CI 1.02-2.32, 3 vs 1: OR 1.70; 95 % CI 1.10-2.62, and 4 vs 1: OR 1.81; 95 % CI 1.13-2.92). Our results suggest that urinary BPA levels are significantly associated with overweight in elderly women but not elderly men.