Body mass index and serum 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane in nulliparous Chinese women

Background: Basic health indicators, such as body mass index (BMI), have been associated with serum 1,1,1-trichloro-2,2bis(p-chlorophenyl)ethane/1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (DDT/DDE) levels; however, both positive and inverse associations of BMI with serum DDT/DDE have been reported. Given the association of BMI with a number of outcomes, it may confound studies of DDT/DDE-associated health effects. We investigated the relationship of BMI with serum DDT/DDE accounting for other determinants of exposure among women with relatively recent environmental exposures to DDT. Methods: Serum DDT/DDE was analyzed in 466 nonsmoking, nulliparous women recruited from Anhui province in China between 1996 and 1998 as part of a reproductive health study of textile workers. The women in the sample were born between 1963 and 1977, 8 to 21 years before China's 1984 DDT ban. We used multivariate linear regression to investigate associations of BMI, age, and birth year with serum DDT/DDE. Results: Mean (SD) serum total DDT concentration was 32 ng/ g (17.8 ng/g). Birth year showed an inverse relationship with serum DDT independent of age. Despite limited variability in BMI, there was a consistent inverse relationship between BMI and serum DDT. Specifically, each kg/m(2) increase in BMI was associated with a -1.34 ng/g (95% confidence interval, -2.12 to -0.56 ng/g) decrease in serum total DDT. Conclusions: There were high total DDT levels in this sample of nulliparous Chinese women relative to Western populations, birth year was more strongly associated with serum DDT than age, and BMI was inversely related to serum DDT in this study.