Exposure to organochlorine compounds in relation to weight maintenance.

BACKGROUND: The purpose was to test the hypothesis that exposures to organochlorine compounds are associated with body weight increases in a dietary intervention study. METHODS: In the DioGenes trial, adults with obesity who had at first lost at least 8% of their body weight then completed at least 26 weeks on a specific diet. Concentrations of major organochlorine compounds were assessed in plasma samples obtained at study baseline. RESULTS: A total of 372 participants with complete data were examined for plasma concentrations of major organochlorine compounds. A doubling in total-PCB in plasma was associated with an increase in weight (in kg) at 26 weeks by 0.43 (0.04;0.83), independent of diet group and sex. Associations for most individual organochlorines were in the same direction, though mostly not statistically significant, especially after adjustment. However, p,p'-DDE showed opposite effects. Adjustment for exposure to perfluorinated alkyl substances (PFASs) only minimally affected the findings. CONCLUSIONS: Elevated plasma concentrations of some organochlorine compounds were weakly associated with increased weight gain, although most individual associations did not reach statistical significance after adjustment for PFAS exposure. However, p,p'-DDE concentrations showed a clear association with lowered body weight. Overall, the halogenated pollutants examined are likely to contribute to the obesity pandemic. TRIAL REGISTRATION: The original RCT is with ClinicalTrials.gov number NCT00390637.