Circulating levels of persistent organic pollutants associate in divergent ways to fat mass measured by DXA in humans

Abstract

Background: Environmental contaminants have recently been implicated in the pathogenesis of obesity.

Objective: To explore relations between persistent organic pollutants (POPs) and fat mass independently of body stature, using a cross-sectional design.

Methods: In the Prospective Study of the Vasculature in Uppsala Seniors (PIVUS), fat mass was determined in 70-year-old subjects (n=890) by dual-energy X-ray absorptiometry (DXA). The plasma levels of 21 POPs (including 16 PCB congeners, 3 OC pesticides, 1 BDE47, and 1 dioxin) were measured by high resolution chromatography coupled with high resolution mass spectrometry (HRGC/HRMS).

Results: Lipid-standardized plasma concentrations of octachlorodibenzo-p-dioxin (OCDD), the PCBs 74, 99, 105 and 118, and the pesticides HCB, TNK, and DDE were all positively related to fat mass (p=0.03-0.0001). Subjects in the fifth quintile for PCB 105 showed a mean fat mass that was 4.8 kg more than subjects in the first quintile. On the other hand, the PCBs 156, 157, 169, 170, 180, 189, 194, 206, and 209 were negatively related to fat mass (p=0.0001). For PCB 194, subjects in the fifth quintile showed a mean fat mass that was 10.8 kg less than subjects in the first quintile. Following adjustment for smoking, physical activity, education level, height, lean mass, and gender, these results remained significant (p=0.01-0.0001) except for the PCBs 74 and 99. For some PCBs, the associations vs. fat mass were more pronounced in women than in men.

Conclusion: Plasma concentrations of some pesticides are positively related to fat mass, while divergent associations are seen for the PCBs. These results implicate a complex role of POPs in obesity.