Changes in adipose tissue and circulating concentrations of persistent organic pollutants: the Study of Women's Health Across the Nation

Background: Polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) are persistent organic pollutants (POPs) that bioaccumulate in adipose tissue and can negatively impact health often via endocrine system disruption. In the U.S., regulations on the industrial production or commercial use of POPs have reduced external exposure. Nevertheless, POPs can be released from adipose tissue and constitute a continued internal source of exposure. Objective: We investigated the relationship between a change in central adiposity and changes in circulating concentrations of POPs. Methods: We measured serum concentrations of 34 PCBs and 19 OCPs at four timepoints in a longitudinal cohort of midlife women within the Study of Women’s Health Across the Nation. For PCBs, 65 women with at least two serum measurements were included, for a total of 181 observations. For OCPs, 59 women with at least two serum measurements were included, for a total of 151 observations. Linear mixed models were used to test the association between an increase in waist circumference and a change in serum POPs concentrations. Results: After adjustment for confounding variables, as the difference in waist circumference between visits increased by one inch, the difference in the serum concentration of PCB-194 decreased by 4.8% (95% CI: -7.9, -1.6). No significant associations were found for other PCB congeners or OCPs. Of all the POPs analyzed, PCB-194 has the greatest lipophilicity. Conclusions: POPs may be released from adipose tissue into the blood or conversely sequestered in adipose tissue following adiposity loss or gain, respectively. The dynamics and distribution of POPs may be influenced by a compound’s lipophilicity. Further research is warranted on intra-person variation in serum POPs concentrations as well as other factors that may affect trends in serum concentrations.