Effects of Exposure to Environmental Pollutants on Markers of Adiposity and Inflammation

There is growing concern over the role of persistent organic pollutants (POPs) in the global obesity epidemic, particularly given their potential to disrupt lipid metabolism and promote inflammation. This dissertation included 2,264 adults aged 45–74 years from the Hispanic Community Health Study/Study of Latinos (HCHS/SOL) and examined the prospective associations of POPs with change in adiposity measures, as well as cross-sectional and prospective associations with inflammation. Additionally, we explored whether inflammation mediates the relationship between POPs and adiposity. To complement findings from the general population, we evaluated cross-sectional associations between polychlorinated biphenyls (PCBs) and inflammatory markers in 217 participants from the La Salle Electrical Utilities Company Morbidity Study, including both former workers and nearby residents with high occupational and environmental exposure. In HCHS/SOL, we observed sex-specific associations between POPs and adiposity. In women, PCBs were positively associated with change in waist circumference (WC), while in men, organochlorine pesticides (OCPs) were more strongly associated with change in body mass index (BMI) and WC. In both sexes, β-hexachlorocyclohexane (β-HCH) was positively associated with change in BMI and WC. Effect modification analyses further indicated that associations between specific OCPs and adiposity were present only among postmenopausal women. We also examined associations between POPs and inflammatory markers, including high-sensitivity C-reactive protein (hs-CRP), intercellular adhesion molecule-1 (ICAM-1), gamma-glutamyl transferase (GGT), white blood cell count (WBCC), neutrophil-to-lymphocyte ratio (NLR), and monocyte-to-lymphocyte ratio (MLR). Results were inconsistent and varied by sex, chemical class, and specific marker. There was no evidence that inflammation mediated the association between POPs and adiposity. In the La Salle cohort, we observed positive associations between PCB groupings and C-reactive protein (CRP) in women. Among men, PCB groupings and occupational exposures (job score and quarters worked) were positively associated with MLR, and job score was negatively associated with WBCC. Our findings support sex-specific associations between POPs and adiposity and suggest that POP exposure may influence inflammation in a dose-dependent manner. Future research should explore a broader range of inflammatory markers and the modifying role of lifestyle factors such as physical activity.