Serum PCBs, OCPs, PBDEs and PCAs: Associations with metabolic syndrome risk factors in the Flemish Gut Flora Project cohort

Metabolic syndrome (MetS) is a complex, multifactorial disorder mainly linked to lifestyle factors. However, emerging evidence suggests that environmental exposures, such as persistent organic pollutants (POPs), may also contribute to its development. This study investigated serum POP levels and their associations with MetS and related cardiometabolic outcomes in Belgian adults. The study included 403 adults from the Flemish Gut Flora Project (FGFP), a Belgian population-based cohort. Serum concentrations of polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs) and polybrominated diphenyl ethers (PBDEs) were measured using GC-ECNI/MS, while polychlorinated alkanes (PCAs) were quantified using LC/MS. MetS and its components (central obesity, hypertriglyceridemia, low HDL cholesterol, hypertension, impaired fasting glucose) were defined by the International Diabetes Federation criteria. The overall prevalence of MetS was 16.5 % (n = 23) for males and 8.0% (n = 21) for females. Detection frequencies (DFs) were generally high: 13 of the 21 POPs, including PCBs and OCPs were present in 40% of the samples. In pooled serum extracts, DFs for PCAs were 44% for ΣPCA(C₁₀-C₁₃), 68% for ΣPCA(C₁₄-C₁₇) and 5% for ΣPCA(C₁₈-C₂₀). Multi-pollutant models revealed significant associations between POPs and several MetS indicators stratified by sex. Notably, females exhibited significantly increased odds of elevated blood pressure (OR: 2.29, FDR <0.05). This study provides evidence of ongoing exposure to POPs in Belgium, linking these mixtures to cardiometabolic alterations. These findings emphasize a potential differential susceptibility in females and underscore the need for targeted public health considerations.