Association of exposure to organochlorine pesticides with the antioxidant bilirubin: Mediation analysis in the NHANES

Exposure to organochlorine pesticides (OCPs) has been linked to adverse health effects through oxidative stress. Bilirubin, an endogenous antioxidant, may play a key role in regulating oxidative stress. This study utilized NHANES data (2007–2016) to investigate the relationship between exposure to seven OCPs and serum total bilirubin (TB) levels in American adults, as well as potential mediating effects. Among the 6583 adults studied, HCB, β-HCCH, p, p′-DDE, p, p′-DDT, OXYCHLOR, and T-NONA were all significantly and positively correlated with TB levels among the seven OCPs analyzed (p < 0.05). HCB, β-HCCH, and OXYCHLOR showed inverted "J"-, a similar "S"-, and "U"-shaped nonlinear relationships with TB, respectively (p for nonlinear < 0.05). OXYCHLOR had the strongest cumulative effect, and platelets partially mediated the association between p, p′-DDE, p, p′-DDT, T-NONA, OXYCHLOR, and TB. Exposure to OPCs was significantly positively associated with antioxidant TB levels, and platelets played a partially negative mediating role in this association. This finding suggests that OCPs exposure may adversely affect human health by impacting the redox system.