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.