Interactive and joint effects of toxic metals and oxidative balance score on the risk of mortality in adults with NAFLD

High oxidative balance score (OBS) may mitigate inflammation levels and thereby alleviate the adverse health effects induced by toxic metals. We assessed the independent, joint effects as well as their interactions of toxic metals and OBS on mortality among individuals with non-alcoholic fatty liver diseases (NAFLD). Participants with NAFLD from the National Health and Nutrition Examination Survey (NHANES) 1999-2018 were included. Mortality and underlying causes of death were certain by National Death Index records through 31 December 2019. Cox regression models were used to estimate hazard ratios (HRs) for all-cause and disease-specific mortality. Additionally, we assessed multiplicative and additive interactions of OBS and toxic metals on mortality. Among 5263 patients with NAFLD, 1097 deaths occurred during a mean follow-up of 10.27 years. Compared with those in the OBS tertile 1, participants in tertile 3 had lower risk of all-cause mortality (HR=0.79, 95 %CI: 0.64, 0.96). Compared with individuals in the lowest lead concentration in blood, those in the highest had an increased risk of mortality, with the HRs (95 %CIs) being 1.23 (1.01, 1.51), 1.53(1.06, 2.20) and 1.94(1.25, 3.01) for all-cause, CVD and cancer mortality, respectively. Similar results were also found for blood cadmium level. Joint associations analyses found that individuals with low lead and high-OBS levels had the lowest risk of all-cause, CVD and cancer mortality, with the HRs(95 %CIs) being 0.58(0.40, 0.85), 0.45(0.21, 0.93) and 0.35(0.15, 0.81), respectively. Multiplicative interactions between OBS and blood cadmium on all-cause death (HR=0.87, 95 %CI: 0.78, 0.97) and CVD death (HR=0.81, 95 %CI: 0.67, 0.99) were found. High OBS and low exposure to toxic metals were associated with lower risk of mortality among participants with NAFLD. Adopting anti-oxidative lifestyle could alleviate the harmful effects of toxic metals in NAFLD patients. Comprehensive strategies are essential to decrease the risk of mortality and potentially mitigate the overall burden of NAFLD.