Long-term exposure to fine particulate matter constituents and the prognosis of oral cancer patients: a prospective study in Southeastern China

Evidence on the association of long-term exposure to fine particular matter (PM_2.5) and its chemical constituents with the prognosis of oral cancer patients is limited. We identified 1673 oral cancer patients from 2011 to 2021 in Fujian, China. We evaluated annual average concentrations of PM_2.5 and constituents, including nitrate, sulfate, ammonium, black carbon (BC), and organic matter (OM), using bilinear interpolation based on the patients’ residential address. Cox proportional hazard models were used to calculate the hazard ratio (HR) and 95% confidence interval. We used counterfactual analyses to evaluate the population attributable fractions (PAF). During a median follow-up duration of 3.58 years, 484 (28.93%) died. For per-SD increase in PM_2.5, nitrate, sulfate, ammonium, OM, and BC, the adjusted HRs were 1.18, 1.16, 1.18, 1.19, 1.17, and 1.20 for all-cause mortality, and 1.26, 1.22, 1.27, 1.28, 1.24, and 1.29 for oral cancer-specific mortality, respectively. The corresponding PAFs of PM_2.5, nitrate, sulfate, ammonium, OM, and BC were 25.43%, 24.19%, 25.73%, 25.78%, 25.28%, and 26.59% for all-cause mortality, and 26.61%, 24.19%, 27.15%, 27.01%, 26.19%, and 28.41% for oral cancer-specific mortality, respectively. Our study showed that long-term exposure to PM_2.5 and constituents might be an important risk factor for mortality among oral cancer patients.