The association between environmental exposure to perchlorate, nitrate, and thiocyanate and all-cause and cause-specific mortality

The aim is to examine the environmental exposure to perchlorate, nitrate, and thiocyanate and their associations with all-cause and cause-specific mortality in a general population. A total of 17,982 participants were enrolled from the National Health and Nutrition Examination Survey and urinary perchlorate, nitrate, and thiocyanate are measured using ion chromatography coupled with electrospray tandem mass spectrometry. Multivariable linear and logistic regression models were performed to explore the associations between urinary perchlorate, nitrate, and thiocyanate with all-cause and cause-specific mortality. Restricted cubic spline models were used to explore the nonlinearity. During a 7.5-year of follow-up, 1730 deaths occurred. Kaplan-Meier analysis suggested that urinary perchlorate, thiocyanate, and nitrate were associated with all-cause mortality (all log-rank P<0.001). After adjusted for traditional risk factors, we found that urinary perchlorate was inversely associated with cancer mortality (hazard ratio [HR] 0.87; 95% confidence interval [0.76, 0.99]; P=0.038) while nitrate was positively related to cancer mortality (HR 1.19, [1.05, 1.34]; P=0.006). Besides, urinary thiocyanate exposure was U-shape associated with the risk of all-cause mortality (P for nonlinearity<0.001). Urinary perchlorate was inversely while nitrate was positively associated with the risk of cancer mortality. The thiocyanate exposure was U-shape associated with the risk of all-cause mortality.