Associations of perchlorate, nitrate, and thiocyanate with oxidative stress, inflammatory, and lung diseases:...

The relationships among exposure to perchlorate, nitrate, and thiocyanate, oxidative stress, inflammation, and lung diseases remain unclear. This study included 6978 adults from the National Health and Nutrition Examination Survey 2007-2016. Survey weighted regression and weighted quantile sum (WQS) regression were used to evaluate the associations of perchlorate, nitrate, and thiocyanate exposures with the prevalence of lung diseases. Mediation analysis was conducted to assess the roles of oxidative stress biomarkers, including total bilirubin (TBIL) and γ-glutamyltransferase, as well as inflammatory biomarkers, including alkaline phosphatase, white blood cell (WBC), and WBC subtypes. In single exposure analysis, each 2-fold increment in urinary perchlorate level was associated with 18 % (odd ratio: 1.18; 95 % confidence interval: 1.07, 1.29) and 21 % (1.21; 1.01, 1.52) increments in the risks of chronic obstructive pulmonary disease (COPD) and emphysema, respectively. Each 2-fold increment urinary thiocyanate level was associated with 8 % (1.08; 1.01, 1.18), 14 % (1.14; 1.01, 1.28), 15 % (115; 1.01, 1.29), and 14 % (1.14; 1.01, 1.29) increments in risks of COPD, emphysema, chronic bronchitis, and asthma, respectively. WQS regression indicated that combined exposure to perchlorate, nitrate, and thiocyanate was associated with increased risks of COPD (1.07; 1.02, 1.13), emphysema (1.10; 1.01, 1.22), chronic bronchitis (1.12; 1.05, 1.19), and asthma (1.04; 1.01, 1.08). TBIL partially suppressed the associations of urinary perchlorate, thiocyanate, and the mixture with lung diseases, with proportions ranging from -9.01 % to -2.89 %, while neutrophil and WBC partially mediated those associations, with proportions ranging from 1.13 % to 9.59 %. Exposure to perchlorate and thiocyanate, as well as the combined exposure to perchlorate, nitrate, and thiocyanate, were associated with lung diseases. Oxidative stress and inflammation may mediate these associations.