Association of short-term exposure to ambient air pollutants with exhaled nitric oxide in hospitalized patients with respiratory-system diseases.

BACKGROUND

Previous studies have suggested that exposure to ambient air pollutants may adversely affect human health. However, few studies have examined the health effects of exposure to ambient air pollutants in hospitalized patients.

OBJECTIVES

To evaluate the association between short-term exposure to ambient air pollutants and exhaled nitric oxide fraction (FeNO) in a large cohort of hospitalized patients.

METHODS

FeNO was detected for 2986 hospitalized patients (ages 18-88 years). Daily average concentrations of SO, NO, O, CO, PM and PM in 2014 and 2015 were obtained from nine fixed-site monitoring stations. Multiple linear regression models were chosen to assess the associations of exposure to ambient air pollutants with FeNO while adjusting for confounding variables. Lagged variable models were selected to determine the association between FeNO and ambient air pollutants concentrations with lags of up to 7 days prior to FeNO testing.

RESULTS

Interquartile-range (IQR) increases in the daily average SO (8.00 μg/m) and PM (37.0 μg/m) were strongly associated with increases in FeNO, with increases of 3.41% [95% confidence interval (CI), 0.94-5.93%] and 2.72% (95%CI, -0.09% to 5.61%), respectively. However, FeNO levels were not statistically associated with PM, NO, O or CO. In the two-pollutant models, the maximum correlation was for ambient SO. We also found that FeNO was associated with IQR increases in daily average ambient concentrations of SO up to 3 and 4 days after the exposure events.

CONCLUSIONS

Short-term exposure to SO and PM were positively correlated with FeNO levels in hospitalized patients in Shanghai.