Air Pollution Associated Dry Eye Disease May Be Increased by Qi Stagnation in Young: A Nested Case-Control Study in Liaoning, China

Background: Little information exists regarding the interaction of Qi stagnation and air pollution on young’s dry eye disease (DED) in fixed area with an epidemic threat. The aim of this study is to assess the modification by Qi stagnation on the associations of exposure with DED in Chinese young. Methods: A nested case-control study was conducted in Chinese young population aged 17-20 years, within a cohort of He Eye Health screening project. All cases newly diagnosed (n = 576) were matched to controls (n = 576) by age and sex. Logistic regression model was used to assess the odds ratio (OR) and 95% confidence interval (CI) of DED for exposure to different air pollutants in terms of an interquartile range (IQR) increase in exposure level, adjusted for potential confounders. Results: In single-pollutant model, the DED ORs (95% CI) for the 20th to 40th percent of quintile (vs. lowest) were 2.64 (1.66, 4.18) for PM2.5, 1.70 (1.09, 2.66) for PM10, for the highest quintile (vs. lowest) were 1.74 (1.13, 2.66) for CO, and 1.57 (0.98, 2.51) NO2. In contrast, the odds ratios for the highest quintile (vs. lowest) were 0.23 (0.07, 0.78) for O3. Corresponding estimates were higher among Stagnant qi constitution [ORPM10 = 1.69 (1.08, 2.16), ORCO = 1.93 (1.19, 3.54)] than Balanced constitution [ORPM10 = 1.29 (0.79, 2.05), ORCO = 1.70 (1.09, 3.43)] for PM10 and CO2, respectively. In addition, O3 was inversely associated for Stagnant qi constitution [0.67 (0.23, 1.90)] and Balanced constitution [0.51 (0.08, 1.40)]. Conclusion: Exposure to ambient PM2.5, PM10, CO and NO2 was positively associated with DED in Chinese young population. Qi stagnation might amplify the association of exposures to PM10 and CO with DED.