The impact of the synergistic effect of SO(2) and PM(2.5)/PM(10) on obstructive lung disease in subtropical Taiwan

BACKGROUND: Chronic Obstructive lung diseases (COPD) are complex conditions influenced by various environmental, lifestyle, and genetic factors. Ambient air pollution has been identified as a potential risk factor, causing 4.2 million deaths worldwide in 2016, accounting for 25% of all COPD-related deaths and 26% of all respiratory infection-related deaths. This study aims to evaluate the associations among chronic lung diseases, air pollution, and meteorological factors. METHODS: This cross-sectional study obtained data from the Taiwan Biobank and Taiwan Air Quality Monitoring Database. We defined obstructive lung disease as patients with FEV1/FVC < 70%. Descriptive analysis between spirometry groups was performed using one-way ANOVA and the chi-square or Fisher’s exact test. A generalized additive model (GAM) was used to evaluate the relationship between SO(2) and PM(2.5)/PM(10) through equations and splines fitting. RESULTS: A total of 2,635 participants were enrolled. Regarding environmental factors, higher temperature, higher relative humidity, and lower rainfall were risk factors for obstructive lung disease. SO(2) was positively correlated with PM(10) and PM(2.5), with correlation coefficients of 0.53 (p < 0.0001) and 0.52 (p < 0.0001), respectively. Additionally, SO(2) modified the relative risk of obstructive impairment for both PM(10) [β coefficient (β) = 0.01, p = 0.0052] and PM(2.5) (β = 0.01, p = 0.0155). Further analysis per standard deviation (per SD) increase revealed that SO(2) also modified the relationship for both PM(10) (β = 0.11, p = 0.0052) and PM(2.5) (β = 0.09, p = 0.0155). Our GAM analysis showed a quadratic pattern for SO(2) (per SD) and PM(10) (per SD) in model 1, and a quadratic pattern for SO(2) (per SD) in model 2. Moreover, our findings confirmed synergistic effects among temperature, SO(2) and PM(2.5)/PM(10), as demonstrated by the significant associations of bivariate (SO(2) vs. PM(10), SO(2) vs. PM(2.5)) thin-plate smoothing splines in models 1 and 2 with obstructive impairment (p < 0.0001). CONCLUSION: Our study showed high temperature, humidity, and low rainfall increased the risk of obstructive lung disease. Synergistic effects were observed among temperature, SO(2), and PM(2.5)/PM(10). The impact of air pollutants on obstructive lung disease should consider these interactions.