Ambient nitrogen dioxide and years of life lost from chronic obstructive pulmonary disease in the elderly: A multicity study in China.

Abstract Background Chronic obstructive pulmonary disease (COPD) is a leading cause of morbidity and mortality worldwide, and nitrogen dioxide (NO2) is a potential environmental risk factor for COPD. However, association between ambient NO2 and COPD risk remains underrecognized, especially in the elderly. This study aimed to explore association between NO2 and years of life lost (YLL) from COPD in the elderly from 2013 to 2017 in 37 major cities in China. Methods Ambient NO2 data and COPD morality information were obtained from the National Urban Air Quality Real-time Publishing Platform and the Chinese Centers for Disease Control and Prevention, respectively. City-specific relative changes in YLL were estimated by generalized additive models, and meta-analysis was used to combine city-specific results. Potential modifications were evaluated. Economic loss due to excess YLL from COPD associated with ambient NO2 was evaluated. Results An increase of 10 μg/m3 in NO2 for 2-day moving average led to 0.94% (95% CI: 0.56%, 1.31%) relative increase in COPD YLL. The associations were significantly higher in South than North China. Higher estimated effects were found in the warm than the cool season in the southern region. The relevant economic loss accounted for 0.04% (95% CI: 0.02%, 0.05%) of the gross domestic product (GDP) in China during the same period. Conclusions The findings provide evidence on the impact of short-term NO2 exposure on COPD YLL in the elderly, which indicated more stringent control of NO2 pollution and highlighted the need to protect the elderly during the warm season in South China.