Associations of long-term exposure to nitrogen oxides with all-cause and cause-specific mortality

Associations between long-term exposure to nitrogen oxides (NO_x) and cause-specific mortality remain insufficiently explored. This study utilizes data from 502,040 participants registered in the UK Biobank. Time-varying Cox regression is used to estimate mortality risks associated with NO_x. Cause-specific mortality risks, including non-accidental, accidental and 15 major disease categories across 103 subcategories, are assessed for each 10 μg/m³ increase in NO_x. Positive associations are observed between NO_x and mortality from all-cause (HR: 1.036; 95% CI: 1.024, 1.049) and non-accidental diseases (HR: 1.032; 95% CI: 1.019, 1.045). We further identify 20 specific diseases related to NO_x, notably respiratory diseases, mental and behavioral disorders, and circulatory diseases, with generally linear exposure-response relationships. Sex and residential areas are potential modifiers of the observed associations. Our findings suggest long-term exposure to NO_x may increase mortality risks from a range of diseases, emphasizing the urgent need for clean air policies to alleviate the health burden.