Objective: Cardiovascular disease (CVD) is the leading cause of death in China. While air pollution is a recognized risk factor, the long-term impact of nitrogen dioxide (NO2) on CVD mortality remains insufficient. This study aims to evaluate the effects of prolonged exposure to NO2 on CVDs mortality in the Chinese population from 2010 to 2021, and to identify specific demographic groups most vulnerable to these effects.Design and method: Participants were derived from the 2010/2013 China Chronic Disease and Risk Factor Surveillance Project which linked to the National Death Surveillance System. We analyzed 178,839 individuals (mean age 48.42 years; 55.32% female; 60.49% rural) followed from 2010 to 2021. The pollutant concentration grid information with a spatial resolution of 1 km × 1 km was constructed using national air quality monitoring network and random forest model. Individual exposure was residential-based, calculated as the average annual concentration from enrollment to the year of CVD death or follow-up end. Cox proportional hazards models estimated hazard ratios (HR) per 10 μg/m3 increase in NO2, adjusted for demographics, socioeconomic status, and lifestyle. Results: From 2010 to 2021, 8,069 deaths occurred, including 3522 from CVD (43.65%). Each 10 μg/m3 increment in NO2 was significantly associated with increased risk of CVD mortality (HR: 1.244, 95%CI: 1.122-1.380). Specifically, HRs for ischemic heart disease, cerebrovascular disease, and hypertensive mortality were 1.131 (1.113-1.150), 1.112 (1.097-1.128), and 1.076 (1.023-1.130), respectively. Subgroup analysis revealed that individuals aged 45 and below experienced higher mortality risk from hypertension. Female, current smoker and alcohol consumer and rural residents were also more vulnerable. A non-linear increasing trend was observed for CVD mortality (Pnon-linear=0.015). Findings remain robust after adjusting PM2.5 and O3, excluding deaths within the first year of follow-up and employing alternative exposure metrics. Importantly, no association was found between NO2 and accidental mortality (HR=1.010, 95% CI: 0.977-1.143), reinforcing the specificity of the cardiovascular connection. Conclusions: Long-term NO2 exposure is a significant driver for CVD mortality in China. The heightened vulnerability of younger adults to hypertensive complications underscores the urgent need for stricter air quality standards to mitigate early cardiovascular burden.
Zhou et al. (Fri,) studied this question.