Acute cardiovascular mortality in communities living near a major airport: mutual effects of fine particulate matter and nitrogen dioxide

Abstract

BACKGROUND AND AIM: Ambient air pollution is the leading cause of environmental mortality and morbidity worldwide. However, the individual contributions to acute mortality of traffic-related air pollutants such as nitrogen dioxide (NO2) and fine particulate matter (PM2.5) are still debated. METHODS: We conducted a time-stratified case-crossover study for a study population located around Zurich airport in Switzerland, including 24,886 adult cardiovascular deaths from the Swiss National Cohort. We estimated the risk of cause-specific cardiovascular mortality associated with daily NO2 and PM2.5 exposure at home using distributed lag models up to 7 days preceding death, adjusted for daily temperature, acute night-time aircraft noise, firework celebrations, and holidays. RESULTS:Cardiovascular mortality was associated with NO2; whereas the association with PM2.5 disappeared upon adjustment for NO2. The strongest association was observed between NO2 and ischemic stroke (OR = 1.55 per 10µg/m3, 95% CI = 1.20-2.00). Cause-specific analyses showed differences in terms of delayed effect: OR were highest at 1-3 days after exposure for most health outcomes but at lags of 3-5 days for heart failure. Individual and social vulnerabilities to NO2 associated cardiovascular mortality also varied by health outcome, possibly highlighting the role of different behaviours and risk factors in these groups. CONCLUSIONS:This study confirms the association between ambient, as a marker for primary emissions, and acute cardiovascular mortality in a specific setting around a major airport. Future research should further investigate the role of additional air pollutants including ultra-fine particles on cardiovascular disease to inform most efficient control measures. KEYWORDS: Air pollution (traffic-related), cardiovascular diseases