Association Between Ambient Air Pollution and Cardiovascular Disease Outcomes in Peri-Urban Communities in Lagos State, South West Nigeria

While extensive evidence links ambient air pollution to cardiovascular morbidity and mortality in high-income countries, empirical data from African urban settings remain limited, creating a significant knowledge gap for environmental health policy in Nigeria. This study examined the association between ambient air pollution and cardiovascular disease outcomes in four peri-urban communities in Lagos State, South West Nigeria. Fixed-site monitors deployed at twenty-four locations measured PM2.5, PM10, nitrogen dioxide, and carbon monoxide concentrations continuously over a twelve-month period. A case-control study compared ambient air pollution exposure estimates (based on residential proximity to monitoring stations and land use regression modeling) between 200 confirmed cardiovascular disease cases drawn from secondary hospital records and 400 matched controls from the same communities. Logistic regression analysis adjusted for age, sex, smoking status, body mass index, and socioeconomic status. Results showed that residing in high PM2.5 zones (above 35 micrograms per cubic metre annual mean) was associated with a 2.4-fold increased odds of hypertension diagnosis and 1.8-fold increased odds of acute coronary syndrome hospitalization. Nitrogen dioxide exposure independently predicted ischemic heart disease risk. Seasonal variation analysis showed significantly higher exposure during the dry harmattan season. The study provides one of the first empirically rigorous estimates of the air pollution-cardiovascular disease association in Nigerian peri-urban settings. Findings support urgent air quality standard enforcement and emission source control. Keywords: ambient air pollution, cardiovascular disease, Lagos, PM2.5, epidemiology.