Air pollutants are important contributors to cardiovascular diseases, but associations between long-term exposure to air pollutants and the risk of abdominal aortic aneurysm (AAA) are still unknown.

This study was conducted using a sample of 449 463 participants from the UK Biobank. Hazard ratios and 95% confidence intervals for the risk of AAA incidence associated with long-term exposure to air pollutants were estimated using the Cox proportional hazards model with time-varying exposure measurements. Additionally, the cumulative incidence of AAA was calculated by using the Fine and Grey sub-distribution hazards regression model. Furthermore, this study investigated the combined effects and interactions between air pollutants exposure and genetic predisposition in relation to the risk of AAA onset.

Long-term exposure to particulate matter with an aerodynamic diameter <2.5 µm [PM_2.5, 1.21 (1.16, 1.27)], particulate matter with an aerodynamic diameter <10 µm [PM₁₀, 1.21 (1.16, 1.27)], nitrogen dioxide [NO₂, 1.16 (1.11, 1.22)], and nitrogen oxides [NO_x, 1.10 (1.05, 1.15)] was found to be associated with an elevated risk of AAA onset. The detrimental effects of air pollutants persisted even in participants with low-level exposure. For the joint associations, participants with both high levels of air pollutants exposure and high genetic risk had a higher risk of developing AAA compared with those with low concentrations of pollutants exposure and low genetic risk. The respective risk estimates for AAA incidence were 3.18 (2.46, 4.12) for PM_2.5, 3.09 (2.39, 4.00) for PM₁₀, 2.41 (1.86, 3.13) for NO₂, and 2.01 (1.55, 2.61) for NO_x.

In this study, long-term air pollutants exposure was associated with an increased risk of AAA incidence.