Air Pollution, Traffic Noise and Development of Subclinical Atherosclerosis in the Thoracic Aorta

Background: Air pollution and noise are suggested to be related to subclinical atherosclerosis, but evidence is scarce and inconsistent. We investigated the independent associations and interactions of long-term exposure to air pollution and road traffic noise with development and progression of thoracic aortic calcification (TAC). Methods: We used baseline (2000-2003) and follow-up (2006-2008) data from the German Heinz Nixdorf Recall Study, a population-based cohort of 4,814 randomly selected participants. We assessed residential long-term exposure to air pollution and noise with chemistry transport and noise propagation models, respectively. TAC was quantified from non-contrast enhanced electron beam computed tomography. Incident TAC and percent increase in TAC progression were analyzed with multiple logistic and linear regression, respectively, adjusted for age, sex, lifestyle variables, and individual and area-level socioeconomic status. Results: The analysis sample comprised 3,125 participants (mean age 59.4 years, 49.9% male) with a mean follow-up of 5 years. Traffic-related air pollutants and night-time noise (L night ) were associated with incident TAC (OR 1.18 [95%CI: 0.98-1.41] per IQR of particle number concentration and 1.20 [0.99, 1.46] per 5 dB(A) L night ). Similar associations were observed for TAC progression (0.14% [0.00; 0.28%] per IQR of NO 2 and 0.18% [0.02; 0.35%] per 5 dB(A) L night ), in those with minimal calcification at baseline. Results did not change upon mutual adjustment. Conclusion: Our study suggests that air pollution and road traffic noise may be weakly associated with the development of subclinical atherosclerosis, which remained robust when taking the other exposure into account.