Exposure to Road, Railway, and Aircraft Noise and Arterial Stiffness in the SAPALDIA Study: Annual Average Noise Levels and Temporal Noise Characteristics

BACKGROUND: The impact of different transportation noise sources and noise environments on arterial stiffness remains unknown. OBJECTIVES: We evaluated the association between residential outdoor exposure to annual average road, railway, and aircraft noise levels, total noise intermittency (IR), and total number of noise events (NE) and brachial-ankle pulse wave velocity (baPWV) following a cross-sectional design. METHODS: We measured baPWV (meters/second) in 2,775 participants (49-81 y old) at the second follow-up (2010-2011) of the Swiss Cohort Study on Air Pollution and Lung and Heart Diseases in Adults (SAPALDIA). We assigned annual average road, railway, and aircraft noise levels (Ldensource), total day- and nighttime NEtime and IRtime (percent fluctuation=0%, none or constant noise; percent fluctuation=100%, high fluctuation) at the most exposed facade using 2011 Swiss noise models. We applied multivariable linear mixed regression models to analyze associations. RESULTS: Medians [interquartile ranges (IQRs)] were baPWV = 13.4 (3.1) m/s; Lden(air) (57.6% exposed) = 32.8 (8.0) dB; Lden(rail) (44.6% exposed) = 30.0 (8.1) dB; Lden(road) (99.7% exposed): 54.2 (10.6) dB; NEnight = 123 (179); NEday = 433 (870); IRnight = 73% (27); and IRday = 63.8% (40.3). We observed a 0.87% (95% CI: 0.31, 1.43%) increase in baPWV per IQR of Ldenrail, which was greater with IRnight > 80% or with daytime sleepiness. We observed a nonsignificant positive association between Lden(road) and baPWV in urban areas and a negative tendency in rural areas. NEnight, but not NEday, was associated with baPWV. Associations were independent of the other noise sources and air pollution. CONCLUSIONS: Long-term exposure to railway noise, particularly in an intermittent nighttime noise environment, and to nighttime noise events, mainly related to road noise, may affect arterial stiffness, a major determinant of cardiovascular disease. Ascertaining noise exposure characteristics beyond average noise levels may be relevant to better understand noise-related health effects.