High Blood Pressure and Long-Term Exposure to Indoor Noise and Air Pollution from Road Traffic

Background: Traffic noise has been associated with prevalence of hypertension, but reports are inconsistent for blood pressure (BP). To ascertain noise effects and to disentangle them from those suspected to be from traffic-related air pollution, it may be essential to estimate people’s noise exposure indoors in bedrooms.Objectives: We analyzed associations between long-term exposure to indoor traffic noise in bedrooms and prevalent hypertension and systolic (SBP) and diastolic (DBP) BP, considering long-term exposure to outdoor nitrogen dioxide (NO₂).Methods: We evaluated 1,926 cohort participants at baseline (years 2003–2006; Girona, Spain). Outdoor annual average levels of nighttime traffic noise (L_night) and NO₂ were estimated at postal addresses with a detailed traffic noise model and a land-use regression model, respectively. Individual indoor traffic L_night levels were derived from outdoor L_night with application of insulations provided by reported noise-reducing factors. We assessed associations for hypertension and BP with multi-exposure logistic and linear regression models, respectively.Results: Median levels were 27.1 dB(A) (indoor L_night), 56.7 dB(A) (outdoor L_night), and 26.8 μg/m³ (NO₂). Spearman correlations between outdoor and indoor L_night with NO₂ were 0.75 and 0.23, respectively. Indoor L_night was associated both with hypertension (OR = 1.06; 95% CI: 0.99, 1.13) and SBP (β = 0.72; 95% CI: 0.29, 1.15) per 5 dB(A); and NO₂ was associated with hypertension (OR = 1.16; 95% CI: 0.99, 1.36), SBP (β = 1.23; 95% CI: 0.21, 2.25), and DBP (β⊇= 0.56; 95% CI: –0.03, 1.14) per 10 μg/m³. In the outdoor noise model, L_night was associated only with hypertension and NO₂ with BP only. The indoor noise–SBP association was stronger and statistically significant with a threshold at 30 dB(A).Conclusion: Long-term exposure to indoor traffic noise was associated with prevalent hypertension and SBP, independently of NO₂. Associations were less consistent for outdoor traffic L_night and likely affected by collinearity.Citation: Foraster M, Künzli N, Aguilera I, Rivera M, Agis D, Vila J, Bouso L, Deltell A, Marrugat J, Ramos R, Sunyer J, Elosua R, Basagaña X. 2014. High blood pressure and long-term exposure to indoor noise and air pollution from road traffic. Environ Health Perspect 122:1193–1200; http://dx.doi.org/10.1289/ehp.1307156