Disentangling the effects of traffic-related noise and air pollution on blood pressure: indoor noise levels and protections

Background In urban areas, traffic-related noise and air pollution may be correlated, thus effects mutually confounded. To disentangle effects, considering peoples’ exposure indoors is essential. This has not been done so far which may explain inconsistent findings for blood pressure (BP) and hypertension (HT) and these two environmental stressors. We integrate for the first time indoor traffic noise to disentangle their effects. Aims We analysed associations of long-term exposure to home outdoor nitrogen dioxide (NO2) and outdoor and indoor estimates of traffic noise levels with HT, systolic BP (SBP), and diastolic BP (DBP; mmHg). Methods We evaluated 1926 participants at baseline (years 2003-2006) from the Catalan REGICOR cohort. We collected data on measures against noise at home indoors. Outdoor residential traffic noise at night (Lnight) and NO2 levels were estimated at facades with a city-specific noise model and land-use regression model, respectively. Individual indoor traffic noise levels were de...