association and moderation of self-reported hypotension with traffic noise exposure: a neglected relationship

In a short-term experimental study about one-third of subjects exposed to noise shows both increases and decreases in blood pressure. While the association of noise with hypertension is established it is not yet known whether hypotension is associated with noise in field studies. In a cross-sectional study the association of self-reported hypotension and low blood pressure readings with traffic noise was examined in adults (age 25-65, N = 1989, participation = 62%). Noise exposure was based on both, short and long-term day/night recordings and standard noise mapping. Questionnaire data on socio-demographics, housing, life-style, noise and weather sensitivity, health status, mental and physical symptoms were available to adjust for potential confounding and testing for moderation. Non-linear multiple regression was applied to estimate the association between the two outcomes and overall noise exposure. We did not observe a stable relation between noise and low blood pressure readings since the number of subjects based on the recommended cut-off points (5 th percentile or 110 (100)/60 mmHg) was too small. However, self-reported hypotension was non-linearly associated with noise exposure ( P = 0.044) in the presence of a strong sex × age effect modification ( P < 0.0001). Another significant moderation by noise were observed with reported symptoms of exhaustion ( P = 0.03). Weather sensitivity showed a significant interaction with noise sensitivity ( P = 0.02) and also a non-linear interaction with age ( P = 0.02). The results remained stable after adjustment for variables known to be associated with constitutional hypotension. The exposure-effect curve ascends around sound levels of 55 dBA. The results suggest a novel moderated association of noise with self-reported hypotension, predominantly in weather sensitive women with symptoms of exhaustion. Further and larger studies are needed to replicate the potential moderating effect of noise on persons with constitutional hypotension.