Road traffic noise and hypertension.
BACKGROUND
It has been suggested that noise exposure increases the risk of hypertension. Road traffic is the dominant source of community noise exposure.


OBJECTIVE
To study the association between exposure to residential road traffic noise and hypertension in an urban municipality.


METHODS
The study population comprised randomly selected subjects aged 19-80 years. A postal questionnaire provided information on individual characteristics, including diagnosis of hypertension. The response rate was 77%, resulting in a study population of 667 subjects. The outdoor equivalent traffic noise level (Leq 24 h) at the residence of each individual was determined using noise-dispersion models and manual noise assessments. The individual noise exposure was classified in units of 5 dB(A), from <45 dB(A) to >65 dB(A).


RESULTS
The odds ratio (OR) for hypertension adjusted for age, smoking, occupational status and house type was 1.38 (95% confidence interval (CI) 1.06 to 1.80) per 5 dB(A) increase in noise exposure. The association seemed stronger among women (OR 1.71; 95% CI 1.17 to 2.50) and among those who had lived at the address for >10 years (OR 1.93; 95% CI 1.29 to 2.83). Analyses of categorical exposure variables suggested an exposure-response relationship. The strongest association between exposure to traffic noise and hypertension was found among those with the least expected misclassification of true individual exposure, as indicated by not having triple-glazed windows, living in an old house and having the bedroom window facing a street (OR 2.47; 95% CI 1.38 to 4.43).


CONCLUSIONS
The results of our study suggest an association between exposure to residential road traffic noise and hypertension.
Leon Bluhm
Gösta
G
Unit of Environmental Epidemiology, Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden. gosta.bluhm@ki.se
Berglind
Niklas
N
Nordling
Emma
E
Rosenlund
Mats
M
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004781:Environmental Exposure / Q000009:adverse effects / Q000032:analysis; D004784:Environmental Monitoring / Q000379:methods; D004812:Epidemiologic Methods; D062665:Epidemiological Monitoring; D005260:Female; D006801:Humans; D006973:Hypertension / Q000453:epidemiology / Q000209:etiology*; D008297:Male; D008875:Middle Aged; D009624:Noise, Transportation / Q000009:adverse effects*; D012111:Residence Characteristics; D013548:Sweden / Q000453:epidemiology; D014504:Urban Health / Q000706:statistics & numerical data