Exposure to road traffic and railway noise and associations with blood pressure and self-reported hypertension: a cohort study.
BACKGROUND
Epidemiological studies suggest that long-term exposure to transport noise increases the risk for cardiovascular disorders. The effect of transport noise on blood pressure and hypertension is uncertain.


METHODS
In 1993-1997, 57,053 participants aged 50-64 year were enrolled in a population-based cohort study. At enrollment, systolic and diastolic blood pressure was measured. Incident hypertension during a mean follow-up of 5.3 years was assessed by questionnaire. Residential long-term road traffic noise (Lden) was estimated for 1- and 5-year periods preceding enrollment and preceding diagnosis of hypertension. Residential exposure to railway noise was estimated at enrollment. We conducted a cross-sectional analysis of associations between road traffic and railway noise and blood pressure at enrollment with linear regression, adjusting for long-term air pollution, meteorology and potential lifestyle confounders (N = 44,083). Incident self-reported hypertension was analyzed with Cox regression, adjusting for long-term air pollution and potential lifestyle confounders.


RESULTS
We found a 0.26 mm Hg higher systolic blood pressure (95% confidence intervals (CI): -0.11; 0.63) per 10 dB(A) increase in 1-year mean road traffic noise levels, with stronger associations in men (0.59 mm Hg (CI: 0.13; 1.05) per 10 dB(A)) and older participants (0.65 mm Hg (0.08; 1.22) per 10 dB(A)). Road traffic noise was not associated with diastolic blood pressure or hypertension. Exposure to railway noise above 60 dB was associated with 8% higher risk for hypertension (95% CI: -2%; 19%, P = 0.11).


CONCLUSIONS
While exposure to road traffic noise was associated with systolic blood pressure in subgroups, we were not able to identify associations with hypertension.
Institute of Cancer Epidemiology, Danish Cancer Society, Copenhagen, Denmark. mettes@cancer.dk
Mette
M
Sørensen
Martin
M
Hvidberg
Barbara
B
Hoffmann
Zorana J
ZJ
Andersen
Rikke B
RB
Nordsborg
Kenneth G
KG
Lillelund
Jørgen
J
Jakobsen
Anne
A
Tjønneland
Kim
K
Overvad
Ole
O
Raaschou-Nielsen
D000368:Aged; D000397:Air Pollution / Q000009:adverse effects; D001794:Blood Pressure; D002947:Cities / Q000453:epidemiology; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D003718:Denmark / Q000453:epidemiology; D004781:Environmental Exposure / Q000009:adverse effects* / Q000032:analysis; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006973:Hypertension / Q000209:etiology*; D015994:Incidence; D008019:Life Style; D008297:Male; D008875:Middle Aged; D018986:Motor Vehicles; D009624:Noise, Transportation / Q000009:adverse effects*; D011890:Railroads; D012044:Regression Analysis; D057566:Self Report; D011795:Surveys and Questionnaires; D014887:Weather