Long-term exposure to traffic-related air pollution and progression of carotid artery atherosclerosis: a prospective cohort study.
OBJECTIVE
Epidemiological studies have demonstrated associations between long-term exposure to traffic-related air pollution and coronary heart disease (CHD). Atherosclerosis is the principal pathological process responsible for CHD events, but effects of traffic-related air pollution on progression of atherosclerosis are not clear. This study aimed to investigate associations between long-term exposure to traffic-related air pollution and progression of carotid artery atherosclerosis.


METHODS
Healthy volunteers in metropolitan Vancouver, Canada.


METHODS
509 participants aged 30-65 years were recruited and followed for approximately 5 years. At baseline and end of follow-up, participants underwent carotid artery ultrasound examinations to assess atherosclerosis severity, including carotid intima-media thickness, plaque area, plaque number and total area. Annual change of each atherosclerosis marker during the follow-up period was calculated as the difference between these two measurements divided by years of follow-up. Living close to major roads was defined as ≤150 m from a highway or ≤50 m from a major road. Residential exposures to traffic-related air pollutants including black carbon, fine particles, nitrogen dioxide and nitric oxide were estimated using high-resolution land-use regression models. The data were analysed using general linear models adjusting for various covariates.


RESULTS
At baseline, there were no significant differences in any atherosclerosis markers between participants living close to and those living away from major roads. After follow-up, the differences in annual changes of these markers between these two groups were small and not statistically significant. Also, no significant associations were observed with concentrations of traffic-related air pollutants including black carbon, fine particles, nitrogen dioxide and nitric oxide.


CONCLUSIONS
This study did not find significant associations between traffic-related air pollution and progression of carotid artery atherosclerosis in a region with lower levels and smaller contrasts of ambient air pollution.
Department of Population Health, Hofstra North Shore-LIJ School of Medicine, Great Neck, New York, USA.
Wen Qi
WQ
Gan
Ryan W
RW
Allen
Michael
M
Brauer
Hugh W
HW
Davies
G B John
GB
Mancini
Scott A
SA
Lear
D000328:Adult; D000368:Aged; D000397:Air Pollution / Q000009:adverse effects*; D001161:Arteriosclerosis / Q000000981:diagnostic imaging / Q000453:epidemiology*; D002170:Canada / Q000453:epidemiology; D002340:Carotid Artery Diseases / Q000000981:diagnostic imaging / Q000453:epidemiology*; D003430:Cross-Sectional Studies; D018450:Disease Progression; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D018986:Motor Vehicles; D011446:Prospective Studies; D012307:Risk Factors; D014463:Ultrasonography
Epidemiology; Occupational & Industrial Medicine; Preventive Medicine; Public Health