The association between ambient particulate air pollution and fatal coronary heart disease among persons with respiratory symptoms/disease

Abstract

PurposeTo assess the effects of ambient particulate matter (PM) air pollution on risk of fatal coronary heart disease (CHD) in persons characterized as a sensitive subgroup, e.g. persons with known respiratory disease.MethodsThe Adventist Health Study on Smog (AHSMOG) is a cohort study of 3769 nonsmoking, adults who have been followed for 22 years. A total of 806 persons free of CHD, stroke or diabetes at baseline and who reported having symptoms of asthma, some kind of bronchial condition, or emphysema on one of the 4 follow-up questionnaires (1977, 1987, 1992, 2000) constitute the study population. Monthly concentrations of ambient air pollutants were obtained from monitoring stations (PM10, Ozone, SO2, and NO2) or airport visibility data (PM2.5) and interpolated to zip code centroids of work and residence locations. PM10-2.5 concentrations were calculated as the differences between PM10 and PM2.5. Time-dependent Cox proportional hazards regression was used for analyses. Analyses were controlled for a number of potential confounders available from a detailed lifestyle questionnaire at baseline and for environmental tobacco smoke and other personal sources of air pollution available from the 4 subsequent questionnaires.ResultsElevated risk of fatal CHD was found for all ambient PM fractions with the highest risk estimates for coarse fraction (PM10-2.5). The relative risk (RR) for fatal CHD with each 10 [mu]g/m3 increase in PM10-2.5 was 2.1 (95% confidence interval (CI): 1.3, 3.3) in the single pollutant model and 2.2 (95 % CI: 1.3, 3.8) in the two-pollutant model with ozone. Risk appeared to be stronger in females than in males.ConclusionHigh ambient concentrations of PM, especially coarse fraction, are associated with increased risk of fatal CHD among persons with known chronic respiratory disease (asthma, bronchial condition, or emphysema). The risk appears to be stronger in females than in males.