Background: Evidence based largely on US cohorts suggests that long-term exposure to fine particulate matter is associated with cardiovascular mortality. There is less evidence for other pollutants and for cardiovascular morbidity. By using a cohort of 836,557 patients age 40 to 89 years registered with 205 English general practices in 2003, we investigated relationships between ambient outdoor air pollution and incident myocardial infarction, stroke, arrhythmia, and heart failure over a 5-year period.
Methods: Events were identified from primary care records, hospital admissions, and death certificates. Annual average concentrations in 2002 for particulate matter with a median aerodynamic diameter <10 (PM10) and <2.5 microns, nitrogen dioxide (NO2), ozone, and sulfur dioxide at a 1 × 1 km resolution were derived from emission-based models and linked to residential postcode. Analyses were performed using Cox proportional hazards models adjusting for relevant confounders, including social and economic deprivation and smoking.
Results: While evidence was weak for relationships with myocardial infarction, stroke, or arrhythmia, we found consistent associations between pollutant concentrations and incident cases of heart failure. An interquartile range change in PM10 and in NO2 (3.0 and 10.7 µg/m3, respectively) both produced a hazard ratio of 1.06 (95% confidence interval = 1.01–1.11) after adjustment for confounders. There was some evidence that these effects were greater in more affluent areas.
Conclusions: This study of an English national cohort found evidence linking long-term exposure to particulate matter and NO2 with the development of heart failure. We did not, however, replicate associations for other cardiovascular outcomes that have been reported elsewhere.
From the aDivision of Population Health Sciences and Education and MRC-HPA Centre for Environment and Health, St George’s, University of London, London, United Kingdom; bAEA Technology plc, Harwell IBC, Didcot, Oxfordshire, United Kingdom; cClinical Practice Research Datalink, Medicines and Healthcare Products Regulatory Agency, London, United Kingdom; and dMRC-HPA Centre for Environment and Health, King’s College London, London, United Kingdom.
Submitted 25 October 2011; accepted 27 July 2012.
Supported by funding from Policy Research Programme in the Department of Health.
The authors report no conflict of interests.
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Correspondence: Richard W. Atkinson, Division of Population Health Sciences and Education and MRC-HPA Centre for Environment and Health, St George’s, University of London, Cranmer Terrace, London SW17 0RE, United Kingdom. E-mail: firstname.lastname@example.org.