Background: Certain subgroups in the general population, such as persons with existing cardiovascular or respiratory disease, may be more likely to experience adverse health effects from air pollution.
Methods: In this European multicenter study, 25,006 myocardial infarction (MI) survivors in 5 cities were recruited from 1992 to 2002 via registers, and daily mortality was followed for 6 to 12 years in relation to ambient particulate and gaseous air pollution exposure. Daily air pollution levels were obtained from central monitor sites, and particle number concentrations were measured in 2001 and estimated retrospectively based on measured pollutants and meteorology. City-specific effect estimates from time-series analyses with Poisson regression were pooled over all 5 cities.
Results: Particle number concentrations and PM10 averaged over 2 days (lag 0–1) were associated with increased total nontrauma mortality for patients of age 35 to 74 (5.6% [95% confidence interval, 2.8%–8.5%] per 10,000/cm3 and 5.1% [1.6%–9.3%] per 10 μg/m3, respectively). For longer averaging times (5 and 15 days), carbon monoxide and nitrogen dioxide were also associated with mortality. There were no clear associations with ozone or sulfur dioxide.
Conclusion: Exposure to traffic-related air pollution was associated with daily mortality in MI survivors. Point estimates suggest a stronger effect of air pollution in MI survivors than among the general population.
From the aInstitute of Environmental Medicine, Karolinska Institutet; bDepartment of Occupational and Environmental Health, Stockholm County Council, Stockholm, Sweden; cDepartment of Epidemiology, Rome E Health Authority, Rome, Italy; dInstitute of Epidemiology, Helmholtz Zentrum München, Neuherberg, Germany; eDepartment of Physical Sciences, University of Helsinki, Finland; fInstitut Municipal d'Investigació Mèdica (IMIM), Barcelona, Spain; gCIBER Epidemiología y Salud Pública (CIBERESP), Barcelona, Spain; hUnit of Environmental Epidemiology, KTL-National Public Health Institute, Kuopio, Finland; iDepartment of Epidemiology and Health Promotion, KTL-National Public Health Institute, Helsinki, Finland; jEnvironmental Epidemiology Research Centre (CREAL-IMIM), Barcelona, Spain; kUniversitat Pompeu Fabra, Barcelona, Spain; and lAstraZeneca R&D Mölndal, Mölndal, Sweden.
Submitted 7 October 2007; accepted 21 July 2008; posted 23 September 2008.
Funded by European Union (QLK4-2000-00708). In Finland, the study was also financially supported by the Centre of Excellence Programme 2002–2007 of the Academy of Finland (Contract 53307) and the National Technology Fund (TEKES, Contract 40715/01). Fredrik Nyberg, employed by AstraZeneca, is also Lecturer in Epidemiology at Karolinska Institutet; AstraZeneca did not contribute any direct financing to this study. Annette Peters was partially supported by the US Environmental Protection Agency STAR center Grant R-827354.
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Correspondence: Niklas Berglind, Institute of Environmental Medicine, Karolinska Institutet, Box 210, SE-171 77 Stockholm, Sweden. E-mail: Niklas.Berglind@ki.se.