A Case-Control Study on Long-Term Exposure to AIr Pollution and Myocardial Infarction

ISEE-36 Introduction: Cross-sectional and mainly large-scale differences in exposure to air pollution have been associated with a long-term increase in risk for cardiopulmonary mortality in cohort studies. Our objective is to study the association between myocardial infarction (MI) and the historical residential exposure to combustion-related air pollution during 30 years in a population-based case-control study. Methods: The study population includes all first events of MI in people aged 45–70 during 1992–1994, and population controls matched on age, gender, and hospital catchment area. The subjects or next-of-kin have answered an extensive questionnaire covering a large set of potential risk factors for MI. A supplementary telephone interview was conducted and a health examination was carried out on hospitalized cases and their controls to collect data on biological parameters. Information of historical home-addresses was collected for 4,069 subjects since 1960 using a questionnaire. The 10,662 addresses have been transformed into geographical coordinates using GIS in combination with a regional geographical address database. Based on a detailed regional emission database from 1993 and statistics of changes in traffic and other historical land-use variations from 1960, emission databases for air pollution have been reconstructed for the years 1960, 1970, and 1980. These databases describe emissions of nitrogen oxides (NOX, NO2) and sulfur dioxide (SO2) from traffic-related line sources, different point sources, area sources, and grid sources. The emission databases provide information used in dispersion calculations to obtain annual mean levels of NOX, NO2, and SO2 throughout the study area, with a resolution of 500*500 m in rural areas and 25*25 m in the inner-city area. In addition, historical dispersion models of carbon monoxide (CO) and current particulate matter (PM10 and PM2.5) under development will be used. The study design and the long-term exposure assessment makes it feasible to investigate the importance of different aspects of the exposure, such as cumulative dose, intensity and duration of exposure, and different time windows for individual exposure. Results: In a preliminary analysis, using exposure assessment with lower geographical resolution, an association between the 30-year average residential level of combustion-related air pollution and myocardial infarction was suggested. We will present results from epidemiological analyses of the association between MI and air pollution using more detailed exposure assessment during several decades.