ISEE/ISEA 2006 Conference Abstracts Supplement: Symposium Abstracts: Abstracts
The project brings together the investigators who have carried out the Air Pollution and Health: A European Approach (APHEA 1 and 2) studies, the National Morbidity and Mortality Study (NMMAPS) in the United States, and national studies in Canada. The findings of these studies have substantial implications for public health policies directed at controlling health effects of air pollution; each has shown adverse effects of air pollution on morbidity and mortality at current concentrations of air pollution in Europe and North America. A principal objective of APHENA is to characterize heterogeneity in the effects of particulate matter on mortality and morbidity across the included cities. The principal goals include: 1) development of core models for the first-stage (within-city) analyses of time-series data on mortality and hospitalization for the APHENA cities; 2) development of harmonized databases on potential modifying factors across the cities; and 3) parallel and combine analyses of data on air pollution and mortality and morbidity with exploration of heterogeneity in the effect of particulate matter and its determinants.
There have now been multiple meetings and exchanges to develop a protocol for first-stage (within-city) analyses, to review findings of these analyses, and to carry out second-stage analyses. The approach to the first-stage analyses is based on initial simulation studies and extensive exploratory and sensitivity analyses. The decisions taken specified the outcome categories, pollutants, core models, and sensitivity analyses. Additionally, a set of potential effect modifiers for the second-stage analysis was identified. The first-stage analyses have been completed for mortality and hospitalization and second-stage analyses are being completed for mortality. The results provide estimates for exposure to PM10 and ozone and outcomes, including the daily total, cardiovascular disease, and respiratory numbers of deaths by age categories. Several models have been applied with varying degrees of freedom and smoothers and results compared. For PM10, estimates are generally similar in the United States and Europe; for ozone, estimates tend to be higher in the United States compared with Europe and the highest in Canada. The second-stage analyses tests whether factors representing pollution and population characteristics explain heterogeneity of first-stage estimates.