Quantification of the impacts of air pollution on chronic cause-specific mortality

In previous work, the IOM has developed a systematic framework for calculating predicted impacts of changes in mortality hazard rates, in the specific context of a relationship between mortality and air pollution. We report on extensions of the theoretical and computational aspects to perform the calculations in a spreadsheet package, and to predict the impacts in situations where different causes of death have different (including non-existent) relationships with air pollution, which in turn may imply different patterns of impact at different ages. The spreadsheet package is now operational, and can be adapted to any pattern of differential impacts. Based on information about relationships derived from the principal American cohort study, comparisons are made of the total impacts of changes in cardio-respiratory hazard rates, and in all-cause mortality rates. Although not identical, the predicted impacts are very similar in the all-cause and cause- specific impact scenarios. There has been much debate historically over possible connections between results from time-series and cohort studies. The report includes an Appendix in which this question is considered in detail. Overall, its conclusions are consistent with many previous opinions that the estimated results of time-series studies are too small to explain, on their own, the magnitude of the cohort study results. “”