Mortality Risk Analyses Should be Based on Long-Term Studies
A debate has raged in the public policy arena about whether to use the short-term or the long-term epidemiological studies to estimate the risks of premature mortality attributable to particulate air pollution.
A study by Kunzli et al. presents a conceptual model for the interpretation of these studies, which shows that short-term time-series and long-term cohort studies address different aspects of the association between air pollution and death. Time-series studies capture only cases in which death has been triggered by air pollution exposures that occur shortly before death, while cohort studies capture all air pollution-related categories of death, including deaths of persons whose underlying health condition leads to premature death, without being related to the level of pollution shortly before death.
For these reasons, the authors conclude “that time-series analyses underestimate cases of death attributable to air pollution and that assessment of the impact of air pollution on mortality should be based on cohort studies.”
Kunzli, N., Medina, S., Kaiser, R., Quenel, P., Horak, F., Jr., and Studnicka, M. Assessment of Deaths Attributable to Air Pollution: Should We Use Risk Estimates Based on Time Series or on Cohort Studies? Am. J. Epidemiol. Vol. 53, pp. 1050-1055, 2001.
The American Journal of Epidemiology [www.aje.oupjournals.org] offers the abstract online.
