RT Journal Article
SR Electronic
T1 Case-crossover design in air pollution epidemiology
JF European Respiratory Journal
JO Eur Respir J
FD European Respiratory Society
SP 81s
OP 85s
DO 10.1183/09031936.03.00402703
VO 21
IS 40 suppl
A1 J.J.K. Jaakkola
YR 2003
UL http://erj.ersjournals.com/content/21/40_suppl/81s.abstract
AB The case-crossover design was developed to study the effects of transient, short-term exposures on the risk of acute events, such as myocardial infarction, in the early 1990s. This paper illustrates how the principles of case-crossover design are related to the principles of crossover and case-control designs and stipulates the possibilities of case-crossover design in air pollution epidemiology. In the case-crossover design, the study population consists of subjects who have experienced an episode of the health outcome of interest. Similar to a crossover study, each subject serves as his or her own control. As in a matched case-control study, the inference is based on a comparison of exposure distribution rather than the risk of disease. The case-crossover study is most suitable for studying relations with the following characteristics: 1) the individual exposure varies within short time intervals; 2) the disease has abrupt onset and short latency for detection; and 3) the induction period is short. Case-crossover design allows use of routinely monitored air pollution information and at the same time makes it possible to study individuals rather than days as the unit of observation. Case-crossover design is amenable for studying the effects of varying short-term air pollution exposure on health outcomes with an abrupt onset, such as myocardial infarction or asthma attack.