Sources of heterogeneity in the meta-analysis of observational studies The example of SIDS and sleeping position

The study objective was to provide an example of how risk estimates might vary across studies of observational design, even when a causal association is present and to explore the possible sources of such variation. A meta-analysis of studies on the association between prone sleeping position and sudden infant death syndrome (SIDS) is used to illustrate how risk estimates might vary across studies. Data used were reported case-control studies …