1 Clinical Epidemiology Program, University of California, San Francisco, San Francisco General Hospital, 1001 Potrero Ave, Bldg 1, Rm 201, San Francisco, CA 94110
To the Editor.
The recent cohort study by Oren et al1 examined risk factors for sudden infant death syndrome (SIDS) in infants with prolonged unexplained sleep apnea with color change (severe apnea of infancy). This analysis revealed three possible risk factors for SIDS death: having a subsequent monitored apnea episode needing resuscitation or vigorous stimulation, being a sibling of a SIDS victim, or developing a seizure disorder after monitoring began. Unfortunately, there are two serious problems with the authors' analysis: the misrepresentation of relative risk and the use of the
2 statistic to test associations in small subgroups.