Recall bias in a case-control study of sudden infant death syndrome.

Case-control differences in the accuracy of maternal recall may create spurious associations between suspected risk factors and perinatal conditions. We examined case-control differences in the accuracy of maternal recall and evaluated the impact of maternal reporting errors on observed measures of association. We compared interview information with information recorded on medical records for the mothers of 226 cases of Sudden Infant Death Syndrome (SIDS) and the mothers of 226 living controls. We found that having a child die from SIDS increased the sensitivity of recall for less than half of the 25 study variables. However, for 18 of the 25 variables, the mothers of SIDS cases were more likely than the mothers of living controls to report events that could not be confirmed on medical records. Case-control differences in recall accuracy did not appear to create spurious associations with SIDS or to bias most associations away from the null value.