Sudden infant death syndrome in New Zealand: are risk scores useful? New Zealand National Cot Death Study Group.

STUDY OBJECTIVE

To evaluate the Christchurch, Invercargill, Dunedin (CID) and Oxford record linkage study (ORLS) risk scores in five regions of New Zealand and examine the effect of risk factors for sudden infant death syndrome (SIDS), such as prone sleeping position, maternal smoking, breast feeding, measures of illness, the use of antenatal classes, community health care, and medical services on a high and low risk group delineated by the CID score.

DESIGN

This was a case-control study of infants dying of SIDS.

SETTING

Both the cases and controls were born in one of five health districts in New Zealand and their parents were interviewed between 1 November 1987 and 31 October 1990.

PARTICIPANTS

The cases were 485 infants who died of SIDS. The controls were a random sample drawn from the same five regions in which the cases were born, chosen so that their age on the day on which they were interviewed was similar to the age at death of the cases. Risk scores were calculated for 387 case and 1579 controls.

MEASUREMENTS AND MAIN RESULTS

Using the recommended cut off points the sensitivity and specificity of the CID and ORLS were found to be similar to those described for other samples. The differences among the regions were significant. There was, however, no evidence that the association between SIDS and the risk factors considered was different in the high and low risk groups delineated by the CID score. The relative attributable risk for smoking was 32.3% in the high risk group. The excess risk that could be attributed to a different prevalence of any of the other risk factors in the high risk group was small when compared with the low risk group.

CONCLUSIONS

Health care resources should be spent on promoting and evaluating good child care practices for all, rather than identifying and promoting special interventions for those in the high risk category.