Risk factors for sudden infant death syndrome following the prevention campaign in New Zealand: a prospective study.

OBJECTIVES To identify the risk factors for sudden infant death syndrome (SIDS) following a national campaign to prevent SIDS. METHODS For 2 years (October 1, 1991 through September 30, 1993) data were collected by community child health nurses on all infants born in New Zealand at initial contact and at 2 months. RESULTS There were 232 SIDS cases in the postneonatal age group (2.0/1000 live births) and these were compared with 1200 randomly selected control subjects. Information was available for 127 cases (54.7%) and 922 (76.8%) of controls. The previously identified modifiable risk factors were examined. The prevalence of prone sleeping position of the infant was very low (0.7% at initial contact and 3. 0% at 2 months), but was still associated with an increased risk of SIDS. In addition, the side sleeping position was also found to have an increased risk of SIDS compared with the supine sleeping position (at 2 months: adjusted odds ratio (OR) = 6.57; 95% confidence interval (CI) = 1.71, 25.23). Maternal smoking was found to be the major risk factor for SIDS. Bed sharing was also associated with an increased risk of SIDS. There was an interaction between maternal smoking and bed sharing on the risk of SIDS. Compared with infants not exposed to either bed sharing or maternal smoking, the adjusted OR for infants of mothers who smoked was 5.01 (95% CI = 2.01, 12.46) for bed sharing at the initial contact and 5.02 (95% CI = 1.05, 24. 05) for bed sharing at 2 months. In this study breastfeeding was not associated with a statistically significant reduction in the risk of SIDS. The other risk factors for SIDS identified were: unmarried mother, leaving school at a younger age, young mother, greater number of previous pregnancies, late attendance for antenatal care, smoking in pregnancy, male infant, Maori ethnicity, low birth weight, and shorter gestation. CONCLUSIONS After adjustment for potential confounders, prone and side sleeping positions, maternal smoking, and the joint exposure to bed sharing and maternal smoking were associated with statistically significant increased risk of SIDS. A change from the side to the supine sleeping position could result in a substantial reduction in SIDS. Maternal smoking is common in New Zealand and with the reduction in the prevalence of prone sleeping position is now the major risk factor in this country. However, smoking behavior has been difficult to change. Bed sharing is also a major factor but appears only to be a risk to infants of mothers who smoke. Addressing bed sharing among mothers who smoke could reduce SIDS by at least one third. Breastfeeding did not appear to offer a statistically significant reduction in SIDS risk after adjustment of potential confounders, but as breastfeeding rates are comparatively good in New Zealand, this result should be interpreted with caution as the power of this study to detect a benefit is small.

[1]  J Golding,et al.  Environment of infants during sleep and risk of the sudden infant death syndrome: results of 1993-5 case-control study for confidential inquiry into stillbirths and deaths in infancy , 1996, BMJ.

[2]  P. J. Fleming,et al.  Smoking and the sudden infant death syndrome: results from 1993-5 case-control study for confidential inquiry into stillbirths and deaths in infancy , 1996 .

[3]  A. Forsdahl,et al.  [Crib death and infant mortality in the Nordic countries 1988-93]. , 1995, Tidsskrift for Den Norske Laegeforening.

[4]  S. Edelstein,et al.  Bed sharing and the sudden infant death syndrome , 1995, BMJ.

[5]  E. Mitchell,et al.  Public health policy on bed sharing and smoking in the sudden infant death syndrome. , 1995, The New Zealand medical journal.

[6]  T. Dwyer,et al.  The contribution of changes in the prevalence of prone sleeping position to the decline in sudden infant death syndrome in Tasmania. , 1995, JAMA.

[7]  C. Wild,et al.  Infant feeding patterns in Canterbury. , 1995, The New Zealand medical journal.

[8]  K. Helweg-larsen,et al.  [Overheating and sudden infant death. Temperature regulation in relation to the prone position, the possible pathogenesis of sudden infant death]. , 1994, Ugeskrift for laeger.

[9]  R. Gilbert.  The changing epidemiology of SIDS. , 1994, Archives of disease in childhood.

[10]  E. Mitchell,et al.  Reduction in mortality from sudden infant death syndrome in New Zealand: 1986-92. , 1994, Archives of disease in childhood.

[11]  P. Kostense,et al.  Sleeping position for infants and cot death in The Netherlands 1985-91. , 1993, Archives of disease in childhood.

[12]  E. Mitchell,et al.  Bed sharing, smoking, and alcohol in the sudden infant death syndrome. New Zealand Cot Death Study Group. , 1993, BMJ.

[13]  E. Mitchell,et al.  Breastfeeding and the risk of sudden infant death syndrome. , 1993, International journal of epidemiology.

[14]  H C Van Houwelingen,et al.  Risk ratio and rate ratio estimation in case-cohort designs: hypertension and cardiovascular mortality. , 1993, Statistics in medicine.

[15]  E. Mitchell,et al.  Publicity and infants' sleeping position. , 1993, BMJ.

[16]  E. Mitchell,et al.  The national cot death prevention program in New Zealand. , 2010, Australian journal of public health.

[17]  B. Taylor,et al.  Further evidence supporting a causal relationship between prone sleeping position and SIDS , 1992, Journal of paediatrics and child health.

[18]  P. Kostense,et al.  An analysis of trends in the incidence of sudden infant death in The Netherlands 1969–89 , 1991, Journal of paediatrics and child health.

[19]  E. Mitchell,et al.  Results from the first year of the New Zealand cot death study. , 1991, The New Zealand medical journal.

[20]  D. P. Davies,et al.  Sudden infant death syndrome in Hong Kong: confirmation of low incidence. , 1989, BMJ.

[21]  Cyrus R. Mehta,et al.  Computing an Exact Confidence Interval for the Common Odds Ratio in Several 2×2 Contingency Tables , 1985 .

[22]  A. Whittemore.  Estimating attributable risk from case-control studies. , 1983, American journal of epidemiology.

[23]  J. L. Luke.  Sleeping arrangements of sudden infant death syndrome victims in the District of Columbia--a preliminary report. , 1978, Journal of forensic sciences.