Breastfeeding and reduced risk of Sudden Infant Death Syndrome: A meta-analysis

Abstract

Introduction: The benefits of breastfeeding include lower risk of postneonatal mortality. It is unclear whether breastfeeding specifically affects SIDS risk. Aim: A meta-analysis was undertaken to measure the association between breastfeeding and SIDS. Method: We identified 285 studies with data on breastfeeding and SIDS through a Medline search (1966–2009), review papers and meta-analyses, of which 31 were original case-control studies. Two teams of 2 reviewers independently evaluated study quality according to preset criteria. Univariate and multivariate odds ratios (ORs) were extracted. A summary OR (SOR) was calculated for the univariate and multivariate ORs using the fixed effect and random effect inverse-variance methods of meta-analysis. The Breslow-Day test for heterogeneity was calculated, with a p-value <0.05 indicating that heterogeneity was present. Results: For infants who received any amount of breast milk for any duration, univariate SOR (95% confidence interval [CI]) was 0.49 (0.45, 0.53); multivariate was 0.68 (0.58, 0.80). For any breastfeeding for >2 months, univariate SOR was 0.32 (0.26, 0.40) and multivariate was 0.55 (0.28, 1.07). The univariate SOR for exclusive breastfeeding of any duration was 0.32 (0.28, 0.36); there were no studies reporting multivariate analyses for exclusive breastfeeding. Heterogeneity was present for all analyses, except multivariate analysis of breastfeeding >2 months. Conclusion: Breastfeeding was protective against SIDS. The protective effect was stronger for exclusive breastfeeding and for longer duration of breastfeeding. The recommendation to breastfeed infants should be included with other SIDS risk reduction messages to both reduce the risk of SIDS and to promote breastfeeding for its many other infant and maternal health benefits.