Duration of Breastfeeding and Risk of SIDS: An Individual Participant Data Meta-analysis
John M D Thompson1, Kawai Tanabe2, Rachel Y Moon3
1Department of Paediatrics: Child and Youth Health and Obstetrics and Gynaecology, University of Auckland, Auckland, New Zealand; j.thompson@auckland.ac.nz.
Context:
Sudden infant death syndrome (SIDS) is a leading cause of postneonatal infant mortality. Our previous meta-analyses showed that any breastfeeding is protective against SIDS with exclusive breastfeeding conferring a stronger effect.The duration of breastfeeding required to confer a protective effect is unknown.
Objective:
To assess the associations between breastfeeding duration and SIDS.
Data Sources:
Individual-level data from 8 case-control studies.
Study Selection:
Case-control SIDS studies with breastfeeding data.
Data Extraction:
Breastfeeding variables, demographic factors, and other potential confounders were identified. Individual-study and pooled analyses were performed.
Results:
A total of 2267 SIDS cases and 6837 control infants were included. In multivariable pooled analysis, breastfeeding for <2 months was not protective (adjusted odds ratio [aOR]: 0.91, 95% confidence interval [CI]: 0.68-1.22). Any breastfeeding ≥2 months was protective, with greater protection seen with increased duration (2-4 months: aOR: 0.60, 95% CI: 0.44-0.82; 4-6 months: aOR: 0.40, 95% CI: 0.26-0.63; and >6 months: aOR: 0.36, 95% CI: 0.22-0.61). Although exclusive breastfeeding for <2 months was not protective (aOR: 0.82, 95% CI: 0.59-1.14), longer periods were protective (2-4 months: aOR: 0.61, 95% CI: 0.42-0.87; 4-6 months: aOR: 0.46, 95% CI: 0.29-0.74).
Limitations:
The variables collected in each study varied slightly, limiting our ability to include all studies in the analysis and control for all confounders.
Conclusions:
Breastfeeding duration of at least 2 months was associated with half the risk of SIDS. Breastfeeding does not need to be exclusive to confer this protection.
