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Breast-feeding and Infant Hospitalization for Infections: Large Cohort and Sibling Analysis
Ketil Størdal1, Karen M Lundeby, Anne L Brantsæter
1*Norwegian Institute of Public Health, Oslo †Paediatric Department, Ostfold Hospital Trust, Grålum ‡Oslo University Hospital, Children's Center, Oslo §Department of Pediatric and Adolescent Medicine, Akershus University Hospital, Nordbyhagen ||Department of Pediatric Research, Oslo University Hospital, Rikshospitalet, Oslo, Norway.
Insights
Full breastfeeding for at least 4 months and continued breastfeeding beyond 6 months may reduce infection hospitalizations in infants. Protection against infections appears limited to the first 12 months of life.
Area of Science:
- Pediatrics
- Public Health
- Epidemiology
Background:
- Breastfeeding is recognized for its protective effects against infant infections.
- The optimal duration of breastfeeding for sustained protection remains a subject of ongoing research and debate.
Purpose of the Study:
- To investigate the association between the duration of full and any breastfeeding and the incidence of infections during the first 18 months of life.
- To determine if the timing of complementary feeding introduction influences infection risk in breastfed infants.
Main Methods:
- Analysis of data from the prospective Norwegian Mother and Child study cohort (n=70,511) and sibling sets (n=21,220).
- Parental reports of breastfeeding duration and infant infections were collected.
- Relative risks (RRs) for hospitalization due to infections were calculated based on breastfeeding duration and complementary feeding timing.
Main Results:
- A longer duration of full breastfeeding showed a trend towards lower infection hospitalization risk.
- Infants breastfed for 6 months or less had a higher risk of hospitalization (10.0%) compared to those breastfed for 12 months or more (7.6%).
- Matched sibling analyses indicated weaker, non-significant associations, suggesting confounding factors.
Conclusions:
- Findings support recommendations for 4 months of full breastfeeding and continued breastfeeding beyond 6 months.
- The protective effect of breastfeeding against infections appears to be most significant within the first 12 months of life.
Objectives:
Breast-feeding may protect against infections, but its optimal duration remains controversial. We aimed to study the association of the duration of full and any breast-feeding with infections the first 18 months of life.
Methods:
The Norwegian Mother and Child study (MoBa) is a prospective birth cohort which recruited expecting mothers giving birth from 2000 to 2009. We analyzed data from the full cohort (n = 70,511) and sibling sets (n = 21,220) with parental report of breast-feeding and infections. The main outcome measures were the relative risks (RRs) for hospitalization for infections from 0 to 18 months by age at introduction of complementary foods and duration of any breast-feeding.
Results:
Although we found some evidence for an overall association between longer duration of full breast-feeding and lower risk of hospitalizations for infections, 7.3% of breast-fed children who received complementary foods at 4 to 6 months of age compared to 7.7% of those receiving complementary foods after 6 months were hospitalized (adjusted RR 0.95, 95% confidence interval 0.88-1.03). Higher risk of hospitalization was observed in those breast-fed 6 months or less (10.0%) compared to ≥12 months (7.6%, adjusted RR 1.22, 95% confidence interval 1.14-1.31), but with similar risks for 6 to 11 months versus ≥12 months. Matched sibling analyses, minimizing the confounding from shared maternal factors, showed nonsignificant associations and were generally weaker compared with the cohort analyses.
Conclusions:
Our results support the recommendation to fully breast-feed for 4 months and to continue breast-feeding beyond 6 months, and suggest that protection against infections is limited to the first 12 months.
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