Breast-feeding and Infant Hospitalization for Infections: Large Cohort and Sibling Analysis
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.
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.
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.
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.
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.
Keywords: human milk; infancy; infectious disease; weaning
Document Type: Research Article
Affiliations: 1: Norwegian Institute of Public Health, Oslo, Paediatric Department, Ostfold Hospital Trust, Grålum 2: Oslo University Hospital, Children's Center, Oslo 3: Norwegian Institute of Public Health, Oslo 4: Department of Pediatric and Adolescent Medicine, Akershus University Hospital, Nordbyhagen 5: Department of Pediatric Research, Oslo University Hospital, Rikshospitalet, Oslo, Norway.
Publication date: 01 August 2017
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