Objective: The objective of this study was to measure the effect of breastfeeding on hospitalization for diarrheal and lower respiratory tract infections in the first 8 months after birth in contemporary United Kingdom.
Methods: The study was a population-based survey (sweep 1 of the United Kingdom Millennium Cohort Study). Data on infant feeding, infant health, and a range of confounding factors were available for 15,890 healthy, singleton, term infants who were born in 2000-2002. The main outcome measures were parental report of hospitalization for diarrhea and lower respiratory tract infection in the first 8 months after birth.
Results: Seventy percent of infants were breastfed (ever), 34% received breast milk for at least 4 months, and 1.2% were exclusively breastfed for at least 6 months. By 8 months of age, 12% of infants had been hospitalized (1.1% for diarrhea and 3.2% for lower respiratory tract infection). Data analyzed by month of age, with adjustment for confounders, show that exclusive breastfeeding, compared with not breastfeeding, protects against hospitalization for diarrhea and lower respiratory tract infection. The effect of partial breastfeeding is weaker. Population-attributable fractions suggest that an estimated 53% of diarrhea hospitalizations could have been prevented each month by exclusive breastfeeding and 31% by partial breastfeeding. Similarly, 27% of lower respiratory tract infection hospitalizations could have been prevented each month by exclusive breastfeeding and 25% by partial breastfeeding. The protective effect of breastfeeding for these outcomes wears off soon after breastfeeding cessation.
Conclusions: Breastfeeding, particularly when exclusive and prolonged, protects against severe morbidity in contemporary United Kingdom. A population-level increase in exclusive, prolonged breastfeeding would be of considerable potential benefit for public health.