title: Breastfeeding and the risk of hospitalization for respiratory disease in infancy: a meta-analysis.
abstract: OBJECTIVE
  To examine breastfeeding and the risk of hospitalization for lower respiratory tract disease in healthy full-term infants with access to modern medical care.
  
  
  METHODS
  MEDLINE, personal communication with researchers, the OVID databases, Dissertation Abstracts Online, and BIOSIS.
  
  
  METHODS
  The titles, abstracts, and text of studies from developed countries were explored for breastfeeding exposure measures and lower respiratory tract disease hospitalization rates. For summary statistics, we required 3 inclusion criteria: (1) a feeding contrast of a minimum of 2 months of exclusive breastfeeding (no formula supplementation) vs no breastfeeding and (2) study populations that excluded sick, low birth weight or premature infants and (3) reflected affluent regions; 27% of studies met these criteria.
  
  
  METHODS
  We abstracted data from all relevant reports.
  
  
  RESULTS
  Data from all primary material (33 studies) indicated a protective association between breastfeeding and the risk of respiratory disease hospitalization. Nine studies met all inclusion criteria, and 7 cohort studies were pooled. The feeding contrasts in these 7 studies were 4 or more months of exclusive breastfeeding vs no breastfeeding. The summary relative risk (95% confidence interval) was 0.28 (0.14-0.54), using a random-effects model. This effect remained stable and statistically significant after adjusting for the effects of smoking or socioeconomic status.
  
  
  CONCLUSIONS
  Among generally healthy infants in developed nations, more than a tripling in severe respiratory tract illnesses resulting in hospitalizations was noted for infants who were not breastfed compared with those who were exclusively breastfed for 4 months.
authors.affiliation: virginia.bachrach@stanford.edu
authors.forename: Virginia R Galton
authors.initials: VR
authors.lastname: Bachrach
authors.forename: Eleanor
authors.initials: E
authors.lastname: Schwarz
authors.forename: Lela Rose
authors.initials: LR
authors.lastname: Bachrach
mesh_terms: D001942:Breast Feeding; D016001:Confidence Intervals; D006760:Hospitalization / Q000706:statistics & numerical data*; D006801:Humans; D007223:Infant; D012140:Respiratory Tract Diseases / Q000517:prevention & control*; D012307:Risk Factors; D012923:Social Class