Breast-feeding and infant illness: a dose-response relationship?

Am J Public Health. 1999 Jan;89(1):25-30. doi: 10.2105/ajph.89.1.25.


Objectives: The purpose of this study was to determine whether breast-feeding has a dose-related protective effect against illness and whether it confers special health benefits to poor infants.

Methods: The association between breast-feeding dose and illnesses in the first 6 months of life was analyzed with generalized estimating equations regression for 7092 infants from the National Maternal and Infant Health Survey. Breast-feeding dose (ratio of breast-feedings to other feedings) was categorized as full, most, equal, less, or no breast-feeding.

Results: Compared with no breast-feeding, full breast-feeding infants had lower odds ratios of diarrhea, cough or wheeze, and vomiting and lower mean ratios of illness months and sick baby medical visits. Most breast-feeding infants had lower odds ratios of diarrhea and cough or wheeze, and equal breast-feeding infants had lower odds ratios of cough or wheeze. Full, most, and equal breast-feeding infants without siblings had lower odds ratios of ear infections and certain other illnesses, but those with siblings did not. Less breast-feeding infants had no reduced odds ratios of illness. Findings did not vary by income.

Conclusions: Full breast-feeding was associated with the lowest illness rates. Minimal (less) breast-feeding was not protective. Breast-feeding conferred similar health benefits in all economic groups.

MeSH terms

  • Adult
  • Breast Feeding / statistics & numerical data*
  • Child Health Services / statistics & numerical data
  • Cough / epidemiology
  • Diarrhea, Infantile / epidemiology
  • Female
  • Health Surveys
  • Humans
  • Infant
  • Infant Welfare / statistics & numerical data*
  • Infant, Newborn
  • Male
  • Morbidity*
  • Odds Ratio
  • Poverty / statistics & numerical data
  • Regression Analysis
  • Surveys and Questionnaires
  • United States / epidemiology
  • Vomiting / epidemiology