by Amy Spangler
April 23, 2007

The Agency for Healthcare Research and Quality (AHRQ) has released a new evidence report on breastfeeding and health outcomes. The report, Breastfeeding and Maternal and Infant Health Outcomes in Developed Countries, found evidence that breastfeeding decreases infants’ and mothers’ risks for a number of short-term and chronic diseases.

AHRQ was clear in stating that because almost all the data in this review were gathered from observational studies, one should not infer causality based on these findings. Additionally, there is a wide range of quality of the body of evidence across different health outcomes.

For future studies, clear subject selection criteria and definition of “exclusive breastfeeding,” reliable collection data, controlling for important confounders including child-specific factors, and blinded assessment of the outcome measures will help. Sibling analysis provides a method to control for hereditary and household factors that are important in certain outcomes. In addition, cluster randomized controlled studies on the effectiveness of various breastfeeding promotion interventions will provide further opportunity to investigate any disparity in health outcomes as a result of the intervention.

The findings
There is good evidence that breastfeeding reduces infants’ risks of ear infections by up to 50 percent, serious lower respiratory tract infections by 72 percent, and a skin rash similar to eczema by 42 percent.

Children with a family history of asthma who were breastfed were 40 percent less likely to have asthma, and children who were not prone to asthma had a 27 percent reduced risk compared to children who were not breastfed.

The risk of developing type 1 diabetes was reduced by about 20 percent. These benefits were seen in infants who were breastfed for three or more months. Breastfeeding also reduced the risk of type 2 diabetes by 39 percent compared to those who were not breastfed.

The report also found that breastfeeding was associated with fewer episodes of diarrhea during infancy, decreased incidence of childhood leukemia, and decreased deaths from sudden infant death syndrome (SIDS).

The report found no clear relationship between breastfeeding and improvement in IQ. In premature infants, breastfeeding decreased the occurrence of necrotizing enterocolitis, a serious gastrointestinal infection that often results in death.

For health outcomes in mothers, there is good evidence that women who breastfed their infants had up to a 12 percent reduced risk of type 2 diabetes for each year they breastfed. Breastfeeding decreased the risk of ovarian cancer by up to 21 percent. Breastfeeding also decreased the risk of breast cancer by up to 28 percent in those whose lifetime duration of breastfeeding was 12 months or longer.

Women who did not breastfeed their infants were more likely to have postpartum depression—however, unmeasured factors (such as depression that was undiagnosed prior to giving birth) may have increased the rate of depression seen in this group.

Breastfeeding did not increase the risk of fractures due to osteoporosis. The effect of breastfeeding on a woman’s weight could not be determined based on the available studies.

The report was nominated and funded by the U.S. Department of Health and Human Services’ Office on Women’s Health and prepared by Stanley Ip, MD, Joseph Lau, MD, and colleagues at AHRQ’s Tufts-New England Medical Center Evidence-based Practice Center in Boston, Massachusetts. AHRQ’s EPCs develop evidence reports and technology assessments on topics relevant to clinical, social science/behavioral, economic, and other health care organization and delivery issues—specifically those that are common, expensive, and/or significant for the Medicare and Medicaid populations.