In a study published in the medical journal JAMA Internal Medicine, researchers from the managed care consortium Kaiser Permanente reported that mothers who breastfeed their babies for six months or more have a nearly 50 percent lower chance of developing Type 2 diabetes during their childbearing years. According to lead author Erica P. Gunderson, PhD, MS, MPH, “We found a very strong association between breastfeeding duration and lower risk of developing diabetes, even after accounting for all possible confounding factors.”
The study’s designers analyzed data collected over a 30-year period as part of a long-term national investigation of cardiovascular disease factors. The analysis began in 1985–1986 with the enrollment of about 5,000 people ages 18–30. The researchers discovered that women who breastfed for six months or more across all births had a 47 percent reduction in the risk of developing Type 2 diabetes compared to women who did not breastfeed. Women who breastfed for six months or less had a risk reduction of 25 percent. Factors such as race, lifestyle habits, body size, and the presence of gestational diabetes did not affect the numbers. These findings were consistent with other research that has shown breastfeeding to have a protective effect on the risks of breast and ovarian cancer.
The researchers conjectured that the one of the mechanisms by which breastfeeding protects against Type 2 diabetes may be the effect of certain hormones association with lactation. These hormones, they think, influence the pancreatic cells that control blood insulin levels. Whatever the cause, said Tracy Flanagan, MD, director of women’s health for Kaiser Permanente Northern California, the new research gives “yet another reason that doctors, nurses, and hospitals, as well as policymakers, should support women and their families to breastfeed as long as possible.”