Breastfeeding for six months or longer can reduce the risk of developing Type 2 diabetes by nearly half for women throughout their childbearing years, according to a study.
Women who breastfed for six months or more across all births had a 47 percent reduction in their risk of developing Type 2 diabetes compared to those who did not breastfeed at all.
Women who breastfed for six months or less had a 25 percent reduction in diabetes risk.
"We found a very strong association between breastfeeding duration and lower risk of developing diabetes, even after accounting for all possible confounding risk factors," said lead author Erica P. Gunderson, senior research scientist with the Kaiser Permanente -- a US-based health care company.
"The incidence of diabetes decreased in a graded manner as breastfeeding duration increased, regardless of race, gestational diabetes, lifestyle behaviours, body size, and other metabolic risk factors measured before pregnancy, implying the possibility that the underlying mechanism may be biological," Gunderson added.
Several plausible biological mechanisms are possible for the protective effects of breastfeeding, including the influence of lactation-associated hormones on the pancreatic cells that control blood insulin levels and thereby impact blood sugar, the researchers said.
For the study, published in the journal JAMA Internal Medicine, the team included 1238 black and white women who did not have diabetes when they enrolled.
Over the next 30 years, each woman had at least one live birth and was routinely screened for diabetes. Participants also reported lifestyle behaviours (such as diet and physical activity) and the total amount of time they breastfed their children.
The findings add to a growing body of evidence that breastfeeding has protective effects for both mothers and their offspring, including lowering a mother's risk of breast and ovarian cancer, the researchers said.