Breastfeeding for over 6 months may cut diabetes risk by half

Breastfeeding for six months or longer cuts the risk of developing type 2 diabetes nearly in half for women throughout their childbearing years, a study has found.
Women who breastfed for six months or more across all births had a 47 per cent 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 per cent reduction in diabetes risk, according to the study published in the journal JAMA Internal Medicine.
"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 Erica P Gunderson, senior research scientist with the Kaiser Permanente, a health care company in the US.

Researchers analysed data during the 30 years of follow up from the Coronary Artery Risk Development in Young Adults (CARDIA) study, an centre investigation of cardiovascular disease risk factors that originally enrolled about 5,000 adults aged 18 to 30 in 1985 to 1986, including more than 1,000 members of Kaiser Permanente Northern California.
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 long-term benefits of breastfeeding on lower diabetes risk were similar for black women and white women, and women with and without gestational diabetes.

Black women were three times as likely as white women to develop diabetes within the 30-year study, which is consistent with higher risk found by others. Black women enrolled in CARDIA were also less likely to breastfeed than white women.
"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 said.
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 study included 1,238 black and white women who did not have diabetes when they enrolled in CARDIA, or prior to their subsequent pregnancies.
Over the next 30 years, each woman had at least one live birth and was routinely screened for diabetes under the CARDIA protocol, which included diagnostic screening criteria for diabetes.
Participants also reported lifestyle behaviours (such as diet and physical activity) and the total amount of time they breastfed their children.
"We were able to follow women specifically during the childbearing period and screen them regularly for diabetes before and after pregnancies," Gunderson said.
Researchers were also able to account for pre-pregnancy metabolic risk, including obesity and fasting glucose and insulin, lifestyle behaviours, family history of diabetes, and perinatal outcomes.