Exclusively breastfed babies had roughly a 34% reduced risk of being overweight during childhood, compared to children exclusively formula-fed, according to a new analysis of data from a study involving more than 15,000 children.
"It is important for mothers who have diabetes or who are at risk for developing the disease to know that there are things that they can do for their children that can make a real difference," Mayer-Davis tells WebMD, adding that breastfeeding appears to be an important first step for reducing a child's risk for and related diseases such as type 2 diabetes.
Born at High Risk
More than 12.5 million children and teens in the U.S. are overweight, according to the latest government statistics, from 2003-2004. That accounts for 17.1% of children and teens aged 2 to 19.
The CDC reports that the percentage of young people in the U.S. considered overweight has more than tripled since 1980.
There has been a corresponding rise in the incidence of type 2 diabetes, a disease linked to overweight and obesity and once seen only rarely in children and teens.
It is now widely accepted that being breastfed helps protect babies from becoming overweight or obese later in life, Katherine Shealy, MPH, IBCLC, of the CDC tells WebMD.
One recent analysis of 17 studies found that every month of breastfeeding reduced the risk of childhood overweight by 4%. Babies breastfed for nine months had a 31% overall reduction in risk.
But it has not been clear from previous research if breastfeeding conveys similar protection to babies at higher risk of becoming overweight or developing diabetes due to family history.
15,000 Children in Study
Mayer-Davis analyzed data from the Harvard School of Public Health's Nurses Health Study II to help answer the question.
The study included information on 15,253 children between the ages of 9 and 14 and their mothers.
Roughly 6,000 of the mothers were overweight or obese without diabetes; 473 had diabetes.
The data suggested that children breastfed during their first year of life were less likely to become overweight or obese than children who were not, regardless of their mothers' weight or diabetic status.
The findings are published in the October issue of Diabetes Care.
Protection May Be Greater
The American Academy of Pediatrics (AAP) recommends exclusive breastfeeding during a baby's first six months of life, and urges mothers to continue breastfeeding for at least a year.
University of Rochester professor of pediatrics Ruth Lawrence, MD, who helped write the AAP's latest breastfeeding guidelines, says the published studies may actually underestimate the importance of breastfeeding on weight later in life.
"Babies who are exclusively breastfed seem to have a big advantage," she says. "There is not one single study that suggests that formula is better than breast milk."
Shealy, public health breastfeeding specialist at the CDC, says mothers who are overweight or have diabetes can do a lot to reduce their children's risk.
"Kids born to moms who are overweight and diabetic are inherently at higher risk, but that doesn't mean that obesity is inevitable," she says. "There is strong evidence that the longer a mom breastfeeds, the better."