Study shows that the link doesn’t hold true for the first-born kids. Adult women who were breast-fed as infants may have a lower risk of developing breast cancer than those who were not breast-fed, unless they were first-born.

“As a general group, women who reported that they had been breast-fed in infancy had a 17 percent decrease in breast cancer risk,” Hazel B. Nichols, who was involved in the study, told Reuters Health.

However, in analyses restricted to breast-fed women, those with 3 or more older siblings had a lesser risk for breast cancer than first born women, the researchers found. But breast-fed women showed no altered breast cancer risk according to their mothers’ age at childbirth.

The current results hint that breast cancer risk may differ according to whether or not women were breast-fed during infancy. Additional studies are necessary to determine if these associations vary with duration of breast-feeding or according to measured levels of environmental contaminants present in breast milk, Nichols said.

Source: Msnbc