Breastfeeding May Prevent Breast Cancer
Diet, Activity Level, Hormone Replacement Therapy Play Bigger Roles
July 18, 2002 -- Here's more news about the protective effects of breastfeeding -- this time for mom. When a woman breastfeeds more than a year, she may be reducing her breast cancer risk.
The study builds on previous research, outlining the preventive effects of childbirth and breastfeeding, and appears in this week's issue of The Lancet.
However, other cancer experts note, this study overstates that impact.
"Lifestyle plays an even greater role," says Debbie Saslow, PhD, director of breast and gynecological cancer at the American Cancer Society. "Diet, activity level, hormone replacement therapy are all factors that affect women's risk [of developing breast cancer]. This study gives the impression that breastfeeding offers more protection than it does."
In the study, researchers pooled and analyzed data on nearly 150,000 women involved in 47 studies in 30 countries. All the studies included information on breastfeeding patterns and other aspects of childbearing for about 50,000 women with invasive breast cancer. They combined that data with information on 97,000 women without breast cancer.
Among their findings: Women in Western countries breastfeed for shorter periods than other women around the world. Yet, when women do breastfeed, they decrease their risk of breast cancer by 4% for every year spent breastfeeding, in addition to a decrease of 7% for each birth.
The patterns "are significant and are seen consistently for women from developed and developing countries, of different ages and ethnic origins, and with various childbearing patterns and other personal characteristics," writes study author Valerie Beral, PhD, an epidemiologist at Oxford University in England.
True, "we've known that the longer a woman breastfeeds, the more protection she has against breast cancer -- this is more evidence," Saslow tells WebMD.
"Policymakers in developed countries should make it as easy as possible to breastfeed, especially when women want to go back to work," she says. "However, I don't think we should overstate the value of breastfeeding -- or make women feel guilty if they didn't breastfeed."
The decision to breastfeed is a very personal one, and "women have a lot of reasons whether they breastfeed or not," says Saslow. "Some reasons may be more important to the individual mother than protecting herself from breast cancer."
Women should not feel guilty -- or that they are going to be at a greatly increased risk for breast cancer -- if they choose not to breastfeed, she says.