Cutting Breast Cancer Risk: Reason to Breastfeed
Katherine A. Dettwyler, PhD
Texas A&M University
From: LEAVEN, Vol. 35 No. 2, April-May 1999, p. 29
We provide articles from our publications from previous years for reference for our Leaders and members. Readers are cautioned to remember that research and medical information change over time
Between the two factors, having been breastfed oneself and breastfeeding one's own children, one could reduce the risk of breast cancer by almost half. Now breast cancer strikes about one in eight women over the course of their lifetimes. If one could reduce the chances to one in 16, that would be worth doing, I would think.
These studies do not promise anyone that they won't get breast cancer if they were breastfed and breastfeed their own children; they merely lower the risk by half. Chances are good that you won't get breast cancer no matter what you do - as seven out of eight women don't. You can play the odds, or you can change the way you live to reduce your risk.
It is interesting to look at the steady rise in incidence of breast cancer over the last few decades in light of this new information. Let me use my own mother as an example. She was born in 1920, when almost all babies were still breastfed for several years; her mother breastfed her. Thus she got the first type of protection. By the time she started having children in the late 1940s and up to the mid 1950s, many women were not breastfeeding their children anymore (although my mother did). That means that there was an entire cohort of women who had been breastfed as infants, but did not breastfeed their own children. Thus they got the first type of protection, but not the second. As they aged, they were at greater risk for breast cancer than their mothers and grandmothers had been (because their mothers and grandmothers had had both types of protection).
Then you come to my generation, most of whom were born in the 1950s and 1960s and were not breastfed as children, so they missed out on the first type of protection. When they started to have babies in the 1970s and 1980s, many still did not breastfeed their own children, thus missing out on the second type of protection. As this cohort ages, those who were neither breastfed nor breastfed their own children are at even greater risk than their mothers bad been.
Could it be that the steady erosion of these two sources of protection account for the steady rise in breast cancer incidence in the US over the past four decades? At the moment, this is just speculation based on the timing of the two processes. I hope I have given you more to think about.
Freudenheim, J et al. Exposure to breastmilk in infancy and the risk of breast cancer. Epid 1994; 5:324-31.
Newcomb, PA et al. Lactation and a reduced risk of premenopausal breast cancer. New Eng J Med 1994; 330(2):81-87.