My name is Heidi and I’m a nursing student at the University of
North Dakota. As part of my childbearing class we were assigned to
subscribe to an OB listserv that was discussion based.
 As I was reading through the Lactnet issues looking for an
interesting topic. I came upon a post about contacting local cancer
societies. The idea was to start a campaign to promote breastfeeding by
using the idea that breastfeeding reduces the risk of breast cancer.
 I have always supported breastfeeding but I was pretty skeptical
about it having any benefits to women in preventing breast cancer. I
decided to do some more research on the topic.
 One of the first articles I found was a study by Freudenheim et al.
(1997). It studied women in two counties in New York, which included both
women with breast cancer and women without breast cancer. It also tested
both premenopausal and postmenopausal women. The article stated
that, “while there are a number of reports that lactation, particularly
prolonged lactation, may have a weak protective effect against breast
cancer, the epidemiologic findings are far from conclusive”(Freudenheim,
1997 p.932). As the authors explained their results they stated “there was
a trend toward decreased risk associated with ever lactating… 95%
confidence intervals included the null. The odds ratio for 20 months or
more of lactation in the lifetime was .50 (95% confidence interval .21-
1.21)” (Freudenheim, 1997 p.937). They later included “ there was a trend
toward protection for premenopausal women. Among postmenopausal women, the
protective effect of lactation was restricted to women who had first
lactated before age 25. (Freudenheim, 1997 p. 937).
A recent reanalysis of over 100,000 women, from 47 epidemiological studies,
resulted in clearer findings. The opening of this article stated, ”although
childbearing is known to protect against breast cancer whether or not
breastfeeding contributes to this protective effect is unclear” (Beral,
Bull, Doll, Peto, & Reeves, 2002 p 187). However in the results/discussion
portion of the article it stated that their “analyses shows that the
relative risk of breast cancer is reduced by 4.3%(95% CI 2.9-5.8) for each
year that a woman breastfeeds, in addition to a reduction of 7.0% for each
birth” (Beral, et al. 2002 p 193). The results also revealed “no
significant difference for women by age or menopausal status” (Beral, et
al. 2002 p. 187).
  Zheng, an associate professor at Yale School of Medicine conducted
a study in China because long-term breastfeeding is part of the Chinese
culture. According to the study, “what they found was a 50% reduction in
pre and postmenopausal breast cancer risk among those women who breastfeed
for more than 24 months per child, compared to women who breastfed their
children for less than 12 months” (p50-58).
 In my research I read several articles that support the theory of
breastfeeding to help reduce cancer risk. I’m no longer skeptical about
this issue. However, is it feasible that in our country and our culture
women would breastfeed for two years to get the added reduction in breast
cancer risk? I like the campaign idea that was proposed on Lactnet that
brought this topic to my attention, but would women be willing to stick to
it?
 If anyone has comments or additional information to answer some of
my questions I would very much welcome them. I have thought about working
in OB after I graduate and would like to gain as much information about
breastfeeding as I can. We have to write a research proposal as part of my
nursing research class, and I am interested in this topic as the basis for
that assignment as well. Thank you for your time.


References:
 Beral, V. Bull, D. Doll, R. Peto, R. & Reeves, G. (2002). Breast
cancer and breastfeeding: Collaborative reanalysis of individual data from
47 epidemiological studies in 30 countries, including 50,302 women with
breast cancer and 96,973 women without disease. Lancet, 360 187-195.

 Freudenheim, J. Marshall, J. Vena, J. Moysich, K. Muti, P.
Laughlin, R. Nemoto, T. & Graham, S. (1997). Lactation history and breast
cancer risk. American Journal of Epidemiology, 146 932-938.

 Zheng, T. Holford, TR. Tessari, J. Mayne, ST. Owens, PH. Ward, B.
Carter, D. Boyle, P. Dubrow, R. Archibeque-Engle, S. & Zahm, SH. (2001).
Breast cancer risk associated with congeners of polychlorinated biphenyls.
American Journal of Epidemiology. 152 50-58.

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