Posted on February 5th, 2009 by
Adult Weight Changes and Breast Cancer Risk
Women with a higher body mass index (a comparison of weight to height) are known to have a higher risk of postmenopausal breast cancer. Furthermore, several studies have linked adult weight gain with an increased risk of breast cancer. Less is known, however, about whether weight loss can decrease risk or about the effects of weight change later in life (after the time of menopause).
To explore how adult weight change affects risk of breast cancer, researchers evaluated information from the Nurses’ Health Study. The study included over 87,000 postmenopausal women who did not have cancer when the study began. They were followed for up to 26 years. Over the course of follow-up, more than 4,000 cases of breast cancer were diagnosed.
This study confirms that weight gain in adulthood, including weight gain after the time of menopause, increases the risk of breast cancer in postmenopausal women. Importantly, however, the study also suggests that weight loss may decrease risk for some women. The researchers point out that because weight loss can be difficult, the best approach is to maintain a healthy weight throughout adulthood.
Adult Weight Gain and Type and Stage of Breast Cancer
A second study evaluated the link between adult weight gain and type and stage of breast cancer. The study involved 44,161 postmenopausal women, 1,200 of whom developed breast cancer. The study included only women who were not using postmenopausal hormones.
These results, like the previous study, suggest a link between adult weight gain and increased risk of postmenopausal breast cancer.
Weight Gain and BRCA1/2 Carriers
Finally, a third study explored the effect of weight gain among women at very high risk of breast cancer due to a BRCA1 or BRCA2 mutation. Women who had gained the most weight in adulthood (after the age of 18) had a more than four-fold increase in breast cancer risk. Weight gain after the age of 30 was also linked with an increased risk. This suggests that the link between weight gain and breast cancer risk also applies to this very high-risk group of women.
These three studies provide additional motivation to maintain or to work towards a healthy body weight in adulthood. Furthermore, the results of the first study suggest that it’s never too late to start.
Eliassen A, Colditz G, Rosner B, et al. Adult Weight Change and Risk of Postmenopausal Breast Cancer. Journal of the American Medical Association. 2006; 296:193-201.
Feigelson HS, Patel AV, Teras LR, Gansler T, Thun MJ, Calle EE. Adult Weight Gain and Histopathologic Characteristics of Breast Cancer Among Postmenopausal Women. Cancer. Early Online Publication May 22, 2006.
Nkondjock A, Robidoux A, Paredes Y, Narod SA, Ghadirian P. Diet, Lifestyle and BRCA-related Breast Cancer Risk among French-Canadians. Breast Cancer Research and Treatment. 2006;98:285-294.
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