A woman who gains weight after the menopause raises her risk of developing breast cancer, while a woman who loses weight after the menopause lowers her risk, say researchers from Harvard Medical School and the Harvard School of Public Health, USA. You can read about this study in the Journal of the American Medical Association (JAMA).
The researchers monitored 49,514 women for up to 24 years. They were looking at rates of invasive breast cancer. They found that 15% of all the breast cancers were as a result of women gaining over 4.4lbs (2 kilos) since they were 18 years old. They also found that a woman who loses weight after her menopause reduces her chances of developing breast cancer by 57% when compared to women who stayed the same weight or put on weight.
Lead author, Dr. Eliassen wrote “An important finding from this study is that weight loss may reduce breast cancer risk, even if weight is not lost until after menopause. Although these data suggest that it is never too late to lose weight to decrease risk, given the difficulty in losing weight, the emphasis must also remain on weight maintenance throughout adult life.”
Here were some of their findings after monitoring 49,514 women for up to 24 years:
— 4,393 developed invasive breast cancer
— Those who gained 55lbs (25 kilos) or more since 18 years of age were 45% more likely to develop invasive breast cancer when compared to women who did not put on weight
— Women who put on weight after the menopause had a significantly raised risk of breast cancer compared to women who did not put on weight after the menopause
— Women who lost weight after the menopause had a significantly reduced risk when compared to women who did not lose weight or put on weight after the menopause
— Women who never used postmenopausal hormones also had a lower risk, especially those who also lost weight after the menopause
As weight-loss is particularly difficult to achieve after the menopause, the authors suggest that good bodyweight maintenance throughout life is the best strategy to get optimum protection from developing breast cancer.
In most cases the researchers had to rely on the women being monitored trying to remember what their weight was at 18 rather than collecting this data from proper medical records.
Most women put on weight after the age of 18, and also after the menopause.
Title: “Adult Weight Change and Risk of Postmenopausal Breast Cancer”
A. Heather Eliassen, ScD; Graham A. Colditz, MD, DrPH; Bernard Rosner, PhD; Walter C. Willett, MD, DrPH; Susan E. Hankinson, ScD
JAMA. 2006;296:193-201.
Written by: Christian Nordqvist
Editor: Medical News Today