Just got this over the newswire on my medical weekly digest of good studies to know. This was a study out of the Journal of the National Cancer Institute, published December 2019. They state that excess body weight is an established cause of post menopausal breast cancer.
So they ask the question, does weight loss then reduce breast cancer risk?
Study:
- Women aged 50 or older
- Prospective studies of Diet and Cancer
- Women were in US, Asia, and Australia
- 10 cohorts: weight was assessed on three surveys
- Looked at weight change patterns over 10 years (median 5 years for interval 1, and 4 years for interval 2)
- Sustained weight loss was defined at 2 kg or more lost in interval 1, that was not regained in interval 2
- 180,885 women were evaluated. 6,930 invasive breast cancers were identified
Findings?
Compared to women with stable weight, those with sustained weight loss (2 kg or more = 4.5 pounds) had a lower risk of breast cancer.
- The lowered risk reduction was linear
- Specific to women NOT using postmenopausal hormone replacement
- Women who lost 9 kg or more (20 pounds) and then regained some (but not all) of it back were also at lower risk of breast cancer
Conclusion?
When women lost 4.5 pounds and kept it off, they reduced the risk of breast cancer by 18%.
When they lost 20 pounds and kept it off, they lowered the risk of breast cancer by 32%.
“The research does not prove cause and effect, but indicates an association between weight loss and reduced risk of breast cancer.”
My thoughts?
Who knows why. Does fat have something to do with hormone levels? (Many postmenopausal breast cancers are hormone receptor positive.) As a woman of a certain age, menopause can be super frustrating, as your metabolism slows, your fat deposition pattern changes, and alas, most of us gain weight. It is not uncommon to see women gain 10-20 pounds around menopause. This study is important. The numbers of women studied were huge, and the reduction in the rate of breast cancer significant.
If this study doesn’t make you skip that cupcake or hop on the Peleton, I don’t know what will. It is for sure motivating me.