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Research has previously suggested a link between being overweight and breast cancer risk, but a new study shows stronger evidence linking body weight and breast cancer.
The large study has gotten a lot of attention because it looked at over 67,000 women ages 50 to 79 years old across the country, followed them for over 13 years, and found strong links between Body Mass Index and chances of developing the most common form of breast cancer (hormone receptor-positive).
What they found is that the greater the weight of women, the greater their risk of being diagnosed with breast cancer. The study grouped women and their body mass index (BMI), which is a ratio of weight to height.
Women with a BMI of 35 or over (very obese) were were 86 percent more likely than normal-weight women to be diagnosed with this breast cancer. Women with BMI’s this high were also 56% more likely to develop invasive, aggressive forms of breast cancer compared to normal weight women.
Women with a BMI over 30 (considered obese) were also more likely to have large tumors and cancer that spread beyond the breast and into the lymph nodes.
For those thinking the term “obese” is a rarity keep in mind that a woman who is 5-foot-7 and weighs 225 pounds would fall into this category.
Also, normal-weight women who gained more than 5 percent of their starting weight over the study period had a 35 percent increased risk of breast cancer.
Interestingly, no link was found between body weight and breast cancers that are hormone receptor-negative.
Why this link to hormone receptor-positive cancers? The working theory is that fat cells release inflammatory mediators that can fuel potential cancer cells. We know that more fat tissue means more inflammation, and this is now fascinatingly linked to hormone receptor positive breast cancers.
What is key to take away from this is that the data suggests that when it comes to one’s risk of this common form of breast cancer, women can do something about it if they lose weight or don’t gain excess weight immediately after menopause.
Our genetics and family history aren’t changeable, but our lifestyle is! Menopause makes it very difficult for women to lose weight, but not impossible. Even more key is that keeping a healthy weight pre-menopause is a major benefit for women.
Moreover, women who gained weight in early postmenopause increased their risk even if they were a normal weight at the start of the study! Healthy weight is important for prevention of this cancer but maintaining that weight is just as important.
This study doesn’t actually prove that excess body fat causes the cancer, but the association is so strong that we cannot ignore it! Women need to understand that maintaining a healthy body weight isn’t about beauty and aesthetics, but plays a key role in prevention of serious diseases like breast cancer!
Next we need a good study looking at whether weight loss decreases breast cancer risk at any point!
Obesity is a growing problem in the western world and studies like this show it isn’t just heart disease and diabetes we are bringing upon ourselves.
