Dose-Response Relationship Between Obesity And Breast Cancer

With all the concern about the impact of obesity on metabolic and cardiovascular health, it is often forgotten that after smoking, obesity is the single most important risk factor for many common cancers, including of course breast cancer.

The importance of this relationship is again documented by Marian Neuhouser and colleagues in a paper published in JAMA Oncology.

The study examines the associations of overweight and obesity with risk of postmenopausal invasive breast cancer after extended follow-up (about 13 years) in the Women’s Health Initiative (WHI) clinical trials, involving over 67,000 postmenopausal women ages 50 to 79 years at 40 US clinical centers..

Overall, 3388 invasive breast cancers were observed over the follow-up period with women who were overweight or obese having increased risk that was related to their degree of excess weight.

Compared to normal weight women, individuals with Class II and III obesity had a 60% greater risk for invasive breast cancer with an almost 2-fold greater risk for estrogen receptor–positive and progesterone receptor–positive breast cancers.

Class II and III obesity was also associated with a 2-fold greater risk for larger tumor size, positive lymph nodes and deaths.

Furthermore, risk was increased in women with a baseline BMI of less than 25.0 who gained more than 5% of body weight over the follow-up period.

Given this importance of obesity for breast cancer, one can only wonder just how much of the Cancer research funding raised by the Pink Ribbon campaign and other Cancer charities, finds its way into research on obesity treatment and prevention – can’t say I know of any cancer funding that has knocked on the doors of my fellow obesity researchers.

@DrSharma
Edmonton, AB