Staying healthy, keeping fit and staying within the normal weight range could be more important than you think. According to an analysis from the Women’s Health Initiative (WHI), postmenopausal women who are overweight or obese have a higher risk of invasive breast cancer than women of normal weight and breast cancer risk increases as a woman’s weight rises beyond obesity (1).
Researchers followed 67,142 postmenopausal women ages 50 to 79 years enrolled from 1993 to 1998 across 40 US clinical centers. After a median of 13 years of follow-up through 2010, 3388 invasive breast cancers were observed.
The researchers then analysed the distribution of breast cancer among different weight classes and calculated the risks for women who were overweight (body mass index, or BMI, of 25 to 30), obese (BMI 30 to 35), or very obese (BMI over 35) compared with women of normal weight (BMI 25 or less). They found that the increased risk of developing breast cancer ranged from 17% in women who were overweight to 59% in those with a BMI over 35. Among women who began the study at a normal weight, those who gained at least 5% of their original weight had a 12% higher risk of developing breast cancer than those who maintained their original weight.
You can calculate your personal risk at the National Cancer Institute website,
1: Neuhouser ML, Aragaki AK, Prentice RL, Manson JE, Chlebowski R, Carty CL, Ochs-Balcom HM, Thomson CA, Caan BJ, Tinker LF, Urrutia RP, Knudtson J, Anderson GL. Overweight, Obesity, and Postmenopausal Invasive Breast Cancer Risk: A Secondary Analysis of the Women's Health Initiative Randomized Clinical Trials. JAMA Oncol. 2015 Aug;1(5):611-21. doi: 10.1001/jamaoncol.2015.1546. PubMed PMID: 26182172.
Dr Nicole Ng (MBBS) is a medical doctor with a passion in women's health and medical research