Study Finds Higher BMI Associated With Reduced Breast Cancer Risk

Higher body mass index (BMI), especially in early adulthood, is associated with reduced risk for premenopausal breast cancer, according to a study published in JAMA Oncology. 

This multicenter study used pooled individual-level data from 758,592 premenopausal women (18-54 years) from 19 prospective cohorts from North America, Europe, Asia, and Australia. Patients were recruited between January 1, 1963, and December 31, 2013. At a median follow-up of 9.3 years (interquartile range = 4.9-13.5 years), there were 13,082 incident cases of breast cancer.  

Reduced risk of premenopausal #BreastCancer seen in women w increased adiposity/higher body mass index (BMI), particularly in early adulthood, based on large pooled analysis of data from 758,592 premenopausal women. https://t.co/zQUWNB7TVz #BCSM

— JAMA Oncology (@JAMAOnc) June 25, 2018

The researchers observed inverse linear associations of BMI with breast cancer risk that were stronger for BMI at ages 18 to 24 years than for BMI at ages 45 to 54 years. The inverse associations were observed even among non-overweight women.  

Association of Body Mass Index and Age With Subsequent Breast Cancer Risk in Premenopausal Womenhttps://t.co/E9ORPYzeT7#Cancer

— Anthony Johns (@AnthonyJohns1) June 25, 2018

The youngest women were 4.2 times less likely to develop early breast cancer if they were obese (BMI ≥35.0 kg/m2) than if they were underweight (BMI <17.0 kg/m2). In women older than 25 years, there was a 1.9- to 2.5-fold decreased risk for breast cancer in the same obese/underweight BMI categories. 

Source: JAMA Oncology