Increased adiposity associated with decreased risk of breast CA before menopause

(HealthDay) – Cross-Scale Body Mass Index (BMI) Distribution, Increased BMI is Associated with a Reduced Risk of Premenopausal Breast Cancer, according to a study published online June 21 JAMA Oncology.

Minouk J. Schoemaker, Ph.D., of the Institute of Cancer Research, London, and colleagues at the Premenopausal Breast Cancer Collaborative Group have examined the correlation of BMI with the risk of premenopausal breast cancer in a multicenter analysis using pooled individual data of 758,592 premenopausal women from 19 prospective cohorts. Participants were followed for a median of 9.3 years per participant to estimate risk ratios of premenopausal breast cancer in association with BMI; there were 13,082 incident cases of breast cancer during follow-up.

The researchers found that linear inverse associations of BMI with breast cancer risk were stronger for BMI between 18 and 24 years of age than for BMI between 45 and 54 years of age (hazard ratios by difference of 5 kg / m², respectively 0.77 and 0.88)). Even among non-overweight women, these reverse associations were observed. Between 18 and 24 years, there was a 4.2-fold risk gradient between the highest and lowest BMI categories (BMI ≥ 35.0 vs. breast cancer risk factors).

"The increase in adiposity is associated with a reduced risk of premenopausal breast cancer to a greater extent than previously shown and across the entire distribution of BMI," the authors write.

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