Risk of breast cancer in men in relation to weight change

Breast cancer in men (MaBC) is uncommon, and knowledge about its causation in limited. Obesity is a known risk factor for MaBC, but there has been no investigation of whether weight change is an independent risk factor, as it is for breast cancer in women. A case-control study in England and Wales included MaBC patients and male controls, who were interviewed about risk factors for breast cancer including anthropometric factors at several ages. Increases in BMI between age 20 and 40, and between age 40 and 60, were signicantly associated with MaBC, as was increase in waist/height ratio from age 20 to 5 years before diagnosis. The associations were independent of each other and of BMI or waist/height ratio at te start of the period of change analyzed.