Body weight is the single biggest factor which causes breast cancer in women beyond menopausal age, according to new research carried out by the University of Oxford and commissioned by Cancer Research UK.
According to the report, obesity alters the level of hormones associated with the disease, while alcohol consumption and smoking were also highlighted as increasing the risk of contracting breast cancer.
"Hormone levels might explain the association of established risk factors such as obesity with breast cancer risk," said co-author Dr Gillian Reeves. "Other studies have found that weight and alcohol can affect hormone levels."
Cancer Research UK senior science information manager Dr Julie Sharp added that women can take steps to reduce the likelihood of developing the condition, including maintaining physical fitness and restricting alcohol consumption.
Earlier in the week, a separate study from the charity revealed cancer rates in the UK climbed by almost one-fifth between 1979 and 2008.