HK study shows breast cancer risks from stress and lack of exercise
Researchers say stress and lack of exercise are big risk factors, especially for younger women - whose tumours are more aggressive
Too little exercise and a stressful lifestyle are the most common risk factors for developing breast cancer, scientists have warned.
Most patients aged under 40 exercise less than three hours a week and suffer from high stress levels, according to research by the Hong Kong Breast Cancer Registry.
Breast tumours in this age group are usually more aggressive and toxic than in older patients, it found.
"Young patients are more likely to have breast cancer with more aggressive biological features, but the reason is not known," said Professor Winnie Yeo, a member of the organisation's steering committee. "Genetic factors may be one of the reasons."
There are about 3,000 new cases of breast cancer every year in Hong Kong. The registry analysed 7,241 local cases, assessing lifestyle-related factors.
Lack of exercise topped the list for most patients, and was more significant for younger women - 85 per cent reported doing less than three hours of physical activity per week.
High stress levels were identified in 46 per cent of younger patients. Nine per cent said they worked night shifts, which is strongly associated with stress.