"Left handedness is associated with breast cancer, most specifically pre-menopausal breast cancer," says Cuno Uiterwaal, an assistant professor of clinical epidemiology at the university.
"We found that left-handed women are more than twice as likely to develop pre-menopausal breast cancer as non-left handed women," the researchers say in the report published online by the British Medical Journal.
About eight to nine per cent of women are left-handed. But the scientists said the findings should not alarm them.
"What our study intends to do is focus on this area. We do not know all the causes of breast cancer, that is why we should continue. This may be one new factor that leads us to a better understanding of the aetiology (cause of the illness)," Professor Uiterwaal added.
