Researchers probe link between left-handed women, breast cancer

A new study suggests left-handed women might be at increased risk for breast cancer.

Cuno Uiterwaal of the University Medical Center in the Netherlands and colleagues examined the relationship between handedness and breast cancer in 12,178 healthy, middle-age women participating in a breast cancer screening study.

Between 1982 and 2000, the left-handed women in the study were more than twice as likely as right-handed women to develop breast cancer before going through menopause, the researchers found.

The association held up even after the researchers took into account other factors, such as social and economic status, smoking habits, family history of breast cancer and reproductive history.

Much more research is needed to explore whether the relationship is real and what may explain it. But the researchers speculated that left-handed women may be at risk for breast cancer because they were exposed to higher levels of certain hormones in the womb.