According to the results of a research project conducted by Dutch scientists, pre-menopausal women who are left-handed have a twofold increased risk of developing breast cancer compared to right-handed women. Every year, over one million women worldwide are diagnosed with breast cancer, with three-quarters of these cases occurring after menopause (around the age of 50).
Scientists suggest that the innate phenomenon of left-handedness and the risk of later developing breast cancer share a common origin, potentially due to the fetus being exposed to certain hormones present in the womb.
A member of the research team, Associate Professor Cuno Uiterwaal, stated: “Left-handedness in women has a direct correlation with the risk of developing breast cancer, and the majority of cases will occur before menopause.”
To reach this conclusion, researchers studied 12,000 women participating in a breast cancer detection program. All were healthy middle-aged women born between 1932 and 1941. The scientists relied on their handedness characteristics and previous medical information to identify who had breast cancer.
Regarding left-handed women, Professor Uiterwaal remarked: “When combining both pre- and post-menopausal breast cancer cases, the risk of breast cancer in this group of women increases by up to 40%.”
Upon further analysis, the scientists discovered that the risk of breast cancer before menopause was particularly high. Specifically, compared to right-handed women, left-handed women had a 50% higher rate of breast cancer diagnosis before menopause.
Other influencing factors were also considered in this study, such as family history of breast cancer, pregnancy history, smoking habits, as well as economic status and social position.
While these results are significant, scientists advise left-handed women not to worry excessively, as these are merely preliminary findings. More importantly, this discovery provides new insights into the causes of breast cancer.
