Bad News for Left-Handed Women

Left-handed people have always had some (or many) struggles to fit in. Musical instruments, hand-tools, and even public drinking fountains are often designed without a thought to those who might approach differently (literally). That ubiquitous and essential tool, the computer mouse, is often made to fit the right hand only, and most computer installations have the mouse placed on the right side, making it awkward for left handers to use. Women, who are statistically less likely to be left-handed than a man, also have a few unique struggles for their gender. In ancient Japan, a man could divorce his wife for being left-handed.

Now, left-handed women have a new worry. A report published in Epidemiology March 2007 finds that left-handed women are more likely to contract some serious diseases, and to die sooner. The study suggests that women who are left-handed have a higher risk of dying, particularly from cancer and cerebrovascular disease - damage to an artery in the brain or an artery that supplies blood to the brain. When left-handed women were compared with the other women, and the data were adjusted for a number of other factors, lefties had a 40 percent higher risk of dying from any cause, a 70 percent higher risk of dying from cancer, and a 30 percent higher risk of dying from diseases of the circulatory system.

One problem with the study is the decreasing sample size. There are fewer left-handed women in older generations, presumably because being left-handed was strongly discouraged. Children were corrected, or even punished, for preferring to use their left-hand. Statistics show that older people are less likely to be left-handed than their younger counterparts - the percentages of left-handed people sharply drop off with increased age. In America, 12% of 20 year olds are left-handed, while only 5% of 50 year olds and less than 1% of people over 80 are. It is also possible that this does indeed reflect the assertation that left-handed people die sooner.

This is not the first research to report these type of results. Researchers in the Netherlands in 2005 observed a 39 percent higher risk for developing breast cancer in left-handed women. Adjusting for risk factors hardly affected the overall association, they report. They found that left-handed women were more than twice as likely to develop pre-menopausal breast cancer as non-left handed women.

Dr Olga Basso, who is left-handed, is highly skeptical of research relating disease and death with handedness. "I am not alone in thinking that the literature on handedness suffers from a number of ills," she notes. "Having successfully dodged a number of disorders," adds Basso, "I doubt that my left hand is prematurely pulling me toward my grave."

SOURCE: Epidemiology March 2007