Handedness and mortality risk in older women.

Left-handedness has been associated with decreased longevity, although this finding is controversial and not universal. The authors prospectively studied 39,691 women aged 55-69 years from the Iowa Women's Health Study through 5 years of mortality follow-up. No increase in mortality risk was found for left-handed women as compared with right-handed women (age-adjusted hazard ratio 1.10, 95% confidence interval (CI) 0.86-1.39) or for ambidextrous women (age-adjusted hazard ratio 1.05, 95% CI 0.73-1.49). Adjustment for body mass index, body fat distribution, smoking, and education did not alter these findings. Further analysis by cause-specific mortality (breast cancer, all other cancer, and circulatory disease) showed no relation to handedness. There was no difference in the mean age at death of left-handed, right-handed, and ambidextrous women. These findings do not support an association between left-handedness and increased mortality risk.