Background: Left-handedness has been reported to be associated with reduced life expectancy, but the evidence is far from conclusive.
Methods: We studied the association between innate handedness and total mortality, as well as cause-specific mortality, in a cohort of 12,178 middle-aged Dutch women who were followed for almost 13 years. The relation between handedness and mortality was analyzed using Cox regression in a case-cohort approach, in which a random sample of 1500 women was used to represent person-years under observation for the entire cohort.
Results: During a median follow-up of 12.6 years, 252 women died. Hazard ratios comparing left-handed women with other women were 1.4 for all-cause mortality (95% confidence interval = 0.9-2.0), 1.7 for total cancer mortality (1.0-2.7), 2.0 for breast cancer mortality (0.8-4.6), 4.6 for colorectal cancer mortality (1.5-14.3), 1.3 mortality from diseases of the circulatory system (0.5-3.3), and 3.7 for cerebrovascular mortality (1.1-12.1), after adjusting for potential confounders (socioeconomic status, age, body mass index, and cigarette smoking status at study recruitment).
Conclusions: Left-handedness is associated with higher mortality in women.