1: Psychol Bull. 1991 Jan;109(1):90-106

Left-handedness: a marker for decreased survival fitness.

Coren S, Halpern DF.

Department of Psychology, University of British Columbia, Vancouver, Canada.

Life span studies have shown that the population percentage of left-handers diminishes steadily, so that they are drastically underrepresented in the oldest age groups. Data are reviewed that indicate that this population trend is due to the reduced longevity of left-handers. Some of the elevated risk for sinistrals is apparently due to environmental factors that elevate their accident susceptibility. Further evidence suggests that left-handedness may be a marker for birth stress related neuropathy, developmental delays and irregularities, and deficiencies in the immune system due to the intrauterine hormonal environment. Some statistical and physiological factors that may cause left-handedness to be selectively associated with earlier mortality are also presented. 

Comment in:

·         Psychol Bull. 1993 Sep;114(2):203-34; discussion 235-47.

1: Percept Mot Skills. 1993 Apr;76(2):403-6

A replay of the baseball data.

Coren S, Halpern DF.

Department of Psychology, University of British Columbia, Vancouver, Canada.

Fudin, Renninger, Lembessis, and Hirshon (1993) reported a nonsignificant longevity advantage for right-handers in their analysis of archival baseball data, although the absolute values are still in the predicted direction. Differences in specific data entries and analyses are difficult to resolve; however, there is some indication that the data base that they analyzed differs from that in our study. Further, their use of parametric statistics, given distributional problems and grossly unequal group sizes, may account for the nonsignificance they observed, when compared to the nonparametric analyses that we used. While we considered our original study a pilot project, the literature now contains hundreds of studies that show that left-handedness is associated with a wide range of health-risk factors including serious accidents, immune system disorders, and birth-related complications that involve reduced oxygen. A recent study of the archival records of over 3000 cricket players showed a significant advantage of over 2 years in longevity for right-handed cricket players. On the basis of these findings, we still believe that left-handedness is a marker for reduced longevity

{study found accidents were nearly all the cause of the statistical difference of 25 months}

1: J Epidemiol Community Health. 1993 Jun;47(3):206-9

Evidence for longevity differences between left handed and right handed men: an archival study of cricketers.

Aggleton JP, Kentridge RW, Neave NJ.

Department of Psychology, University of Durham.

STUDY OBJECTIVE--The aim was to examine the relationship between handedness and longevity. DESIGN--This was an archival (retrospective) survey of a cohort of adult men who had played 'first-class cricket'. SETTING--The United Kingdom PARTICIPANTS--The subjects consisted of all of the deceased players included in an encyclopedia of 'first-class cricket' whose bowling hand had been recorded (n = 3165). The study also considered a further 2314 players, born before 1951 but still alive at the time the book was published (1984). MEASUREMENTS AND MAIN RESULTS--Using the bowling hand as an indicator of handedness it was possible to compare the lifespans of 2580 right handed men and 585 left handed men. The average life spans of the two groups differed by 25 months (right = 65.62, left = 63.52), a highly significant difference (p = 0.006). An examination of cause of death (where noted) strongly indicated that the left handed men were more likely to die prematurely in accidents or in warfare. As a consequence, when these unnatural deaths were removed from the sample the longevity difference between the right handers and left handers was considerably reduced. There was no evidence that these results related to any longitudinal change in the proportion of right handers to left handers across the time course of the sample. CONCLUSION--The study found clear evidence that left handedness was associated with a decrease in longevity among a cohort of adult, athletic men. A major factor responsible for this result seemed to be a differential likelihood of accidental death or death during warfare.

Handedness and accidents with injury.

Hicks RA, Pass K, Freeman H, Bautista J, Johnson C.

Department of Psychology, San Jose State University, CA 95192-0189.

As evidence for the hypothesis on the claim of reduced longevity for left-handers, Coren in 1989 reported data which suggested that left-handers were 1.89 times more likely to report injuries which required medical attention. This left-handed group included both left- and mixed-handed individuals. To clarify the results of his study, we repeated in part Coren's study but defined handedness so that groups of right-, mixed-, and left-handed individuals were considered. In contrast to Coren's data, we found that right- and left-handers did not differ significantly in the frequency with which they reported having experienced accidents with injury and that mixed-handers reported being significantly more likely to have had an injury-accident than either right- or left-handers. These data underscore the need to consider mixed-handedness as a separate group in studies of this type

Am J Epidemiol. 1994 Aug 15;140(4):368-74

Handedness and mortality risk in older women.Cerhan JR, Folsom AR, Potter JD, Prineas RJ.

Division of Epidemiology, University of Minnesota School of Public Health, Minneapolis 55454.

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.