The study is the first to suggest that the previously documented susceptibility of left-handers to accidents is associated with increased mortality. It is also the first to suggest that health problems linked to high rates of birth trauma in left-handers may be potentially life-threatening.
Both the authors and other researchers were surprised at the large difference shown in the study, published in the New England Journal of Medicine. Searleman of St. Lawrence University in Canton, N. But Diane F. Halpern of Cal State San Bernardino, one of the co-authors, countered that no one had ever looked for such differences until now. There is nothing peculiar about this study. Searleman said the study could have significant practical ramifications, including the possibility that life insurance companies might charge a higher rate for left-handers or that auto insurers might charge more for left-handed drivers.
Some left-handedness, perhaps the bulk, is genetically based, but much of it is also associated with some disturbance of brain development.
Among the factors implicated in previous studies are high levels of male hormones in the mother during pregnancy and trauma during birth, including Rh incompatibility, prolonged labor, breech birth, prematurity and low birth weight. Perhaps as a result of such factors, researchers have suggested, lefties are more prone to a variety of problems, including neuroticism, allergies, insomnia, learning disorders, migraines, autism and disorders of the immune system.
They also have higher rates of alcoholism and smoking. In the current study, Halpern and Coren collected all the death certificates recorded in the two counties over a period of several months--about 2, in total. If it's so implausible why was it published in respected academic journals and why has the myth endured? Because, according Chris McManus, the researchers made a "very subtle error". The studies were conducted in Southern California, where lists are published of everyone who has died.
Halpern and Coren took a list of the people who had recently died and contacted their families, asking whether or not their relative had been right- or left-handed. Looking at 2, cases, they saw that the average age at death of the left-handers was about nine years younger than of the right-handers. On that basis, they concluded that left-handers died earlier. At first glance, that seems persuasive. What did the researchers do wrong? The point is that left-handers are more common now than they used to be, so - at least at the time the research was published - left-handers were on average younger than right-handers.
Not only would left-handed people have been encouraged not to be during this period, life was also pretty difficult for them and they quickly became very conspicuous. The result of all of this was that left-handers became stigmatised - regarded as cack-handed, stupid. Using the same approach as Halpern and Coren, one would conclude that nursery school is more dangerous than paratrooper training, since the mean age at death of children in nursery school is much lower than that of paratrooper trainees.
This same issue of longevity and handedness was pondered using data from the Danish Twin Registry, which looked at opposite-handed twin pairs to see which individual died first:.
We compared mortality in a subgroup of opposite-handed twin pairs by counting in how many instances the right-handed twin died first. There was no evidence of differential survival between right-handed and non-right-handed individuals in the entire — cohort … We did not find evidence of excess mortality among non-right-handed adult twins in this follow-up study. This approach, which was not biased by the same statistical issues as the previous studies, agrees with the general scientific consensus that longevity and handedness are completely unrelated.
Fact Checks. Left-handed people, on average, die younger than right-handed people. False About this rating.
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