Why do left handers die earlier

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.

Excluding individuals under the age of 6 and those who died from homicides or suicides, they wrote the families of the deceased and asked for information about the cause of death and whether the victim wrote, drew and threw a ball with the right or the left hand. They obtained usable data on individuals. To see why, imagine an exaggerated scenario where there were no left handers at all born before - 40 years ago.

If we now look at death records for and ask who, among the dead, was left-handed we would see that all of them died at or before the age of That would be much younger than the average of age at death of right-handers. Nothing like this exaggerated scenario ever occurred in reality - but the number of people identifying as left-handed did grow dramatically during the 20th Century.

So the idea that left-handers die nine years earlier than right-handers is a myth. What about non-fatal injuries? Should we be worried about people like Claire Allen struggling in the kitchen with knives designed for the right-handed?

Or my own mother for that matter, if she were forced to use right-handed scissors? You can follow the Magazine on Twitter and on Facebook. Left-handers were once mistakenly regarded as cack-handed. Obama is the third left-handed US president since ambidextrous Ronald Reagan. Since this confirms earlier research in California, it can probably now be added with some confidence to the stock of human knowledge. Except that it leaves many questions unanswered. Is the higher death rate of lefties attributable to their so-called cack-handedness?

Or to the discrimination they suffer when classed as cack-handed - or as "sinister", "maladroit" or "lacking dexterity? No, as with all the best research, there is only one safe conclusion to be drawn from these findings.