Left-handed people don't necessarily die any younger than right-handers, says new research that runs counter to what some studies have suggested.
In a nine-year study, Dr. Simon Ellis and his colleagues at Keele University in England examined the link between left-handedness and the risk of dying earlier using 6,049 people ranging in age from 15 to 70."Handedness did not make a significant contribution to the outcome of death," concluded the study, published today in this week's issue of The Lancet, a British medical journal.
The question of whether lefties die younger is controversial. Several studies have suggested a connection, but others have shown no link.
One theory suggests that older age groups contain fewer left-handers not because they die earlier, but because many in the older generation were forced as children to become right-handed, whereas children today are less likely to be pressured into switching.
Researchers found in 1991 that the proportion of left-handers decreases with age, dropping from 13 percent in 20-year-olds to less than 1 percent in 80-year-olds.
That led scientists to suggest that left-handedness may be associated with a shorter lifespan, perhaps because southpaws are less adapted to survival and thus more prone to immune disease or accidents.
One study suggested that right-handed people live about nine years longer than left-handers.
But some researchers, such as Richard Peto, professor of medical statistics and epidemiology at Oxford University, dispute those conclusions.
"I haven't seen any competent studies showing a link," said Peto, who was not involved in the Keele University study. "You've got to adjust for age."
In the study, the left-handed group was younger than the right-handed group, but the analysis accounted for the effect of age.