Lefties Live Just as Long, Scientists Say

Contrary to the conclusion of a highly publicized report two years ago, left-handers do not die at an earlier age than right-handed people, researchers at Harvard and the National Institute of Aging said Friday.

The researchers studied 3,800 people in East Boston over age 65 for six years and found that the two groups, righties and lefties, died at exactly the same rate.

“There was no difference, period,” said Dr. Jack M. Guralnik, an epidemiologist at the institute and a co-author of the report appearing in the February issue of the Journal of the American Public Health Assn.

“Unfortunately, far too much attention has been paid to flawed and unsubstantiated claims about the higher risk of mortality among lefties, and many people have been unnecessarily frightened,” said his colleague, Dr. Marcel E. Salive.

The new results should put an end to the idea that lefties have a higher risk of death “once and for all,” said epidemiologist Ralph D’Agostino of Boston University.

The idea that left-handers are at higher risk of death has been promoted most vigorously by psychologists Stanley Coren of the University of British Columbia in Vancouver and Diane F. Halpern of Cal State San Bernardino. They reported in early 1991 on a study of nearly 1,000 people who died in San Bernardino and Riverside counties.

They found that the average age of right-handers at death was 75, while that of left-handers was 66. The left-handers were also more likely to die of accidents.

Coren and Halpern attributed much of the dramatic increase in accidental deaths to the fact that most machines are designed for right-handers. Certain neurological and immunological defects often associated with left-handedness were also thought to play a role in the shortened life spans.

Later researchers have strongly criticized Coren and Halpern’s interpretation of their data. The most common and most important criticism was that the population of lefties they examined was younger than the population of righties. Simply because of that, epidemiologists said, the expected average age of death had to be younger.

Furthermore, the fact that lefties were more likely to die from accidents reflected the fact that younger people are more likely to have accidents.

Those earlier publicized results “say nothing about the reasons for the deaths,” Guralnik said Friday.

The basis of the contradiction is that left-handedness shows a peculiar age distribution in the United States. In the general population, 9% of women and 13% of men are left-handed, but the numbers decline with age.

For instance, at age 10, 15% of the population is left-handed. By age 50, the figure drops to 5%. And by 80, it is less than 1%.

Halpern and Coren argue that this strange distribution arises because left-handers die earlier. Most researchers, however, believe that it is the result of the widespread effort by parents early in this century to convert natural left-handers into more socially acceptable right-handers. It was only as prejudice against left-handers eased that parents allowed left-handers to remain so.

“There are hardly any lefties over 80 years old, but lots of righties, and that’s what really affects the average age of death,” Guralnik said.

Neither Coren nor Halpern could be reached Friday. Coren is scheduled to update his results in Los Angeles on Monday at a meeting of the American Assn. for the Advancement of Science.

To reach their new conclusion, Guralnik, Salive and Glynn turned to an ongoing study of the health problems of the aging in East Boston. Most participants had been questioned about their handedness at the beginning of the study.

Over six years, the researchers found that 32.2% of the right-handed subjects and 33.8% of the left-handed subjects died. Comparisons of death rates for specific age groups showed that there were virtually no differences in the risk of death between the two groups.

Some questions remain, such as why there are so few old lefties. “Neither study can address that definitively,” Guralnik said.

But if Coren’s and Halpern’s results were right, he added, “there would have to be a tremendous mortality risk worldwide--on the order of that caused by smoking. Somebody would have seen that long ago, but nobody has.”