A baseball mystery: Why do players seem to live longer than the average?

Major League Baseball has its problems. Attendance has slipped, fans complain about the pace of play, players are convinced the balls are juiced and even the people running the sport admit its fusty rules could use an upgrade.

Yet its players might take comfort in one promising bit of news: they appear to have longer life spans than other Americans.

That’s the tantalizing possibility raised by a study published by Harvard researchers in the medical journal JAMA Internal Medicine.

The sample size used to draw its conclusions is not large — a review of 10,451 major-leaguers who died between 1979 and 2013 — and the differences in longevity with the general population are not great. But scientists determined that, based on their sample, major-leaguers live 24 per cent longer than the average male. They have also found some limited evidence that players at some positions — notably middle infielders — might live longer than others.

Not all players find these assertions convincing. Didi Gregorius of the New York Yankees seemed skeptical that shortstops like him lived any longer than anyone else. “I don’t do anything special about exercise or diet,” he said. “I just hang out.”

Austin Romine, the Yankees catcher, said he thought better fitness — the baseball season is seven months long — could be the explanation. “We’re exercising our entire bodies, every day, for (162) games,” he said. “It’s the longest season in sports.”

The study offered a number of possible explanations, including what the players mentioned, that they are generally fitter than average people.

Another study, published in 2006, found that while major league players lived an average of 4.1 years longer than the general public, those with careers lasting 11 years or more lived 7.4 years longer. This suggests a simple answer: healthier baseball players have longer careers, and healthier people live longer.

Yet the new study found subtle differences between major-leaguers and the rest of the population in causes of death.

For example, while a long career was associated with a decrease in the mortality rate for cardiovascular disease, those same longtime players had higher rates of death from cancer, particularly of the lungs and skin.

“We could suspect sun exposure or tobacco for those cancers,” said the senior author of the study, Marc G. Weisskopf, a professor of epidemiology at the Harvard T.H. Chan School of Public Health, “but they also had higher rates of blood cancer, which is surprising.” The authors could only speculate on reasons — including the possibility of exposure to chemicals used to treat fields — because they did not study possible causes.

Some major league stadiums ban the use of tobacco during games by players and fans, and tobacco use in the minor leagues has been banned since 1993. Smokeless tobacco is prohibited for any player entering the league after 2016. All teams participate in a joint effort of MLB, the Major League Baseball Players Association and the American Academy of Dermatology to raise awareness about the dangers of sun exposure and provide information about skin cancer prevention and screening.