Kim Painter

Special to USA TODAY

Hillary Clinton, Donald Trump and their rivals might want to reconsider this running-for-president thing. A new study suggests ascending to the top office might take years off the winner's life.

The idea that presidents age fast – developing gray hair and wrinkles at an accelerated pace – is not new. But the new study, based on three centuries of data on presidents and prime ministers in 17 countries, looks at the price of political success in a new way. It compares the lifespans of electoral winners and losers and finds the defeated George McGoverns of the world tend to outlive the victorious Richard Nixons.

The study, published Monday in the always-quirky Christmas issue of the BMJ medical journal, is potentially good news for Al Gore and Mitt Romney, not so good for George W. Bush and President Barack Obama.

"One would think that presidents live longer," than average citizens "because they are in a completely different socioeconomic stratum," said Anupam Jena, an associate professor of health care policy at Harvard Medical School and lead author of the study. A previous study found just that: average U.S. presidents live a few months longer than average Joes.

But history's also-rans – candidates who came in second and never reached the top office – make better comparison cases, Jena says, because they tend to be just as privileged.

To get a bigger sample than possible in any one country, Jena and colleagues looked at 540 electoral winners and losers from Australia, Austria, Canada, Denmark, Finland, France, Germany, Greece, Ireland, Italy, New Zealand, Norway, Poland, Spain, Sweden, the United Kingdom and the USA, from 1722 to 2015.

Starting from the final elections won by the presidents and prime ministers, the researchers compared the subsequent life spans of winners and losers.

Results among those who had died by 2015: winners lived an average of 4.4 fewer years after the elections. After adjusting for age differences and life expectancies, winners still lived 2.7 fewer years.

One possible explanation is that busy national leaders, at least in the past, neglected their health, eating poorly and shooing away doctors, Jena says. Another: "The stress of running a nation, ensuring world peace and dealing with economic downturns, could impose enough emotional stress that it has an impact on your well-being."

But if the study wants to make that case, it has at least one big flaw, said S. Jay Olshansky, a professor of public health at the University of Illinois at Chicago: "The authors failed to eliminate causes of death that were unrelated to aging, such as being at the wrong end of a gun." Olshansky was not involved in the new study but did lead the previous study showing (un-assassinated) presidents outlived average Americans.

Jena said his team did not exclude assassinated leaders because "it's so uncommon that it doesn't really matter whether you include them. We also kind of viewed being assassinated as a risk of the job."

Jena ran a quick analysis for USA Today and found that U.S. presidents lived 5.7 fewer post-election years than their chief rivals, after adjusting for age and after eliminating our four assassinated presidents. (The result is less statistically vigorous than that of the larger published study, he noted).

Olshansky said that even if presidents and prime ministers die sooner, that does not prove the stress of office is to blame. And those pictures showing visibly aging leaders don't prove anything either, he says: "We don't die from gray hair and wrinkled skin."