Washington ? If John McCain is elected and goes on to win a second term, there’s as much as a one-in-four chance America could see its first woman president – Sarah Palin.

It’s actuarial math.

The odds highly favor either McCain or Barack Obama completing a first term in good health. After that, McCain’s odds are still fairly solid, but his chances of dying or being in poor health go up faster than Obama’s, mainly because of his age.

An Atlanta actuarial company specializing in individualized estimates of life and health expectancy has run the numbers for McCain, 72, and Obama, 47. The firm, Bragg Associates, calculated the odds of the candidates dying in office, adjusted for their known health problems.

McCain would be the oldest president to begin a first term in office. By the end of a second term, Jan. 20, 2017, he would have a 24.44 percent chance of dying, compared with 5.76 percent for Obama, the firm estimates.

“Can either candidate expect to serve two terms in a healthy state? The answer is yes,” says James C. Brooks Jr., an actuary with the firm. “They’re both in outstanding health for people of their age.”

Illness is another issue.

Because chances of developing a serious ailment are higher for any person than are the chances of dying, Bragg used the candidates’ medical information to estimate how many years of good health might be in store for each. After all, a debilitating illness could force a president to step down.

The firm estimates that McCain has a health expectancy of 8.4 years, while Obama can expect another 21.9 years of good health. The calculations are from January 2009, covering two terms in office for either candidate. McCain, if he’s like others in his age group, would have a cushion of just about five months.

But no one really knows. Actuaries like Brooks make statistical calculations for insurance companies, based on numbers culled from large databases. No matter how sophisticated, they can’t predict anyone’s future.

“There’s a randomness to it that we don’t know,” said Ron Gebhardtsbauer, who directs the actuarial science program at Penn State’s Smeal College of Business.

For example, he said, “if McCain is president, he’ll get the best health care in the world. I can’t crank that into any of my numbers.”

Health expectancy calculations, although relatively new, are becoming increasingly important as people buy long-term-care insurance.

“We’ve done thousands of these health expectancy calculations for financial planners,” Brooks said. “People, especially those with high net worth, are concerned more about the risk of living too long than about what happens if they die prematurely. What if they need long-term care?”

The firm’s estimates for McCain and Obama relied on medical information disclosed by the candidates. Bragg Associates has no partisan agenda, said Brooks: “We don’t have a dog in this hunt.”

Obama’s health

He classified the Democrat as a smoker with minor upper respiratory problems, probably linked to his smoking. Obama announced in February that he was trying to quit smoking again, with the aid of nicotine gum.

“We don’t consider you a nonsmoker until you stay quit for 12 months,” Brooks said.

In the spring, the Obama campaign released a letter from the candidate’s doctor declaring him to be in excellent health. He had very good cholesterol levels, his EKG was normal, his pulse was 60 beats per minute, and his blood pressure was an outstanding 90 over 60. Obama also exercises regularly.

But Obama has a family history of cancer. His mother died of ovarian cancer and his maternal grandfather died of prostate cancer. Obama’s PSA screening test for prostate cancer showed no sign of abnormalities.

McCain’s health

For the Republican, Brooks took into account a history of skin cancer, degenerative arthritis from his Vietnam war injuries, moderately high cholesterol, mild vertigo and that McCain is a former smoker who quit in 1980.

McCain allowed reporters to review eight years of medical records, more than 1,000 pages. They show that he is cancer-free, has a strong heart and is generally in good health.

As a three-time melanoma survivor, his biggest health worry is a recurrence of that cancer. But he is closely watched by his dermatologist, and any future melanoma should be caught in time to be treated successfully. McCain maintains a healthy weight and blood pressure, and takes medication for his cholesterol.

To underscore his chances of long life, he’s campaigned with his mother, 96 and going strong.