WEDNESDAY, Aug. 3 (HealthDay News) -- Want to live to a ripe old age?

New research suggests that your life choices might not be the crucial factor in determining whether you make it to 95 or beyond; it finds that many extremely old people appear to have been as bad as everyone else at indulging in poor health habits during their younger years.

Of course, don't take this as an excuse to blow off the gym and enjoy a steak dinner with fries and a cigarette. Your lifestyle matters. But genes seem to provide an extra boost to those who end up living the longest, said Dr. Jill P. Crandall, a professor of clinical medicine at Albert Einstein College of Medicine and co-author of a new study on longevity.

"The genetic component that allows people to survive into extreme old age is probably a very powerful one," she said, even counteracting the effects of unhealthy lifestyle choices.

The study focuses on the genes of extremely old people, who are a hot topic in anti-aging research. "When there is going to be a breakthrough that allows us to slow biological aging, it's probably going to come from the genetics of these people," said S. Jay Olshansky, a professor of epidemiology at the University of Illinois at Chicago who studies aging.

The study authors interviewed people living independently at ages 95 to 109, and asked them to recall things such as their weight, height, alcohol consumption, smoking and their physical activity at age 70; they were also asked whether they ate a low-calorie, low-fat or low-salt diet at that age. All the subjects were Ashkenazi Jews, who share a similar genetic heritage.

The researchers then compared the responses to those from a group of 3,164 people who took part in a survey in the 1970s. At the time, they were at about the same ages as the elderly subjects who appear in the new study.

In essence, the researchers wanted to know whether today's elderly people acted any differently back around age 70 than people in general. Were they healthier? Did they smoke less and exercise more?

The answer: Not really. "We found that our centenarians by and large did not adhere to any specific healthful diet more than the other population did," Crandall said. It was the same for smoking and exercise. Only 43 percent of men aged 95 and older, for example, reported engaging in regular exercise of moderate intensity, compared with 57 percent of men in the comparison group.

However, there was one interesting difference. Researchers found that although men and women aged 95 and older were just as likely to be overweight as their counterparts in the general population, the centenarians were significantly less likely to become obese.

It's not clear if the extremely old people in the study continued to indulge in bad habits such as smoking. When the elders were asked why they thought they had been able to live so long, most (apparently correctly) did not single out lifestyle factors. One-third reported a history of family longevity, while 20 percent believed that physical activity also played a role in their long life. Others attributed a positive attitude (19 percent), a busy or active life (12 percent), less smoking and drinking (15 percent), good luck (8 percent), and religion or spirituality (6 percent) to their centenarian status.

Although lifestyle factors did not appear to greatly influence the centenarians' longevity, the researchers stressed that people not blessed with longevity genes should definitely watch their weight, avoiding smoking and exercise regularly -- all things associated with a longer life span.

Olshansky said the findings underscore the importance of genetics to life span. "The only way anyone has any chance at all of living an exceptionally long life is if they won the genetic lottery at birth," he said.

But, he said, your choices about health can do one thing: lead you to the grave earlier than otherwise. "The only control we have over our duration of life is to shorten it. We exercise that control all the time."

The findings appear in the current issue of the Journal of the American Geriatrics Society.

More information

To find out more about longevity research, visit National Public Radio's review of The Longevity Project.