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DNA, not lifestyle is key to longevity
By JUDY SIEGEL-ITZKOVICH
03/08/2011
Israeli researcher at Yeshiva University: These people do not need to maintain the healthy lifestyle the rest of us should observe.
 
Healthy centenarians lucky enough to have inherited “longevity genes” can thank their genetic makeup for their long lives. Unlike everybody else, they didn’t have to watch their diet, exercise daily or avoid alcohol to reach that age. They didn’t even have to stop smoking – although tobacco use would certainly harm their descendants.

This was the discovery of a team at Yeshiva University’s Albert Einstein College of Medicine in New York headed by Prof. Nir Barzilai, an Israeli physician, aging researcher and geneticist. The team studied 477 Ashkenazi Jews aged 95 to 109 who were compared with a control group of Caucasians from the general American population.

Barzilai and colleagues wrote in the online edition of the Journal of the American Geriatrics Society, released for publication on Wednesday morning, that “people with exceptional longevity are not distinct in terms of lifestyle factors from the general population,” which has to work hard over many years to stay healthy. But they were not healthier at an earlier stage in life, according to measurements of their weight, physical activity and other lifestyle factors. Instead, their genes have protected them and they apparently “interact with environmental factors differently than others.”

In the general population, lifestyle factors play a bigger role in human longevity than genetic factors, and those who lack longevity genes can add up to eight years by living according to these rules.

Those who inherit the good genes don’t have to, Barzilai said, and can escape chronic disorders usually linked to poor lifestyle choices.

Thus, these long-lived souls seem to be “no more virtuous than the rest of us in terms of their diet, exercise routine or smoking and drinking habits, suggesting that ‘nature’ (in the form of protective longevity genes) may be more important than ‘nurture’ (lifestyle behaviors) when it comes to living an unusually long life,” he said.

Barzilai, who holds the medical school’s Ingeborg and Ira Rennert Chair of Aging Research and is director of its Institute for Aging Research, said the Jews aged 95 and older were still living independently. They were enrolled in Einstein’s Longevity Genes Project, an ongoing study that seeks to understand why centenarians live as long as they do.

Ashkenazi Jews, he said, were not chosen because they have a better chance of inheriting longevity genes. As they have long married among themselves, they are more genetically uniform, making it easier to spot gene differences.

At their 70th birthdays – an age considered representative of the lifestyle they followed for most of their adult lives – the participants in the longtern study were asked about those lifestyles.

They answered questions about their weight and height, making it possible to calculate their body mass index (BMI). They also provided information about their alcohol consumption, smoking habits, physical activity and whether they followed a low-calorie, low-fat or low-salt diet.

To compare them with the general population, the researchers used data from 3,164 people who had been born at around the same time as the centenarians and were examined between 1971 and 1975 while participating in the US National Health and Nutrition Examination Survey (NHANES I).

Overall, people with exceptional longevity did not have healthier habits than the comparison group in terms of diet, BMI, smoking or physical activity.

For example, 27 percent of the elderly women and an equal percentage of the women in the general population strove to eat a lowcalorie diet. Among long-living men, 24% said they had consumed alcohol daily, compared with 22% of the general population. And only 43% of the male centenarians reported engaging in regular exercise of moderate intensity, compared with 57% of men in the comparison group.

“In previous studies of our centenarians, we identified gene variants that exert particular physiological effects, such as causing significantly elevated levels of HDL (highdensity lipoprotein, the socalled good cholesterol),” said Barzilai. “This study suggests that centenarians may possess additional longevity genes that help to buffer them against the harmful effects of an unhealthy lifestyle.”

The research did find, however, that overweight centenarians tended to have lower rates of obesity than the control group. Although male and female centenarians were just as likely to be overweight as their counterparts in the general population, they were significantly less likely to become obese. Only 4.5% of the male centenarians were obese, compared to 12.1% among the males in the control group. For women, 9.6% of the centenarians were obese, compared to 16.2% of the control group. Both of these differences are statistically significant.

The paper itself will be published after 9 a.m. Wednesday at http://doi.wiley.com / 10.1111/j.1532-5415.2011.03498.x Future studies of the subject, the researchers concluded, should be conducted to confirm the findings and evaluate specific gene-environment interactions in relation to age-related diseases and longevity.
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