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.