Why do some people live to be hundred while some do not even get to celebrate their 60th birthday? Is it nature or nurture? Scientists believe it is a combination of the influence of environmental factors (i.e. lifestyle choices) and genetic factors that leads to healthy aging. American researchers investigated the extent of the genetic contribution by conducting a genetic study of people with exceptional longevity – a total of 1055 people 100 years or older and are still healthy – and compared them to 1267 people with normal longevity.
The study results showed that most of the centenarians (77%) have genetic variations specific for longevity, something which we can consider a “genetic signature of exceptional longevity.”
According to study researcher Dr. Paola Sebastiani of Boston University:
The longevity genes seem to be most common among people of European descent, 15% whom have a 50% likelihood of living up to 100 years. Gender, too, plays a role. 85% of those who are 100 years or older are females.
But the role of the environment and lifestyle should not be underestimated. Despite the genetic predisposition to live long, only 0.016% of people in many developed countries live to be 100. The authors believe that the ingredients of the right lifestyle choices, the right environment, and plain luck are also needed to complement the genes.
According to Dr. Thomas T. Perls, head of the New England Centenarian Study at Boston University:
“If 15% of people have an increased probability of living to 100, and they are not hit by a bus or killed in a war, maybe they get to fulfill that. Now maybe these people need not to smoke and not to be obese and to have other lifestyle factors as well. So a lot goes into the question of whether 15% of the population will go on to be 100 or not.”
What about age-related diseases? The researchers found that the likelihood of centenarians to suffer from diseases that comes with aging such as dementia, diabetes, hypertension and stroke. However, their longevity genes seem to cancel out the risk for these diseases so that these diseases occur only much, much later in life.
So far, 150 genetic variants have been linked to healthy aging.
What about a longevity genetic test?
Dr Perls replies:
“Is a test for exceptional longevity ready for prime time? I think a lot more study needs to be done as to what guidance doctors and others can give. What do you do when you’re told you absolutely don’t have the signature for exceptional longevity? Do you go and do a lot of risk-taking behaviors and say, ‘Well, I’m hanging it up’? Or does it give you an impetus to take all the more care of yourself and to recognize that you may well fall into the 23% of individuals who don’t have the signature but very well could go on to be 100?”
Would you want to know if you have the longevity gene?