The genes you inherit play a bigger role in determining your lifespan than previously thought, according to a new study.
Previous studies have concluded genetics plays a 6% to 33% role in how long a person lives – but new research published in the journal, Science, has boosted that figure to as high as 55%.
Ben Shenhar, lead author of the study, from the Weizmann Institute of Science in Israel, said: “Lifespan is undoubtedly shaped by many factors including lifestyle, genes and, importantly, randomness – take for example genetically identical organisms raised in similar environments that die at different times.
“In our work, we tried to give a handle on the amount of variance between different people that can be attributed to genetics.
“Our study tried to partition the longevity factors into genetics and ‘everything else’. The ‘everything else’ is around 50% of the pile.”
Researchers looked at historical data from human twin studies and found factors such as deaths caused by violence, accidents and infectious diseases had not been taken into account.
The cause of death was absent, which provided merely the age at death. So if one twin died at age 90 of natural causes and the other at age 30 due to an infectious disease, it could provide a misleading impression about the role of hereditary characteristics in lifespan.
Researchers re-ran their analysis, accounting for the fact that vulnerability to infections and falls rises as people get older. The findings still revealed that genetic makeup contributes to around 50% of life expectancy.
“The number that we got is not out of nowhere,” Mr Shenhar, who researches the physics of aging, told Sky’s US partner network NBC News.
“If you look at twin studies on pretty much anything in humans, you get this 50%.
“If you look at the heritability of age of onset at menopause, which is an age-related decline, that is also around 50%.”
He also pointed to centenarians – people who live past 100.
“These people are not just clawing their way to 100,” he said. “No, they have protective genes that protect against the harms of age.”
Read more from Sky News:
Groundbreaking MND drug a lifeline for some -‘mental torture’ for others
AI mammograms result in fewer aggressive breast cancers, study suggests
Study prompts fierce debate
While genetics may play a larger role in lifespan than previously thought, Eric Verdin, president and chief executive of the Buck Institute for Research on Aging in California, who was not involved in the study, cautioned a healthy lifestyle cannot be discounted.
“There are multiple genes that have been shown to be associated with aging, but if you study many centenarians, you don’t find these genes in all of them,” he said.
He warned “the depressing thing” about the new study “is that it makes people be fatalistic”.
“‘It doesn’t matter what I do. Why should I try to live better and not drink and do sport if it’s determined by genes basically?'” he said.
Mr Shenhar said “that is not our message, not at all”.
“The message of our paper is not that lifestyle, exercise and diet are not important,” he said.
“That is not our message, not at all. Even if your genetics gives you a particular potential or range for what your natural lifespan would be, depending on lifestyle, that might shift slightly one way or another. So it’s still important.”
