In the life expectancy of a person are influenced by different factors, including their genetic inheritance, but lifestyle habits appear to have a decisive impact not only on health, but also on longevity, as new research that has analyzed the findings of several large long-term studies suggest that a healthy lifestyle can compensate for the effects of genes that shorten life by more than 60%.
The results have been published in the journal BMJ Evidence-Based Medicine and indicate that, although genes and lifestyle appear to have an additive effect on a person’s life expectancy, a unhealthy lifestyle is independently linked to a 78% increased risk of dying prematurely, regardless of genetic predisposition.
The polygenic risk score (PRS) combines multiple genetic variants to arrive at a person’s overall genetic predisposition to a longer or shorter life expectancy. And lifestyle (tobacco use, alcohol consumption, diet quality, sleep quality and physical activity levels) is a key factor.
But it was unclear to what extent a healthy lifestyle could offset the genetic predisposition to a shorter life expectancysay the researchers, so they decided to explore this further and to do so they analyzed data from 353,742 adults recruited to the UK Biobank between 2006 and 2010, whose health was tracked until 2021.
Four factors that make up an optimal lifestyle
A polygenic risk score was derived for long (20% of participants), intermediate (60%), and short (20%) lifetime risks using data from the LifeGen cohort study. And a weighted healthy lifestyle score that included current non-smoking, moderate alcohol consumption, regular physical activity, a healthy body shape, adequate sleep, and a healthy diet; lifestyles were classified as favorable (23% of participants), intermediate (56%), and unfavorable (22%), using data from the US NHANES study.
During an average follow-up period of almost 13 years, 24,239 participants died. Those genetically predisposed to a short life were 21% more likely to die prematurely than those genetically predisposed to a long life, regardless of their lifestyle. Similarly, those who had an unfavorable lifestyle were 78% more likely to die early than those with a favorable lifestyle, regardless of their genetic predisposition.
And those at high genetic risk for a shorter life and who had an unfavorable lifestyle were twice as likely to die as those genetically predisposed to a long life and who had a favorable lifestyle. Four factors in particular seemed to constitute the optimal lifestyle combination: not smoking, engaging in regular physical activity, getting an adequate night’s sleep, and eating a healthy diet.
“The optimal combination of healthy lifestyles could provide greater benefits for a longer life, regardless of genetic background”
This is an observational study and cannot draw definitive conclusions about cause and effect, and the researchers acknowledge several limitations. Lifestyle was assessed only at one point in time, for example, and lifestyle choices differ by age. Furthermore, all participants were of European ancestry, which may limit the generalizability of the findings. However, the authors suggest that their findings indicate that the genetic risk of a shortened life or premature death could be offset by a favorable lifestyle by around 62%.
Those with a high genetic risk for a shorter life expectancy could extend their life expectancy by almost 5.5 years if they adopted a healthy lifestyle at the age of 40, they say, adding that considering that Life habits tend to become consolidated before middle age, it is necessary to adopt measures that mitigate the genetic predisposition to a shorter life before reaching that stage.
“Genetic and lifestyle factors were independently associated with life expectancy. Adherence to healthy lifestyles could greatly attenuate the genetic risk of a shortened life or premature death. The optimal combination of “Healthy lifestyles could provide better benefits for a longer life, regardless of genetic background,” the authors conclude in their article.