As research shows that our grandparents' diets can influence our health decades later, it's hard to shake the feeling that genetics determine our health trajectory maybe.
But how much of our health is actually determined by our genes? What effect does our lifestyle have, for better or for worse? Eating well and exercising frequently can have a positive impact on us, as some studies suggest. Can we really overcome our genetic cards and extend our lifespan?
A new study of more than 350,000 people in the UK has found that healthy lifestyle choices can offset the genetic risk of dying young by up to 62 per cent.
“To our knowledge, our study is the first to investigate the association between genetic risk and lifestyle factors and human longevity,” the researchers wrote in their published paper.
While previous epidemiological studies have focused on one or the other, this new study draws on data from three large, long-term population studies examining the link between genetics, environment, and disease. It may be possible to simultaneously compare the effects of genetic risk and lifestyle factors on longevity. .
A team of researchers from multiple universities in China and the University of Edinburgh in the UK looked at data from more than 350,000 adults of European descent who were recruited into the UK Biobank study between 2006 and 2010 and followed for a median of almost 13 years. analyzed. .
Participants were asked questions about diet, physical activity, smoking, alcohol intake, body shape, and sleep duration, and were grouped into three groups based on their answers. The researchers also divided participants into three categories based on known genetic risk factors, called polygenic risk scores that influence lifespan, derived from a US study.
Similar to previous family studies, the researchers found that genetics alone can increase the risk of early death by 21 percent.
An unhealthy lifestyle, including lack of sleep, lack of exercise, processed foods, tobacco, and alcohol, was also associated with a 78% increased risk of early death, regardless of genetic predisposition.
People with unhealthy lifestyles and a genetic predisposition to shorter lifespans were less likely to have an incidental, coronavirus-related infection during the study period than people with lower genetic risk and more favorable lifestyle habits. They were twice as likely to die from the disease.
However, researchers found that the genetic risk of a shorter lifespan can be offset by 62 percent by making healthier lifestyle choices, primarily by quitting smoking, exercising regularly, eating well, and getting enough sleep. discovered.
“This study reveals the pivotal role of a healthy lifestyle in mitigating the influence of genetic factors on shortened lifespan,” the researchers concluded.
However, because this is an observational study, no clear conclusions can be drawn about causality. The results also cannot be generalized to other populations, as most of the participants were of Caucasian European ancestry.
Additionally, participants were only surveyed about their lifestyles at one point in time when they entered the study, and the genetic variants studied only capture a small portion of the genetic risk associated with shortened lifespans, meaning that more DNA may exist. play.
Another big question that is only briefly touched upon in this study is at what age do people make positive changes to their lifestyles?
The analysis found that people with a high genetic risk of shortening their lifespans could add about five years to their life expectancy at age 40 by making lifestyle changes. Other studies have shown the importance of maintaining them.
“Given that lifestyle behaviors are typically formed before middle age, for people at high genetic risk, effective public health and “It is very important to receive intervention,” the researchers concluded.
This research BMJ Evidence-Based Medicine.