Scientists find lifestyle and living conditions have greater impact on healthy ageing than genes

It’s a favourite refrain among health experts: your postcode is as important for your health as your genetic code, determining where people live, what kind of food they eat, how good their medical care is, and how much pollution they breathe.

Now, a major new study in the journal Nature Medicine suggests that environmental factors, including both lifestyle choices and living conditions, are about 10 times more important than genetics when it comes to healthy ageing and early death.

Taken together, age, sex, and environmental factors – known as the exposome – explain about 66 per cent of mortality risks, according to the research led by the UK’s Oxford University.

"We were surprised at just how stark the difference was, how much more the environment matters than genetics," Austin Argentieri, the study’s first author and a researcher at Harvard University, said during a press briefing.

The study included nearly half a million people in the United Kingdom.

Researchers identified the participants’ genetic risks for 22 diseases, tracked common health issues like obesity, high blood pressure, and dyslipidemia, and used protein from their blood to measure how quickly people were ageing biologically.

How lifestyle and living conditions shape health

They initially focused on 164 environmental factors, but narrowed them down to 25 key measures that were associated with both death and biological ageing.

These factors spanned everything from education level, household income, employment, sleep levels, exercise, smoking, social support, mental well-being, body weight at age 10, and whether someone’s mother smoked around the time they were born.

Individually, these factors played a small role in the risk of dying prematurely, but combined over the lifetime, they added up.

"Real life is messy. All of these different environmental influences come together," Argentieri said.

These factors are "the really fundamental aspects of environment and behaviour and lifestyle, and our broader sociocultural, physical contexts," he added.

The importance of genetics and environmental factors differed when it came to specific health issues.

Genetic risks were bigger drivers of dementia and breast, prostate, and colorectal cancers, while environmental factors were more important when it came to lung, heart, and liver diseases, the study found.

'Our genes do not determine our future'

The study has several limitations. The results might be different in other countries; other factors that were not included in the study could also be tied to health, and the study does not establish cause and effect, only correlations.

"The exposome is really a context-specific concept" and more studies are needed “other places in the world to understand what’s important where," Argentieri said.

Still, given many of the environmental factors could be changed, independent researchers said the findings offer a roadmap for policy interventions to improve people’s health.

Dr Stephen Burgess, a biostatistician at the University of Cambridge who was not involved in the study, said in a statement that the results underscore that in most cases, "our genes do not determine our future".

"Genetics can load the dice, but it is up to us how we play our hand," Burgess said.