Environmental and lifestyle factors play a far greater role than genetics in determining the likelihood of dying young, according to the largest study yet to untangle the contributions of nature and nurture to healthy aging.

A range of external factors including exercise and smoking — collectively dubbed the “exposome” — was almost 10 times more likely than genetic risk factors to explain premature mortality, scientists from the University of Oxford and Massachusetts General Hospital said in the Nature Medicine journal.

They analyzed mortality trends in the UK Biobank, which stores medical and genetic data from about 500,000 people.

The study shows how broader social context and environment shapes the likelihood of disease, a crucial factor as governments and payers wrestle with how to deal with rising health-care costs and an aging society. Many of the factors found to be linked to longer life were proxies for wealth and status, such as years of education, gym use and household income.

Understanding the role of environmental factors in aging could have a “profound impact on improving health for all of us,” said Austin Argentieri, a researcher in the analytic and translational genetics unit at Massachusetts General Hospital. “We were surprised at just how stark the difference was, how much more the environment matters.”

Factors from childhood, including whether a mother smoked around the time of her baby’s birth and a person’s being “relatively plumper” at around the age of 10, were also linked to cellular signs of aging as an adult. Being shorter at the age of 10 was associated with a lower mortality risk, however.

“We are not prisoners of our genes,” Aimee Aubeeluck, a professor of health psychology at the University of Surrey, who wasn’t involved in the research, said in a comment reacting to the study distributed by the Science Media Centre. “If we know that where we are born and how we live dictate our chances of aging well — or dying prematurely — why is policy action so slow?”

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