The environment in which people live has a far bigger impact on their health and mortality than genetics, according to a new study that underscores how an individual’s lifestyle and living conditions can substantially heighten their risk of early death and disease.
The research, led by Oxford Public Health, found that environmental factors collectively — known scientifically as the exposome — were about 10 times more important than an individual’s genome in predicting premature mortality.
It has long been understood how individual factors such as smoking, diet, education, social interactions, physical activity and exposure to pollution affect the body. But the new research, which assessed more than 160 different environmental factors, is the first to lay out their combined effect.
“It was not a surprise to learn that the environment matters more than genetics, but we were surprised by how stark the differences are,” said Austin Argentieri, lead author of the study published in the journal Nature Medicine on Wednesday.
Gary Miller, professor of environmental health science at Columbia University who was not involved in the research, also expressed surprise at the conclusions of the study of almost 500,000 participants in the UK Biobank project.
“When I saw the data demonstrating the predominance of the environment or exposome on all-cause mortality, I was stunned,” he said.
UK Biobank, which holds extensive environmental, genetic and health records of 500,000 middle-aged Britons, is the world’s leading biomedical research database.
The Oxford researchers assessed the influence of participants’ genetic profiles and their exposure to 164 different environmental factors on susceptibility to 22 major age-related diseases and premature mortality.
The analysis used a new measure of ageing — an “ageing clock” — based on levels of hundreds of proteins in participants’ blood samples.
Although the study found several important exceptions in which genes are the main predisposing factor, including Alzheimer’s and breast cancer, the environment dominates the risk of suffering the most common disorders of the heart, lungs and liver.
The biggest influences came from smoking, socio-economic factors, living conditions, physical activity and mental wellbeing.
“Our research demonstrates the profound health impact of exposures that can be changed either by individuals or through policies to improve socio-economic conditions, reduce smoking or promote physical activity,” said Cornelia van Duijn, professor of epidemiology at Oxford university and the study’s senior author.
But the researchers acknowledged they could not quantify the benefits of changing particular risk factors in the environment, for example by adopting a healthier diet or exercising more.
“For the majority of conditions that western people die from, disease risk is more strongly attributable to modifiable risk factors and our wider environment, as shaped by our upbringing and choices, than to genes,” said Stephen Burgess, group leader of the Medical Research Council Biostatistics Unit at Cambridge university, who was also not part of the study. “Genetics can load the dice, but it’s up to us how we play our hand.”
Miller said that although the Oxford study was the largest analysis carried out so far of the effect of the environment on mortality, scientists around the world were planning a large expansion of exposome research.
“Combining genomics and exposome foreshadows a revolution in the study of human disease,” he said.