Researchers from Oxford Population Health analysed data from nearly 500,000 UK Biobank participants to assess the influence of 164 environmental factors and genetic risk scores for 22 major diseases on ageing, age-related diseases, and premature death.
The study found environmental factors explained 17 per cent of the variation in risk of death, compared to less than two per cent explained by genetic predisposition.
Of the 25 independent environmental factors identified, smoking, socioeconomic status, physical activity, and living conditions had the most impact on mortality and biological ageing.
Smoking was associated with 21 diseases, socioeconomic factors such as household income, home ownership, and employment status were associated with 19 diseases, and physical activity was associated with 17 diseases.
Professor Cornelia van Duijn, St Cross Professor of Epidemiology at Oxford Population Health and senior author of the paper, said: “Our research demonstrates the profound health impact of exposures that can be changed either by individuals or through policies to improve socioeconomic conditions, reduce smoking, or promote physical activity.
“While genes play a key role in brain conditions and some cancers, our findings highlight opportunities to mitigate the risks of chronic diseases of the lung, heart, and liver which are leading causes of disability and death globally.”
The authors used a unique measure of ageing to monitor how rapidly people are ageing using blood protein levels.
This enabled them to link environmental exposures that predict early mortality with biological ageing.
Professor Bryan Williams, chief scientific and medical officer at the British Heart Foundation, said: “Your income, postcode, and background shouldn’t determine your chances of living a long and healthy life.
“But this pioneering study reinforces that this is the reality for far too many people.
“We have long known that risk factors such as smoking impact our heart and circulatory health, but this new research emphasises just how great the opportunity is to influence our chances of developing health problems, including cardiovascular disease, and dying prematurely.
“We urgently need bold action from government to target the surmountable barriers to good health that too many people in the UK are facing.”
The research shows while many of the individual exposures identified played a small part in premature death, the combined effect of these multiple exposures together over the life course explained a large proportion of premature mortality variation.
