A new study led by researchers from Oxford Population Health has shown that a variety of environmental factors, including lifestyle choices (such as smoking and physical activity) and living conditions, have a more significant impact on health and premature death than our genes.
The study, which analysed data from nearly half a million UK Biobank participants, examined the influence of 164 environmental factors and genetic risk scores for 22 major diseases on ageing, age-related diseases, and premature death. The findings were published today in Nature Medicine.
As per the key findings, the environmental factors explained 17% of the variation in risk of death, compared to less than 2% explained by genetic predisposition (as per the present).
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.
Lifestyle habits since birth matter
The early life exposures, including body weight at 10 years and maternal smoking around birth, were shown to influence ageing and risk of premature death 30-80 years later.
Risk factors based on environmental exposure
Environmental exposures had a greater effect on diseases of the lung, heart and liver, while genetic risk dominated for dementia and breast cancer.
Professor Cornelia van Duijn, St Cross Professor of Epidemiology at Oxford Population Heath 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.
The research shows that whilst 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 (referred to as the exposome) explained a large proportion of premature mortality variation. The insights from this study pave the way for integrated strategies to improve the health of ageing populations by identifying key combinations of environmental factors that shape the risk of premature death and many common age-related diseases simultaneously.