Lifestyle vs genes: which has more influence on aging?

New research from the University of Oxford has examined whether a person’s lifestyle or their genes has more of an impact on the way in which they age.

The researchers from Oxford Population Health found that a range of environmental factors, including lifestyle (smoking and physical activity) and living conditions, have a greater impact on health and premature death than genes do.

The researchers used data from nearly half a million UK Biobank participants to assess the influence of 164 environmental factors and genetic risk scores for 22 major diseases on aging, age-related diseases and premature death. The study was published in Nature Medicine.

What were the key findings?

• Environmental factors explained 17% of the variation in risk of death, compared to less than 2% explained by genetic predisposition (as we understand it at present).
• Of the 25 independent environmental factors identified, smoking, socioeconomic status, physical activity and living conditions had the most impact on mortality and biological aging.
• 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.
• 23 of the factors identified are modifiable.
• Early life exposures, including body weight at 10 years and maternal smoking around birth, were shown to influence aging and risk of premature death 30–80 years later.
• Environmental exposures had a greater effect on diseases of the lung, heart and liver, while genetic risk dominated for dementias 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.

“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 early life exposures are particularly important as they show that environmental factors accelerate aging early in life but leave ample opportunity to prevent long-lasting diseases and early death.”

How was the rate of aging determined?

The authors used a unique ‘aging clock’ to monitor how rapidly people age, using blood protein levels. This enabled them to link environmental exposures that predict early mortality with biological aging.

Dr Austin Argentieri, lead author of the study at Oxford Population Health and Research Fellow at Massachusetts General Hospital, said, “Our exposome approach allowed us to quantify the relative contributions of the environment and genetics to aging, providing the most comprehensive overview to date of the environmental and lifestyle factors driving aging and premature death. These findings underscore the potential benefits of focusing interventions on our environments, socioeconomic contexts, and behaviours for the prevention of many age-related diseases and premature death.”

The research shows that 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 (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 aging populations by identifying key combinations of environmental factors that shape risk of premature death and many common age-related diseases simultaneously.

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