We all age, but not at the same speed. A large number of factors influence our aging, and make us more or less likely to develop diseases and die prematurely. genetic, of course, but also our healthy lifestyle, exposure to the pollution, etc. There are so many different factors that it's difficult to know which ones have the greatest impact on our aging. A new study has attempted to rank these risk factors, showing that socioeconomic status weighs more heavily than genetics and lifestyle. These results, which highlight the extent to whichsocial injustice affects health, were published on February 19, 2025 in the journal Nature Medicine.
High income may be one of the most protective factors against premature death
To reach this conclusion, researchers from the universities of Oxford (UK), Harvard and MIT (USA), and Montpellier, analyzed the genome and exposome (i.e., the set of environmental exposures we undergo during our lives) of more than 400,000 English people, with a follow-up of approximately 12 years. Nearly 32,000 of these people died during the study, three-quarters of whom died prematurely (i.e., before reaching the age of 75).
The authors estimated the influence of 164 environmental factors on these premature deaths. The three factors most strongly correlated with these deaths were smoking, renting their home (versus owning their home), and being poor. In contrast, the most protective factors were living with a partner, owning multiple cars, and having a job and a high salary. Since several of these factors were associated (for example, the number of cars and salary level), the authors removed them, finding a total of 85 factors with an influence on aging.
Income may influence the body's aging rate
To determine whether these factors actually impact aging, the authors also analyzed the biological aging of 45,000 participants whose data they had. Of these 85 factors, only 28 also had an impact on the body's aging rate, 25 of which were associated with mortality.
This second analysis confirms the initial results, showing that the most protective non-genetic factors are: having a job, a high income, physical activity, and living with a partner. In contrast, the most harmful factors were smoking, not owning one's home, and how often one feels tired. Taking genetic factors into account did not change these results, highlighting that genetics may not weigh as heavily on aging as previously thought, and that the exposome has a much greater impact than the genome.
“ Our study shows that the environmental contribution to mortality and aging is composed of many interrelated factors, which individually explain only a small proportion of the variation in premature mortality, but together explain a large part of this variation, surpassing the influence of genetic factors.", summarize the authors. These results were confirmed in a second cohort of 55,000 people from Wales and Scotland.
Some diseases are more influenced by genetics
This was also the case for most age-related diseases, with a few exceptions. Genetics was the most important factor for breast, prostate, and colon cancers, as well as Alzheimer's disease and other dementias. In contrast, non-genetic factors were more important for lung cancer and other respiratory diseases such as chronic obstructive pulmonary disease (COPD), as well as liver disease and rheumatoid arthritis. For other diseases, the most important factors were age and biological sex, including some cardiovascular diseases.
“ While genes play a key role in brain health and some cancers, our findings highlight the potential to mitigate the risk of some chronic lung, heart, and liver diseases, which are among the biggest causes of disability and death in the world today. asserts in a press release Cornelia van Duijn, an epidemiologist at the University of Oxford and author of the study. Our study shows that policies aimed at improving socioeconomic conditions and encouraging people not to smoke and to be physically active could have a significant impact on health.
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