Beyond genetics: The biggest factors that influence health and aging

Health is often thought to be written in our genes, but a new study suggests otherwise. Researchers from Oxford Population Health have uncovered compelling evidence that environment plays a far greater role in determining health and longevity than genetic predisposition.

The experts analyzed data from nearly half a million UK Biobank participants to examine how environmental influences compare with genetic risk scores for major diseases.

The findings challenge the common belief that genetic makeup determines health outcomes. Instead, lifestyle choices, socioeconomic conditions, and early-life exposures appear to shape the risk of developing diseases and experiencing premature death.

This research provides fresh insight into how our environment affects biological aging and highlights opportunities to improve public health through changes in policy and personal habits.

What affects health and aging?

The study showed that environmental factors explained 17 percent of the variation in mortality risk, while genetic predisposition accounted for less than 2 percent.

The researchers assessed 164 environmental factors and their effects on 22 major diseases, revealing that lifestyle and living conditions have a much stronger influence on long-term health than previously thought.

Among the key environmental factors identified, smoking, socioeconomic status, physical activity, and living conditions played the most significant roles in mortality and biological aging.

The research also showed that early-life exposures, such as childhood body weight and maternal smoking, have long-term consequences, affecting health and longevity decades later.

“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,” noted Professor Cornelia van Duijn, senior author of the study.

Role of lifestyle in health and aging

The study examined how various lifestyle choices contribute to disease risk. Smoking emerged as a major factor, being linked to 21 different diseases.

Socioeconomic factors, including household income, home ownership, and employment status, influenced 19 diseases. Physical activity also played a critical role, with associations found in 17 diseases.

Importantly, the research indicated that 23 of the identified environmental factors are modifiable, meaning that changes in behavior or policy could significantly reduce the risk of age-related diseases and premature death.

The study also revealed that environmental influences had a greater effect on diseases affecting the lungs, heart, and liver, whereas genetic factors played a more prominent role in conditions such as dementias and breast cancer.

Measuring biological aging

To assess how environmental exposures accelerate aging, the researchers used a novel measurement tool known as the “aging clock.”

This method tracks biological aging by analyzing blood protein levels, providing a more precise way to determine how fast an individual is aging.

“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,” noted Dr. Austin Argentieri, lead author of the study.

This technique had already been validated in studies involving large cohorts from China and Finland, demonstrating its reliability in detecting age-related changes.

The findings reinforce the idea that aging is not solely dictated by genetics but is significantly influenced by external factors, many of which can be adjusted to improve health outcomes.

Poorer environments increase health risks

One of the most striking aspects of the research is the impact of socioeconomic conditions on health and longevity. People with lower incomes, insecure housing, or unstable employment faced significantly higher risks of developing chronic illnesses and dying prematurely.

Professor Bryan Williams, Chief Scientific and Medical Officer at the British Heart Foundation, stressed the urgent need for systemic change.

“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,” he stated.

The study highlights the need for stronger public health policies aimed at reducing socioeconomic disparities.

Addressing issues such as income inequality, access to healthcare, and education could have a profound effect on overall health outcomes, giving more people the opportunity to lead longer, healthier lives.

Improving population health

Although individual lifestyle factors and environmental exposures each contribute to disease risk, their combined impact is even greater. The study found that the cumulative effect of these influences over a lifetime plays a major role in determining health outcomes.

This concept, known as the exposome, highlights how long-term exposure to multiple environmental factors collectively shapes aging and mortality.

This research paves the way for new strategies aimed at improving population health by identifying key environmental factors that contribute to common age-related diseases.

By understanding how different exposures interact, scientists and policymakers can develop more targeted interventions to reduce health risks.

Linking environment to major health risks

Professor van Duijn emphasized the need for a more comprehensive approach to studying environmental health.

“Studies on environmental health have tended to focus on individual exposures based on a specific hypothesis. While this approach has seen many successes, the method has not always yielded reproducible and reliable findings,” she noted.

Instead, the researchers used a broader approach, analyzing all available exposures without preconceived hypotheses. This method allowed them to uncover the most significant drivers of disease and mortality, offering a clearer picture of how different factors contribute to health outcomes.

“We have made a big leap forward in understanding how to provide accurate evidence on the causes and consequences of age-related diseases by combining novel computational methods with clinical and epidemiological knowledge to explore the interplay between multiple exposures,“ said Professor van Duijn.

“In an ever-changing environment, it is critical that we combine these techniques with novel advances in smart technology to monitor lifestyle and environment, as well as with biological data, to understand the impact of the environment over time.”

Rethinking health and aging

The study’s findings provide a strong case for shifting focus toward environmental and lifestyle interventions to improve health outcomes.

There is still much to learn about how factors like diet, exposure to pollutants, and emerging infectious diseases affect long-term health. Researchers must continue investigating how different populations are impacted by environmental and genetic interactions.

“There are a lot of questions still to be answered related to diet, lifestyle, and exposure to new pathogens (such as bird flu and COVID-19) and chemicals (think of pesticides and plastics), and the impact of environmental and genetic factors in different populations,” said Professor van Duijn.

By shedding light on the profound impact of environmental factors on aging and disease, this study presents an opportunity to rethink how health is managed on both personal and policy levels.

With greater emphasis on reducing harmful exposures and improving living conditions, society has the potential to extend healthy lifespans and reduce premature mortality.

The study is published in the journal Nature Medicine.

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