Environmental factors, including a person’s lifestyle and living conditions, increase the likelihood of premature death more than their genes, according to a recent study.
The study, led by Oxford Population Health researchers, used data from almost 500,000 people in the UK Biobank and analysed how 164 environmental factors and 22 major diseases impacted ageing, age-related diseases, and premature death.
Findings from the study suggested environmental factors increased risk of death by 17%, whereas genetic predisposition – the likelihood of developing a disease due to genetics – increased risk of death by under 2%. The main areas affected by environmental factors included the lung, heart and liver. Genetic predisposition mainly contributed to a greater risk of developing dementias and breast cancer.
Researchers identified 25 environmental factors that had a significant impact on mortality and ageing, including smoking, exercise, living conditions and socioeconomic status. They also found that 23 of these factors can be changed. Smoking was linked to 21 diseases, socioeconomic status was linked to 19 diseases, and exercise was linked to 17 diseases.
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Exposure to environmental factors early on in life, such as a greater body weight at 10 years old and a person’s mother smoking around birth, affected ageing and increased the risk of premature death 30 to 80 years later.
Senior author of the paper Professor Cornelia van Duijn, St Cross Professor of Epidemiology at Oxford Population Heath, explained: “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 ageing early in life but leave ample opportunity to prevent long-lasting diseases and early death.”
Using a new way of measuring how quickly someone ages through blood protein levels enabled the researchers to connect biological ageing with environmental factors that are associated to premature death.
Although environmental factors were found to individually contribute to premature death, the impact of multiple over a person’s lifetime, referred to by the researchers as “exposome”, accounted for a “greater proportion of variation” in mortality.
Lead author Dr Austin Argentieri, Research Fellow at Massachusetts General Hospital, said: “Our exposome approach allowed us to quantify the relative contributions of the environment and genetics to ageing, providing the most comprehensive overview to date of the environmental and lifestyle factors driving ageing 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.”
Professor Bryan Williams, Chief Scientific and Medical Officer at the British Heart Foundation, added: “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.”
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The results of this study will help improve health by identifying combinations of factors that lead to a substantial risk of premature death and developing diseases due to ageing.
Professor van Duijn explained: “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. Instead, we have followed a ‘hypothesis free’ exposome approach and studied all available exposures to find the major drivers of disease and death.
‘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. 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.
“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.”
