A new study revealed that environmental factors may have a larger role to play in disease risks than previously thought, overshadowing genetic contributions. The study was conducted by researchers at Penn State College of Medicine and published in the journal Nature Communications. The study highlights that lifestyle and environmental factors such as air pollution can increase the risk of diseases.

This gives scope for future research on ways to mitigate such health risks. Bibo Jiang, assistant professor of public health sciences at the Penn State College of Medicine and senior author of the study said, “We’re trying to disentangle how much genetics and how much the environment influences the development of disease. If we more accurately understand how each contributes, we can better predict disease risk and design more effective interventions, particularly in the era of precision medicine.”

For the study, the researchers developed a spatial mixed linear effect (SMILE) model that uses both genetics and geolocation data. Geolocation is a person’s approximate geographical location which serves as a surrogate measure for community-level environmental risk factors. The team used data from IBM MarketScan and they filtered out information for more than 257,000 nuclear families and compiled disease outcomes for 1,083 diseases. They then augmented the data to include publicly available environmental data, including climate and socio-demographic data, as well as levels of particulate matter 2.5 (PM2.5) and nitrogen dioxide (NO2).

The team’s analysis led to more refined estimates of the contributors to disease risk. For example, the genetic risk of type 2 diabetes was recalibrated from 37.7 per cent to 28.4 per cent, highlighting a greater role for environmental factors. Similarly, the genetic contribution to obesity risk decreased from 53.1 per cent to 46.3 per cent.

Dajiang Liu, distinguished professor, vice chair for research, director of artificial intelligence and biomedical informatics at the Penn State College of Medicine and co-senior author of the study said, “Previous studies concluded that genetics played a much larger role in disease risk prediction, and our study recalibrated those numbers.

“That means that people can stay hopeful even though they have family relatives with Type 2 diabetes, for example, because there's a lot they can do to reduce their own risk.”

The study also highlighted the effects of specific pollutants, such as PM2.5 and NO2, on health conditions. NO2 directly causes conditions like high cholesterol, irritable bowel syndrome and both Type 1 and Type 2 diabetes, but not PM2.5. On the other hand, PM2.5 has a more direct causal effect on lung function and sleep disorders.

This research suggests that understanding the balance between genetic and environmental factors can enhance disease prevention strategies, particularly in precision medicine.