By Published: March 6, 2023

Genes matter, says CU Boulder’s Jason Boardman, but so does the environment

Young adults living in high-crime areas have an increased genetic risk for Type 2 diabetes, according to a recently published study co-authored by Jason Boardman, University of Colorado Boulder professor of sociology and director of the Institute of Behavioral Science’s Health and Society Program.

Boardman and his co-authors published their paper, “Does Crime Trigger Genetic Risk for Type 2 Diabetes in Young Adults? A G x E Interaction Study Using National Data,” in Social Science & Medicine in November. 

A key takeaway is that genes are not an irrefutable crystal ball predicting people’s health future. The environment plays a significant role as well. 

Image of Professor Jason Boardman

Jason Boardman teaches undergraduate and graduate-level courses in statistics, social demography, and the sociology of race and ethnicity. 

“Genes matter,” says Boardman, “but how they are linked to your health depends on where you live.” 

Key to understanding why, says Boardman, who studies the social determinants of health, is the notion of environmental triggering, a phenomenon by which the environment elicits certain genetic responses. 

It’s a bit like planting a flower, Boardman says, with the seed being people’s genes and the soil, water and sunlight being the environment. The seed may be planted, but without the right environmental conditions, it won’t sprout. 

Something similar happens with Type 2 diabetes. 

“Genetic risk for Type 2 diabetes does not manifest as a risk absent environmental triggers—in this case, local area crime rate,” Boardman explains. “Indeed, we find that the polygenic risk for Type 2 diabetes is non-existent among residents of communities with little to no crime.” 

In other words, genetic variants linked to Type 2 diabetes are not enough to give someone the disease. What counts is how those genes interact with the environment. 

Boardman and his colleagues’ findings recast what many consider the primary driver of Type 2 diabetes: obesity, which Boardman says plays not so much a causal role as a mediating one.  

To understand how this works, Boardman explains, imagine the same person in two scenarios. 

In the first scenario, this person lives in an area with a low crime rate. He or she therefore experiences little stress and has access to healthy coping mechanisms, such as walking or riding a bike outside. This person is consequently unlikely to become obese and develop diabetes. 

In the second scenario, however, this same person lives in a high-crime area and has elevated stress levels and limited access to healthy coping mechanisms. This person is therefore more likely to internalize stress, adopt an unhealthy dietary pattern, gain weight and become diabetic. 

Same person, same genes, opposite outcomes. The only difference between the two scenarios is the environment. 

“Thus,” says Boardman, “what appears to be a biological process is in large part a social process.”

Boardman began studying the social influences of health several decades ago. 

“I was fortunate to be part of the Social Environment Working Group of the National Children’s Study in the early 2000s,” he says. 

While working with this group, Boardman witnessed the scientific community placing “a great deal of emphasis on collecting and summarizing rich biological measures of population health” while overlooking “comparably rich measures of the social and physical communities in which people live, go to school and play.” 

But rather than criticize the field of statistical genetics, Boardman decided to gain training in it. He received a career development award from the Eunice Kenney Shriver National Institute of Child Health and Development and, as a tenure-track professor, enrolled in the graduate-training program at CU’s Institute for Behavioral Genetics.  

Boardman says that research exploring gene-environment interactions provides a more nuanced understanding of what causes Type 2 diabetes than does the nature-nurture argument.  

“The nature-nurture dichotomy gets us nowhere in terms of understanding complex phenomena like the increase in obesity in recent years,” says Boardman, adding that it’s not either nature or nurture that people should be focusing on, but both. 

“Nurture fundamentally affects nature, and nature fundamentally affects nurture.” 

Boardman also hopes his research will provide a counterpoint to what he considers a worrying trend. 

“I am most concerned about the routine practice among researchers utilizing genome-wide data and related summary scores to limit their analyses to individuals who identify with a similar socially defined racial group,” he says. 

“My hope is to contribute to methods that provide summary genetic scores that belie the unnecessary need to run models separately by racial and ethnic group.”