UW-Madison: New UW-Madison research reveals a genetic influence on quitting smoking

MADISON, Wis., – In a novel study that is among the first in economics to combine genetic information and data from a randomized controlled study, a team of researchers led by Associate Professor Lauren Schmitz of the La Follette School of Public Affairs identified that smoking cessation efforts may be less effective for individuals with a high genetic risk for smoking.

The National Bureau of Economic Research working paper, which also includes La Follette Professor Jason Fletcher as a co-author, finds that participants in the landmark Lung Health Study with more genetic variants that predisposed them to smoking addiction were less likely to  benefit from a five-year smoking cessation intervention program.

“While we have intuitively understood for some time that genes likely play a factor in making it easy for some to quit smoking while difficult for others, we didn’t have the capabilities to test this until quite recently,” Schmitz says. “This study leverages advances in statistical genetics to better understand the interplay between genes and behavior and hopefully improve treatment options.”

This study uses the polygenic index from 4,145 participants in the Lung Health Study, a randomized controlled trial conducted from 1989 to 1994 with heavy smokers between 35 and 60 who were diagnosed with early stages of chronic obstructive pulmonary disease and were motivated to quit smoking.

A polygenic index is a weighted average of an individual’s genetic predisposition for a given trait, such as smoking addiction, based on the cumulative effects of measured genetic variants. Polygenic index measures have become an important tool for connecting genetic data with social outcomes in social science research.

Although both treatment groups in the Lung Health Study were 23% more likely to quit smoking on average, the success of the intervention declined by approximately 2.5% for every standard deviation increase in the polygenic index associated with the likelihood of beginning to smoke.

Smoking has declined in popularity in the US over the last several decades, with 2024 matching a historical low as only 11% of adults reported smoking cigarettes in the previous week. Despite the decrease in prevalence, smoking remains a significant public health concern.

“Tobacco use is still the leading cause of preventable disease, disability, and death in the US. Precision medicine approaches that tailor smoking cessation efforts to individuals’ genes could help improve cessation outcomes in high-risk smokers,” Schmitz says.

Schmitz and Fletcher are leading scholars in the emerging field of social genomics, and core faculty members for the Initiative in Social Genomics at the La Follette School of Public Affairs.

The Initiative in Social Genomics integrates social science and genetic research to study how genes are linked with human behavior and socio-economic outcomes, how genes and environments interact, and how social conditions can influence humans all the way down to the molecular level.