Questionnaire-based polyexposure assessment outperforms polygenic scores for classification of type 2 diabetes in a multi-ancestry cohort

Objective. Environmental exposures may have greater predictive power for type 2 diabetes than polygenic scores (PGS). Studies examining environmental risk factors, however, have included only individuals with European ancestry, limiting the applicability of results. We conducted an exposome-wide association study in the multi-ancestry Personalized Environment and Genes Study to assess the effects of environmental factors on type 2 diabetes.

Research Design and Methods. Using logistic regression for single-exposure analysis, we identified exposures associated with type 2 diabetes, adjusting for age, body mass index (BMI), household income, and self-reported sex and race. To compare cumulative genetic and environmental effects, we computed an overall clinical score (OCS) as a weighted sum of BMI and prediabetes, hypertension, and high cholesterol and a polyexposure score (PXS) as a weighted sum of 13 environmental variables. Using UK Biobank data, we developed a multi-ancestry PGS and calculated it for participants.

Results. We found 76 significant associations with type 2 diabetes, including novel associations of asbestos and coal dust exposure. OCS, PXS, and PGS were significantly associated with type 2 diabetes. PXS had moderate power to determine associations, with larger effect size and greater power and reclassification improvement than PGS. For all scores, the results differed by race.

Conclusions. Our findings in a multi-ancestry cohort elucidate how type 2 diabetes odds can be attributed to clinical, genetic, and environmental factors and emphasize the need for exposome data in disease-risk association studies. Race-based differences in predictive scores highlight the need for genetic and exposome-wide studies in diverse populations.