Interaction between physical activity and polygenic risk score for type-2 diabetes in older Americans

Abstract

Abstract Background Genetics plays an important role in the development of type-2 diabetes (T2D). Polygenic risk scores (PRS) are increasingly used to quantify genetic risk of T2D in epidemiological studies. These scores, when integrated into analyses of modifiable lifestyle factors, may improve understanding of T2D etiology, as the strength of association with T2D and some lifestyle or demographic factors may vary according to genetic predisposition. Methods We examined PRS-lifestyle factor interactions on T2D with data from the United States Health and Retirement Study (HRS), a prospective longitudinal cohort of older adults (≥50 at baseline). HRS contains nationally representative samples of Black and White Americans with pre-calculated PRS for T2D (N = 14,001). Covariates included sex, education, BMI, smoking, alcohol, and physical activity. Predicted prevalence and incidence of T2D were calculated with logistic regression models. Nonparametric bootstrap method was performed to calculate differences in T2D prevalence and incidence by PRS percentiles and interaction variables. Results Significant interaction (p_interaction=0.0096) was detected between PRS and physical activity among Whites only. In those with the lowest decile of PRS, T2D prevalence was similar (∼10%) for those reporting no physical activity compared to low or moderate activity. In those with the top decile of PRS, lower T2D prevalence (17%, 95%CI:14.8,19.6) was observed among those with moderate compared to no activity (24%, 95%CI:20.4,27.5). Incident T2D in Whites followed a similar pattern (p_interaction=0.0194). Among Black participants, no significant interaction with any lifestyle variables was detected. Conclusions Interaction of different genetic risk profiles with lifestyle factors may inform understanding of why certain inventions are more or less effective in different groups of people, potentially improving clinical and prevention interventions. Key messages Protection conferred by physical activity on T2D varied by underlying genetic risk. Gene-environment interaction studies provide insights on why lifestyle factors vary in their associations with T2D.