Genetic vulnerability to diabetes and obesity: does education offset the risk?

INTRODUCTION:  While previous research has found genetic risk and education to be strong predictors of health, few studies have examined their joint effects. This study investigated whether education reduces risk of type 2 diabetes (T2D) and obesity among individuals with known genetic risk factors for each condition.

METHODS:  We estimated the associations of a polygenic risk score (GRS) specific to T2D and a score specific to obesity among participants in the Health and Retirement Study (HRS).  Both the T2D and obesity GRS algorithms were developed using genetic loci and weights derived in external data. HRS is a nationally representative sample of individuals 50 years of age or older and their spouses. We used average BMI as an indicator of obesity and HbA1c as an indicator of T2D risk. The sample for the models with BMI as the outcome was comprised of 8,398 non-Hispanic whites with at least one BMI assessment and the sample for the models with HbA1c as the outcome was comprised of 8,247 non-Hispanic whites who contributed at least one HbA1c measurement.  We estimated linear and quantile regression models with years of education by GRS interactions, comparing interaction effects at the mean, and the 10^th and 90^th percentiles of BMI and HbA1c. 

RESULTS:  The estimated effect of genetic risk on HbA1c is smaller among people with more years of schooling (p<0.05). In addition, the estimated effects of years of schooling systematically increased along the HbA1c outcome distribution.  For example years of schooling decreased the effect of genetic risk on HbA1c by -0.01 (95% CI=-0.02, 0.00) at the 10th percentile compared to -0.05 (95% CI=-0.07, -0.04) at the 90th percentile. We found no evidence of education by GRS interactions in predicting BMI.

CONCLUSIONS:  Education may help individuals who are genetically vulnerable to at least some chronic conditions, such as T2D, to either prevent or manage the condition.