For risk score analyses we calculate a single BP GRS, as the average of the SBP and DBP GRSs. We standardize the average GRS to have mean of zero and standard deviation of one. We assess the association of the continuous average GRS variable with each BP trait by simple linear regression. We also run a logistic regression to examine the association of the average GRS with risk of hypertension. We perform each analysis both with and without adjustment for sex. We test for interaction between age (< 50, and ≥50 years) and the effect of the GRS on BP. We then compare BP levels and risk of hypertension for individuals in the top and bottom 20% of the GRS distribution at ≥50 years using linear and logistic regression, respectively.
