We subsequently investigated the impact of multiple BP measurements in an analysis restricted to individuals who had ≥5 measurements (Supplementary Figure 8). Using all measurements, compared to just one, reduced the regression coefficient standard error (SE) by 25%; the regression coefficient estimate itself did not change significantly. With a large number of measurements, the GRS approximately doubled variance explained for SBP and DBP, but was over 3-fold greater for PP, due to the latter's greater measurement error (Supplementary Table 7). The BP variance due to measurement error was estimated (Online Methods) as 56.5% (SBP), 47.5% (DBP) and 71.5% (PP). Lastly, the number of genome-wide significant variants that would have been found when using 1/2/3/4/all measurements (in a fixed subset of non-Hispanic white individuals with ≥5 measurements and using genotyped SNPs only) was 2/3/3/7/7 SBP, 2/4/7/7/11 DBP, and 4/7/15/14/23 PP, demonstrating a large increase with more measurements included. However, when not fixing the sample size, and using all individuals with at least 1/2/3/4/5+ measurements, we found 12/10/11/10/7 genome-wide SBP, 14/14/14/13/11 DBP, and 20/21/23/21/23 PP significant loci, using a total of 80,792/78,372/75,446/71,834/67,547
