Statistical analysis
Association analyses were performed using PLINK (http://pngu.mgh.harvared.edu/~purcell/plink/) [6], SAS version 9.2 (SAS institute Inc., Cary, NC, USA), and R statistics package (version 2.7.1) (http://r-project.org/). The SNP association for pulse rate was tested by linear regression analysis with an additive model, adjusting for age, sex, and recruitment area. The KARE GWAS and replication GWAS were combined by an inverse-variance meta-analysis method, assuming fixed effects, with Cochran's Q test used to assess between-study heterogeneity [7]. Meta-analysis calculations were performed using METAL (http://www.sph.umich.edu/csg/abecasis/Metal) in the R program (version 2.7.1).