We used QUANTO software (Gauderman 2002) to calculate the power of current association studies for each investigated phenotype at the 0.05 level of significance with a two-sided test. In the AA sample, for the quantitative log transformed CPD trait with a mean 2.38 and standard deviation 0.70, under a log-additive genetic model with MAF = 0.1 (0.3), the CPD sample (N=1385) had 62% (93%) power to detect a main effect of 0.1. For the two binary traits in AAs, under a log-additive genetic model with MAF = 0.1 (0.3), our study had 71% (96%) and 68% (95%) power to detect an effect with a relative risk 1.5 for ND (990 cases/237 controls) and FTND (897 cases/225 controls), respectively. In the EA sample, for the quantitative log transformed CPD trait with a mean 2.78 and standard deviation 0.62, under a log-additive genetic model with MAF = 0.1 (0.3), the CPD sample (N = 915) had 54% (89%) power to detect a main effect of 0.1. For the two binary traits in EAs, under a log-additive genetic model with MAF = 0.1
