We calculated asymptotic power for the Cochran-Armitage trend test (Armitage, 1955;Cochran, 1954) by specifying the non-centrality parameter based on work by Chapman and Nam (Chapman and Nam, 1968) and we set the vector of scores to x = (0, 1, 2) for genotypes (dd, Dd, DD), respectively (Slager and Schaid, 2001). In particular, the non-centrality parameter, explicitly stated by Ahn et al. (Ahn et al., 2007), was
