The combined sample of 4,989 subjects in this report had reasonable power to detect modest effect sizes at α level of 1 × 10−4, the threshold used for follow-up replication. The power was 65% to detect a difference of 0.09 s.d. unit per BMI-increasing allele at a frequency of 0.66 (as for rs268972) and 89% to detect a difference of 0.17 s.d. unit per BMI-increasing allele at frequency of 0.9 (as for rs6794092). The power for these loci was low for α level of 5 × 10−8 (12 and 36%, respectively), thus additional samples are required to confirm or refute these association signals at the genome-wide significance level.
