We next performed analyses that combined evidence for association across the five ethnic groups. In this analysis the power to achieve nominal significance for the allelic effects reported previously was >80% for 18 out of 19 alleles (average 94%; Table S1). In this analysis all 19 (100%; P = 1.9×10−6, binomial probability) variants were associated with risk in the same direction as the initial report (odds ratios>1) and 14 (P = 5.7×10−15; binomial probability) with nominal statistical significance (P<0.05). All 19 associations remained in the same direction as previous reports (OR>1) and 13 of the variants were significantly associated with T2D risk when the European American subjects were excluded from the analysis. The association of rs8050136 in FTO was attenuated by adjustment for BMI (odds ratio (95% confidence interval), 1.06(1.00–1.11) prior to adjustment; 1.02(0.96–1.08) after adjustment). Only 5 of the 19 risk variants showed nominal evidence for heterogeneity in the odds ratio across ethnic groups, and only one of these (CDKAL1) was significant after correction for having performed 19 tests (PPARG, rs1801282, Phet = 0.048; WFS1, rs10010131, Phet = 0.032; CDKAL1, rs7754840, Phet = 6.2×10−4; HHEX, rs1111875, Phet = 0.037; and, HNF1B, rs4430796, Phet = 0.043; Table 2).
