Table 2.

Empirical power of various adjustment strategies in analyzing 2509 causal variants (each designed to achieve 90% power in an unstructured study) in four simulated MEC case-control cancer studies with all 5 ethnic groups

Cancer type	Total number of cases1	α	Odds ratio range2	Unadjusted	Adjusted for race3	Adjusted for 4 PCs		Adjusted for 10 PCs
						all SNPs	100 P1-CONT4	all SNPs	100 P1-CONT
Colorectal	2000	0.01	1.19-1.48	0.825	0.876	0.872	0.870	0.872	0.871
Lung	600	0.01	1.37-1.98	0.828	0.881	0.872	0.872	0.873	0.872
Lymphoma	300	0.05	1.46-2.22	0.846	0.881	0.877	0.874	0.875	0.874
Leukemia	200	0.05	1.59-2.54	0.857	0.891	0.884	0.877	0.879	0.880

¹Equal number of cases and controls within each ethnic group was assumed. See Table S1 for case fractions across ethnic groups.

²The range of odds ratios among the simulated causal variants. For each causal variant, odds ratio was calculated to ensure 90% power at significance level α for an unstructured study with the same sample size.

³Race/ethnicity categories were used.

⁴P1-CONT markers were selected to separate Asians, Europeans and Africans.