Table 2.

Calculation of an Optimal ROC Curve: Adding Four SNPs—One Shown—and Four Environmental Factors—One Shown—to the Calculations in Table 1

Information for Environmental Risk Factorsa (Percentage;Relative Risk)		Allele Freq.b (Case;Control)		Genotype Freq.c (Case;Control)		Frequencies of Environmentald and Genetic Risk Factors (Case;Population)						Environmental and Genetic Risk Factors Combination Frequencies (Case;Control)	Likelihood Ratio	Rank Percentagee
Dietary Score	…	rs5219	…	rs7903146	…	Dietary Score	…	rs5219	…	rs7903146	…	Dietary Score x … x rs5219x …
0.150;1.000	…	0.384;0.354	…	0.163; 0.084	…	0.197;0.150	…	0.147;0.126	…	0.163;0.089	…	8.238e-09;1.450e-09	5.680	0.20%
	…	:	…	…	…	:	…	…	…	…	…	…	…	…
0.270;0.860	…	0.384;0.354	…	0.163; 0.084	…	0.305;0.270	…	0.147;0.126	…	0.163;0.089	…	1.275e-08;2.767e-09	4.608	0.50%
	…	:	…	…	…	:	…	…	…	…	…	…	…	…
0.170;0.770	…	0.384;0.354	…	0.163; 0.084	…	0.172;0.170	…	0.147;0.126	…	0.163;0.089	…	7.189e-09;1.806e-09	3.982	0.90%
	…	:	…	…	…	:	…	…	…	…	…	…	…	…
0.260;0.670	…	0.384;0.354	…	0.163; 0.084	…	0.229;0.260	…	0.147;0.126	…	0.163;0.089	…	9.568e-09;2.869e-09	3.335	1.75%
	…	:	…	…	…	:	…	…	…	…	…	…	…	…
0.150;0.490	…	0.384;0.354	…	0.163; 0.084	…	0.097;0.150	…	0.147;0.126	…	0.163;0.089	…	4.037e-09;1.767e-09	2.285	5..86%
	…	:	…	…	…	:	…	…	…	…	…	…	…	…

Details of using the optimal ROC-curve approach to combine the SNPs in Table 1, four environmental factors, and four novel risk SNPs from the first genome-wide association study⁹ by assuming $\rho =0.07$ (five combinations only, out of a total of $9\times {10}^5$ combinations).

^aDistribution and relative risk of the environmental risk factors obtained from Hu et al.²⁹

^bAllele frequency estimates obtained from Weedon et al.³

^cGenotype frequency estimates for cases and controls obtained from the confirmatory stage (stage 2) of the first genome-wide association study.⁹

^dDistribution of the environmental factors in cases calculated by applying Equation 1.

^e100•(rank of LR)/(total number of combinations).