Table 1.
Simulation parameters for covariate distributions
| Covariate | Distribution | Population Prevalence | Reference |
|---|---|---|---|
| Smoking | Multivariate normal with Alcohol. Mean 0, variance 1, correlation 0.54 | 0.2 | Centers for Disease Control and Prevention, 2006 [41] |
| Alcohol | Multivariate normal with Smoking. Mean 0, variance 1, correlation 0.54 | 0.44 | Encyclopedia of Public Health, 2002 [26], Correlation from Batel, 1995 [24] |
| XPD (Lys751Gln) | N(0,1) | LL = 0.442 LG = 0.45 GG=0.108 |
Spitz, M.R. et al., 2001 [42] |
| Fiber | Multivariate normal with Folate. Mean 77.8 g, variance 7.842, correlation 0.35 | Continuous Covariate | Hudson, TS et al., 2006 [22] |
| Folate* | Multivariate normal with Fiber. Mean 331 mcg, variance 1372, correlation 0.35 | Continuous Covariate | Shen H. et al, 2001 [43] Correlation: Bingham et al, 2005 [21] |
| MTHFR (C677T) | N(0,1) | TT = 0.42 TC = 0.455 CC=0.105 |
Shi, Q. et al, 2005 [44] |
| X6† | N(74.47, 25.53) | Continuous | Arbitrary |
| X7† | N(0, 33.55) | Continuous | Arbitrary |
| X8* | N(237.25,7.57) | Continuous | Arbitrary |
| X9 | N(15, 5) | Continuous | Arbitrary |
| X10 | N(0,1) | AA = 0.5 AB=0.45 BB=0.05 |
Arbitrary |
| X11 | N(17, 5) | Continuous | Arbitrary |
| X12 | N(22, 6) | Continuous | Arbitrary |
| X13 | N(25, 7) | Continuous | Arbitrary |
| X14 | N(12, 5) | Continuous | Arbitrary |
| X15 | N(0, 1) | 1 = 95% 2= 5% |
Arbitrary-Similar to recessive coding for a SNP** |
*
Covariates transformed by dividing by 100 before simulating the disease and analysis to facilitate computations of the probabilities.
†
Covariates transformed by dividing by 10 before simulating the disease and analysis to facilitate computations of the probabilities.
**
SNP = single nucleotide polymorphism.