Table 3A. Variable Impact on the Apparent C-Statistic for the Colorectal Cancer Model in Men
VariableC-StatisticChange in C-StatisticVariables (n)
No Model0.50
Pack-years of smoking0.6782140.0052243
Alcoholic drinks per day0.6814420.0032294
Body mass index0.6842630.0028215
Years of education0.6865960.0023336
Regular use of aspirin0.6884050.0018097
Family history of colon cancer0.6899310.0015268
Regular use of multivitamins0.6911430.0012129
Red meat intake (oz) per day0.6917650.00062210
History of diabetes0.6923650.00060011
Moderate physical activity per day (hours)0.6928790.00051312
History of cancer*0.6931760.00029713
Regular use of NSAIDs*0.6933970.00022114
Preference for well-done meat*0.6935380.00014115 (Full)
  • The outcome was colorectal cancer.

  • * The variable was excluded from the final model because of the relatively small amount of additional prediction accuracy that it could have contributed to the model. The final model, which included 12 variables, had an apparent c-statistic of 0.6929, which was within 0.001 of the accuracy associated with the c-statistic of the full model, which was 0.6935.

  • NSAIDS, nonsteroidal anti-inflammatory drugs.