Table 3.

Association between prediagnostic plasma C-peptide concentration and prostate cancer by stage and grade, CLUE II, 1989-2002

Fourth of the C-peptide distribution (pmol/L)P-trend*
Lowest (<849)Second (849-<1,367)Third (1,367-<2,017)Highest (≥2,017)
Localized (127 pairs)
    95% CIReference0.361-1.660.24-1.050.19-1.03
Advanced (57 pairs)
    95% CIReference0.47-4.090.47-4.820.50-6.78
Low grade (128 pairs)
    95% CIReference0.56-2.310.44-1.910.30-1.54
High grade (80 pairs)
    95% CIReference0.37-2.680.11-0.970.18-1.83

NOTE: Adjusted for BMI (overweight or obese versus normal) and family history of prostate cancer (yes or missing versus no).

  • *From a Wald test of the coefficient estimated when entering C-peptide in the model as a single ordinal variable with values corresponding to the median of the fourth into which a man's concentration fell.