Table 2.

Association between prediagnostic plasma C-peptide concentration and prostate cancer, 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)
Cases (n)79755357
Controls (n)66676566
95% CIReference0.57-1.490.39-1.100.37-1.14
Excluding the first 5 y of follow-up
Cases (n)48403021
Controls (n)39363331
95% CIReference0.43-1.630.35-1.360.17-0.96

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.