Table 3.

Relationship between plasma levels of C-peptide and risk of distal colorectal adenoma among 380 cases and 380 controls nested in the Nurses' Health Study, 1989-1998

Quartile
Ptrend
1234
C-Peptide
    Median (ng/mL)0.91.42.03.4
    Distal colon and rectum
        Cases/controls84/9475/9694/94127/96
        RR* (95% CI)1.000.88 (0.57-1.35)1.14 (0.74-1.76)1.53 (1.01-2.32)0.007
        MVRR (95% CI)1.000.91 (0.58-1.43)1.12 (0.70-1.81)1.63 (1.01-2.66)0.01
    Advanced adenoma
        Cases/controls37/3837/3739/5155/42
        RR* (95% CI)1.001.02 (0.55-1.91)0.77 (0.40 -1.49)1.40 (0.73-2.69)0.22
        MVRR (95% CI)1.001.12 (0.56-2.24)0.69 (0.33-1.45)1.46 (0.64-3.32)0.29
IGFBP-1
    Median (ng/mL)5.916.531.652.1
    Distal colon and /Rectum
        Cases/controls54/5682/5850/6348/57
        RR* (95% CI)1.001.41 (0.85-2.33)0.82 (0.47-1.42)0.86 (0.49-1.50)0.18
        MVRR (95% CI)1.001.56 (0.90-2.70)0.97 (0.51-1.82)1.08 (0.56-2.07)0.63
    Advanced adenoma
        Cases/controls27/2948/2419/3318/26
        RR* (95% CI)1.002.24 (1.07-4.70)0.53 (0.23-1.23)0.62 (0.27-1.43)0.06
        MVRR (95% CI)1.002.76 (1.20-6.31)0.71 (0.25-1.99)0.87 (0.31-2.45)0.49
HbA1c
    Distal colon and rectum
        Cases/controls71/8585/7696/110119/100
        RR*1.001.39 (0.87-2.21)1.11 (0.71-1.72)1.56 (0.98-2.49)0.07
        RR (95% CI)1.001.49 (0.91-2.43)1.18 (0.74-1.89)1.47 (0.89-2.44)0.16
    Advanced adenoma
        Cases/controls32/3238/3240/5454/46
        RR*1.001.18 (0.56-2.50)0.79 (0.40-1.56)1.25 (0.60-2.60)0.58
        RR (95% CI)1.001.43 (0.62 -1.84)0.87 (0.41-1.84)1.22 (0.54-2.77)0.80
  • * RR from conditional logistic regression.

  • RR from conditional logistic regression adjusted for: BMI, physical activity, pack-years smoked, and alcohol intake as continuous variables, family history of colorectal cancer, aspirin use (<10 and ≥10 years), and menopausal status, and use of hormone replacement therapy.

  • IGFBP-1 results only among 234 fasting cases and 234 fasting controls (≥8 hours since last meal).