Table 3.
Overall and Colorectal Cancer–Specific Mortality by Quartile of Prediagnosis Plasma C-Peptide and IGFBP-1
| Plasma Marker | Quartiles of Plasma Marker
|
P for Trend | |||
|---|---|---|---|---|---|
| 1 | 2 | 3 | 4 | ||
| C-peptide | |||||
| Median, ng/mL | 1.04 | 1.67 | 2.42 | 4.45 | |
| Overall mortality | |||||
| No. of patients | 88 | 86 | 89 | 87 | |
| No. of deaths | 18 | 24 | 26 | 30 | |
| Age-adjusted analysis* | .03 | ||||
| HR | 1.0 | 1.44 | 1.58 | 1.87 | |
| 95% CI | 0.78 to 2.67 | 0.87 to 2.90 | 1.04 to 3.36 | ||
| Multivariable-adjusted analysis† | .08 | ||||
| HR | 1.0 | 1.69 | 1.79 | 2.11 | |
| 95% CI | 0.89 to 3.22 | 0.93 to 3.44 | 1.06 to 4.21 | ||
| Colorectal cancer–specific mortality | |||||
| No. of patients | 88 | 86 | 89 | 87 | |
| No. of deaths | 13 | 18 | 17 | 16 | |
| Age-adjusted analysis* | .71 | ||||
| HR | 1.0 | 1.45 | 1.37 | 1.31 | |
| 95% CI | 0.71 to 2.97 | 0.66 to 2.82 | 0.63 to 2.72 | ||
| Multivariable-adjusted analysis† | .33 | ||||
| HR | 1.0 | 1.65 | 1.72 | 1.51 | |
| 95% CI | 0.79 to 3.45 | 0.72 to 3.74 | 0.65 to 3.47 | ||
| IGFBP-1 | |||||
| Median, ng/mL | 5.0 | 13.8 | 27.5 | 53.7 | |
| Overall mortality | |||||
| No. of patients | 94 | 92 | 92 | 90 | |
| No. of deaths | 33 | 24 | 29 | 21 | |
| Age-adjusted analysis* | .02 | ||||
| HR | 1.0 | 0.72 | 0.76 | 0.48 | |
| 95% CI | 0.42 to 1.22 | 0.46 to 1.25 | 0.28 to 0.84 | ||
| Multivariable-adjusted analysis† | .004 | ||||
| HR | 1.0 | 0.86 | 0.75 | 0.44 | |
| 95% CI | 0.48 to 1.55 | 0.43 to 1.31 | 0.24 to 0.81 | ||
| Colorectal cancer–specific mortality | |||||
| No. of patients | 94 | 92 | 92 | 90 | |
| No. of deaths | 23 | 16 | 15 | 14 | |
| Age-adjusted analysis* | .13 | ||||
| HR | 1.0 | 0.69 | 0.63 | 0.57 | |
| 95% CI | 0.36 to 1.31 | 0.33 to 1.22 | 0.29 to 1.11 | ||
| Multivariable-adjusted analysis† | .006 | ||||
| HR | 1.0 | 0.80 | 0.60 | 0.43 | |
| 95% CI | 0.40 to 1.60 | 0.30 to 1.21 | 0.21 to 0.89 | ||
Abbreviations: IGFBP-1, insulin-like growth factor binding protein-1; HR, hazard ratio.
*
Adjusted for age at diagnosis.
†
Adjusted for age at diagnosis, cohort (sex), stage of disease, histologic differentiation, tumor location (colon or rectum), time period of diagnosis (1990-1995, 1996-1999, or 2000-2004), time between last meal and plasma collection, receipt of chemotherapy, and patient characteristics from the most recent questionnaire before blood draw, including smoking status (current, past, or never), aspirin use (< or ≥ 2 times a week), alcohol consumption (g/d), total vitamin D intake (U/d), and postmenopausal hormone use.