Table 1.

Baseline characteristics of participants by tertile of baseline IGF-I levels

Tertile of baseline IGF-I (mean, ng/mL)
1 (68.0 ± 22.8)2 (116.4 ± 12.2)3 (176.3 ± 35.5)P* analyses for categorical variables
n1009999
Age65.6 ± 7.865.5 ± 9.063.9 ± 8.90.17
BMI (kg/m2)28.8 ± 4.628.4 ± 4.127.9 ± 4.00.15
White (yes, %)94 (94.0)94 (94.9)95 (96.0)0.82
Family history (yes, %)17 (17.0)17 (17.2)16 (16.2)0.98
Previous polyp (yes, %)34 (38.2)34 (41.5)25 (29.4)0.24
Aspirin use (yes, %)§32 (32.0)29 (29.3)27 (27.3)0.76
Diabetes (yes, %)15 (15.5)9 (9.6)6 (6.3)0.11
Physical activity (kcal/d)2498.7 ± 673.12582.6 ± 702.72544.8 ± 677.70.63
Dietary variables
    Protein (g/d)75.8 ± 26.580.4 ± 26.583.4 ± 28.20.05
    Energy (kcal/d)1998.7 ± 699.42072.3 ± 629.62144.6 ± 678.50.13
    Total fat (g/d)72.4 ± 30.176.1 ± 27.977.3 ± 30.80.24
    Saturated fat (g/d)23.8 ± 11.025.2 ± 10.325.4 ± 11.10.29
    Alcohol (g/d)7.4 ± 12.47.6 ± 10.46.1 ± 9.00.42
    Total fiber (g/d)22.8 ± 9.123.1 ± 9.724.8 ± 11.00.14
    Calcium (mg/d)892.9 ± 395.8913.2 ± 386.7999.8 ± 387.20.05
    Milk (servings/d)1.16 ± 1.21.13 ± 1.11.47 ± 1.30.07
Blood biomarkers
    Glucose (mg/dL)112.1 ± 27.1107.6 ± 25.5107.6 ± 26.70.23
    Cholesterol (mg/dL)210.1 ± 40.5211.4 ± 38.7213.4 ± 39.00.56
    Triglycerides (mg/dL)186.8 ± 137.7166.6 ± 85.9155.4 ± 72.60.03
    HDL (mg/dL)46.1 ± 12.846.1 ± 12.246.5 ± 10.70.81
    LDL (mg/dL)123.9 ± 44.2133.2 ± 39.3136.7 ± 36.60.03
    TG/HDL ratio4.7 ± 5.04.1 ± 2.63.6 ± 2.00.02
    IGFBP-1 (ng/mL)32.2 ± 24.433.0 ± 25.634.8 ± 27.90.47
    IGFBP-3 (ng/mL)3156.6 ± 1097.13512.0 ± 1207.14526.6 ± 1349.80.01
  • Abbreviations: LDL, low-density lipoprotein; TG/HDL, triglyceride/HDL; BMI, body mass index.

  • * P values were calculated with regression models for continuous variables and χ.

  • History of colorectal cancer in one or more first-degree relatives.

  • History of polyps before baseline.

  • § Aspirin use in the last month at baseline.

  • Self-reported diagnosis of diabetes; data missing for 12 subjects.