Table 2.

Baseline characteristics of colorectal cancer case and control participants in the Nurses' Health Study (1990)a

VariableCases (n = 378)Controls (n = 689)P
Age at blood draw, year58.7 (6.8)58.5 (6.9)0.95
Colorectal cancer in a parent or sibling, %23190.15
History of lower gastrointestinal endoscopy, %35370.60
Postmenopausal, %8786>0.99
 Current use of hormones, %b33410.01
Current multivitamin use, %32380.40
Regular aspirin/NSAID use, %c45500.19
Current smoker, %14130.77
Pack-years of smoking14.9 (21.7)12.7 (18.5)0.14
BMI, kg/m225.9 (5.0)25.3 (4.7)0.03
Physical activity, MET-hours/week16.1 (18.7)16.4 (20.5)0.86
Alcohol consumption, g/d5.3 (9.6)5.4 (9.4)0.41
Folate intake, μg/d426 (259)445 (235)0.03
Calcium intake, mg/d982 (535)1,050 (536)0.003
Total fiber intake, g/d18.6 (5.7)18.8 (5.5)0.54
AHEI diet score46.2 (9.2)46.2 (9.6)0.94
Plasma biomarkers levels, median (IQR)d
 Total 25(OH)D, nmol/L64.5 (48.7–79.9)68.7 (52.7–84.0)<0.001
 VDBP, nmol/L4,749 (3,521–6,273)4,815 (3,656–6,237)0.37
 Free 25(OH)D, pmol/L18.6 (13.9–27.2)20.9 (15.2–28.3)0.15
 Bioavailable 25(OH)D, nmol/L7.8 (5.6–11.4)8.0 (5.9–11.2)0.68
 VDBP-bound 25(OH)D, nmol/L54.1 (41.1–70.5)59.0 (45.6–73.9)<0.001
 Albumin, g/dL4.60 (4.40–4.70)4.60 (4.40–4.80)0.71
 CRP, mg/L1.52 (0.65–3.22)1.64 (0.73–3.53)0.29
 IL6, pg/mL1.18 (0.81–1.89)1.13 (0.76–1.78)0.59
 sTNFR-2, pg/mL2,658 (2,234–3,162)2,582 (2,167–3,056)0.15
 MIC-1, ng/L751 (602–930)748 (571–964)0.91
rs7401 genotype, %e0.92
 TT3433
 GG4546
 TG2121
rs4588 genotype, %f0.35
 CC79
 AA3738
 AC5653
  • Abbreviations: AHEI, Alternative Healthy Eating Index; IQR, interquartile range; MET, metabolic equivalent; NSAID, non-steroidal anti-inflammatory drug; VDBP, vitamin D binding protein.

  • aMean (SD) is presented for continuous variable unless otherwise specified. Percentage is presented for categorical variable.

  • bPercentage is among postmenopausal women only.

  • cRegular use is defined as ≥2 standard (325-mg) tablets of aspirin or NSAIDs per week.

  • dThe number of paricipants that had missing measurements: 78 cases and 352 controls for free and bioavailable 25(OH)D, 45 cases and 315 controls for albumin, 41 cases and 81 controls for CRP, 42 cases and 82 controls for IL6, 43 cases and 81 controls for sTNFR-2, 42 cases and 313 controls for MIC-1.

  • eThe percentage is calculated after excluding 31 cases and 48 controls that had missing rs7401 genotype.

  • fThe percentage is calculated after excluding 30 cases and 53 controls that had missing rs4588 genotype.