Table 1.

Baseline characteristics of participants in the Nurses' Health Study (1990)a

VariableCases (n = 757)Controls (n = 757)P
Age at blood draw, years56.9 (6.8)56.8 (6.7)0.24
Body mass index, kg/m225.9 (4.7)25.4 (4.5)0.01
Physical activity, MET-hours/week14.7 (16.8)16.9 (25.2)0.14
Colorectal cancer in a parent or sibling, %17150.20
History of lower gastrointestinal endoscopy, %33320.61
Postmenopausal, %84840.70
Current use of menopausal hormone therapy, %b42480.09
Current multivitamin use, %37380.60
Regular aspirin use (≥2 tablets/week), %c39430.14
Regular NSAID use (≥2 tablets/week), %d19210.36
Current smoker, %14100.01
Alcohol consumption, g/d5.6 (10.2)4.9 (8.6)0.78
Calcium intake, mg/d1001 (519)1035 (484)0.06
Dietary AHEI score44.0 (9.1)45.0 (8.9)0.03
Plasma biomarker levels, median (IQR)e
 MIC-1, ng/L609 (494–783)595 (488–741)0.04
 CRP, mg/L1.91 (0.90–4.04)1.56 (0.75–3.62)0.01
 IL6, ng/L0.96 (0.62–1.59)0.96 (0.59–1.58)0.55
 sTNFR-2, μg/L2.68 (2.30–3.16)2.64 (2.30–3.10)0.07
 Time of diagnosis since blood draw, month118 (57)
Size of adenoma, mm14.4 (9.8)
Multiple (≥2) adenoma, %34
Adenoma location, %
 Proximal colon28
 Distal colon41
 Rectum13
 Multiple adenomas in ≥2 locations18
Histology of adenoma, %
 Tubular38
 Tubulovillous, villous or high-grade dysplasia (CIS)62

Abbreviations: AHEI, Alternative Healthy Eating Index; CIS, carcinoma in situ; CRP, C-reactive protein; IQR, interquartile range; MET, metabolic equivalent; MIC-1, macrophage inhibitory cytokine-1; NSAID, non-steroidal anti-inflammatory drug; sTNFR-2, soluble tumor necrosis factor receptor 2.

  • aMean (SD) is presented for continuous variables unless otherwise specified.

  • bPercentage is among postmenopausal women only.

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

  • dRegular use is defined as ≥2 tablets of NSAIDs per week.

  • eThe number of pairs of subjects with missing measurements: 19 for MIC-1, 3 for CRP, and 24 for IL6.