Table 2.

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

Variable	Cases (n=378)	Controls (n=689)	P value
Age at blood draw, year	58.7 (6.8)	58.5(6.9)	0.95
Colorectal cancer in a parent or sibling, %	23	19	0.15
History of lower gastrointestinal endoscopy, %	35	37	0.60
Postmenopausal, %	87	86	>0.99
Current use of hormones, %b	33	41	0.01
Current multivitamin use, %	32	38	0.40
Regular aspirin/NSAID use, %c	45	50	0.19
Current smoker, %	14	13	0.77
Pack-years of smoking	14.9 (21.7)	12.7 (18.5)	0.14
Body mass index, kg/m2	25.9 (5.0)	25.3 (4.7)	0.03
Physical activity, MET-hours/week	16.1 (18.7)	16.4 (20.5)	0.86
Alcohol consumption, g/d	5.3 (9.6)	5.4 (9.4)	0.41
Folate intake, µg/d	426 (259)	445 (235)	0.03
Calcium intake, mg/d	982 (535)	1,050 (536)	0.003
Total fiber intake, g/d	18.6 (5.7)	18.8 (5.5)	0.54
AHEI diet score	46.2 (9.2)	46.2 (9.6)	0.94
Plasma biomarkers levels, median (IQR)d
Total 25(OH)D, nmol/L	64.5 (48.7–79.9)	68.7 (52.7–84.0)	<0.001
VDBP, nmol/L	4749 (3521–6273)	4815 (3656–6237)	0.37
Free 25(OH)D, pmol/L	18.6 (13.9–27.2)	20.9 (15.2–28.3)	0.15
Bioavailable 25(OH)D, nmol/L	7.8 (5.6–11.4)	8.0 (5.9–11.2)	0.68
VDBP-bound 25(OH)D, nmol/L	54.1 (41.1–70.5)	59.0 (45.6–73.9)	<0.001
Albumin, g/dL	4.60 (4.40–4.70)	4.60 (4.40–4.80)	0.71
CRP, mg/L	1.52 (0.65–3.22)	1.64 (0.73–3.53)	0.29
IL6, pg/mL	1.18 (0.81–1.89)	1.13 (0.76–1.78)	0.59
sTNFR-2, pg/mL	2,658 (2,234–3,162)	2,582 (2,167–3,056)	0.15
MIC-1, ng/L	751 (602–930)	748 (571–964)	0.91
rs7401 genotype, %e			0.92
TT	34	33
GG	45	46
TG	21	21
rs4588 genotype, %f			0.35
CC	7	9
AA	37	38
AC	56	53

Abbreviations: 25(OH)D, 25-hydroxyvitamin D; AHEI, Alternative Healthy Eating Index; CRP, C-reactive protein; IL6, interleukin 6; IQR, inter-quartile range; MET, metabolic equivalent; MIC-1, macrophage inhibitory cytokine-1; 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 31cases and 48 controls that had missing rs7401 genotype.

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