Table 1. Baseline characteristics of study participants.
| Baseline characteristics | Cases (n=274) | Controls (n=532) | P-value |
|---|---|---|---|
| Mean age at blood draw (s.d.), year |
65.8 (8.3) |
65.9 (8.3) |
0.29 |
| Non-white, no. (%) |
17 (6.2) |
31 (5.8) |
0.83 |
| CRC in a parent or sibling, no. (%) |
54 (19.7) |
73 (13.7) |
0.03 |
| History of previous endoscopy, no. (%) |
154 (56.2) |
358 (67.3) |
0.002 |
| Current multivitamin use, no. (%) |
130 (47.5) |
275 (51.7) |
0.25 |
| Regular aspirin use, no. (%)a |
115 (42.0) |
258 (48.5) |
0.08 |
| Regular NSAID use, no. (%)b |
31 (11.3) |
63 (11.8) |
0.82 |
| Current or past smoker, no. (%)c |
152 (57.6) |
273 (54.0) |
0.34 |
| Mean pack-years of smoking (s.d.)d |
24.6 (17.9) |
24.8 (18.9) |
0.72 |
| Mean BMI (s.d.), kg m−2 |
26.2 (3.1) |
25.3 (2.7) |
<0.001 |
| Mean waist circumference (s.d.), inche |
38.6 (3.5) |
37.5 (3.3) |
<0.001 |
| Mean waist-to-hip ratio (s.d.)e |
0.96 (0.05) |
0.94 (0.05) |
<0.001 |
| Mean MET-hours (s.d.) |
31.9 (26.9) |
30.9 (25.1) |
0.60 |
| Mean daily intakes (s.d.)f | |||
| Alcohol, g |
12.2 (14.8) |
11.9 (14.7) |
0.77 |
| Folate, μg |
494 (209) |
520 (228) |
0.13 |
| Calcium, mg |
917 (385) |
928 (343) |
0.62 |
| Red meat, servings |
1.15 (0.77) |
1.08 (0.69) |
0.17 |
| Total fiber, g |
22.1 (6.4) |
22.6 (6.5) |
0.23 |
| Median CRP (IQR), mg l−1 |
1.36 (0.68–2.62) |
1.11 (0.59–2.18) |
0.72 |
| Median IL-6 (IQR), pg ml−1 |
1.60 (0.99–2.65) |
1.39 (0.93–2.24) |
0.42 |
| Median sTNFR-2 (IQR), pg ml−1 | 2746 (2346–3232) | 2725 (2345–3336) | 0.28 |
Abbreviations: BMI=body mass index; CRC=colorectal cancer; CRP=C-reactive protein; IL-6=interleukin-6; IQR=inter-quartile range; MET=metabolic equivalent=(caloric need per kilogram body weight per hour activity)/(caloric need per kilogram body weight per hour at rest); NSAID=non-steroidal anti-inflammatory drug; sTNFR-2=soluble tumour necrosis factor receptor 2.
A standard tablet contains 325 mg aspirin, and regular users were defined as those who used at least two tablets per week.
Regular users were defined as those who used at least two tablets per week.
Thirty six participants with missing values were excluded from calculation.
Never smokers (N=345) and participants with missing values (N=45) were excluded when calculating means and s.d.
Measured in 1987, and 147 and 149 participants with missing information on waist circumference and waist-to-hip ratio were excluded from calculation of means and s.d., respectively.
For dietary factors, up to 12 participants have missing information.