Table 2.
Frequency distribution of comorbidities, lifestyle factors and healthcare use of CRC cases and controls, and their association with risk of CRC
| Characteristic | Controls N = 10,000 n (%) |
Cases N = 3033 n (%) |
RR (95% CI)a |
|---|---|---|---|
| PCP visitsb | |||
| 0–1 | 486 (4.9) | 92 (3.0) | 1.00 (−) |
| 2–4 | 1094 (10.9) | 261 (8.6) | 1.37 (1.06–1.79) |
| 5–9 | 2624 (26.2) | 699 (23.0) | 1.76 (1.38–2.25) |
| 10–19 | 3715 (37.1) | 1164 (38.4) | 2.28 (1.79–2.91) |
| ≥ 20 | 2081 (20.8) | 817 (26.9) | 3.07 (2.38–3.96) |
| Referralsb | |||
| 0–1 | 4760 (47.6) | 1182 (39.0) | 1.00 (−) |
| 2–4 | 2778 (27.8) | 917 (30.2) | 1.28 (1.16–1.43) |
| 5–9 | 1716 (17.2) | 612 (20.2) | 1.35 (1.19–1.53) |
| ≥ 10 | 746 (7.5) | 322 (10.6) | 1.57 (1.33–1.85) |
| Hospitalizationsb | |||
| None | 8496 (85.0) | 2424 (79.9) | 1.00 (−) |
| 1 | 930 (9.3) | 375 (12.4) | 1.32 (1.16–1.51) |
| 2 | 328 (3.3) | 148 (4.9) | 1.45 (1.18–1.77) |
| ≥ 3 | 246 (2.5) | 86 (2.8) | 1.08 (0.83–1.39) |
| BMI (kg/m2)c | |||
| < 20 | 343 (3.4) | 111 (3.7) | 1.07 (0.85–1.35) |
| 20–24 | 2665 (26.7) | 774 (25.5) | 1.00 (−) |
| 25–29 | 3793 (37.9) | 1144 (37.7) | 1.03 (0.93–1.15) |
| ≥ 30 | 2324 (23.2) | 714 (23.5) | 1.04 (0.92–1.17) |
| Unknown | 875 (8.8) | 290 (9.6) | 1.25 (1.06–1.47) |
| Smoking status | |||
| Non-smoker | 4378 (43.8) | 1231 (40.6) | 1.00 (−) |
| Current | 1292 (12.9) | 376 (12.4) | 1.07 (0.94–1.23) |
| Former | 4102 (41.0) | 1362 (44.9) | 1.20 (1.09–1.31) |
| Unknown | 228 (2.3) | 64 (2.1) | 0.93 (0.69–1.27) |
| Alcohol consumption (units/week)d | |||
| None | 1771 (17.7) | 483 (15.9) | 1.00 (−) |
| 1–9 | 4722 (47.2) | 1401 (46.2) | 1.12 (0.99–1.26) |
| 10–20 | 1521 (15.2) | 480 (15.8) | 1.21 (1.04–1.41) |
| ≥ 21 | 725 (7.3) | 274 (9.0) | 1.46 (1.20–1.78) |
| Unknown | 1261 (12.6) | 395 (13.0) | 1.15 (0.97–1.36) |
| Comorbiditiese | |||
| Diabetes | 1852 (18.5) | 598 (19.7) | 0.98 (0.87–1.10) |
| IBD | 124 (1.2) | 40 (1.3) | 1.04 (0.72–1.50) |
| IBS | 534 (5.3) | 176 (5.8) | 1.02 (0.85–1.22) |
| Gout | 765 (7.6) | 250 (8.2) | 1.10 (0.94–1.29) |
| Hypertension | 5626 (56.3) | 1740 (57.4) | 1.01 (0.93–1.11) |
| Hypercholesterolemia | 1655 (16.6) | 484 (16.0) | 0.96 (0.83–1.35) |
| Upper GI disorders | 2165 (21.6) | 656 (21.6) | 0.93 (0.84–1.03) |
BMI body mass index, CI confidence interval, CRC colorectal cancer, GI gastrointestinal, IBD inflammatory bowel disease, IBS irritable bowel syndrome, NSAIDS non-steroidal anti-inflammatory drugs, PCP primary care practitioner, RR rate ratio, u/w units per week
aAdjusted by the matching variables (age, sex and year of index date) and number of PCP visits, smoking (any time before index date), insulin, NSAIDs, BMI (any time before index date) and oral steroids
bIn the year before the index date
cAny time before the index date taking the value recorded nearest to the index date
dUnits per week = 10 ml (8 g) of pure ethanol
eAny time before the index date except for GI disorders, which were ascertained anytime up to and including the start date. Reference group for all comorbidities was not having the respective condition