Table 2.
Selected Characteristics of the Study Population
| Population-based Families | Clinic-based Families | |||||
|---|---|---|---|---|---|---|
| Cases (n=1,806) | Sibling Controls (n=2,879) | P- value† | Cases (n=269) | Sibling Controls (n=475) | P- value† | |
| Person Characteristic | ||||||
| Mean Age ± SD | 53.5± 10.9 | 54.0 ± 11.8 | <0.01 | 49.1 ± 11.4 | 51.4 ± 11.8 | <0.01 |
| Sex, No. (%) | ||||||
| Male | 927 (51.3) | 1278 (44.4) | <0.01 | 133 (49.4) | 204 (42.9) | 0.19 |
| Female | 879 (48.7) | 1601 (55.6) | 136 (50.6) | 271 (57.1) | ||
| Race, No. (%) | ||||||
| Non-Hispanic White | 1580 (87.5) | 2512 (87.3) | 1.00 | 262 (97.4) | 463 (97.5) | 1.00 |
| Black | 32 (1.8) | 42 (1.5) | 1 (0.4) | 2 (0.4) | ||
| Asian | 69 (3.8) | 113 (3.9) | 0 (0) | 0 (0) | ||
| Other¥ | 104 (5.8) | 189 (6.6) | 5 (1.9) | 9 (1.9) | ||
| Unknown/Missing | 21 (1.2) | 23 (0.8) | 1 (0.4) | 1 (0.2) | ||
| Center, No. (%) | ||||||
| Ontario, Canada | 308 (17.1) | 515 (17.9) | - | 0 (0) | 0 (0) | 1.00 |
| USC Consortium, U.S. | 384 (21.3) | 519 (18.0) | 38 (14.1) | 48 (10.1) | ||
| Melbourne, Australia | 344 (19.0) | 611 (21.2) | 110 (40.9) | 213 (44.8) | ||
| Hawaii, U.S. | 63 (3.5) | 103 (3.6) | 0 (0) | 0 (0) | ||
| Mayo Foundation, U.S. | 282 (15.6) | 526 (18.3) | 121 (45.0) | 214 (45.1) | ||
| Seattle, U.S. | 425 (23.5) | 605 (21.0) | 0 (0) | 0 (0) | ||
| Family History of CRC, No. (%) | ||||||
| No 1st degree relative | 1177 (65.2) | - | - | 101 (37.5) | - | - |
| At least 1st degree relative | 546 (30.2) | 70 (26.0) | ||||
| Unknown/Missing | 83 (4.6) | 98 (36.4) | ||||
| BMI (kg/m2) § | ||||||
| 15–18 (underweight) | 22 (1.2) | 25 (0.9) | <0.01 | 6 (2.2) | 12 (2.5) | 0.82 |
| 18–25 (normal) | 629 (34.8) | 1155 (40.1) | 97 (36.1) | 174 (36.6) | ||
| 25–30 (overweight) | 670 (37.1) | 1036 (36.0) | 100 (37.2) | 174 (36.6) | ||
| 30+ (obese) | 422 (23.4) | 594 (20.6) | 53 (19.7) | 92 (19.4) | ||
| Unknown/Missing | 63 (3.5) | 69 (2.4) | 13 (4.8) | 23 (4.8) | ||
| Alcohol use (drinks/wk) | ||||||
| None | 467 (25.9) | 829 (28.8) | 0.08 | 76 (28.3) | 132 (27.8) | 0.43 |
| 1–7 (moderate) | 857 (47.5) | 1353 (47.0) | 124 (46.1) | 226 (47.2) | ||
| 8+ (heavy) | 229 (12.7) | 362 (12.6) | 39 (14.5) | 61 (12.8) | ||
| Unknown/Missing | 253 (14.0) | 335 (11.6) | 30 (11.2) | 56 (11.8) | ||
| Smoking | ||||||
| Never | 781 (43.2) | 1309 (45.5) | 0.24 | 138 (51.3) | 226 (47.6) | <0.01 |
| Former | 632 (35.0) | 1001 (34.8) | 58 (21.6) | 153 (32.2) | ||
| Current | 343 (19.0) | 509 (17.7) | 66 (24.5) | 87 (18.3) | ||
| Unknown/Missing | 50 (2.8) | 60 (2.1) | 7 (2.6) | 9 (1.9) | ||
| Folate supplements¶ | ||||||
| No | 1586 (87.8) | 2557 (88.8) | 0.14 | 233 (86.6) | 411 (91.3) | 0.25 |
| Yes | 196 (10.9) | 274 (9.5) | 31 (11.5) | 39 (8.7) | ||
| Unknown/Missing | 24 (1.3) | 48 (1.7) | 5 (1.9) | 11 (2.3) | ||
| Multivitamins¶ | ||||||
| No | 820 (45.4) | 1497 (52.0) | <0.01 | 138 (51.3) | 267 (56.2) | 0.27 |
| Yes | 971 (53.8) | 1346 (46.8) | 129 (48.0) | 200 (42.1) | ||
| Calcium Supplements¶ | ||||||
| No | 1335 (73.9) | 2063 (71.7) | 0.03 | 208 (77.3) | 345 (76.7) | 0.33 |
| Yes | 459 (25.4) | 785 (27.3) | 56 (20.8) | 105 (23.3) | ||
| Unknown/Missing | 12 (0.7) | 31 (1.1) | 5 (1.9) | 2 (0.4) | ||
| Dietary folate (μg) (Mean ± SD)* | 327.4 ±118.7 | 334.1 ±126.8 | 0.32 | 349.6 ± 154.9 | 346.0 ± 145.0 | 0.95 |
| Total folate DFE(Mean ± SD)* | 477 ± 265.6 | 525.4 ± 439.7 | <0.01 | 606.5 ± 463.1 | 549.6 ± 322.2 | 0.29 |
| Dietary B12 (Mean ± SD)* | 3.0 ± 1.2 | 2.9 ± 1.3 | 0.67 | 3.1 ± 1.4 | 3.0 ± 1.4 | 0.36 |
| Total B12 (Mean ± SD)* | 6.2 ± 6.4 | 7.4 ± 11.8 | <0.01 | 10.0 ± 17.6 | 8.8 ± 10.0 | 0.41 |
| Dietary B6 (Mean ± SD)* | 1.1 ± 0.4 | 1.1 ± 0.4 | 0.26 | 1.1 ± 0.5 | 1.1 ± 0.4 | 0.64 |
| Total B6 (Mean ± SD) | 1.9 ± 2.0 | 2.3 ± 3.8 | <0.01 | 3.0 ± 6.0 | 2.6 ± 3.3 | 0.48 |
| Tumor Characteristics | ||||||
| Site, No. (%) | ||||||
| Right Colon | 598 (33.1) | - | 85 (31.6) | - | ||
| Left Colon | 525 (29.1) | 44 (16.4) | ||||
| Rectum | 593 (32.8) | 77 (28.6) | ||||
| Unknown/Missing | 90 (5.0) | 63 (23.4) | ||||
| MSI, No. (%) | ||||||
| MSS | 855 (47.3) | - | 61 (22.7) | - | ||
| MSI-L | 151 (8.4) | 14 (5.2) | ||||
| MSI-H | 179 (9.9) | 55 (20.4) | ||||
| Unknown/Missing | 621 (34.4) | 139 (51.7) | ||||
¥
includes individuals who self-identified themselves as Hispanic, Native, Hawaiian/Pacific Islander and Mixed Race.
†
p-values using a 1-degree of freedom likelihood test from a conditional logistic regression model.
§
Self-reported weight and height two years prior to questionnaire completion date used to calculate body mass index.
¶
Ever use of supplements regularly during the two years prior to recruitment (at least 2x/week for more than a month)
*
Calorie adjusted calculated from food frequency questionnaire using post-fortification food composition tables (N cases=585; N controls=837).
‡
Met-hours per week