Table 1. Descriptive characteristics of the Kentucky colon cancer study.
| Variable | Controls (n = 1,589) | Cases (n = 1,093) | P-value1 |
|---|---|---|---|
| Mean total caloric intake (kcal/day) (SD) | 1940.1 (1042.6) | 2142.3 (1251.9) | < 0.0001 |
| Mean total dietary fiber (g) (SD) | 20.7 (11.9) | 21.2 (13.0) | 0.26 |
| Mean calcium intake (mg/day) (SD) | 986.6 (562.6) | 996.2 (600.9) | 0.67 |
| Mean vitamin D intake (IU/day) (SD) | 416.4 (343.5) | 388.0 (340.1) | 0.03 |
| Mean glycemic load adj. for energy2 (SD) | 132.8 (25.2) | 136.4 (24.5) | 0.0003 |
| Glycemic load (%) | |||
| 1st quintile | 407 (25.6) | 208 (19.0) | 0.0003 |
| 2nd quintile | 350 (22.0) | 232 (21.2) | |
| 3rd quintile | 422 (26.6) | 333 (30.5) | |
| 4th quintile | 410 (25.8) | 320 (29.3) | |
| Sex (%) | |||
| Male | 553 (34.8) | 528 (48.3) | < 0.0001 |
| Female | 1036 (65.2) | 565 (51.7) | |
| Mean age (yrs) (SD) | 61.1 (10.3) | 62.4 (10.3) | 0.001 |
| Age (%) | |||
| < 63 | 861 (54.2) | 515 (47.1) | 0.0003 |
| ≥ 63 | 728 (45.8) | 578 (52.9) | |
| Mean BMI (kg/2) (SD) | 28.3 (6.4) | 29.5 (6.2) | < 0.0001 |
| Body Mass Index (%) | |||
| underweight (< 18.5 kg/m2) | 8 (0.5) | 5 (0.5) | < 0.0001 |
| normal (18.5 - 24.99 kg/m2) | 482 (31.1) | 243 (22.9) | |
| overweight (25 - 29.99 kg/m2) | 596 (38.4) | 394 (37.1) | |
| obese (≥ 30 kg/m2) | 466 (30.0) | 421 (39.6) | |
| Missing | 37 | 30 | |
| Family history of colorectal cancer (%) | |||
| Yes | 416 (26.2) | 385 (35.2) | < 0.0001 |
| No | 1173 (73.8) | 708 (64.8) | |
| Race (%) | |||
| African American | 84 (5.3) | 41 (3.8) | 0.17 |
| Caucasian | 1477 (93.0) | 1034 (94.6) | |
| Other | 28 (1.8) | 18 (1.7) | |
| Regular NSAID use (%) | |||
| < 6 months | 596 (44.0) | 429 (46.4) | 0.27 |
| > 6 months | 758 (56.0) | 496 (53.6) | |
| Missing | 235 | 168 | |
| Mean lifetime physical activity (MET) (SD) | 11.7 (9.0) | 10.2 (7.9) | < 0.0001 |
| Physical Activity (%) | |||
| Light3 | 153 (10.4) | 134 (13.7) | 0.02 |
| Moderate3 | 245 (16.7) | 179 (18.3) | |
| Vigorous3 | 1069 (72.9) | 666 (68.0) | |
| Missing | 122 | 114 | |
| Income (%) | |||
| < $15,000 | 156 (10.5) | 143 (13.8) | < 0.0001 |
| $15,000 - 29,000 | 273 (18.4) | 236 (22.7) | |
| $30,000 - 44,000 | 284 (19.1) | 226 (21.7) | |
| $45,000 - 69,000 | 313 (21.0) | 216 (20.8) | |
| ≥ $70,000 | 462 (31.1) | 219 (21.1) | |
| Missing | 101 | 53 | |
| Smoking status (%) | |||
| Current | 234 (14.8) | 138 (12.8) | < 0.0001 |
| Former | 624 (39.3) | 524 (48.5) | |
| Nonsmoker | 728 (45.9) | 419 (38.8) | |
| Missing | 3 | 12 |
1
P-value for t-test for continuous variables and for χ2-test for categorical variables.
2
Glycemic load was adjusted for energy intake with nutrient residual model.
3
Light intensity (< 3 metabolic equivalents (METs)); Moderate intensity (3-6 METs); Vigorous intensity (> 6 METs).