Table 1. Descriptive data of the study population by colorectal cancer phenotype.
| Total | Cases | Controls | pa | |
|---|---|---|---|---|
| Number of participants (%)b | 2,042 (100) | 681 (33.4) | 1361 (66.7) | |
| Sex (%) | 0.955 | |||
| Male | 1,390 (68.1) | 463 (68.0) | 927 (68.1) | |
| Female | 652 (31.9) | 218 (32.0) | 434 (31.9) | |
| Age (mean, year) | 56.1 ± 9.3 | 56.5 ± 9.6 | 56.0 ± 9.1 | 0.258 |
| Body mass index (kg/m2) | 0.437 | |||
| < 25 | 1,374 (67.3) | 466 (68.4) | 908 (66.7) | |
| ≥ 25 | 668 (32.7) | 215 (31.6) | 453 (33.3) | |
| Tobacco smoking (%) | 0.088 | |||
| Never | 909 (44.5) | 308 (45.2) | 601 (44.2) | |
| Former | 742 (36.3) | 228 (33.5) | 514 (37.8) | |
| Current | 391 (19.15) | 145 (21.3) | 246 (18.1) | |
| Alcohol drinking (%) | 0.001 | |||
| Never | 619 (30.3) | 208 (30.5) | 411 (30.2) | |
| Former | 220 (10.8) | 97 (14.2) | 123 (9.0) | |
| Current | 1,203 (58.9) | 376 (55.2) | 827 (60.76) | |
| Regular exercise (%) | < .001 | |||
| Yes | 1,029 (50.4) | 217 (31.9) | 812 (59.6) | |
| No | 1,006 (49.3) | 646 (68.1) | 542 (39.8) | |
| Missing | 7 (0.3) | - | 7 (0.5) | |
| First-degree family history of colorectal cancer (%) | 0.039 | |||
| Yes | 127 (6.2) | 53 (7.8) | 74 (5.4) | |
| No | 1,915 (93.8) | 628 (92.2) | 1,287 (94.6) | |
| Marital status (%) | < .001 | |||
| Married or with a partner | 1,800 (88.2) | 576 (84.6) | 1,224 (89.9) | |
| Single | 171 (8.4) | 82 (12.0) | 89 (6.5) | |
| Never married | 65 (3.2) | 21 (3.1) | 44 (3.2) | |
| Missing | 6 (0.3) | 2 (0.3) | 4 (0.3) | |
| Education level (%) | < .001 | |||
| Middle school graduate or less | 439 (21.5) | 249 (36.6) | 190 (14.0) | |
| High school graduate | 855 (41.9) | 261 (38.3) | 594 (43.6) | |
| College graduate or more | 739 (36.2) | 171 (25.1) | 568 (41.7) | |
| Missing | 9 (0.4) | - | 9 (0.7) | |
| Household income (10,000 won/month) | < .001 | |||
| < 100 | 176 (8.6) | 91 (13.4) | 85 (6.3) | |
| 100–200 | 373 (18.3) | 143 (21.0) | 230 (16.9) | |
| 201–400 | 883 (43.2) | 301 (44.2) | 582 (42.8) | |
| > 400 | 570 (28.0) | 146 (21.4) | 424 (31.2) | |
| Missing | 40 (2.0) | - | 40 (2.9) | |
| Dietary zinc intake (mg/day) | 8.4 ± 1.6 | 8.1 ± 1.4 | 8.5 ± 1.6 | < .001 |
aP-values present the difference between cases and controls. Age and zinc intake were examined using Student's t-tests; other variables were assessed using chi-square analyses.
bNumbers in parentheses are percentages; other data are presented as the means ± standard deviation.