Table I.
Baseline characteristics of subjects in a nested case-control study of advanced colorectal adenoma in the PLCO Cancer Screening Trial (N = 1,466).
| Characteristics | Cases N = 720a Mean ± SD | Controls N = 746 a Mean ± SD | P-valueb |
|---|---|---|---|
| Age | 63.1 ± 5.2 | 61.9 ± 5.2 | <0.01 |
| Gender, n (%) | 0.74 | ||
| Male | 501 (69.6) | 513 (68.8) | |
| Female | 219 (30.4) | 233 (31.2) | |
| Ethnicity, n (%) | 0.81 | ||
| Non-Hispanic white | 681 (94.6) | 704 (94.4) | |
| Non-Hispanic black | 15 (2.1) | 19 (2.6) | |
| Other | 24 (3.3) | 23 (3.1) | |
| Study Center | <0.01 | ||
| Colorado | 65 (9.0) | 84 (11.3) | |
| Georgetown | 36 (5.0) | 43 (5.8) | |
| Hawaii | 14 (1.9) | 13 (1.7) | |
| Henry Ford Health System | 61 (8.5) | 90 (12.1) | |
| Minnesota | 136 (18.9) | 173 (23.2) | |
| Washington | 77 (10.7) | 75 (10.1) | |
| Pittsburg | 112 (15.6) | 58 (7.8) | |
| Utah | 62 (8.6) | 38 (5.1) | |
| Marshfield | 130 (18.1) | 156 (20.9) | |
| Alabama | 27 (3.8) | 16 (2.1) | |
| First degree family history of colorectal cancer, n (%) | 90 (12.5) | 67 (9.0) | 0.03 |
| Education, n (%) | 0.04 | ||
| 12 years or less | 245 (34.0) | 217 (29.1) | |
| At least some college | 475 (66.0) | 528 (70.9) | |
| Body mass index (kg/m2) | 27.9 ± 4.8 | 27.5 ± 4.6 | 0.09 |
| Physical activity (hours/week) | 2.5 ± 1.8 | 2.8 ± 1.8 | <0.01 |
| Regular use of NSAIDs, n (%) | 418 (58.1) | 449 (60.2) | 0.42 |
| Smoking status, n (%) | <0.01 | ||
| Never | 243 (33.8) | 300 (40.2) | |
| Former cigarette smoker | 344 (47.8) | 353 (47.3) | |
| Current cigarette smoker | 98 (13.6) | 50 (6.7) | |
| Never cigarettes, but pipe and cigar | 34 (4.7) | 43 (5.8) | |
| Alcohol (g/day) | 14.5 ± 25.1 | 12.6 ± 24.0 | 0.27 |
| Total caloric intake (kcal/day) | 2114 ± 834 | 2168 ± 827 | 0.17 |
| Red meat (g/day) | 86.8 ± 64.3 | 87.7 ± 67.6 | 0.88 |
| MeIQx (ng/day) | 37.0 ± 51.8 | 35.8 ± 43.7 | 0.86 |
| PhIP (ng/day) | 203.1 ± 461.4 | 205.8 ± 458.6 | 0.83 |
| B[a]P (ng/day) | 30.7 ± 57.1 | 31.5 ± 53.3 | 0.92 |
a
Numbers may not sum to total due to missing values
b
P-value is for χ2 test for categorical variables and for Wilcoxon rank sum test for continuous variables.