Table 1.
Selected characteristics of the study population
| Variable | Controls n = 696 |
Cases n = 655 |
p Valuea |
|---|---|---|---|
| Age mean (SD)b | 61.59 (6.7) | 61.72 (6.9) | 0.66 |
| Sex n (% male)b | 458 (65.8) | 418 (63.8) | 0.42 |
| Race/ethnic groupb | |||
| White | 372 (53.5) | 351 (53.6) | 0.32 |
| Black | 108 (15.5) | 117 (17.9) | |
| Hispanic | 73 (10.4) | 74 (11.3) | |
| Asian | 114 (16.5) | 81 (12.4) | |
| Other | 29 (4.15) | 32 (4.9) | |
| Calories mean (SD) | 2,052 (960.7) | 2,090 (939.2) | 0.14 |
| BMI mean (SD) | 27.13 (4.6) | 27.51 (4.5) | 0.24 |
| Alcohol (g/day) mean (SD)c,d | 7.93 (27.2) | 9.78 (29.5) | 0.22 |
| Smoking | |||
| Never n (%) | 283 (42.7) | 233 (37.0) | <0.01 |
| Former n (%) | 314 (47.4) | 284 (45.2) | |
| Current n (%) | 66 (9.95) | 112 (17.8) | |
| Missing/unknown | 33 | 26 | |
| Smoking (pack years) mean (SD) | 16.85 (32.1) | 18.83 (30.5) | 0.01 |
| Multivitamin use (% Yes)b | 58.8 | 57.9 | 0.64 |
| Dietary B12 (mcg/day) mean (SD)b,c | 6.14 (4.8) | 6.09 (4.5) | 0.59 |
| Dietary folate (mcg/day) mean (SD)b,c | 367.5 (212.5) | 337.0 (181.9) | <0.01 |
| Plasma total homocysteine (μmol/L)b | 10.35 (3.75) | 10.48 (4.73) | 0.74 |
| Total dietary fiber g/day mean (SD)b,c | 22.84 (13.3) | 21.46 (12.3) | <0.01 |
| Vegetable fiber g/day mean (SD)b,c | 8.38 (7.05) | 7.51 (5.6) | <0.01 |
| Saturated fat g/day mean (SD)b,c | 23.45 (13.6) | 24.56 (13.6) | 0.12 |
| Red meat g/day mean (SD)b,c | 66.21 (67.4) | 68.47 (56.1) | 0.63 |
| Number of adenomas n (%) | |||
| 1 | 698 (89.4) | ||
| ≥2 | 83 (10.6) | ||
| Missing | 1 | ||
| Adenoma size n (%) | |||
| <1 cm | 526 (68.1) | ||
| ≥1 cm | 247 (31.9) | ||
| Missing | 9 | ||
| Adenoma site n (%) | |||
| Rectum (<15 cm) | 146 (18.8) | ||
| Colon (≥15 cm) | 631 (81.2) | ||
| Missing | 5 | ||
aComparisons between cases and controls for selected baseline characteristics were made using multiple regression controlling for the matching factors (age, sex, clinic, and examination date) and study phase
b1 control was missing sex and age data, 2 controls were missing sex data, and 7 controls and 10 cases were missing data on race/ethnic group. For phase 2 subjects, 7 controls and 7 cases were missing plasma total homocysteine data
cAll dietary intakes were defined as average use in the year before the sigmoidoscopy. Comparisons between cases and controls are adjusted for the matching factors, study phase, and calorie intake
dSum of alcohol content of wine (10.9 g/serving), beer (12.8 g/serving), and spirits (15.0 g/serving) in the year before the sigmoidoscopy