TABLE 1.
Characteristics of the study population, by treatment group1
| Placebo (n = 42) | Folate (n = 52) | P value | |
| Sex [n (%)] | 0.292 | ||
| Male | 28 (66.7) | 29 (55.8) | |
| Female | 14 (33.3) | 23 (44.2) | |
| Age (y)3 | 0.834 | ||
| Mean ± SD | 57.8 ± 7.8 | 57.4 ± 8.8 | |
| Race [n (%)] | 1.002 | ||
| White | 40 (95.2) | 50 (96.2) | |
| Other | 2 (4.8) | 2 (3.8) | |
| Baseline alcohol intake [n (%)] | 0.472 | ||
| 0 drinks/d | 13 (31.7) | 17 (33.3) | |
| <0.5 drinks/d (≈<7 g/d) | 9 (22.0) | 15 (29.4) | |
| ≥0.5 drinks/d (>7 g/d) | 19 (46.4) | 19 (37.3) | |
| Baseline smoking status [n (%)] | 0.922 | ||
| Never | 22 (52.38) | 25 (48.08) | |
| Former | 17 (40.48) | 23 (44.23) | |
| Current | 3 (7.14) | 4 (7.69) | |
| Lifetime number of adenomas at baseline [n (%)] | 0.512 | ||
| 1–2 | 26 (61.9) | 36 (69.2) | |
| ≥3 | 16 (38.1) | 16 (30.8) | |
| Uracil misincorporation, mucosa56 | |||
| Median (interquartile range) | 4.31 (1.17) | 4.21 (1.31) | 0.177 |
| Year 3 plasma folate (ng/mL)8 | |||
| Mean ± SD | 9.81 ± 3.95 | 29.43 ± 15.73 | <0.00014 |
| Median (interquartile range) | 8.85 (5.10) | 24.80 (26.25) | <0.00017 |
| Year 3 RBC folate (ng/mL)8 | |||
| Mean ± SD | 680.77 ± 223.67 | 1023.72 ± 207.43 | <0.00014 |
| Median (interquartile range) | 648.90 (275.37) | 1014.06 (229.95) | <0.00017 |
| Year 3 tHcy (μmol/L)8 | |||
| Mean ± SD | 9.69 ± 2.39 | 8.64 ± 2.45 | 0.044 |
| Median (interquartile range) | 9.21 (1.51) | 8.09 (2.36) | 0.0037 |
1
tHcy, total homocysteine; RBC, red blood cell.
2
Fisher's exact test.
3
Age at randomization.
4
test.
5
Uracil measurements in mucosa from rectal biopsy samples.
6
Total sample size = 92 for rectal mucosa uracil measurements; total sample size = 60 for white blood cell uracil measurements.
7
Wilcoxon's rank-sum by folate treatment status.
8
Year 3 of this study was defined as the time of the surveillance colonoscopy ≈3 y after the qualifying examination.