Full factorial randomization | Two-group randomization | ||||||||
---|---|---|---|---|---|---|---|---|---|
Men (N = 1606) | Women (N = 301) | Women (N = 666) | |||||||
Randomized | Voluntary run-in failure | p | Randomized | Voluntary run-in failure | p | Randomized | Voluntary run-in failure | p | |
N (%) | N (%) | N (%) | N (%) | N (%) | N (%) | ||||
Total participants | 1423 (89) | 183 (11) | 252 (84) | 49 (16) | 584 (88) | 82 (12) | |||
PERSONAL FACTORS | |||||||||
Age mean (SD) | 58.8 (6.9) | 57.5 (7.1) | 0.01 | 56.6 (6.9) | 57.5 (6.0) | 0.41 | 56.8 (6.3) | 57.3 (7.2) | 0.59 |
Race | 0.02a | 0.04a | 0.02a | ||||||
White | 1214 (90) | 140 (10) | 211 (85) | 37 (15) | 475 (90) | 55 (10) | |||
Black | 100 (83) | 21 (17) | 31 (86) | 5 (14) | 53 (78) | 15 (22) | |||
Asian | 35 (88) | 5 (12) | 1 (100) | 0 (0) | 15 (94) | 1 (6.3) | |||
Native American | 9 (100) | 0 (0) | 2 (67) | 1 (33) | 2 (100) | 0 (0) | |||
Pacific Islander | 1 (100) | 0 (0) | 1 (100) | 0 (0) | 0 (0) | 0 (0) | |||
Multiple races | 9 (75) | 3 (25) | 0 (0) | 1 (100) | 1 (100) | 0 (0) | |||
Unknown/refused | 55 (80) | 14 (20) | 6 (55) | 5 (45) | 38 (78) | 11 (22) | |||
Hispanic ethnicity | <0.0001 | 0.06a | 0.13 | ||||||
No | 1337 (90) | 154 (10) | 243 (85) | 44 (15) | 530 (88) | 70 (12) | |||
Yes | 83 (77) | 25 (23) | 9 (64) | 5 (36) | 54 (82) | 12 (18) | |||
Unknown/refused | 3 (43) | 4 (57) | 0 | 0 | 0 | 0 | |||
Marital status | 0.001 | 0.04 | 0.04 | ||||||
Married/cohabitating | 1232 (90) | 140 (10) | 182 (87) | 28 (13) | 421 (89) | 50 (11) | |||
Single | 191 (82) | 41 (18) | 70 (77) | 21 (23) | 162 (84) | 32 (16) | |||
Unknown/refused | 0 | 2 (100) | 0 | 0 | 1 (100) | 0 | |||
Education | <0.0001 | 0.07 | 0.03 | ||||||
Did not graduate high school | 63 (71) | 26 (29) | 16 (70) | 7 (30) | 46 (78) | 13 (22) | |||
Graduated high school | 196 (90) | 21 (9.7) | 41 (79) | 11 (21) | 83 (85) | 15 (15) | |||
Any college education | 1164 (90) | 135 (10) | 195 (86) | 31 (14) | 455 (89) | 54 (11) | |||
HEALTH-RELATED FACTORS | |||||||||
Smoking status | 0.40 | 0.06 | 0.46 | ||||||
Never | 664 (89) | 85 (11) | 156 (88) | 22 (12) | 374 (89) | 47 (11) | |||
Former | 629 (89) | 75 (11) | 71 (80) | 18 (20) | 150 (85) | 26 (15) | |||
Current | 130 (86) | 22 (14) | 25 (74) | 9 (26) | 60 (87) | 9 (13) | |||
Unknown/refused | 0 | 1 (100) | 0 | 0 | 0 | 0 | |||
Alcohol use | 0.96 | 0.32 | 0.10 | ||||||
None | 341 (90) | 39 (10) | 116 (81) | 27 (19) | 233 (85) | 40 (15) | |||
≤1 drink/day | 519 (90) | 56 (9.7) | 91 (88) | 13 (12) | 244 (91) | 24 (9.0) | |||
>1 drink/day | 453 (90) | 51 (10) | 26 (79) | 7 (21) | 71 (86) | 12 (14) | |||
Unknown/refused | 110 (75) | 37 (25) | 19 (90) | 2 (9.5) | 36 (86) | 6 (14) | |||
Activity level | 0.96 | 0.72 | 0.66 | ||||||
Low | 318 (89) | 41 (11) | 63 (81) | 15 (19) | 152 (87) | 23 (13) | |||
Moderate | 424 (89) | 52 (11) | 86 (84) | 17 (16) | 202 (87) | 29 (13) | |||
High | 665 (89) | 86 (11) | 98 (85) | 17 (15) | 222 (90) | 26 (10) | |||
missing | 16 (80) | 4 (20) | 5 (100) | 0 | 8 (67) | 4 (33) | |||
Taking a multivitamin | 0.04 | 0.59 | 0.001 | ||||||
No | 650 (87) | 97 (13) | 149 (83) | 31 (17) | 191 (82) | 42 (18) | |||
Yes | 771 (90) | 83 (9.7) | 103 (85) | 18 (15) | 393 (91) | 38 (8.8) | |||
Unknown/refused | 2 (40) | 3 (60) | 0 | 0 | 0 | 2 (100) | |||
Taking calcium supplement | 0.06 | 0.10 | 0.001 | ||||||
No | 1321 (88) | 174 (12) | 221 (82) | 47 (18) | 273 (84) | 53 (16) | |||
Yes | 100 (94) | 6 (5.7) | 30 (94) | 2 (6.3) | 310 (92) | 27 (8.0) | |||
Unknown/refused | 2 (40) | 3 (60) | 1 (100) | 0 | 1 (33) | 2 (67) | |||
Taking vitamin D supplement | 0.04 | 0.39a | 0.0001 | ||||||
No | 1360 (88) | 178 (12) | 229 (83) | 47 (17) | 370 (84) | 68 (16) | |||
Yes | 61 (97) | 2 (3.2) | 21 (91) | 2 (8.7) | 213 (95) | 12 (5.3) | |||
Unknown/refused | 2 (40) | 3 (60) | 2 (100) | 0 | 1 (33) | 2 (67) | |||
Number of prescription medications | 0.27 | 0.02 | 0.77 | ||||||
0 | 307 (86) | 50 (14) | 29 (78) | 8 (22) | 84 (87) | 13 (13) | |||
1 | 360 (90) | 38 (9.6) | 59 (89) | 7 (11) | 145 (90) | 16 (10) | |||
2 | 273 (88) | 36 (12) | 51 (94) | 3 (5.6) | 114 (87) | 17 (13) | |||
3+ | 483 (89) | 59 (11) | 113 (78) | 31 (22) | 241 (87) | 36 (13) | |||
Experienced chronic fatigue in last year | 0.66 | 0.41a | 0.11 | ||||||
None | 1357 (89) | 171 (11) | 219 (83) | 44 (17) | 531 (89) | 69 (11) | |||
Some | 51 (85) | 9 (15) | 23 (92) | 2 (8.0) | 40 (78) | 11 (22) | |||
Severe | 15 (88) | 2 (12) | 10 (77) | 3 (23) | 13 (87) | 2 (13) | |||
Don’t know | 0 | 1 (100) | 0 | 0 | 0 | 0 | |||
Experienced muscular pain in last year | 0.53 | 0.05 | 0.33 | ||||||
None | 1228 (89) | 154 (11) | 210 (83) | 43 (17) | 488 (89) | 63 (11) | |||
Some | 171 (88) | 23 (12) | 38 (93) | 3 (7.3) | 76 (85) | 13 (15) | |||
Severe | 23 (82) | 5 (18) | 4 (57) | 3 (43) | 20 (80) | 5 (20) | |||
Don’t know | 1 (50) | 1 (50) | 0 | 0 | 0 | 1 (100) | |||
Experienced muscular weakness in last year | 0.09 | 0.03a | 0.31 | ||||||
None | 1358 (89) | 167 (11) | 234 (83) | 47 (17) | 534 (88) | 72 (12) | |||
Some | 54 (82) | 12 (18) | 16 (100) | 0 | 38 (81) | 9 (19) | |||
Severe | 11 (79) | 3 (21) | 2 (50) | 2 (50) | 11 (92) | 1 (8.3) | |||
Don’t know | 0 | 1 (100) | 0 | 0 | 1 (100) | 0 | |||
Experienced bone aches or pains in last year | 0.11 | 0.42 | 0.56 | ||||||
None | 1215 (89) | 151 (11) | 208 (85) | 37 (15) | 455 (88) | 63 (12) | |||
Some | 170 (89) | 21 (11) | 30 (77) | 9 (23) | 96 (89) | 12 (11) | |||
Severe | 38 (79) | 10 (21) | 14 (88) | 2 (12) | 33 (83) | 7 (17) | |||
Don’t know | 0 | 1 (100) | 0 | 1 (100) | 0 | 0 | |||
SF-36 mental component summary measure, mean (SD)b | 55.9 (6.0) | 55.0 (7.3) | 0.09 | 53.9 (7.5) | 53.0 (10.4) | 0.58 | 54.2 (6.9) | 51.8 (8.0) | 0.01 |
SF-36 physical component summary measure, mean (SD)b | 53.9 (6.1) | 53.1 (7.5) | 0.65 | 53.5 (6.8) | 51.7 (7.5) | 0.12 | 52.8 (6.8) | 49.3 (8.9) | 0.0004 |
ADENOMA-RELATED FACTORS | |||||||||
Number of baseline adenomas | 0.29 | 0.53 | 0.48 | ||||||
0 | 5 (83) | 1 (17) | 0 | 0 | 0 | 1 (100) | |||
1 | 916 (88) | 128 (12) | 190 (83) | 39 (17) | 453 (88) | 60 (12) | |||
2+ | 502 (90) | 54 (9.7) | 62 (86) | 10 (14) | 131 (86) | 21 (14) | |||
Baseline advanced adenomas | 0.73 | 0.98 | 0.12 | ||||||
No | 1139 (89) | 147 (11) | 201 (84) | 39 (16) | 476 (87) | 73 (13) | |||
Yes | 253 (88) | 35 (12) | 51 (84) | 10 (16) | 103 (92) | 9 (8.0) | |||
Unknown | 31 (97) | 1 (3.1) | 0 | 0 | 5 (100) | 0 | |||
Family history of colorectal cancer | 0.14 | 0.40 | 0.73 | ||||||
No | 1080 (88) | 142 (12) | 200 (84) | 39 (16) | 454 (88) | 60 (12) | |||
Yes | 238 (92) | 22 (8.5) | 39 (89) | 5 (11) | 95 (87) | 14 (13) | |||
Unknown/refused | 105 (85) | 19 (15) | 13 (72) | 5 (28) | 35 (81) | 8 (19) | |||
Colonoscopy surveillance interval | 0.73 | 0.12 | 0.003 | ||||||
3 year | 727 (88) | 96 (12) | 123 (87) | 18 (13) | 287 (92) | 26 (8.3) | |||
5 year | 696 (89) | 87 (11) | 129 (81) | 31 (19) | 297 (84) | 56 (16) | |||
STUDY-RELATED FACTORS | |||||||||
Study center | <0.0001 | 0.33a | <0.0001 | ||||||
A | 227 (98) | 5 (2.2) | 29 (85) | 5 (15) | 86 (97) | 3 (3.4) | |||
B | 119 (97) | 4 (3.3) | 3 (100) | 0 | 57 (95) | 3 (5.0) | |||
C | 75 (96) | 3 (3.9) | 16 (100) | 0 | 45 (96) | 2 (4.3) | |||
D | 75 (90) | 8 (9.6) | 12 (92) | 1 (7.7) | 43 (96) | 2 (4.4) | |||
E | 242 (88) | 33 (12) | 59 (86) | 10 (14) | 64 (93) | 5 (7.3) | |||
F | 137 (87) | 20 (13) | 27 (87) | 4 (13) | 43 (66) | 22 (34) | |||
G | 143 (86) | 23 (14) | 32 (86) | 5 (14) | 62 (94) | 4 (6.1) | |||
H | 170 (85) | 29 (15) | 28 (80) | 7 (20) | 50 (82) | 11 (18) | |||
I | 123 (83) | 25 (17) | 31 (74) | 11 (26) | 73 (84) | 14 (16) | |||
J | 28 (80) | 7 (20) | 0 | 0 | 9 (82) | 2 (18) | |||
K | 84 (76) | 26 (24) | 15 (71) | 6 (29) | 52 (79) | 14 (21) | |||
Taking prescription drug that requires staggered administration with study tablets | 0.10 | 0.13 | 0.21 | ||||||
No | 1310 (89) | 162 (11) | 204 (85) | 35 (15) | 472 (87) | 71 (13) | |||
Yes | 113 (84) | 21 (16) | 48 (77) | 14 (23) | 112 (91) | 11 (8.9) | |||
Counseled at baseline to change diet | 0.57 | 0.13a | 0.09a | ||||||
No | 1381 (89) | 178 (11) | 250 (84) | 47 (16) | 578 (88) | 78 (12) | |||
Yes | 42 (91) | 4 (8.7) | 2 (50) | 2 (50) | 6 (67) | 3 (33) | |||
Unknown | 0 | 1 (100) | 0 | 0 | 0 | 1 (100) | |||
Refused any questions during enrollment in-person questionnairec,d | 0.01a | 1.00a | 0.01a | ||||||
No | 1419 (89) | 179 (11) | 251 (84) | 49 (16) | 583 (88) | 79 (12) | |||
Yes | 4 (50) | 4 (50) | 1 (100) | 0 | 1 (25) | 3 (75) | |||
Answered ”Don’t know” to any questions during enrollment in-person questionnairec,d | 0.01 | 0.59a | 0.05 | ||||||
No | 1314 (89) | 159 (11) | 231 (84) | 44 (16) | 521 (89) | 67 (11) | |||
Yes | 109 (82) | 24 (18) | 21 (81) | 5 (19) | 63 (81) | 15 (19) | |||
Refused any questions during enrollment self-administered questionnairesc | <0.0001 | 0.02 | 0.001 | ||||||
No | 1084 (91) | 103 (8.7) | 225 (86) | 38 (14) | 517 (89) | 62 (11) | |||
Yes | 339 (81) | 80 (19) | 27 (71) | 11 (29) | 67 (77) | 20 (23) | |||
Scheduled next interview during enrollmentc | 0.001 | 0.25 | 0.29 | ||||||
No | 261 (83) | 52 (17) | 44 (79) | 12 (21) | 113 (85) | 20 (15) | |||
Yes | 1162 (90) | 131 (10) | 208 (85) | 37 (15) | 471 (88) | 62 (12) | |||
Number of enrollments conducted by coordinatorc | 0.42 | 0.31 | 0.76 | ||||||
1–10 | 16 (80) | 4 (20) | 6 (100) | 0 | 17 (94) | 1 (5.6) | |||
11–50 | 170 (86) | 27 (14) | 28 (82) | 6 (18) | 86 (87) | 13 (13) | |||
51–100 | 364 (89) | 46 (11) | 77 (89) | 10 (11) | 132 (86) | 21 (14) | |||
>100 | 873 (89) | 106 (11) | 141 (81) | 33 (19) | 349 (88) | 47 (12) | |||
Coordinator worked in a prior polyp prevention trialc | 0.01 | 0.48 | 0.49 | ||||||
No | 1034 (87) | 144 (13) | 211 (84) | 39 (16) | 413 (87) | 61 (13) | |||
Yes | 389 (92) | 34 (8.0) | 41 (80) | 10 (20) | 171 (89) | 21 (11) |