Table 6.

Incident colorectal adenoma outcomes in ACP participants undergoing >1 colonoscopy and by subgroup

SeleniumVitamin E
Active (n = 313)Placebo (n = 345)Active (n = 346)Placebo (n = 312)
Number (%)Number (%)RR95% CIPNumber (%)Number (%)RR95% CIP
Incident colorectal adenoma116 (37.1)108 (31.3)1.180.96–1.460.12106 (30.6)118 (37.8)0.810.66–1.000.05
Subgroups
 Aspirin
  Nonusers63 (38.0)59 (33.2)1.130.85–1.500.4052 (31.0)70 (39.8)0.780.59–1.050.10
  Users53 (36.0)49 (29.3)1.240.90–1.700.1954 (30.3)48 (35.3)0.850.62–1.170.32
P 3-way = 0.454
P all 2-way = 0.933
 BMI
  Normal22 (31.9)16 (29.6)1.100.64–1.880.7417 (28.8)21 (32.8)0.870.51–1.480.60
  Overweight52 (36.9)54 (31.6)1.160.85–1.580.3456 (31.8)50 (36.8)0.870.64–1.180.38
  Obese42 (40.8)38 (31.9)1.260.89–1.790.1933 (29.7)47 (42.3)0.710.50–1.010.06
P 3-way = 0.381
P all 2-way = 0.974
 FDRs with CRC
  093 (38.9)83 (31.2)1.250.98–1.580.0785 (30.7)91 (39.9)0.770.61–0.980.03
  ≥116 (29.1)19 (30.2)0.970.55–1.690.9016 (31.3)19 (28.4)1.100.63–1.930.72
P 3-way = 0.208
P all 2-way = 0.549
 Race/ethnicity
  White103 (35.9)94 (30.6)1.170.93–1.470.1796 (30.7)101 (35.9)0.850.68–1.070.17
  African American11 (52.3)11 (39.3)1.200.65–2.210.579 (34.6)13 (56.5)0.640.33–1.230.18
  Hispanic1 (33.3)3 (50.0)1 (20.0)3 (75.0)
P 3-way = 0.201
P all 2-way = 0.860
 Age
  <63 years50 (33.6)56 (30.9)1.100.81–1.500.5347 (26.3)59 (39.1)0.670.49–0.920.01
  ≥63 years66 (40.2)52 (31.7)1.270.95–1.700.1159 (35.3)59 (36.6)0.980.73–1.300.86
P 3-way = 0.793
P all 2-way = 0.312
  • NOTE: Bold signifies a statistically significant effect within the subgroup (P < 0.05)

  • Abbreviations: CRC, colorectal cancer; P 3-way, P from the test of the 3-way interaction term; P all 2-way, P from the simultaneous test of all 2-way interaction terms.