Table 1.

Characteristics of individuals in the Polyp Prevention Trial of Aspirin and Folate who completed first year follow-up

CharacteristicsAdenoma occurrenceNo adenoma occurrenceP*
No. participants471613
Age at baseline, mean ± SD (y)59.0 ± 9.356.2 ± 9.6<0.001
Male sex, n (%)321 (68.2)369 (60.2)0.007
Body mass index >30 kg/m2, n (%)117 (24.9)125 (20.4)0.080
Current cigarette smoker, n (%)86 (18.5)72 (11.8)0.002
Colorectal cancer in first-degree relative, n (%)143 (37.1)189 (37.4)0.949
Self-identified as White, n (%)412 (87.5)516 (84.2)0.125
Aspirin use at baseline, n (%)291 (61.8)358 (58.5)0.274
Aspirin treatment group, n (%)300 (63.7)421 (68.7)0.085
Folate treatment group, n (%)221 (51.8)280 (50.0)0.584
Baseline plasma folate, mean ± SD (nmol/L)21.9 ± 15.324.4 ± 19.10.025
Baseline plasma B2, mean ± SD30.6 ± 56.827.7 ± 43.60.374
Baseline plasma B6, mean ± SD76.3 ± 89.281.3 ± 86.80.378
Baseline plasma B12, mean ± SD317.1 ± 141.3333.7 ± 177.10.112
Multivitamin use, n (%)153 (32.6)226 (37.1)0.125
Dietary intake, mean ± SD
    Dietary folate intake (mg/d)317.9 ± 150.4320.7 ± 162.40.772
    Total folate§ (mg/d)460.2 ± 309.5461.9 ± 284.70.927
    Dietary vitamin B2 (mg/d)30.6 ± 56.827.7 ± 43.60.729
    Total vitamin B6§ (mg/d)2.6 ± 2.22.5 ± 2.00.718
    Total vitamin B12 (mg/d)2.6 ± 5.82.5 ± 4.60.779
Alcohol (drinks/d), n (%)
    0121 (26.8)206 (35.4)0.006
    ≤1223 (49.4)271 (46.6)
    ≥2107 (23.7)105 (18.0)
Adenoma characteristics (at baseline)**
    n (mean ± SD)1.7 ± 1.11.5 ± 0.9<0.001
    Large adenomas (>1 cm), n (%)107 (22.7)140 (22.8)0.962
    Villous histology, n (%)60 (12.7)93 (15.2)0.254
    Proximal location, n (%)248 (52.7)244 (39.8)<0.001
  • * χ2 test.

  • Two-sample t test.

  • 81 and 325 mg/d aspirin treatment groups combined.

  • § Total folate and total B6 = dietary + supplements.

  • Total B2 from dietary sources only.

  • Total B12 from supplements only.

  • ** Using standard definitions by Polyp Prevention Study Group (28, 29).