Table 1.

Baseline selected characteristics of the study participants with at least one biomarker measurement

Baseline characteristicsPlacebo (N = 296)Aspirin 81 mg/d (N = 296)Aspirin 325 mg/d (N = 284)P-value
Age, yrs, mean (SD)57.5 (9.8)57.2 (9.4)57.6 (4.5)0.88
Male sex, n (%)189 (63.9)193 (65.2)178 (62.7)0.83
White, n (%)253 (85.5)260 (87.8)250 (88.0)0.14
BMI, kg/m2a, mean (SD)27.3 (4.5)27.3 (4.5)27.7 (4.8)0.91
Overweight, n (%)140 (47.5)142 (48.1)130 (45.8)0.89
Obese, n (%)63 (21.4)60 (20.3)70 (24.7)
Current smoker, n (%)41 (13.9)40 (13.6)41 (14.5)0.56
Alcohol drinker, n (%)199 (67.3)189 (63.9)193 (68.0)0.62
Multivitamin use, n (%)104 (35.1)111 (37.5)96 (33.8)0.40
Family history of colorectal polyps, n (%)62 (26.8)72 (29.2)77 (34.1)0.13
Adenoma characteristics (at baseline)b
Number, mean (SD)1.6 (0.9)1.6 (1.0)1.6 (1.1)0.41
Advanced adenomas, n (%)c84 (36.1)80 (34.9)89 (39.6)0.69
Proximal location, n (%)136 (54.4)135 (54.0)133 (55.0)0.74
Folic acid treatment group, n (%)149 (51.0)147 (49.7)143 (50.7)0.98
  • aN = 1 in the placebo, and N = 1 in the aspirin 81 mg/d group had missing BMI data.

  • bData available for 268, 257, 243 participants in the placebo, aspirin 81 mg/d, and aspirin 325 mg/d treatment groups, respectively.

  • cData available for 233, 229, and 229 in the placebo, aspirin 81 mg/d, and aspirin 325 mg/d treatment groups, respectively.