Table 1.

Selected baseline characteristics of the study participants (n = 92)

CharacteristicsTreatment groupP*
Placebo (n = 23)Calcium (n = 23)Vitamin D (n = 23)Calcium + vitamin D (n = 23)
Demographics
Age, y58.5 (8.2)61.9 (8.2)60.2 (8.1)62.1 (7.5)0.39
Men (%)707070701.00
White (%)748365610.13
College graduate (%)656457450.53
Medical history
History of colorectal cancer in 1° relative (%)173017130.60
Take NSAID regularly (%)22139170.77
Take aspirin regularly (%)225230570.05
Habits
Current smoker (%)94000.61
Take multivitamin (%)303026390.86
Physical activity (MET/d)14.5 (11.6)17.9 (17.9)20.7 (12.0)20.9 (14.7)0.43
Mean dietary intakes
Total energy intake, kcal/d1,596 (528)1,788 (691)1,848 (821)1,845 (752)0.59
Total calcium§, mg/d618 (308)746 (335)843 (526)824 (714)0.41
Total vitamin§ D, IU/d277 (230)336 (202)360 (317)415 (316)0.40
Total fat, g/d67 (32)72 (35)70 (32)74 (28)0.59
Dietary fiber, g/d15 (7)17 (9)18 (9)17 (11)0.97
Alcohol, g/d9 (14)11 (15)14 (18)10 (20)0.84
Anthropometrics
Body mass index (BMI), kg/m230.6 (7.2)29.4 (5.5)28.9 (5.6)31.6 (6.0)0.44
Waist-to-hip ratio0.9 (0.1)0.9 (0.1)0.9 (0.1)1.0 (0.1)0.17
Adenoma characteristics
Multiple adenomas (%)172239260.45
Large adenoma ≥ 1 cm (%)19321790.32
Villous/tubulovillous adenoma** (%)49941.00
Mild dysplasia†† (%)100961001001.00
Baseline vitamin D serum levels
25-OH-vitamin D (ng/mL)20.44 (7.5)25.67 (7.6)21.04 (8.3)20.93 (9.6)0.12
1,25-(OH)2-vitamin D (pg/mL)39.2 (12.2)45.4 (35.3)44.5 (22.6)37.9 (12.5)0.60

NOTE: Data are given as means (SD) unless otherwise specified.

  • *By Fisher's exact test for categorical variables, and by ANOVA for continuous variables.

  • Nonsteroidal anti-inflammatory drug.

  • At least weekly.

  • §Diet plus supplements.

  • At least two adenomas.

  • At least one large adenoma.

  • **At least one villous or tubulovillous adenoma.

  • ††Mild dysplasia as highest degree of dysplasia in any adenoma.