Table 3.

8-OH-dG labeling in colorectal crypts stratified by sex, baseline OBS, and baseline colorectal crypt VDR expression

nAbsolute treatment effect*PRelative effectP§
Mean (SE)
Women
    Placebo701.00
    Calcium7−577.4 (714.7)0.430.75
    Vitamin D6253.3 (729.4)0.731.11
    Calcium + vitamin D7508.3 (714.7)0.481.23
Men
    Placebo1401.00
    Calcium14−526.1 (422.9)0.220.80
    Vitamin D16−959.0 (414.3)0.020.62
    Calcium + vitamin D14−26.2 (422.9)0.950.990.35
High OBS
    Placebo801.00
    Calcium13−898.0 (594.8)0.140.67
    Vitamin D12−879.0 (599.7)0.150.67
    Calcium + vitamin D11−120.5 (615.1)0.850.94
Low OBS
    Placebo1301.00
    Calcium825.1 (509.7)0.961.02
    Vitamin D9−421.6 (498.6)0.400.81
    Calcium + vitamin D10383.2 (478.1)0.431.190.71
High baseline colorectal crypt VDR expression
    Placebo1001.00
    Calcium10−827.0 (477.0)0.090.68
    Vitamin D8−1,626.1 (506.7)0.0030.46
    Calcium + vitamin D11−443.6 (462.5)0.340.83
Low baseline colorectal crypt VDR expression
    Placebo801.00
    Calcium9264.6 (532.4)0.621.11
    Vitamin D1363.5 (498.8)0.901.00
    Calcium + vitamin D81,420.4 (551.5)0.021.750.05
  • *Absolute treatment effect = [(treatment group follow-up) − (treatment group baseline)] − [(placebo group follow-up) − (placebo group baseline)].

  • P value for difference between each active treatment group and placebo group from repeated-measures MIXED model.

  • Relative effect = [(treatment group follow-up) / (treatment group baseline)] / [(placebo follow-up) / (placebo baseline)]; interpretation similar to that for an odds ratio (e.g., a relative effect of 1.7 indicates a proportional increase of 70% in the treatment group relative to that in the placebo group).

  • §P value for the category-intervention interaction term.

  • OBS and baseline colorectal crypt VDR expression were dichotomized into high/low categories based on the median value in all study participants at baseline. OBS was calculated as described in Statistical Analysis. VDR was detected immunohistochemically and then its labeling optical density was quantified by image analysis (see text for details).