Table 3.

Effect of study treatment on the risk for any and advanced serrated polyps

PPSn TotalSerrated polypsP for the differenceAdvanced serrated polypsP for the difference
LeftRightLeftRight
n CasesRR* (95% CI)n casesRR* (95% CI)n CasesRR* (95% CI)n CasesRR* (95% CI)
Antioxidant PPS
    Placebo207521.0281.022
    β-Carotene208470.90 (0.63-1.28)170.64 (0.35-1.15)10
    Vitamins C and E220581.06 (0.76-1.48)180.62 (0.35-1.10)02
    β-Carotene, C, E198360.73 (0.50-1.07)150.60 (0.32-1.10)0.3203
Calcium PPS
    Placebo4591351.0491.041.081.0
    Calcium carbonate4541070.81 (0.65-1.01)440.93 (0.63-1.38)0.5371.83 (0.52-6.50)50.63 (0.97-1.10)0.16
Aspirin/folate PPS
    Placebo363851.0411.0231.0221.0
    Aspirin 81 mg366670.77 (0.58-1.04)240.56 (0.34-0.91)151.32 (0.76-2.30)110.60 (0.31-1.15)
    Aspirin 325 mg355850.94 (0.71-1.24)250.58 (0.36-0.95)0.14350.78 (0.41-1.48)150.50 (0.25-1.01)0.03
    Placebo4861011.0381.0311.0151.0
    Folate 1 mg5011181.10 (0.87-1.39)501.26 (0.84-1.89)0.59330.98 (0.61-1.57)322.07 (1.14-3.77)0.10
  • Abbreviation: PPS, polyp prevention study.

  • *Relative risk adjusted for age, sex, center, time since randomization, and smoking status.