Calcium supplements for the prevention of colorectal adenomas. Calcium Polyp Prevention Study Group.

Study answer

What this study found

Calcium carbonate reduced recurrent colorectal adenomas. The adjusted relative risk for any adenoma recurrence was 0.85 (95 percent confidence interval, 0.74 to 0.98; P=0.03), and among those who completed two follow-up colonoscopies it was 0.81 (95 percent confidence interval, 0.67 to 0.99; P=0.04). During the main risk period, the mean number of adenomas per patient was 0.55 with calcium versus 0.73 with placebo, and the ratio of the average number of adenomas was 0.76 (95 percent confidence interval, 0.60 to 0.96; P=0.02). The effect appeared early: during the first study interval, at…

Study & population

This was a multicenter, double-blind, randomized placebo-controlled trial in adults with a prior history of colorectal adenomas who were generally in good health.

Intervention

The active regimen was calcium carbonate 3 g daily, providing 1200 mg of elemental calcium, given as one tablet twice daily with meals in a double-blind design.

Key limitation

The outcome was adenoma recurrence rather than colorectal cancer or severe dysplasia, so long-term clinical benefit remains indirect.

View full study detailsView sourceOpen PDF

Original abstract