Calcium Supplementation and Colorectal Adenomas

Experimental evidence suggests that calcium may have anticarcinogenic effects on colorectal mucosa. In a previously published randomized trial, 930 patients with recently removed colorectal adenomas received either calcium supplements (1.2 g of elemental calcium daily) or placebo for 4 years. Calcium supplementation was associated with a modest but statistically significant 15% reduction in recurrent adenomatous polyps (Journal Watch Jan 22 1999).

Now, the researchers report on 597 participants who underwent at least one additional colonoscopy during an average of 7 years of post-trial follow-up. About half the patients in both the original calcium and placebo groups used calcium supplements after the trial, but accurate information on dose …