Researchers analyzed data from 913 patients enrolled in the Calcium Polyp Prevention Study, a randomized, double-blind, placebo-controlled trial - meaning that neither the patient nor the those following them knew which treatment they were receiving. Patients took either a 1200 mg calcium supplement or a placebo and had a follow-up colonoscopy one and four years after enrolling in the trial.

The results showed that supplemental calcium slightly decreased the risk of all types of colorectal polyps, but effect was greatest for the most advanced colorectal lesions. There was also some evidence that a diet high in fiber and low in fat increased the preventive effect of calcium, but these results were not statistically definitive.

The research was supported by the National Cancer Institute, the National Institutes of Health and the Department of Health and Human Services. Other Dartmouth Medical School researchers who contributed to this study include Bernard Cole, PhD, Margaret Karagas, PhD, Michael Beach, MD, PhD, Loretta Pearson, M. Phil. and Richard Rothstein, MD.

In addition to Dartmouth-Hitchcock Medical Center, the other participating centers were the Cleveland Clinic Foundation, the University of Southern California School of Medicine, the University of Minnesota, the University of North Carolina School of Medicine and Emory University.

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