BETHESDA, MD. — Calcium obtained from dietary sources, but not calcium supplements, may be associated with a protective effect against the development of colon polyps, Janet A. Tooze, Ph.D., reported at the annual meeting of the American Society of Preventive Oncology.
In a retrospective study, 598 participants aged 40–69 years completed a food frequency questionnaire in 1992–1994 when they were participating in the Insulin Resistance Arteriosclerosis Study. They later underwent colonoscopy during 2002–2004.
Overall, people in the three highest quartiles of dietary calcium intake were about 2–3 times more likely to be free of colon polyps than people in the lowest quartile. Supplemental calcium use did not significantly affect the risk for colon polyps. The cutoff for the lowest quartile of calcium intake was about 500 mg per day, according to Dr. Tooze, of Wake Forest University, Winston-Salem, N.C.
One or more polyps were found in 49% of subjects, including 32% with an adenoma or hyperplastic polyp, 23% with any adenoma, and 6% with an advanced adenoma (villous features or size larger than 1 cm).
The prevalence of supplemental calcium use was not high—only 15%, according to the researchers.
“The source of calcium may be related to the protective effect for polyp development and adenoma development,” they wrote in their poster presented at the meeting.