Calcium intake may protect against cancer
Source: Author: Laurie Barclay, MD & Hien T. Nghiem, MD Calcium intake may protect against cancer, particularly gastrointestinal tract cancer, according to the results of a prospective study reported in the February 23 issue of the Archives of Internal Medicine. "Dairy food and calcium intakes have been hypothesized to play roles that differ among individual cancer sites, but the evidence has been limited and inconsistent," write Yikyung Park, ScD, from the National Cancer Institute in Bethesda, Maryland, and colleagues. "Moreover, their effect on cancer in total is unclear." In the National Institutes of Health-AARP (formerly known as the American Association of Retired Persons) Diet and Health Study, the investigators evaluated the association of dairy food and calcium intakes with incidence of total cancer and cancer at individual sites. A food frequency questionnaire was used to determine intakes of dairy food and calcium from foods and supplements. Linkage with state cancer registries allowed identification of incident cancer cases. Relative risks and 2-sided 95% confidence intervals (CIs) were determined with a Cox proportional hazard model. During follow-up (average, 7 years), 36,965 cancer cases were identified in men and 16,605 in women. In men, calcium intake was not associated with total cancer. However, calcium intake was nonlinearly associated with total cancer in women, with the risk decreasing up to approximately 1300 mg/day but with no further risk reduction above those levels. Dairy food and calcium intakes were inversely associated with cancers of the digestive system in both men and women. Multivariate relative risk [...]