A high intake of calcium may cause prostate cancer in African American men who carry a gene that increases intestinal absorption of the mineral, according to the findings of a recent study.
Gary G. Schwartz, PhD—associate professor of cancer biology, urology, and public health sciences at Wake Forest Baptist Medical Center in Winston-Salem, North Carolina—and colleagues examined vitamin D receptor (VDR) Cdx2 genotype and calcium intake in 533 African American men with prostate cancer (256 with advanced-stage disease at diagnosis and 277 with localized stage) as well as in 250 control subjects. The investigators reported in the Journal of Bone and Mineral Research that men in the highest quartile of calcium intake had a 2.2-times increased risk of localized and advanced prostate cancer compared with men in the lowest quartile.
Poor absorbers of calcium—men with the VDR Cdx2 CG genotype—were 59% less likely to have received a diagnosis of advanced prostate cancer. Among men with calcium intake below the median (680 mg/d), genetically poor absorbers (those with the G allele) had an approximately 50% decreased risk of having advanced prostate cancer compared with men who had the AA genotype, which is associated with better calcium absorption.