Too much calcium may increase risk of prostate cancer

Washington, Sep 3 : Too much calcium in the bloodstream may signal increased risk of fatal prostate cancer, according to a new analysis from Wake Forest University and University of Wisconsin.

"We show that men in upper range of the normal distribution of ... calcium subsequently have an almost three-fold increased risk for fatal prostate cancer," said Gary G. Schwartz, associate professor of cancer biology at Wake Forest and co-author of the study.

Co-author Halcyon G. Skinner of the School of Medicine and Public Health, University of Wisconsin, stressed there is "little relationship between calcium in the diet and calcium in serum. So men needn't be concerned about reducing their ordinary dietary intakes of calcium."

Schwartz and Skinner analysed results of 2,814 men who participated in the National Health and Nutrition Examination Survey (NHANES-1). Measurement of the amount of calcium in the bloodstreams was determined an average of 9.9 years before prostate cancer was diagnosed.

The researchers focused on the 85 cases of prostate cancer and 25 prostate cancer deaths among the 2,814 men and divided the group into thirds, based on the serum calcium level. "Comparing men in the top third with men in the bottom third, we found a significantly increased hazard for fatal prostate cancer.

"To our knowledge, this is the first study to examine prostate cancer risk in relation to serum calcium," Schwartz and Skinner wrote. "These results support the hypothesis that high serum calcium, or a factor strongly associated with it, such as high serum parathyroid hormone, increases the risk for fatal prostate cancer."

Too little calcium in blood can cause uncontrolled muscular convulsions or contractions. Too much calcium can cause a coma. "Your body obviously cannot afford to oscillate between convulsions and coma, so the range of serum calcium is tightly controlled." the authors said.

The research appears in the September issue of Cancer Epidemiology, Biomarkers & Prevention, a journal of the American Association for Cancer Research.