Serum Calcium Concentration and Prostate Cancer Risk: A Multicenter Study

Abstract

This study sought to further evaluate the possible effects of serum calcium level on prostate cancer (PC) risk, with considering the age, body mass index (BMI), and sex steroid hormones. Using data from a prospective multicenter study, serum calcium concentration, as well as thorough demographic and medical characteristics, were determined in 194 cases with newly diagnosed, clinicopathologically confirmed PC and 317 controls, without any malignant disease, admitted to the same network of hospitals. Serum total and ionized calcium levels were categorized into tertiles. Multivariate logistic regression model was used to estimate odds ratios (OR) and corresponding 95% confidence intervals (CI) after adjustment for major potential confounders, including age, BMI, smoking, alcohol, education, occupation, marital status, family history of PC, and sex hormones level. The mean serum calcium level (±SD) in case and control groups was 9.22 (±0.46) mg/dl and 9.48 (±0.51) mg/dl, respectively (P < 0.001). After adjustment for mentioned confounders, a significant trend of decreasing risk was found for serum total calcium concentration (OR = 0.27, 95% CI = 0.12–0.59, comparing the highest with the lowest tertile) and ionized calcium (OR = 0.25, 95% CI = 0.10–0.58). An increase of 1 mg/dl in serum calcium level was associated with a significant decrease in PC risk (OR = 0.52; 95% CI = 0.34–0.76). Our findings reveal the inverse association between serum total and ionized concentrations and PC risk, which supports the hypothesis that calcium may protect against PC. Furthermore, no evidence was found regarding age, BMI, and sex steroid hormones to modify the association between serum calcium and PC risk.

ACKNOWLEDGMENTS

The authors would like to thank the nursing, secretary, and administrative staff of the Urology Research Center, Sina Hospital, especially Mrs. F. Heydari and Mrs. G. Abdi for her excellent cooperation in the data entry. Patient recruitment has been the dedicated collaboration of the following contributors: Dr. M. Lotfi, Dr. MA. Amirzargar, Dr. H. Mazdak, Dr. A. Roshani, and Dr. A. Kheirollahi. We are also grateful to Ms. B. Pourmand and Ms. M. Tayebi for their helpful assistance in preparation of the manuscript. This study was supported in part by a grant from the Tehran University of Medical Sciences (No. 2812). The abstract of this article was presented at 108th Annual Meeting of American Urological Association (May 2012), Atlanta, GA.