NEW YORK (Reuters Health) – New evidence indicates that elevated serum levels of ionized calcium may predict the risk of death from prostate cancer. If verified in future prospective studies, levels of ionized calcium in serum could assist physicians and patients in making decisions regarding treatment.

In a previous analysis of data from the National Health and Nutrition Examination Survey (NHANES I) study, Dr. Halcyon G. Skinner, at the University of Wisconsin-Madison, and Dr. Gary G. Schwartz at Wake Forest University in Winston-Salem, North Carolina, observed a link between elevated serum calcium and risk of fatal prostate cancer.

For their current report in the February issue of Cancer Epidemiology, Biomarkers & Prevention, the researchers examined associations between total and ionized serum calcium and prostate cancer fatalities among 6710 men examined between 1988 and 1994 for the NHANES III, which was linked to the National Death Index.

During a mean of 5.3 years of follow-up, there were 25 prostate cancer deaths. Average age at death was 78.1 years.

Compared with men in the lowest tertile, men in the highest tertile of total serum calcium had a relative risk for prostate cancer mortality of 2.02, after adjusting for sociodemographics, body mass index, and general health status.

The relative risk associated with ionized serum calcium corrected for serum pH was 3.12. After excluding three cases that died within the first 3 years of follow-up, the relative hazard in the highest tertile was 4.65.

In a Wake Forest press release, Dr. Schwartz comments that many men with prostate cancer are treated unnecessarily. “These new findings, if confirmed, suggest that men in the lower end of the normal distribution of ionized serum calcium are three times less likely than men in the upper distribution to develop fatal disease.”

“These men may choose to delay treatment or perhaps defer it altogether,” Dr. Schwartz added.