Doctors often measure serum calcium during routine blood tests.

Tag : calcium
Men in the study with high-normal levels had a threefold greaterrisk for fatal prostate cancer later in life than those with thelowest average calcium levels (but still within the normal range).

If confirmed, the finding could help identify men at risk of dyingfrom prostate cancer long before the disease is diagnosed,researchers say.

It could also lead to a simple strategy for reducing risk in menwith high-normal serum calcium.

"If we can show that men with high-normal serum calcium really arethree times as likely to develop a fatal prostate cancer, we mightbe able to alter this risk with existing drugs that have beenproven to be very safe," study researcher Gary G. Schwartz, PhD, ofWake Forest University Baptist Medical Center, tells WebMD.

Calcium and Prostate Cancer

There is good evidence that men whose diets include a lot ofcalcium or those who take calcium supplements are at increased riskfor prostate cancer.

But since there is little relationship between dietary calcium andcalcium in the blood, the new study does not address the questionof how much calcium men should eat.


"Many of your body's functions run on calcium, just like yourlaptop runs on electricity," Schwartz says. "Too little calcium inthe blood can cause convulsions and too much can lead to a coma.Since your body cannot afford to oscillate between convulsions andcoma, the range of serum calcium is tightly controlled."

Other laboratory studies suggest that calcium and parathyroidhormone -- which regulates calcium levels in the blood -- promoteprostate cancer cells' growth, the study researchers report.

In their newly published study, Schwartz and colleague Halcyon G.Skinner, PhD, MPH, of the University of Wisconsin sought to testthe laboratory association in humans.

They did this by examining data from a national health survey thatexamined participants between 1971 and 1975, known as NHANES I, andfrom a follow-up survey years later.

The analysis included 2,814 men who had their serum calcium levelsrecorded an average of 10 years before some of the men developedprostate cancer.

The follow-up survey revealed 85 cases of prostate cancer, whichincluded 25 prostate cancer deaths.

Serum calcium levels were not found to influence prostate cancerrisk overall, but men with the highest serum calcium levels weremore likely to die of the disease than men with the lowest levels.

The study appears in the September issue of the journal Cancer Epidemiology Biomarkers & Prevention.

Many Questions Remain

Schwartz and colleagues are already trying to replicate theirfindings using data from other studies that followed men over longperiods of time.

If the findings are confirmed, the researchers say parathyroidhormone or serum-calcium-lowering drugs may prove useful inprostate cancer prevention, in the same way that cholesterol-lowering drugs are used to lower heart attack and stroke risk.

But Durado Brooks, MD, MPH, of the American Cancer Society, saysthis is a big leap.

"It is important to keep in mind that there were only 25 cases offatal prostate cancer," he says. "Any attempt to assess how thisrelates to the entire male population at risk for this disease isvery preliminary."

The director of prostate and colorectal cancer for ACS, Brooks saysa greater understanding of the mechanism that might linkhigh-normal serum calcium levels with an increased risk for fatalprostate cancer would be needed before preventive treatments couldbe considered.

"We would need to understand the role of the parathyroid hormoneand vitamin D," he says. There are many, many unansweredquestions."


By Salynn Boyles
Reviewed by Louise Chang