What causes high blood calcium?

This answer is provided by Dr. James Norman of the Norman Parathyroid Clinic:

There is a lot written about high calcium being caused by cancer, however, this is not very common. Let us say that again... It is very RARE for high blood calcium to be due to cancer. We know that if you search "high calcium" on the Internet you will find lots of web sites that talk about high calcium being caused by cancer...but relax, that's just because there are a LOT more websites in the world discussing cancer than there are websites dedicated to parathyroid disease. HOWEVER, if you are sitting at a computer researching about your own high calcium, then you are almost guaranteed to NOT have cancer. Keep reading and you will see that people who are not in the hospital dying of cancer and have a high calcium on a blood test almost never have cancer and almost always DO have hyperparathyroidism. This must be fixed, but it is not cancer... its caused by a hormone problem. 

For more information, go to:  http://parathyroid.com/high-calcium.htm