I have osteopenia. The start of osterperosis. It runs in the family. Grandmother had it , and my mom has it. I think genetics has some to do with it. I was on prolia for a few yrs and bones did well. Then my Dr retired. And I had no one to go to. Now I have a new Dr. My t score dropped a little in the 2 yrs I didn't see anyone. So now they want to prevent it from getting worse. I am taking Diet do. Only side affect so far is a terrible headache. I have been on it for 1 week so will see if it goes away.