Dear Joann, You have been a jewel providing me with all this info. My bone density test dropped to the bottom in one year after taking prolia for two years without calcium. I take VitD3, 4000 units per day but that did not seem to help. I don't know what causes the sudden drop of my DEX. Checked my parathyroid was normal my calcium levels normal so I don't know what to do. I feel lost and afraid to stop the prolia.