I went from oseopenia to osteoporosis in what seemed like a short time. I was a very active women, walking 4 miles a day and my bone deterioration did not make sense to me. I had a urine test to determine that I had abnormally high calcium amounts in my urine. I saw an endocrinologist who determined that one of my parathyroid glands (we have four) was overactive and needed to be removed. I am two years post surgery and due for another dexa scan and blood work to see improvement in my bone density. Last year my dexa showed a marked improvement. I am on Fosamax weekly and toleranting it well.
I refused to settle for "older people lose bone density" My mother died at age 90 and never had a broken bone or on any medication. Good luck with your decisions and testing.