Can osteoporosis come on so quickly?

I need your expert opinion on something: I'm taking weekly generic Fosamax, daily 1200 calcium, daily 1400 D, and every other week 50,000 D. I hit menoapuse about 4 years ago. I have some pretty bad arthritis in my R hip, but my L is much more normal, though not totally normal. I walk briskly and climb stairs 5 days a week.
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> 2-3 years ago I had taken the high dose D for 1 year, so my scores momentarily shot way up. Then last year my osteoporosis scores dropped 0.1 or 0.2, ending at: femoral neck -1.3, total hip -1.9, spine -1.4. My new scores--1 year later--are: femoral neck -2.8, total hip -2.0, spine -1.5.
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> That femoral score seems outrageous to me. Is it possible for a score to drop that much in 1 year? I'd have a hard time believing it if it just dropped to -1.8, let alone -2.8. I don't think they've ever dropped more than 0.4 before. I'm thinking there was some sort of mistake. What do you think?

[hoppy7]

I forgot to mention that my D level is above 30.

[Dr Arora]

Hi, Bone mineral density testing does not diagnose fractures. However, along with other risk factors you may have, it helps predict your risk of having a bone fracture in the future. Your doctor will help you understand the results. T score between -1 and -2.5 indicates the beginning of bone loss (osteopenia). T score below -2.5 indicates osteoporosis.
For consistency, before comparing results try to use the same bone density equipment, the same skeletal measures and even the same technician if possible, Ask your doctor for guidance. Then you can readily compare current to previous bone density test results. I hope this helps.