Osteoporosis is quite commonly paired up with MS, particularly in women. It leads to frequent bone fractures, spinal deformities, and other unwelcome developments. I've known people with osteoporosis who broke a bone by just standing up from a sitting position.
For years I've been resisting the frequently offered drugs for this condition. After all, I had only osteopenia according to those bone-density tests, and that is just a condition that is on its way to becoming osteoporosis, maybe.
However, my spinal curvature (I don't like to call it a dowager's hump for some reason) is so bad now that it's very difficult for me even to reach my mailbox or the peephole in my front door. So I've opted to start on Fosamax (alendronate sodium) (70mg once a week), one of the bisphosphanates--osteoporosis drugs that actually build back some of the bone that has disappeared.
I'm about to take my second Fosamax and so far, so good. It has its risks, but then so does osteoporosis.