Allan,
I saw this quite awhile ago and it may have been amended by now - and it may not be appropriate for someone with back issues - but, lifting free weights has been shown to increase bone density in senior citizens. I don't remember if the amount of the weight played a part but you might want to goggle this just to investigate.
I've also read that jaw degeneration side effects for osteoporosis drugs increase with longer lasting drugs. Taking shorter acting drugs, like once weekly is not a guarantee of no side effects but the percentages are lower than once a month which is lower than yearly.
Kind of hard to imagine how lay people investigated on their own before this age of computers.
Dale