I can definitely see alternative methods when you have osteopenia, and particularly if you are pre-menopausal and still have estrogen floating around. Good chance with diet and exercise to maintain what you have and slow down the bone loss overtime. Once you are already osteoporotic, not so easy.
I think there must be with this condition/disease greater emphasis on prevention. There should be public health problems targeting children, teenagers and young adults while they are building their bone so that they achieve an excellent peak bone mass.