Recent advances: osteoporosis in the "oldest old".

Osteoporosis and related fractures disproportionately impact patients with advanced age, those with the frailty phenotype, and those with multiple comorbidities. Recent studies report a changing incidence in fracture type among the oldest old throughout the world, a finding not satisfactorily explained by advances in treatment of lifestyle factors. A growing recognition of the importance of muscle and bone interaction is leading to improved understanding of the underlying biochemical pathways linking them and new therapeutic targets. New models of care for frail older populations, particularly after hip fracture, are being developed but have been challenged to identify appropriate outcomes to target. An appreciation for the relationship between age-related comorbidities, fracture risk, and competing mortality risk is essential for practitioners caring for the oldest-old population.