Jan Bruder, MD, Assistant Professor and Director of Osteoporosis Metabolic Bone Clinic, Division of Endocrinology, University of Texas Health Science Center, Department of Medicine, San Antonio, TX, USA.
Osteoporosis is a disease characterized by low bone mass and bone strength, resulting in an increase in bone fragility and susceptibility to fractures.1 It is asymptomatic prior to fractures, which most commonly occur in the vertebral body, hip and forearm.
Dual energy x-ray absorptiometry is the technology used to measure bone mineral density at the sites of interest. This technology has revolutionized our approach to this disease. In 1994, the World Health Organization (WHO) published diagnostic guidelines for osteoporosis, which are based on an individual's bone mineral density (BMD) according to a T-score.2 The T-score is defined as the number of standard deviations (SD) above or below the mean BMD at peak bone mass at age 30 years. A T-score of -2.5 or lower defines osteoporosis. At risk individuals can now be diagnosed early, thereby allowing the use of highly effective interventional strategies which prevent further bone loss and potentially debilitating fractures. Unfortunately, currently once significant bone mass has been lost, there are no commercially available therapies that are proven to increase bone density. This will likely change in the next few years.