 Introduction/Background Osteoporosis is a systemic skeletal condition characterized by reduced bone density and deterioration of osseous tissue that leads to bone fragility and increased susceptibility to fracture [1]. Bone strength is a product of bone mineral density (BMD), a quantifiable property, and the integrity of trabecular microarchitecture. Currently, the consensus approach to screening and monitoring osteoporosis in the population is measurement of BMD, which is an effective way to identify patients who are at risk for fracture. An estimated 10.2 million adults in the United States >50 years of age have osteoporosis; however, the aging of the population is projected to increase this number by >30% by 2030, even though most experts agree that osteoporosis is generally underdiagnosed [2,3]. Approximately one-half of women and nearly one-third of men >50 years of age will sustain an osteoporotic fracture [4]. The yearly number of fractures is projected to increase from 1.9 million in 2018 to over 3.2 million fractures by 2040, with direct medical costs increasing from $48.8 billion to $81.5 billion during the same time range [5,6]. When indirect societal costs are also considered, the total projected cost could exceed $95 billion by 2040 [6]. Osteoporotic fractures are associated with subsequent fractures and premature mortality. In patients who have sustained a fracture, 10% will have another within 1 year, 18% within 2 years, and 31% within 5 years [7]. The first-year mortality rate is 20%, but there is also a 3- to 4-fold increased risk of mortality in the subsequent 5 years following any fragility fracture [8]. It is highest after sustaining a hip fracture, where there is a 1-year mortality of 24% in women and 38% in men [9]. Fragility fractures are also associated with a decrease in quality of life, diminished physical function, and reduced independence [10].
Osteoporosis and Bone Mineral Density.  Introduction/Background Osteoporosis is a systemic skeletal condition characterized by reduced bone density and deterioration of osseous tissue that leads to bone fragility and increased susceptibility to fracture [1]. Bone strength is a product of bone mineral density (BMD), a quantifiable property, and the integrity of trabecular microarchitecture. Currently, the consensus approach to screening and monitoring osteoporosis in the population is measurement of BMD, which is an effective way to identify patients who are at risk for fracture. An estimated 10.2 million adults in the United States >50 years of age have osteoporosis; however, the aging of the population is projected to increase this number by >30% by 2030, even though most experts agree that osteoporosis is generally underdiagnosed [2,3]. Approximately one-half of women and nearly one-third of men >50 years of age will sustain an osteoporotic fracture [4]. The yearly number of fractures is projected to increase from 1.9 million in 2018 to over 3.2 million fractures by 2040, with direct medical costs increasing from $48.8 billion to $81.5 billion during the same time range [5,6]. When indirect societal costs are also considered, the total projected cost could exceed $95 billion by 2040 [6]. Osteoporotic fractures are associated with subsequent fractures and premature mortality. In patients who have sustained a fracture, 10% will have another within 1 year, 18% within 2 years, and 31% within 5 years [7]. The first-year mortality rate is 20%, but there is also a 3- to 4-fold increased risk of mortality in the subsequent 5 years following any fragility fracture [8]. It is highest after sustaining a hip fracture, where there is a 1-year mortality of 24% in women and 38% in men [9]. Fragility fractures are also associated with a decrease in quality of life, diminished physical function, and reduced independence [10].