Glossary

Bone mineral density (BMD)

a measure of bone density that reflects the strength of bones as represented by calcium content. BMD is expressed as the amount of mineralized tissue in the area scanned (g/cm2)

Bone modelling

skeletal processes that occur during growth to increase bone mass

Bone remodelling

the life-long dual processes of bone formation and resorption after cessation of growth

Bone resorption

the loss of bone through physiological or pathological means

DXA

dual energy X-ray absorptiometry (DXA) or bone-density scan that is used to diagnose osteoporosis

Fragility fracture

a fracture resulting from trauma that is equivalent to or less than a fall from a standing position

FRAT

the Fall Risk Assessment Tool, which is a validated tool for assessing the risk for falling

FRAX®

the WHO Fracture Risk Assessment Tool

Kyphosis

a condition (commonly known as ‘Dowager’s hump’) that causes excessive curvature of the upper spine. In patients with osteoporosis, kyphosis can occur as a consequence of compression fractures of the vertebrae

Osteoblasts

promote bone formation by creating a protein matrix consisting primarily of collagen, which is calcified to produce mineralized bone

Osteoclasts

promote bone resorption by stimulating the production of acid and enzymes that dissolve bone mineral and proteins

Osteomalacia

the softening of bones through impaired mineralization of the bone matrix, most often caused by severe vitamin D deficiency

Osteopenia

low BMD, which for postmenopausal women and men aged ≥50 years is between 1.0 and 2.5 standard deviations below the mean for young normal adults (T-score between –1.0 and –2.5)

Osteoporosis

a chronic, progressive disease that is characterized by compromised bone strength, which comprises both bone mass and bone quality, and is associated with fragility fractures. Postmenopausal women and men aged ≥50 years can be diagnosed with osteoporosis when their hip or spine BMD is 2.5 or more standard deviations below the mean for young normal adults (T-score ≤–2.5)

T-score

the number of standard deviations above or below the mean BMD in a population of young normal adults of the same sex and ethnicity

Z-score

 the number of standard deviations above or below the mean BMD for people of the same age, sex and ethnicity