A high bone mineral density is one where the bone mineral density (BMD) is usually greater than two standard deviations above what is expected for age. This can sometimes be seen on routine DEXA scan assessment. Some authors advocate a definition of a high BMD where the Z-score is greater than +2.5 to highlight to clinicians the potential for underlying pathology 2.
Pathology
A high bone mineral density may result from a number of varied mechanisms. It may be associated with conditions with increased fracture risk, or artifacts that themselves do not affect fracture risk but may mask low bone mineral density or in situations where fracture risk may be reduced but other comorbidities may occur.
Etiology
Focal
Generalized
- for adults: see generalized increased bone density in adults
- for children: see generalized increased bone density in children
Generalized acquired
- fluorosis
- renal osteodystrophy
- acromegaly
- hepatitis C associated osteosclerosis (HCAO)
- myelofibrosis
- mastocytosis
- estrogen implants
Generalized inherited
- decreased bone resorption
- increased bone formation
- LRP5 high bone mass
- sclerosteosis
- van Buchem disease
- unexplained high bone mass
Artifactual causes
- osteoarthritis: degenerative disease
- diffuse idiopathic skeletal hyperostosis
- ankylosing spondylitis
- vertebral fractures
- extrinsic artifact