Osteoporosis is defined as a metabolic bone disease “characterized by low bone mass and microarchitectural deterioration of bony tissue leading to enhanced bone fragility and a consequent increase in fracture risk.
World Health Organization (WHO) definition of osteoporosis is only applicable (at present) to Bone Mineral Density (BMD) measurements using DXA (Dual X-ray Absorptiometry)
BMD as measured by DXA is expressed as absolute BMD (g/cm2) and may be designated by either the number of standard deviations (SD) from the young normal mean (T score). The WHO developed guidelines for their use in the clinical diagnosis of osteoporosis and is based on the T score, with a T score of less than -1.0 being defined as osteopenic and a T score of less than -2.5 being referred as osteoporotic.
WHO Criteria for Osteoporosis
|
Category |
Fracture Risk |
Action |
|
Normal BMD < 1 SD below youngadult reference range |
Below average |
Be watchful for “clinical triggers” |
|
Osteopenia BMD 1-2.5 SD below young adult reference range |
Above average |
Consider prevention in peri/postmenopausal in women. Be watchful for clinical triggers. Possibly repeat investigations in 2-3 years. |
|
Osteoporosis BMD > 2.5 SD below young adult reference mean |
High |
Exclude secondary causes. Therapeutic intervention indicated in most patients. |
|
Severe Osteoporosis BMD > 2.5 SD below young adult reference mean, plus 1 or more fragility fractures |
Established osteoporosis |
Exclude secondary causes. Therapeutic intervention indicated in most patients. |
References:
- World Health Organization Study Group on Assessment of Fracture Risk and Its Application to Screening and Postmenopausal Osteoporosis. Report of a WHO Study Group. Technical Report Series (No. 84), 1994
Created: May 21, 2005
