Osteoporosis and osteopenia by BMD T-score (WHO 1994)
who1994_osteoporosis@1.0Normal. A value for BMD or BMC within 1 SD of the young adult reference mean. Low bone mass (osteopenia). ... more than 1 SD below the young adult mean but less than 2.5 SD below this value. Osteoporosis. ... 2.5 SD or more below the young adult mean.
World Health Organization, Assessment of fracture risk and its application to screening for postmenopausal osteoporosis: report of a WHO Study Group (WHO Technical Report Series 843) (1994) · Section 2.1 Definitions, printed pages 5-6 (PDF pages 11-12) · source
Contested: T-score categories were defined for postmenopausal (white) women; their use in men and other populations relies on later bodies (e.g. ISCD), which were not opened; the report itself calls cut-off values 'somewhat arbitrary'.
Not encoded: Men, premenopausal women and children: the report states the categories for women; not assessable. The site, technique, equipment and reference population (the report notes individuals 'will be categorized differently according to the site and technique') are not checked; the lowest T-score passed is used. Fracture risk (e.g. FRAX) is not assessed.