. Author manuscript; available in PMC: 2024 Feb 23.

Published in final edited form as: Ann Intern Med. 2023 Jan 3;176(2):224–238. doi: 10.7326/M22-1034

Appendix Table 1.

Definitions of Low Bone Mass and Osteoporosis

Condition	Definition
Low bone mass (osteopenia)	A BMD value at the femoral neck, the lumbar spine, or both that is between 1 and 2.5 SDs below the mean BMD value for a young woman (18, 92, 93)
Osteoporosis	A BMD value at the femoral neck, the lumbar spine, or both that is ≥2.5 SDs below the mean BMD value for ayoung woman; osteoporosis may be diagnosed in postmenopausal women and in men aged ≥50 y ifthe T-score forthe lumbar spine, total hip, or femoral neck is −2.5 or less (in certain circumstances, the 33% radius [also called the 1/3 radius] may be used) (18, 92, 93) The reference standard from which the T-score is calculated is the White female population aged 20–29 y in the NHANES III database A uniform White (not adjusted for race) female reference was used for men in all ethnic groups

Condition

Definition

Low bone mass (osteopenia)

A BMD value at the femoral neck, the lumbar spine, or both that is between 1 and 2.5 SDs below the mean BMD value for a young woman (18, 92, 93)

Osteoporosis

A BMD value at the femoral neck, the lumbar spine, or both that is ≥2.5 SDs below the mean BMD value for ayoung woman; osteoporosis may be diagnosed in postmenopausal women and in men aged ≥50 y ifthe T-score forthe lumbar spine, total hip, or femoral neck is −2.5 or less (in certain circumstances, the 33% radius [also called the 1/3 radius] may be used) (18, 92, 93)
The reference standard from which the T-score is calculated is the White female population aged 20–29 y in the NHANES III database
A uniform White (not adjusted for race) female reference was used for men in all ethnic groups

BMD = bone mineral density; NHANES III = Third National Health and Nutrition Examination Survey.