World Health Organization (WHO) definitions for postmenopausal women (or older men)
Normal = T score ≥ -1.0
Osteopenia = -1.0 > T score > -2.5
Osteoporosis = T score ≤ -2.5
BMD Reporting in Females Prior to Menopause and in Males Younger Than Age 50
Z-scores, not T-scores, are preferred
Z-score < -2.0
“below the expected range for age”
Z-score > -2.0
“within the expected range for age”
Osteoporosis cannot be diagnosed in men under age 50 on the basis of BMD alone. The WHO diagnostic criteria may be applied to women in the menopausal transition.