Application of the 1994 WHO Classification to Populations Other Than Postmenopausal Caucasian Women: The 2005 ISCD Official Positions

In 2003, the International Society for Clinical Densitometry (ISCD) developed Official Positions regarding the applicability of the World Health Organization (WHO) classification of bone mineral density to populations other than postmenopausal women. However, these prior Official Positions do not fully address bone mineral density reporting in females prior to menopause, men, and non-whites. During the 2005 ISCD Position Development Conference, members of the ISCD Expert Panel in conjunction with the ISCD Scientific Advisory Committee re-addressed these topics and, based upon stringent reviews of best available data, developed ISCD Official Positions that provide greater specificity and clarification with respect to the following: (1) the utility of the term 'osteopenia'; (2) utilization of T- and Z-scores for bone mineral density reporting; (3) when to apply the WHO densitometric classification; and (4) which normative database(s) should be used for non-white individuals. Briefly, the term “osteopenia” is retained, but 'low bone mass' or 'low bone density' is preferred. Z-scores, not T-scores, are preferred in females prior to menopause and males under age 50. In these individuals, a Z-score of −2.0 or lower is defined as “below the expected range for age” and a Z-score above −2.0 is “within the expected range for age.” T-scores are preferred and the WHO classification is applicable for postmenopausal women and men age 50 and older. These Official Positions, rationale and evidence are discussed in the following report.