Misinterpretation of Osteodensitometry With High Bone Density

Abstract

Osteodensitometry is increasingly used to identify low bone density resulting from osteoporosis. The universally accepted World Health Organization (WHO) criteria for assessing bone mineral density (BMD) contrasts individual T-scores to peak BMD in healthy adult control populations. In this scheme, "osteoporosis" refers arbitrarily to T-values below -2.5, "osteopenia" to values between -1.0 and -2.5, and "normal" to values above -1.0. Although individually rare, numerous conditions cause supranormal BMD in children and adults. Increasingly, elevated BMD is detected by osteodensitometry, especially dual-energy X-ray absorptiometry. Illustrated here, the absence of upper limits for BMD in the WHO criteria jeopardizes recognition of high-BMD disease for all age groups. This oversight requires correction using Z-scores.