Noninvasive estimation of bone mass in ancient vertebrae

Abstract

Histomorphometry is useful in the as-sessment of trabecular bone mass (TBM), and thus, in theestimation of the prevalence and intensity of osteopenia inancient population groups. However, it is a destructivemethod. It is therefore necessary to explore the accuracy ofnondestructive approaches, such as radiography, bonemineral density (BMD) assessed by double-energy X-rayabsorptiometry (DEXA), bone density (BD), or optical den-sity (OD) in the diagnosis of osteopenia. We selected 51vertebrae out of a total sample composed of 333 T12, L1,and L2 vertebrae belonging to adult pre-Hispanic inhab-itants from El Hierro. These vertebrae underwent histo-morphometrical analysis, a fine-grained film radiographywith assessment of trabecular pattern following standardmethods, OD, DEXA-assessed BMD, and BD. The pres-ence of biconcave vertebrae and wedge-shaped vertebraewas also assessed by measuring anterior height (a), pos-terior height (p), and height at the middle point of thevertebral body (m), and further calculating the indices2m/(a p) (“spine score”) and a/p. Significant correlationswere observed between TBM and BMD (r 0.43), TBMand BD (r 0.49), TBM and OD (r 0.52), BMD and OD(r 0.51), and BMD and BD (r 0.36), but not betweenTBM and the indices 2m/(a p) and a/p. In the stepwisemultiple correlation analysis between TBM and BMD,BD, and OD, OD entered into first place and BD intosecond place, whereas BMD became displaced; the multi-ple correlation coefficient was 0.63, with a standard errorof 3.78. A BMD greater than 0.60 g/cm2, or a bone densitygreater than 0.60 g/cm3, excluded osteopenia (TBM 15%)with a specificity greater than 90%, whereas a BMD valueless than 0.35 g/cm2, a BD less than 0.35 g/cm3, or opticaldensity 1.6 excluded a normal bone mass (TBM 20%)with a specificity greater than 90%. Based on radiographiccriteria on the total sample, we also conclude that theoverall prevalence of vertebral fractures in the adult pre-Hispanic population of El Hierro of any age is 7.5%. Am JPhys Anthropol 125:121–131, 2004.