[Normal ranges of bone mineral content of the distal radius determined with single photon absorptiometry. Study of 1521 cases]

The normal ranges and mathematical equations of bone mineral content (BMC), normalized to radial width (BMC/W) vs. age at the distal radius, were obtained by single photon absorptiometry (SPA), and compared in two different normal populations, one of postmenopausal females and the other of control males. The female population included 1359 postmenopausal women, aged 35 to 75 years; normal control males were 162, of the same age. The results obtained in the two groups of patients show a statistically significant (p less than 0.001) correlation between age and BMC/W, expressed in a polinomial third-degree regression. The slope of the regression curves is quite different between males and females: the mean decrement, evaluated from regression polinomial fits, results 0.5% per year for normal females, and 0.3% per year for normal males. The maximum decrement (1% per year) is observed at the mean age of 51 years, which is the average age of peri-menopausal women in our province (Ferrara). The authors believe SPA to be a simple and reliable technique in measuring peripheral bone loss rate. SPA may be useful in the diagnosis and treatment of postmenopausal women, but is not recommended in the short-term follow-up of osteoporosis.