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[Osteoporosis prevention initiated with peripheral quantitative computerized tomography. Thin-layer and multi-layer
Abstract:
In a representative, randomized control group of 70 healthy confirmed postmenopausal women (natural menopause for one to four years) with an average age of 52 years, it was possible to carry out a prospective study over a period of two years, during which the bone mass was investigated regularly by means of peripheral quantitative computed tomography (pQCT, Densiscan type, thin- and multi-layer technology). The distal, purely trabecular and purely compact bone mass of the radius and tibia are measured separately. The epiphyseal trabecular bone masses of the radius and tibia (262 +/- 8 mg/cm3 and 252 +/- 8 mg/cm3, respectively) are initially homogeneous, but over time they show different rates of yearly loss of bone mass: 3.0 +/- 0.4%, compared with 1.5 +/- 0.3% (means +/- SEM). Based on the bimodal frequency distribution of the annual loss rates in the core trabecular volume of the distal radius, fast losers lose more than 3.5% per year, with no significant difference between the first and the second year of observation. Women in the quintile with the highest trabecular bone mass (328 to 458 mg/cm3 at baseline) are slow losers. These women show an absolute loss of 3 mg/cm3 per year, while the women in the lowest quintile (102 to 210 mg/cm3 at baseline), with a proportion of 64% fast losers, lose an average of 10 mg/cm3, irrespective of age, number of fertile years, age at menopause and body-mass index. The bone masses in the metaphyseal compact bone remain constant.2+ a screening program before architectural changes in trabecular bone reach a critical point (i.e. in the reversible stage of osteoporosis), these women can be reliably identified within six months and monitored effectively and economically. With the general risk factors of postmenopausal osteoporosis an individual's risk of rapid bone loss cannot be predicted or determined; therefore, the precise measurement of purely trabecular bone is indispensable.