The authors examined 56 postmenopausal women aged 43 to 68 years and 28 men aged 40 to 66 years with osteopenia or osteoporosis. Every patient was subjected to four densitometric examinations: 1. ultrasonometry (USM) of the left calcaneum (parameter: stiffness index - S, apparatus: Achilles plus, LUNAR, USA), 2. dual-energy X-ray absorptiometry (DEXA) of the left calcaneum (parameter: bone mineral density - BMDp v g of Ca hydroxyapatite/cm 2 , apparatus: PIXI, LUNAR, USA), 3. quantitative computed tomography (QCT) of the trabecular portion and cortical portion of the vertebra L1 (parameter: BMDL1 , BMDCL1 in mg of Ca hydroxyapatite/cm 3 , apparatus: CT, Somatom plus, Siemens, GFR). Objective: 1. To compare assessed absolute values and T-score values of three densitometers. 2. To assess which of the densitometers assessing the peripheral skeleton provides better information on the prevalence of osteoporosis in the axial skeleton. Statistical analysis: Stochastic-stochastic linear regression analysis. Results: 1. In the group of men and women there was a statistically more significant relationship between BMDL1 - S (rM = 0.66 rf = 0.64) than between BML1 - BMDp (rM = 0.60, rf = 0.57). 2. Values of the T-score assessed by different densitometers differed significantly in the group of men and women, 3. Among values of the T-score obtained from measurements of the calcaneum the values of the T-score for BMDL1 (x = -2.56 SD) were closest to the T-score for S (x = -1.50 SD) in the group of postmenopausal women. Conclusion: 1. In postmenopausal women the T-score for the calcaneum provides information on the prevalence of osteoporosis in the axial skeleton better than the T-score for BMDp. 2. When the values of the T-score equal or are smaller than -0.78 SD in men and the T-score is equal or is smaller than 0.75 SD (< 0.62 SD) in women for BMDp (S) there are preprequisites for the finding of osteoporosis of the vetebrae assessed by QCT. The mentioned conclusions do not have general validity and apply only to assessments made on non-reference densitometers used in the authors’ work. They draw attention to the fact that densitometries for measurements on the peripheral skeleton are not an alternative but a supplementary examination for densitometry of the axial skeleton.

        Key words: bone densitometry - ultrasonometry of the calcaneum - DEXA of the calcaneum - QCT of vertebrae