Pacients and methods: The study included 33 women aged 43 to 60 years and 31 men aged 48 to 60 years who had elevated values of the aminoterminal telopeptide of collagen I in the organic bone matrix in the 2-hour diuresis NTx2 (6–8 hours), and diagnosed osteopenia or osteoporosis in the area of the collum femoris. Methods: Dual energy X-ray absorptiometry (DEXA), Hologic, QRD-4000, NTx: Osteomark, OSTEX,USAU-creatinine: Biotrol creatinine H.P., Biotrol Diagnostic,France. Objective: 1. To assess the statistical significance of differences in the bone mineral density measured at four standard sites of the proximal femur (ward’s, neck, trochanter major, total). 2. Assess the correlation betwen NTx2 and BMD values at individual sites (BMD ward’s, BMD neck, BMD trochanter, BMD total). Statistical analysis: Paired Wilcoxon’s test, linear regression analysis. Results: 1. Between the assessed BMD values at different sites significant differences were found. 2.A significant linear correlation was found only between pathologically raised values of NTx2 and BMD in the area of ward’s triangle in the group of men and women (r2 M = 0.53, r2 F = 0.55). Close to statistical significance was the correlation between NTx2 and the site „neck“ (r2 M = 0.43, r2 F = 0.41). The other sites of the proximal femur (trochanter, total) correlated statistically insignificantly with values of NTx2, also in both sexes. Conclusion: The contribution of the presented work is comparison ot the NTx2 levels with the densitometric sites of measurement divided with regard to the rate of bone mass loss. As between the BMD values at the four sites there are significant differences, it is important to compare the parameters of bone turnover selectively with each site of assessment. From the results ensues that in case of a single increase of urinary NTx2 pathologically reduced BMD values in the area of the ward triangle and possibly in the area neck may be assumed. NTx correlates only with the site if rapid diminution of bone mass and is thus a sensitive parameter of osteoresorption.

        Key words: osteoresorption, NTx, DEXA, collum femoris BMC