Osteoporosis in a female population from Bratislava--age-related BMD changes

We analysed 498 women (n=498) in a Bratislava (BA) population aged 21 to 90. We measured bone mineral density (BMD) in the proximal femur with one densitometric instrument (DXA Osteocore II, France; dual energy X-ray absorptiometry), applying BMD and T-score values in three standard regions of interest: Neck (ROI1), Ward's area (ROI2), Trochanter (ROI3).

Measured values of T-score in ROI1, ROI2 had normal distribution and a lognormal distribution of frequency in ROI3. Using chi2-test (chi-square goodness-of-fit statistics), we determined the distribution of the frequency of T-score values and the percentage of osteoporosis incidence in the Bratislava female population. The osteoporosis incidence, according to T-score values measured in ROI1 was 2.40%, in ROI2 16.34% and in ROI3 3.83%. Following the division of women into ten-year intervals, the statistically significant sample averages of T-score values were decreasing in relation to age only for ROI2. Osteoporosis incidence in age intervals was rising with age for ROI2, for ROI1 the number of osteoporotic patients in the 61 to 70-year interval was lower than in the 41 to 50-year interval, and for ROI3 the number of osteoporotic patients in the 51 to 60-year interval was lower than in the 41 to 50-year interval. Except in the above-mentioned intervals, T-score values decreased in relation to age also in ROI1 and ROI3. According to the analysis of variance, the age category explains 9.6% of the overall variability of T-score values for ROI1, 24.7% for ROI2 and 11.70% for ROI3.

As in ROI2 (Ward's area) a greater fraction of trabecular bone is measured in comparison with ROI1 and ROI3, ROI2 reflects best the age-related BMD changes. In ROI1 and ROI3 the relation was distorted by a greater fraction of cortical bone in comparison with ROI2 and by osteoarthritis.