Conventional Bone Mineral Density Research Articles

Inhaled Corticosteroid-Related Tooth Problems in Asthmatics

Background. The recent Global Initiative for Asthma guideline states that inhaled corticosteroids (ICSs) may induce osteoporosis as a systemic adverse effect. New ICSs, such as fluticasone propionate, have a high topical potency and may therefore induce tooth problems as a result of direct exposure without hepatic metabolism more frequently than older ICSs. Objective. We evaluated asthma patients who underwent long-term treatment with a new ICS to determine if they had tooth problems that were related to osteoporosis of the mandible. Methods. When the conventional bone mineral density (BMD) of asthmatics that received the ICS treatment for at least one year was measured using dual-energy X-ray absorptiometry, the BMD of the mandible was also measured. The T-score of the mandible BMD was then determined based on the mean BMD ± the standard deviation of normal young adults. Result. Asthma patients with tooth loss (n = 36) and with caries or other tooth problems (n = 28) were found to have a significantly higher prevalence of osteoporosis in the mandible than those without tooth problems (n = 17; 22.2%, 7.1%, 0%, respectively; χ 2 = 6.34, p < 0.05). In addition, the presence of mandibular osteoporosis (odds ratio: 6.14, p = 0.02) and a T-score of < −1.0 for the femoral neck (odds ratio: 3.25, p = 0.01) were found to be significant risk factors for tooth loss in the asthma patients. Finally, the T-score of the mandible was found to be correlated with age (r = −0.316, p < 0.01), and with the T-scores of the lumbar spine (r = 0.413, p < 0.001) and femoral neck (r = 0.446, p < 0.001). Conclusion. Tooth loss in asthma patients undergoing long-term treatment with a topically potent ICS was found to be related to a decrease in BMD, especially in the mandible. Therefore, patients using these types of ICS should have their mandibular BMD checked regularly, especially if they have any risk factors for osteoporosis. In addition, it would be wise for such patients to reduce their ICS dose.

Bone Mineral Density in Ukrainian Women of Different Age

We determined the bone mineral density (BMD) of normal Ukrainian female subjects and compared results with USA-European reference data. The research was conducted at the Ukrainian Scientific-Medical Centre for the Problems of Osteoporosis and included 353 women aged 20-79 years. Conventional BMD measurements of the spine (L1-L4 in the anterior-posterior position), proximal femur (neck, Ward's triangle, and trochanter regions), and radial shaft (33% site) were determined by dual-energy X-ray absorptiometry using a densitometer Prodigy. Age-related changes in BMD were similar in form to those of USA-European reference data. We found that the BMD values of spine for Ukrainian women of 50-59 years were lower than published values. Regression analyses showed that weight was a significant predictor of female spine and femur BMD for both the premenopausal and the postmenopausal decades. Age was a significant predictor of female spine BMD in the 50- to 79-year age group. The prevalence of osteoporosis and osteopenia for Ukrainian women was 11% at the femoral neck and 20% and 24% at the spine and radial shaft, respectively.

High Degree of Discordance Between Three-Dimensional and Two-Dimensional Lumbar Spine Bone Mineral Density in Turner's Syndrome

Low bone mineral density (BMD) measured by dual-energy X-ray absorptiometry (DXA) has been described in Turner's syndrome (TS). One of the error factors of DXA is short stature, a common finding in TS patients. Aimed to evaluate the influence of a low stature on BMD, we compared the two-dimensional (2D) or conventional BMD (cBMD) with three-dimensional (3D) or volumetric BMD (vBMD) in 62 females (10 to 48 yr old) with TS diagnosis in a case control study. They were compared to 102 normal females (7 to 45 yr old) grouped by age-ranges. All patients were subjected to a lumbar spine densitometry by DXA in the PA and lateral projections, obtained the cBMD and vBMD and calculated for the apparent BMD (appBMD). In TS, the mean of Z-score for cBMD was significantly lower than that for vBMD and for appBMD (-2.31 +/- 1.42; -0.64 +/- 1.55; and -1.72 +/- 1.5; respectively). Most of the patients (83.8%) had a Z-score <-1 for cBMD, whereas the majority (58.1%) had a Z-score <-1 for vBMD. Concluding, the cBMD underestimates the bone mass of the lumbar spine in patients with TS inducing to false diagnoses of bone fragility. Volumetric BMD approached the bone mass of control patients, while appBMD just partially do that.

In vivo short-term precision of hip structure analysis variables in comparison with bone mineral density using paired dual-energy X-ray absorptiometry scans from multi-center clinical trials

Hip structural analysis (HSA) is a technique for extracting strength-related structural dimensions of bone cross-sections from two-dimensional hip scan images acquired by dual energy X-ray absorptiometry (DXA) scanners. Heretofore the precision of the method has not been thoroughly tested in the clinical setting. Using paired scans from two large clinical trials involving a range of different DXA machines, this study reports the first precision analysis of HSA variables, in comparison with that of conventional bone mineral density (BMD) on the same scans. A key HSA variable, section modulus ( Z), biomechanically indicative of bone strength during bending, had a short-term precision percentage coefficient of variation (CV%) in the femoral neck of 3.4–10.1%, depending on the manufacturer or model of the DXA equipment. Cross-sectional area (CSA), a determinant of bone strength during axial loading and closely aligned with conventional DXA bone mineral content, had a range of CV% from 2.8% to 7.9%. Poorer precision was associated with inadequate inclusion of the femoral shaft or femoral head in the DXA-scanned hip region. Precision of HSA-derived BMD varied between 2.4% and 6.4%. Precision of DXA manufacturer-derived BMD varied between 1.9% and 3.4%, arising from the larger analysis region of interest (ROI). The precision of HSA variables was not generally dependent on magnitude, subject height, weight, or conventional femoral neck densitometric variables. The generally poorer precision of key HSA variables in comparison with conventional DXA-derived BMD highlights the critical roles played by correct limb repositioning and choice of an adequate and appropriately positioned ROI.

Normalized BMD as a predictor of bone strength

In the noninvasive evaluation of bone quality, bone mineral density (BMD) has been shown to be the single most important predictor of bone strength and osteoporosis-related fracture. Among the methods of measuring BMD, dual x-ray absorptiometry (DXA) has widespread acceptance due to its low radiation, low cost, and high precision. However, DXA measures area BMD instead of true volumetric density; thus, a larger bone will tend to have a high BMD than will a smaller bone. Therefore, the comparison of BMDs of bones of different sizes can be misleading. In this study, the authors tried to compensate for the size effect by normalizing the area BMD with bone size as measured from a standard pelvic radiograph. The overall method for calculation of normalized BMD included conventional area-based BMD from DXA and the extraction of geometric measures from pelvic radiographs. The database for analysis included 34 femoral neck specimens. Regression analysis was performed between the normalized volumetric BMD, measured from femoral neck region, and the mechanical properties obtained from trabecular bone cubes machined from the same region. After normalization of the area BMD, the coefficient of determination increased from 0.30 to 0.43 for the Young modulus and from 0.27 to 0.37 for bone compressive strength. A noninvasive method of normalizing BMD can improve the prediction of bone mechanical properties and has potential in monitoring changes in growing skeletons and in the clinical evaluation of bone quality.

Geometric variables from DXA of the radius predict forearm fracture load in vitro.

The purpose of this investigation was to determine the cross-sectional geometry of the radius in female and male cadaveric specimens using dual-energy X-ray absorptiometry (DXA), to measure the accuracy of this technique compared with a digitizing procedure, and to measure the correlation between these DXA-based geometric variables and the load required to produce a forearm fracture. Paired intact forearms were scanned at a distal site and at a site approximately 30% of the forearm length from the distal end. The cross-sectional area and the moments of inertia of two sections at 10 and 30% of the forearm length were computed from the X-ray attenuation data. One member of each pair was then sectioned at the 30% location, which is mostly cortical bone, and the section was traced on a digitizing pad. The other forearm was loaded to failure in a servohydraulic materials test system. The DXA-based area and moment of inertia at 30% correlated significantly with the digitized results (r2 = 0.93 for area; r2 = 0.95 for moment; P < 0.001). The conventional bone mineral density from DXA did not associate significantly with failure load, but the minimum moment of inertia and the cross-sectional area at 10% correlated in a strong and significant manner with the forearm fracture force (r2 = 0.67 for area; r2 = 0.66 for moment; P < 0.001). The determination of radial bone cross-sectional geometry, therefore, should have better discriminatory capabilities than bone mineral density in studies of bone fragility and fracture risk.

Lateral spine densitometry is a more sensitive indicator of glucocorticoid-induced bone loss.

Osteoporosis is a common complication of glucocorticoid therapy. Bone density measurement is now commonly used in assessing which steroid-treated patients require specific interventions to reduce fracture risk. The recently developed techniques for the measurement of bone mineral density (BMD) of the vertebral body alone, by dual-energy x-ray absorptiometry (DXA) in the lateral projection, may be particularly useful in this context since steroid-induced bone loss is most marked in trabecular-rich regions like the vertebral body. This possibility has been assessed in the present study by the measurement of BMD in the lateral and anterioposterior (AP) projections in 28 women receiving chronic glucocorticoid treatment. The two BMD measurements were significantly related (r = 0.62, p < 0.001). When expressed in relation to age-appropriate normal values, lateral BMDs were lower than AP BMDs both in percentage terms (70.8 +/- 4.4 versus 90.3 +/- 2.6%, p < 0.001) and in terms of Z scores (-1.42 +/- 0.22 versus -0.91 +/- 0.24, p = 0.027). AP BMD Z scores classified 12 patients as osteopenic, whereas a further 7 were so categorized by lateral BMD Z score. It is concluded that lateral DXA scanning is a more sensitive indicator of glucocorticoid-induced osteopenia than conventional BMD measurement in the AP projection.