Peripheral Dual-energy X-ray Absorptiometry Research Articles

Factor IX-Deficient Mice Have Decreased Skeletal Health

Background:We have previously shown that factor VIII deficiency decreases skeletal health in persons with hemophilia and animal mouse models; however, it is uncertain if this is unique to factor VIII deficiency or persists in factor IX (FIX) deficiency as well. Animal models can eliminate genetic and environmental factors of a complex trait like osteoporosis, and offer more invasive testing beyond bone mass density (BMD), studying bone properties using microtomography (μCT), histomorphometry and biomechanics. Decreased skeletal health can be caused by altered signaling between cells that are responsible for bone remodeling, osteoblasts (build bone) and osteoclasts (absorb bone). Understanding mechanisms of bone disease present in factor deficient mice can impact clinically how it is diagnosed and treated in the future.Methods:FIX-deficient and wild-type (WT) littermates were scanned using peripheral dual energy X-ray absorptiometry (DEXA) to obtain measurements for whole body BMD and femoral BMD at 10 and 20 weeks of age. Cortical bone at the midshaft of the femur was analyzed using microtomography (μCT) and biomechanical testing determined by three-point bending. Three-dimensional high resolution μCT analysis of a tibia is analyzed for bone histomorphometry. Important biomarkers of bone remodeling are analyzed on collected mouse serum and include measuring alkaline phosphatase (ALP) activity spectrophotometrically, osteoprotegrin (OPG), receptor activator of nuclear factor kappa-B Ligand (RANKL) and osteocalcin by commercially available ELISA kits.Results:FIX-deficient mice have decreased skeletal health compared to their wild-type (WT) littermate controls at both 10 and 20 weeks of age, without statistical differences in weight or body length.At 10 weeks, FIX-deficient mice (n=11) have lower whole body BMD (p=0.006) and femoral BMD (p=0.015) compared to WT littermates (n=12). Femoral μCT analysis shows parameters related to bone size, including cortical area (p=0.078) and marrow area (p=0.001) are decreased, and overall cross-sectional area (p=0.002). Three-point bending of the bones have decreased in ultimate failure (p=0.042) and stiffness (p=0.039). High resolution μCT of the tibia show decreased total bone volume (p=0.004) and at the midshaft the cortical bone (p=0.004), marrow area (p=0.029), and the total area (p=0.004).At 20 weeks, FIX-deficient mice (n=14) show decreased whole body BMD (p=0.044) and femoral BMD (p=0.053) trends from their WT littermates (n=15). Femoral μCT analysis shows decreased cortical area (p=0.038). Ultimate failure (p=0.053) and stiffness (p=0.002) differences are present in this group. No differences in cortical bone are seen with high resolution μCT, but do have distinct decreased cancellous bone in the tibia's metaphysis. The FIX-deficient bones show decreased bone volume (p=0.05) and structural differences with decreased trabecular number (p=0.03) and trabecular connectivity (p=0.01), and increased trabecular space (p=0.03).Receptor activator of nuclear factor kappa-B ligand (RANKL) located on osteoblasts plays a direct role in bone metabolism with osteoclasts, by binding to RANK causing precursor osteoclasts to mature and begin bone resorption. At 10 weeks of age RANKL was not detectable in our assays. At 20 weeks of age, RANKL was found to be significantly decreased in FIX-deficient mice over WT littermates (p=2.2E-06).OPG is a receptor decoy that inhibits bone resorption by binding to RANKL on osteoblasts. At 10 weeks, the FIX-deficient mice were found to have lower levels of OPG compared to WT controls (p=0.012); however, at 20 weeks, there was a marked increase in OPG levels of the FIX-deficient mice (p=5.7E-05). Bone building biomarkers, ALP activity and osteocalcin showed no measurable differences in serum at 10 or 20 weeks of age (p>0.5) and (p>0.2) respectively.Conclusions:FIX deficent mice have bone disease suggesting that alteration of the clotting cascade has a direct impact on skeltal health. The mechanism behind of how factor deficiency alters bone health is unclear, but the RANKL/OPG data is consistent with aberrant osteoblast-osteoclast signaling. Our laboratory is actively investigating the mechanism of decreased skeletal health associated with factor deficiencies. DisclosuresTaylor:CSL Behring: Consultancy, Research Funding; Kedrion: Research Funding; Baxalta/Shire: Consultancy, Research Funding; Novo Nordisk: Research Funding.

Daily leptin blunts marrow fat but does not impact bone mass in calorie-restricted mice

Starvation induces low bone mass and high bone marrow adiposity in humans, but the underlying mechanisms are poorly understood. The adipokine leptin falls in starvation, suggesting that hypoleptinemia may be a link between negative energy balance, bone marrow fat accumulation, and impaired skeletal acquisition. In that case, treating mice with leptin during caloric restriction (CR) should reduce marrow adipose tissue (MAT) and improve bone mass. To test this hypothesis, female C57Bl/6J mice were fed a 30% CR or normal (N) diet from 5 to 10 weeks of age, with daily injections of vehicle (VEH), 1mg/kg leptin (LEP1), or 2mg/kg leptin (LEP2) (N=6-8/group). Outcomes included body mass, body fat percentage, and whole-body bone mineral density (BMD) via peripheral dual-energy X-ray absorptiometry, cortical and trabecular microarchitecture via microcomputed tomography (μCT), and MAT volume via μCT of osmium tetroxide-stained bones. Overall, CR mice had lower body mass, body fat percentage, BMD, and cortical bone area fraction, but more connected trabeculae, vs N mice (P<0.05 for all). Most significantly, although MAT was elevated in CR vs N overall, leptin treatment blunted MAT formation in CR mice by 50% vs VEH (P<0.05 for both leptin doses). CR LEP2 mice weighed less vs CR VEH mice at 9-10 weeks of age (P<0.05), but leptin treatment did not affect body fat percentage, BMD, or bone microarchitecture within either diet. These data demonstrate that once daily leptin bolus during CR inhibits bone marrow adipose expansion without affecting bone mass acquisition, suggesting that leptin has distinct effects on starvation-induced bone marrow fat formation and skeletal acquisition.

Correlation Between Central and Peripheral Bone Mineral Density Around the Elbow Measured by Dual-Energy X-Ray Absorptiometry in Healthy Children and Adolescents

This pilot study was performed to evaluate the correlation between central bone mineral density (BMD) and peripheral BMD around the elbow in children and adolescents and to compare BMD values across skeletal sites. Twenty-seven healthy volunteers between 5 and 18 yr of age were recruited for the study. Anthropometric measurements including height and weight were performed. Central BMD at the lumbar spine and left femur and peripheral BMD at the supracondylar area, medial condyle, lateral condyle, and olecranon were measured using dual-energy X-ray absorptiometry (DXA). Higher BMD levels were found in the central skeleton (lumbar spine and femur) than in peripheral sites around the elbow (p < 0.001). BMD values around the elbow ranged from 44.4% to 63.2% compared to the BMD values of the central skeleton. Among the peripheral sites around the elbow, the highest BMD was observed at the supracondylar area and olecranon, and the lowest BMD was found at the lateral condyle. Peripheral DXA measurements around the elbow were significantly correlated with central DXA measurements at the lumbar spine and femur. In conclusion, this study demonstrated that the measurements of BMD around the elbow were correlated with BMD at central sites. Given the small sample size in this pilot study, further study with a large cohort is required to use the BMD measurements around the elbow as a valid clinical tool for fracture risk assessment and population-based epidemiological studies.

Analysis of the relationships between edentulism, periodontal health, body composition, and bone mineral density in elderly women.

ObjectiveThe relationship between bone mineral density (BMD) and tooth loss in conjunction with periodontal disease is not clear. The suggested effects include alteration in bone remodeling rates as well as the multifaceted etiology of edentulism. There is also a question if other body-related variables besides BMD, such as body composition, may be associated with tooth number and general periodontal health. The aim of this study was to evaluate if tooth number and marginal periodontal status are associated with body composition and BMD in a sample of elderly women.Materials and methodsThe study involved 91 postmenopausal women. Data included basic anthropometric characteristics, body composition via bioelectrical impedance analysis, and BMD analysis at the distal end of the radial bone of the nondominant arm via peripheral dual-energy X-ray absorptiometry. A dental examination was performed to assess tooth number, periodontal pocket depth (PD), and gingival bleeding.ResultsIn nonosteoporotic women, a significant positive correlation was found between BMD and lean body mass, total body water, and muscle mass. The indicators of bone metabolism correlated negatively with PD. Such relationships did not appear in osteoporotic women. In both groups, basic anthropometric characteristics and body composition were significantly and positively correlated with PD and bleeding on probing.ConclusionThe results suggest that body composition and BMD are not significantly correlated with tooth number and gingival bleeding.

Analysis of Bone Quality on Panoramic Radiograph in Osteoporosis Research by Fractal Dimension

Objective: To Assess the correlation between different quality analysis parameters of trabecular pattern in digital panoramic radiographies and relations with forearm bone mass density (BMD) performed by DXA. Methods: The study was developed using panoramic and peripheral bone densitometry dual energy X-ray absorptiometry (DXA) of 68 patients, 9 males and 59 females (19 - 73 years old). In the panoramic radiographs, evaluation of the trabecular bone morphology through assessment of fractal dimension (FD), connectivity (C) and total number of “bright” pixels (ET) was performed. In DXA, the exam determines the bone mineral density of the forearm to identify who has a high risk of osteoporosis. Statistics analyzed the relationship of these exams and the contribution of dental radiographs in detecting patients at risk for osteoporosis. Results: The average age of subjects was 43.85. In the analysis of trabecular pattern, a significant correlation between the FD, ET and C factors in level of 5% (Pearson correlation test) was found. Correlation tests showed no significant correlation between DF and BMD. Conclusions: The analysis showed correlations with each other, detecting alterations in the trabecular pattern. It cannot be related to BMD with FD but should be taken into account that examining the bone or trabecular alveolar process, when, for example, diagnostic analysis of pre-implant bone quality, is required.

Do Textiles Impact DXA Bone Density/Body Composition Results?

Osteoporotic patients treated with strontium ranelate show relatively large increases in bone mineral density (BMD) measured by dual-energy X-ray absorptiometry (DXA) due to the replacement of some of the calcium atoms in bone by strontium. A study published by Pors Nielsen and colleagues reported that replacement of 1% of calcium atoms by strontium causes a 10% increase in BMD. We refer to the ratio of the percentage increase in BMD to the molar percentage of strontium in bone as the strontium ratio. Theoretically it is expected that the strontium ratio should vary between different manufacturers' DXA equipment depending on the effective photon energy of the device, an effect that arises because of the proximity of the X-ray energies produced by lower energy devices to the strontium K-edge at 16 keV. In this study we report theoretical estimates of the strontium ratio for two axial DXA systems and two peripheral DXA devices based on their broad spectrum X-ray emission. The theoretical figures were verified in an experimental study in which the strontium ratio for each device was measured using phantoms containing mixtures of hydroxyapatite and strontium hydrogen-phosphate. The theoretical values of the strontium ratio were 11.0 for the Hologic Discovery, 9.9 for the GE-Lunar Prodigy, 9.1 for the Demetech Calscan, and 8.5 for the Osteometer Dexacare G4. Experimental results were 11.2 for the Discovery, 9.9 for the Prodigy, 8.6 for the Calscan and 6.3 for the Dexacare G4. The results confirm both theoretically and experimentally that the effect of bone strontium on BMD measurements is different for different DXA systems. In the future it might be possible to exploit this effect to make a non-invasive estimate of average bone strontium content in groups of patients receiving strontium medication for osteoporosis.

Evaluation of Low Bone Mineral Mass Using a Combination of Peripheral Bone Mineral Density and Total Body Composition Variables by Neural Network

The aim of this work was to evaluate low bone mass using the feed-forward neural network (NN) with good accuracy taking into account the forearm and heel bone mineral density (BMD) as well as total body composition variables. A total number of 162 subjects including 88 women (mean ± SD age = 37.7 ± 15.2 years) and 74 men (mean ± SD age=31.3 ± 10.9 years) were studied. In each subject, BMD (g cm-2) at forearm and heel using peripheral dual-energy X-ray absorptiometry (pDXA) and total body composition variables by multifrequency bioelectrical impedance analyzer were measured. The measured forearm BMD was used to estimate femur neck BMD by DXA using the published formula. Based on its T-score value, subjects were classified as normal and low bone mineral mass groups separately. In women, it was found that the forearm BMD was positively correlated with body fat percentage (r=0.327; p<0.001). It was observed that 27% of women and 15% of men were affected by low bone mass. In the NN modelling, the following 10 measured variables were used in men and women separately: i) BMI ((kg/m2); ii) average forearm BMD (g/cm2); iii) average heel BMD (g/cm2); iv) body fat (%); v) muscle mass (kg); vi) visceral fat index; vii) bone mineral mass (kg); viii) total body water, TBW (%); ix) basal metabolic rate, BMR (kCal); and x) metabolic age (years). Analysis of low bone mineral mass evaluation using NN projected an accuracy of 87.5% and 85.1% in women and men population, respectively. With the aid of BMD at peripheral skeletal sites and total body composition variables, low bone mass can be evaluated with good accuracy.

Vitamin D Status is Associated With Bone Mineral Density and Bone Mineral Content in Preschool-Aged Children

This study examined the associations between vitamin D status, bone mineral content (BMC), areal bone mineral density (aBMD), and markers of calcium homeostasis in preschool-aged children. Children (n = 488; age range: 1.8–6.0 y) were randomly recruited from Montreal. The distal forearm was scanned using a peripheral dual-energy X-ray absorptiometry scanner (Lunar PIXI; GE Healthcare, Fairfield, CT). A subset (n = 81) had clinical dual-energy X-ray absorptiometry (cDXA) scans (Hologic 4500A Discovery Series) of lumbar spine (LS) 1–4, whole body, and ultradistal forearm. All were assessed for plasma 25-hydroxyvitamin D [25(OH)D] and parathyroid hormone concentrations (Liaison; Diasorin), ionized calcium (ABL80 FLEX; Radiometer Medical A/S), and dietary vitamin D and calcium intakes by survey. Age (p < 0.001) and weight-for-age Z-score (p < 0.001) were positively associated with BMC and aBMD in all regression models, whereas male sex contributed positively to forearm BMC and aBMD. Having a 25(OH)D concentration of >75 nmol/L positively associated with forearm and whole body BMC and aBMD (p < 0.036). Sun index related to (p < 0.029) cDXA forearm and LS 1–4 BMC and whole-body aBMD. Nutrient intakes did not relate to BMC or aBMD. In conclusion, higher vitamin D status is linked to higher BMC and aBMD of forearm and whole body in preschool-aged children.

Utility of Heel Dual-Energy X-ray Absorptiometry in Diagnosing Osteoporosis

Although peripheral dual-energy X-ray absorptiometry measurements have been found to predict fractures in population studies of white subjects, little is known about their utility in other races and in patients with greater risk of fracture. In a cross-sectional study of 874 women referred for bone mineral density (BMD) testing, we examined the utility of heel BMD in African-American (AA) compared with Caucasian (CA) women and in women using glucocorticoids. The ability of heel T-score to predict central osteoporosis was similar in AA and CA women (odds ratio [OR] per 1 unit decrease in T-score of 2.79 [95% confidence interval {CI} 2.16–3.60] and 3.15 [95% CI 2.53–3.92], respectively). The association between heel T-score and prevalent vertebral fractures was also similar in the 2 groups (OR 1.46 [95% CI 1.15–1.85] in AA and 1.42 [95% CI 1.16–1.74] in CA). In women using glucocorticoids heel T-score was better than central T-score in predicting vertebral fractures (OR 1.38 [95% CI 1.03–1.85] and 1.22 [95% CI 0.86–1.73], respectively). We conclude that in a multiracial referral population heel BMD predicts central osteoporosis and prevalent vertebral fractures equally well in AA as in CA women and may be better than central BMD in assessing fragility in glucocorticoid users.

Abstract 027: Skeletal Muscle Adipose Tissue Infiltration is Associated with Mortality in Older Men

Background: Emerging evidence suggests that myosteatosis (adipose tissue (AT) infiltration within skeletal muscle (intra-muscular AT) and within the fascia surrounding skeletal muscle (inter-muscular, visible AT), increases with aging, and is positively associated with cardiovascular disease (CVD) risk factors independent of overall adiposity. Studies examining this important fat depot and mortality are lacking. Methods: We evaluated the association of mortality (all-cause, CVD, and non-CVD) with BMI, peripheral quantitative computed tomography (QCT) measured components of lower leg skeletal muscle adiposity (total, subcutaneous, and intermuscular AT, and muscle attenuation), and dual-energy X-ray absorptiometry (DXA) measured total body and trunk fat in 1155 community-dwelling older men (mean age 77.2 ± 5.1 years). Date and cause of death from death certificates were reviewed by a central physician adjudicator, with cause of death classified by ICD9 codes. Cox proportional hazards models were used to estimate the risk of mortality. Stepwise regression was used to select significant covariates for multivariable models. We tested the following covariates: age, race, study site, lifestyle risk factors, DXA total body fat, skeletal muscle area, height, diabetes, hypertension, stroke, myocardial infarction, renal disease, cancer, lipids, and medications that may influence metabolism. Results: During a mean follow-up of 5.9 years (2005-2012), 246 participants died. Among these, 74 participants died from CVD, and 159 died from non-CVD causes (cancer and other causes). After adjustment for significant covariates, lower intra-muscular AT infiltration, as reflected by greater skeletal muscle attenuation, was associated with decreased all-cause mortality, decreased CVD mortality, and decreased non-CVD mortality (Hazard ratio [95% CI] per SD increase in skeletal muscle attenuation: 0.77 [0.67, 0.90], 0.72 [0.55, 0.94], and 0.81 [0.67, 0.97], respectively; all P-values &lt;0.02). No other measures of peripheral QCT and DXA measured adiposity or generalized obesity (BMI) were associated with mortality, regardless of the degree of adjustment. Conclusion: Our study revealed a previously unreported, independent association between myosteatosis and mortality among older men. Further studies are needed to establish if the association of myosteatosis with mortality is independent of inflammation, insulin resistance, visceral and other ectopic fat depots, and to identify possible biological mechanisms underlying this relationship.

Maternal perinatal diet induces developmental programming of bone architecture

Maternal high-fat (HF) diet can alter offspring metabolism via perinatal developmental programming. This study tests the hypothesis that maternal HF diet also induces perinatal programming of offspring bone mass and strength. We compared skeletal acquisition in pups from C57Bl/6J mice fed HF or normal diet from preconception through lactation. Three-week-old male and female pups from HF (HF-N) and normal mothers (N-N) were weaned onto normal diet. Outcomes at 14 and 26 weeks of age included body mass, body composition, whole-body bone mineral content (WBBMC) via peripheral dual-energy X-ray absorptiometry, femoral cortical and trabecular architecture via microcomputed tomography, and glucose tolerance. Female HF-N had normal body mass and glucose tolerance, with lower body fat (%) but higher serum leptin at 14 weeks vs. N-N (P<0.05 for both). WBBMC was 12% lower at 14 weeks and 5% lower at 26 weeks, but trabecular bone volume fraction was 20% higher at 14 weeks in female HF-N vs. N-N (P<0.05 for all). Male HF-N had normal body mass and mildly impaired glucose tolerance, with lower body fat (%) at 14 weeks and lower serum leptin at 26 weeks vs. N-N (P<0.05 for both). Serum insulin was higher at 14 weeks and lower at 26 weeks in HF-N vs. N-N (P<0.05). Trabecular BV/TV was 34% higher and cortical bone area was 6% higher at 14 weeks vs. N-N (P<0.05 for both). These data suggest that maternal HF diet has complex effects on offspring bone, supporting the hypothesis that maternal diet alters postnatal skeletal homeostasis.

Correlation between bone mineral density measured by peripheral and central dual energy X-ray absorptiometry in healthy Indian children and adolescents aged 10–18 years

There are few large-scale studies on the utility of peripheral dual energy X-ray absorptiometry (pDXA) in children. As central dual energy X-ray absorptiometry (cDXA) equipment is not commonly available in the developing world, we assessed the correlation of bone mineral density (BMD) with cDXA and pDXA in children to determine the optimal Z-score thresholds of pDXA for predicting two predefined Z-score cutoffs (≤-1, ≤-2) of cDXA in 844 subjects (441 boys, 403 girls) aged 10-18 years. The BMD of antero-posterior lumbar spine (L1-L4), proximal femur and forearm was measured by cDXA, while the peripheral BMD of forearm and calcaneus was estimated using pDXA. The correlation was statistically significant at all sites (p<0.01). The coefficients ranged from 0.56 to 0.79 in boys and 0.17 to 0.32 in girls. A significant positive correlation was observed between BMD by pDXA and cDXA in Indian children, with a strong gender difference in both the extent of correlation and the ability of peripheral BMD to predict central BMD.

Bone Mineral Density Measured by a Portable X-ray Device Agrees With Dual-Energy X-ray Absorptiometry at Forearm in Preschool Aged Children

Dual-energy X-ray absorptiometry (DXA) measures of bone mineral density (BMD) are generally not feasible in fieldwork. The present study determined the agreement between BMD measured by DXA and portable peripheral DXA in preschool aged children. Fifty-seven children (4.2±1.0yr) had their nondominant distal forearm scanned using a peripheral DXA scanner (PIXI; GE Medical Systems Lunar, Madison, WI) at their daycare and a DXA (4500A Discovery Series; Hologic Inc., Bedford, MA) at our research clinic. Correlation analysis, one-way analysis of variance, and Bland-Altman plots were performed to examine the agreement between measurements. Data were also divided into tertiles for cross-classification analysis and calculation of kappa coefficients. Distal forearm BMD measured by PIXI was significantly correlated with DXA measures of total forearm BMD (r>0.51; p<0.001), proximal 1/3 BMD (r>0.41; p<0.001), mid-BMD (r>0.37; p<0.001), and ultradistal (UD) BMD (r>0.57; p<0.001). Cross-classification in the same or adjacent tertile between measures (UD forearm: 96.5%; UD radius: 94.4%; total forearm: 87.7%; total radius: 84.2%) resulted in weighted kappa coefficients of 0.46, 0.58, 0.42, and 0.43, respectively. Bland-Altman plots further clarified these agreements as all had low bias (UD forearm: bias=0.003±0.002; UD radius: −0.015±0.021; total forearm: −0.062±0.027; total radius: −0.077±0.026). These results demonstrate that portable DXA measures of forearm BMD agree moderately with DXA.

Peripheral and Central Bone Mineral Density in Charcot’s Neuroarthropathy Compared in Diabetic and Nondiabetic Populations

This prospective study was performed to compare calcaneal and lumbar bone mineral density (BMD) in individuals with and without diabetes mellitus. We compared bone density with the time from onset of Charcot's neuroarthropathy (CN) in patients with unilateral, nonoperative, reconstructive-stage CN. The final purpose was to investigate the role that sex, age, and serum vitamin D level may have in osseous recovery. Thirty-three individuals were divided into three groups: controls and patients with diabetes mellitus with and without CN. Peripheral instantaneous x-ray imaging and dual-energy x-ray absorptiometry were performed. The calcaneal BMD of patients with diabetes mellitus and CN was lower than that of the control group (P < .01) but was not significantly lower than that of patients with diabetes mellitus alone. There was no statistically significant difference in lumbar T-scores between groups. Women demonstrated lower BMD than did men (P = .02), but patients 60 years and older did not demonstrate significantly lower BMD than did patients younger than 60 years (P = .135). A negative linear relationship was demonstrated between time and BMD in patients with CN. The results of this study suggest that lumbar BMD does not reflect peripheral BMD in patients with diabetes mellitus and reconstructive-stage CN. This study has clinical implications when reconstructive osseous surgery is planned in patients with CN.

Forearm Bone Mineral Density Varies as a Function of Adiposity in Inuit Women 40–90 Years of Age During the Vitamin D–Synthesizing Period

Aging Inuit women are at increased risk for low vitamin D status due to habitation at higher latitudes, darker skin, and ongoing nutrition transition. Lower serum 25-hydroxyvitamin D (25[OH]D) concentration and higher risk of fracture have been separately reported in Inuit women, with particular relevance to postmenopausal women. We evaluated vitamin D status, forearm bone mineral density (fBMD), and nutrition in Inuit women ≥40years. Women (n=568) were randomly selected to participate in the 2007-2008 International Polar Year Inuit Health Survey from 36 Arctic communities. fBMD was measured using peripheral dual-energy X-ray absorptiometry. Dietary intakes were derived from 24h recall and food-frequency questionnaires. Fasting serum 25(OH)D, parathyroid hormone, and osteocalcin (OC) were measured using a LIAISON(®) automated analyzer. The weighted prevalence of women having 25(OH)D concentration below 37.5, 50, and 75nmol/L was 7.2%, 17.6%, and 48.6%, respectively, with older women having better status. The dietary density of most nutrients increased with age, as did traditional food intake. fBMD was low in 3 (1.4%) premenopausal (Z score<-2) and 107 (29.6%) postmenopausal (T score<-1.5) women. Regression revealed that either weight, body mass index, or percent body fat significantly predicted fBMD in premenopausal women, in addition to age and OC in postmenopausal women. Women ≥50years have higher vitamin D status and more nutrient-dense diets than women 40-49years. While measures of adiposity predicted fBMD in all women, additional predictors after menopause included age and bone turnover.

Evaluation of functional ability of rheumatoid arthritis based on HAQ score and BMD among South Indian patients

Aim of this study is to analyze the functional ability of rheumatoid arthritis among South Indian male and female patients based on HAQ score and forearm ulna-BMD measurement by peripheral DXA, and to investigate the correlation between forearm ulna-BMD and HAQ score among RA patients. Sixty-four patients with RA and 64 age- and sex-matched healthy controls were included in this study. The health assessment questionnaire test was self administered by each RA patients. The bone mineral density (BMD) in forearm ulna region was measured using peripheral Dual energy X-ray absorptiometry (osteometer model-DTX200 Meditech.Inc, Hawthorn, California, USA) both for RA patients and for healthy control group. RA patients (n = 64) and age- and sex-matched healthy controls (n = 64) were selected, of which 46 (72%) patients were women and 18 (28%) were men. The mean age was 47.75 ± 11.37 years, and a majority of the patients were in the age group of 30-75 years. The mean age of healthy controls was 46.42 ± 10.67 years. For male RA patients, U-BMD shows moderate significance with healthy controls (0.371 ± 0.05 (g cm(2)) [mean ± SD], 0.413 ± 0.05 (g cm(2)), P = 0.03). For female RA patients, U-BMD was highly significant with that of healthy controls (0.300 ± 0.132 (g cm(2)), 0.376 ± 0.05 (g cm(2)), P = 0.0006). Because as U-BMD decreases for RA patients, HAQ score increases, hence, Pearson correlation analysis revealed that U-BMD was negatively correlated with HAQ score (r = -0.732, P < 0.0001). Forearm U-BMD for RA patients is significantly lower than the healthy controls both for male and for female patients. There was a negative correlation found between HAQ score and P-DXA forearm U-BMD.

Prevalence and predictors of osteoporosis in an urban Sri Lankan population

To determine the prevalence of osteoporosis in both women and men and to determine the association between osteoporosis and selected risk factors among a sample of urban Sri Lankan adults. The population aged 35-64 years residing in 22 Grama Niladhari divisions, the smallest administrative units in the country, of the Medical Officer of Health area Ragama, Sri Lanka, was identified using the electoral list and stratified into three age groups (n = 3012). A random sample was obtained from each stratum and selected individuals were invited to participate in the study (n = 1100). A structured, interviewer-administered questionnaire was used to collect information on demographic data and details of risk factors. Bone mineral density (BMD) was measured using a peripheral dual-energy X-ray absorptiometry (DEXA) scan in 700 subjects (64%). A BMD < -2.5 was considered as osteoporosis. Although peripheral DEXA is less sensitive and specific compared to central DEXA it was used in this study as it is less costly and easily transportable. Of the 700 subjects who consented to participate in the study, 60% (n = 421) were females. In subjects < 50 years, 9% of women and 3% of men had osteoporosis. In subjects ≥ 50 years, 27% of women and 7% of men had osteoporosis. Female sex (odds ratio [OR] 12.0), smoking (OR 5.5), age > 50 years (OR 3.1), low BMI (OR 3.1) and low level of education (OR 1.7) were positively associated with osteoporosis. Female sex, age, BMI, smoking and level of education were significant predictors of osteoporosis. The prevalence of osteoporosis increased in both women and men after 50 years.

The effect of bone strontium on BMD is different for different manufacturers' DXA Systems

Osteoporotic patients treated with strontium ranelate show relatively large increases in bone mineral density (BMD) measured by dual-energy X-ray absorptiometry (DXA) due to the replacement of some of the calcium atoms in bone by strontium. A study published by Pors Nielsen and colleagues reported that replacement of 1% of calcium atoms by strontium causes a 10% increase in BMD. We refer to the ratio of the percentage increase in BMD to the molar percentage of strontium in bone as the strontium ratio. Theoretically it is expected that the strontium ratio should vary between different manufacturers' DXA equipment depending on the effective photon energy of the device, an effect that arises because of the proximity of the X-ray energies produced by lower energy devices to the strontium K-edge at 16 keV. In this study we report theoretical estimates of the strontium ratio for two axial DXA systems and two peripheral DXA devices based on their broad spectrum X-ray emission. The theoretical figures were verified in an experimental study in which the strontium ratio for each device was measured using phantoms containing mixtures of hydroxyapatite and strontium hydrogen-phosphate. The theoretical values of the strontium ratio were 11.0 for the Hologic Discovery, 9.9 for the GE-Lunar Prodigy, 9.1 for the Demetech Calscan, and 8.5 for the Osteometer Dexacare G4. Experimental results were 11.2 for the Discovery, 9.9 for the Prodigy, 8.6 for the Calscan and 6.3 for the Dexacare G4. The results confirm both theoretically and experimentally that the effect of bone strontium on BMD measurements is different for different DXA systems. In the future it might be possible to exploit this effect to make a non-invasive estimate of average bone strontium content in groups of patients receiving strontium medication for osteoporosis.

Feasibility of Peripheral Bone Densitometry for the Assessment of Bone Density: Comparison with Dual Energy X-ray Absorptiometry of the Axial Skeleton

Purpose: To evaluate the feasibility of peripheral bone densitometry for the assessment of bone density, and to compare it with dual energy X-ray absorptiometry (DXA). Materials and Methods: Radiographic absorptiometry (RA) of the middle phalange, peripheral DXA (pDXA) of the calcaneus, and the DXA were performed for two groups: Group 1 was a normal group of 54 healthy young women and group 2 was a group of 54 postmenopausal women considered to be at a high risk for osteoporosis. For the normal group, RA and pDXA were scanned twice to assess the repeatability of the methods. The Tscores were compared to determine whether there was a correlation between the peripheral and axial bone densitometries. The cutoff values of RA and pDXA for the diagnosis of osteopenia were determined. Results: Each examination showed different T-scores for a given person. The T-scores of RA were higher than those of pDXA for the normal group, whereas the T-scores of pDXA were higher for high-risk group. The coefficients of repeatability were 0.88 in RA and 1.53 in pDXA. The correlation coefficient for DXA was higher in RA than in pDXA. The cutoff values for osteopenia were -1.773 for RA and -1.75 for pDXA, as compared to -1.0 for DXA. Conclusion: The data suggests that RA is a viable screening method for osteoporosis. However, there should be consideration for the fact that bone density depends on examination methods or sites.

Diagnosis and treatment of osteoporotic fractures

Diagnosis and treatment of osteoporotic fractures