Measuring body composition in overweight individuals by dual energy x-ray absorptiometry

BACKGROUND: Dual energy x-ray absorptiometry (DXA) is widely used for body composition measurements in normal-weight and overweight/obese individuals. The limitations of bone densitometers have been frequently addressed. However, the possible errors in assessing body composition in overweight individuals due to incorrect positioning or limitations of DXA to accurately assess both bone mineral density and body composition in obese individuals have not received much attention and are the focus of this report. DISCUSSION: We discuss proper ways of measuring overweight individuals and point to some studies where that might not have been the case. It appears that currently, the most prudent approach to assess body composition of large individuals who cannot fit under the scanning area would be to estimate regional fat, namely the regions of thigh and/or abdomen. Additionally, using two-half body scans, although time consuming, may provide a relatively accurate measurement of total body fat, however, more studies using this technique are needed to validate it. SUMMARY: Researchers using bone densitometers for body composition measurements need to have an understanding of its limitations in overweight individuals and address them appropriately when interpreting their results. Studies on accuracy and precision in measurements of both bone and soft tissue composition in overweight individuals using available densitometers are needed

Bone turnover markers are correlated with total skeletal uptake of 99mTc-methylene diphosphonate (99mTc-MDP)

ABSTRACT: BACKGROUND: Skeletal uptake of 99mTc labelled methylene diphosphonate (99mTc-MDP) is used for producing images of pathological bone uptake due to its incorporation to the sites of active bone turnover. This study was done to validate bone turnover markers using total skeletal uptake (TSU) of 99mTc-MDP. METHODS: 22 postmenopausal women (52-80 years) volunteered to participate. Scintigraphy was performed by injecting 520 MBq of 99mTc-MDP and taking whole body images after 3 minutes, and 5 hours. TSU was calculated from these two images by taking into account the urinary loss and soft tissue uptake. Bone turnover markers used were bone specific alkaline phosphatase (S-Bone ALP), three different assays for serum osteocalcin (OC), tartrate resistant acid phosphatase 5b (S-TRACP5b), serum C-terminal cross-linked telopeptides of type I collagen (S-CTX-I) and three assays for urinary osteocalcin (U-OC). RESULTS: The median TSU of 99mTc-MDP was 23% of the administered activity. All bone turnover markers were significantly correlated with TSU with r-values from 0.52 (p = 0.013) to 0.90 (p < 0.001). The two resorption markers had numerically higher correlations (S-TRACP5b r = 0.90, S-CTX-I r = 0.80) than the formation markers (S-Total OC r = 0.72, S-Bone ALP r = 0.66), but the difference was not statistically significant. TSU did not correlate with age, weight, body mass index or bone mineral density. CONCLUSION: In conclusion, bone turnover markers are strongly correlated with total skeletal uptake of 99mTc-MDP. There were no significant differences in correlations for bone formation and resorption markers. This should be due to the coupling between formation and resorption

Risk factors for bone mineral density at the calcaneus in 40–59 year-old male workers: A cross-sectional study in Korea

<p>Abstract</p> <p>Background</p> <p>Few epidemiologic studies have attempted to investigate the prevalence and risk factors for osteopenia and osteoporosis in middle-aged Asian men. We performed this study to determine the prevalence and risk factors of osteopenia and osteoporosis in this population.</p> <p>Methods</p> <p>This cross-sectional study was conducted from March to July, 2004. The subjects were 2,073 males aged from 40 to 59 years in the KHNP (Korea Hydro & Nuclear Power) workplace-based cohort. Bone mineral density (BMD) was measured by peripheral, dual-energy, X-ray absorptiometry (DXA) at the calcaneus. Anthropometric and lifestyle factors were investigated using a standard, self-reported questionnaire.</p> <p>Results</p> <p>BMD was 0.60 ± 0.09 g/cm²(mean ± standard deviation) and was negatively correlated with age (r = -0.18, <it>P </it>< 0.001), but positively correlated with waist-to-hip ratio (WHR; r = 0.15, <it>P </it>< 0.001), body fat (r = 0.10, <it>P </it>< 0.001), BMI (r = 0.35, <it>P </it>< 0.001), height (r = 0.26, <it>P </it>< 0.001), and weight (r = 0.43, <it>P </it>< 0.001).</p> <p>In multiple linear regression analysis, the independent determinants associated with BMD were increasing age (coefficient = -0.002, <it>P </it>< 0.001), physical activity (≤ 2/week vs. ≥ 3/week; coefficient = 0.017, <it>P </it>< 0.001), WHR (coefficient = -0.796, <it>P </it>< 0.001), body mass index (BMI; coefficient = 0.023, <it>P </it>< 0.001) and smoking status (never vs. ever; coefficient = -0.018, <it>P </it>< 0.001).</p> <p>Conclusion</p> <p>We suggest that BMD of the calcaneus is correlated negatively with exposure to smoke and increased WHR, but positively with regular exercise and increased BMI.</p

Treatment Satisfaction in Postmenopausal Women Previously Treated with Bisphosphonates Who Transitioned to Denosumab Vs Ibandronate Therapy in an Open-Label Study

Background/Purpose: Higher treatment satisfaction is associated with greater persistence with osteoporosis therapy in postmenopausal women (Barrett-Connor OI 2012). Greater satisfaction has been reported with subcutaneous injections of denosumab compared with oral alendronate tablets in a randomized, cross-over study where subjects received both treatments (Freemantle OI 2012). In this open-label trial, we evaluated treatment satisfaction in postmenopausal women with low bone mineral density (BMD) who were sub-optimally treated with prior bisphosphonate therapy and were transitioned to denosumab or ibandronate. Methods: This was a multicenter, randomized, open-label, parallel-group study in which postmenopausal women aged 55 and older were randomized 1:1 to receive open-label denosumab 60 mg subcutaneously every 6 months or ibandronate 150 mg orally every month for 12 months. The treatment satisfaction questionnaire for medication (TSQM) version 1.4 was given at baseline and months 6 and 12 or at time of early termination. TSQM is a validated tool that measures the subject’s perception of the 4 domains of treatment satisfaction: the medication’s effectiveness, convenience, side effects, and global satisfaction (Atkinson Health Qual Life Outcomes 2004). Each TSQM domain score is between 0 and 100 and a higher score indicates a more preferred health status. Treatment comparisons of change in TSQM from baseline to months 6 and 12 were analyzed using an ANCOVA model fitted with treatment group and adjusted for baseline TSQM domain score. Results: The study population included 833 women (417 denosumab; 416 ibandronate) with a mean (SD) age of 66.7 (8.0) years and mean (SD) BMD T-scores of –1.8 (0.7) at the total hip, 2.1 (0.7) at the femoral neck, and –2.5 (0.8) at the lumbar spine. Compared with the TSQM scores at baseline, subjects in both treatment groups reported greater satisfaction in all domains of the TSQM at month 6 and at month 12. However, subjects who transitioned to denosumab therapy had significantly greater improvements among all domains than did subjects who transitioned to ibandronate therapy at month 6 (P 0.0004 in all domains; data not shown) and at month 12 (P 0.0003 in all domains; Table 1).Table 1. TSQM Change From Baseline to Month 12 TSQM Domain Treatment n LS Mean 95% CI P-value* Effectiveness Ibandronate 332 17.9 15.6, 20.2 0.0001 Denosumab 378 24.1 22.0, 26.3 Convenience Ibandronate 338 16.7 14.9, 18.6 0.0001 Denosumab 384 26.3 24.6, 28.0 Side Effects Ibandronate 337 4.2 2.7, 5.8 0.0003 Denosumab 385 8.1 6.7, 9.6 Global Satisfaction Ibandronate 337 14.9 12.8, 17.1 0.0001 Denosumab 382 26.4 24.4, 28.4 n number of subjects with non-missing TSQM domain at baseline and at month 12. LS least squares. CI confidence interval. *P-value from treatment comparison based on an ANCOVA model fitted with treatment group and adjusted for baseline TSQM domain score. Conclusion: In summary, postmenopausal women with low BMD who were sub-optimally treated with prior bisphosphonate therapy reported greater satisfaction if they transitioned to denosumab vs ibandronate in an open-label study. Greater treatment satisfaction may lead to better adherence to therapy and thus improvements in treatment efficac