Bone microstructure changes due to once-/twice-weekly teriparatide administration: A report of five cases using high-resolution peripheral quantitative computed tomography.

This study was conducted with the aim of presenting cases in which high-resolution peripheral quantitative computed tomography (HR-pQCT) was used to investigate changes in the bone microstructure due to once-weekly/twice-weekly administration of teriparatide (TPTD). Of osteoporosis patients who participated in a non-inferiority trial (TWICE study: once-weekly vs twice-weekly TPTD) with lumbar bone mineral density as the primary endpoint, five cases scanned by HR-pQCT before TPTD administration were analysed. Two cases were given once-weekly TPTD, three were given twice-weekly TPD, and HR-pQCT was repeated after 48 weeks. A sufficient anabolic effect of once-weekly/twice-weekly TPTD on the trabecular and cortical bone at the tibia was obtained. In addition, the average change in cortical porosity (Ct.Po) was only 0.3% in the tibia and 0.2% in the radius. These findings indicate that once-weekly and twice-weekly TPTD can be expected to improve the bone microstructure, and the increase in Ct.Po may be suppressed.

Differences in the effects of BMI on bone microstructure between loaded and unloaded bones assessed by HR-pQCT in Japanese postmenopausal women.

OBJECTIVES: The relationship between weight-related load and bone mineral density (BMD)/bone microstructure under normal load conditions using high-resolution peripheral quantitative computed tomography (HR-pQCT) remains unconfirmed. The study aims to investigate the differences in effect of body mass index (BMI) on BMD/bone microstructure of loaded and unloaded bones, respectively, in Japanese postmenopausal women. METHODS: Fifty-seven postmenopausal women underwent HR-pQCT on the tibia and radius. Correlation analysis, principal component (PC) analysis, and hierarchical multiple regression were performed to examine the relationship between BMI and HR-pQCT parameters. RESULTS: Several microstructural parameters of the tibia and radius correlated with BMI through a simple correlation analysis, and these relationships remained unchanged even with an age-adjusted partial correlation analysis. PC analysis was conducted using seven bone microstructure parameters. The first PC (PC1) reflected all parameters of trabecular and cortical bone microstructures, except for cortical porosity, whereas the second PC (PC2) reflected only cortical bone microstructure. Hierarchical multiple regression analysis indicated that BMI was more strongly related to BMD/bone microstructure in the tibia than in the radius. Furthermore, BMI was associated with trabecular/cortical BMD, and PC1 (not PC2) of the tibia and radius. Thus, BMI was strongly related to the trabecular bone microstructure rather than the cortical bone microstructure. CONCLUSIONS: Our data confirmed that BMI is associated with volumetric BMD and trabecular bone microstructure parameters in the tibia and radius. However, although BMI may be more related to HR-pQCT parameters in the tibia than in the radius, the magnitude of association is modest.

Daily activity relates to not only femoral bone mineral density, but also hip structural analysis parameters: A cross-sectional observational study.

OBJECTIVES: Physical activity to maintain bone mass and strength is important for hip fracture prevention. We aim to investigate the relationship between physical performance/activity status and bone mineral density (BMD)/hip structural analysis (HSA) parameters among postmenopausal women in Japan. METHODS: Sixty-two postmenopausal women diagnosed with osteoporosis (mean age: 72.61 ± 7.43 years) were enrolled in this cross-sectional observational study. They were evaluated for BMD and HSA in the proximal femur by dual-energy X-ray absorptiometry and underwent several physical performance tests, the Geriatric Locomotive Function Scale of 25 questions (GLFS-25). Principal component analysis (PCA) was used to summarize data on the BMD/HSA parameters. Partial correlation analysis, multiple regression analysis, and structural equation modeling (SEM) were performed to investigate the relationship between physical performance/activity status and BMD/HSA parameters of the proximal femur. RESULTS: In a partial correlation analysis adjusted for age and body mass index (BMI), GLFS-25 scores were correlated with HSA parameter (|r| = 0.260-0.396, P < 0.05). Principal component 1 (PC1) calculated by PCA was interpreted as more reflective of bone strength based on the value of BMD/HSA parameters. The SEM results showed that the model created by the 3 questions (Q13, brisk walking; Q15, keep walking without rest; Q20, load-bearing tasks and housework) of the GLFS-25 had the best fit and was associated with the PC1 score (ß = -0.444, P = 0.001). CONCLUSIONS: The GLFS-25 score was associated with the BMD/HSA parameter, which may reflect the bone strength of the proximal femur as calculated by PCA.