Search

Based on the current paradigm, a healthy bone is one with adequate mass without microarchitectural decay. However, these two features may not be sufficient to ensure that a bone is healthy. In addition, components must be correctly assembled and aligned. This ensures "the right amount of bone, at the right place" and thus, an optimal cohesion or interplay between constituents. Disorganization may be an independent contributor to bone abnormalities including fragility fractures. Indeed, many bone diseases may be characterized by the presence of disorganized bone, including osteogenesis imperfecta, hypophosphatasia, and atypical femur fractures (AFFs). Despite its likely importance, currently, there are no tools to quantify disorganization in vivo. We address this unmet need by describing a novel method for quantifying bone disorganization from X‐ray images. Disorganization is quantified as variations in the orientation of bone components in relation to a target reference point. True disorganization created by disarranging (misplacing) pixels within the bone served as "gold standard." To further validate the method in clinical settings, we compared disorganization in three groups of femurs: (i) femurs of women with AFFs (n = 9); (ii) fracture‐free femurs contralateral to AFFs (n = 9); and (iii) fracture‐free femurs from controls (n = 25). There was excellent agreement between measured disorganization and "gold standard," with R2 values ranging from 0.84 to 0.99. Precision error ranged from 1.72% to 4.69%. Disorganization produced by abnormalities associated with AFFs was accurately captured. Disorganization level was lowest in fracture‐free control femurs, higher in fracture‐free contralateral femurs to AFFs, and highest in femurs with AFFs (all p < 0.0001). Quantification of disorganization, a novel biomarker, may provide novel insights into the pathogenesis of metabolic bone diseases beyond that provided by bone mineral density (BMD) or microarchitecture. We provide evidence that measurement of disorganization is likely to help identify patients at risk for fractures, especially in those poorly explained by BMD or microarchitecture such as AFFs. © 2023 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research. [ABSTRACT FROM AUTHOR]

Advancing age is accompanied by a reduction in bone formation and remodeling imbalance, which produces microstructural deterioration. This may be partly caused by a diversion of mesenchymal cells towards adipocytes rather than osteoblast lineage cells. We hypothesized that microstructural deterioration would be associated with an increased marrow adiposity, and each of these traits would be independently associated with nonvertebral fractures and improve discrimination of women with fractures from controls over that achieved by femoral neck (FN) areal bone mineral density (aBMD) alone. The marrow adiposity and bone microstructure were quantified from HR‐pQCT images of the distal tibia and distal radius in 77 women aged 40 to 70 years with a recent nonvertebral fracture and 226 controls in Melbourne, Australia. Marrow fat measurement from HR‐pQCT images was validated using direct histologic measurement as the gold standard, at the distal radius of 15 sheep, with an agreement (R2 = 0.86, p < 0.0001). Each SD higher distal tibia marrow adiposity was associated with 0.33 SD higher cortical porosity, and 0.60 SD fewer, 0.24 SD thinner, and 0.72 SD more‐separated trabeculae (all p < 0.05). Adjusted for age and FN aBMD, odds ratios (ORs) (95% CI) for fracture per SD higher marrow adiposity and cortical porosity were OR, 3.39 (95% CI, 2.14 to 5.38) and OR, 1.79 (95% CI, 1.14 to 2.80), respectively. Discrimination of women with fracture from controls improved when cortical porosity was added to FN aBMD and age (area under the receiver‐operating characteristic curve [AUC] 0.778 versus 0.751, p = 0.006) or marrow adiposity was added to FN aBMD and age (AUC 0.825 versus 0.751, p = 0.002). The model including FN aBMD, age, cortical porosity, trabecular thickness, and marrow adiposity had an AUC = 0.888. Results were similar for the distal radius. Whether marrow adiposity and cortical porosity indices improve the identification of women at risk for fractures requires validation in prospective studies. © 2019 American Society for Bone and Mineral Research. [ABSTRACT FROM AUTHOR]

Summary: Objectives: To determine sex‐specific associations between insulin resistance and bone parameters measured by peripheral quantitative computed tomography in overweight and obese community‐dwelling older adults. Study design: Cross‐sectional study of 79 community‐dwelling overweight and obese adults (mean ± SD age 62.8 ± 7.9 years; body mass index 32.3 ± 6.1 kg/m2; 58% women). Main outcome measures: Peripheral quantitative computed tomography assessed distal radius and tibia trabecular volumetric bone mineral density (vBMD) and proximal radius and tibia cortical vBMD, periosteal circumference, endosteal circumference and stress‐strain index. The Homeostatic Model Assessment of Insulin Resistance (HOMA‐IR) score was calculated from fasting glucose and insulin values. Lean mass was assessed using dual‐energy X‐ray absorptiometry. Total minutes of moderate and vigorous physical activity (MVPA) were calculated using the Active Australia Survey. Results: Men and women in this cohort had no significant differences in fasting glucose and insulin concentrations, HOMA‐IR values and diabetes prevalence (all P > 0.05). In women, HOMA‐IR was positively correlated with proximal radius periosteal and endosteal circumference (r = 0.331; P = 0.034 and r = 0.325; P = 0.038, respectively). These associations became nonsignificant in multivariable regression analyses; however, HOMA‐IR was negatively associated with proximal radius cortical vBMD (B = −4.79; 95% CI −8.66, −0.92) after adjusting for age, lean mass and MVPA. All associations between HOMA‐IR and bone parameters became nonsignificant in a sensitivity analysis excluding individuals with diabetes, or self‐reported use of glucose‐lowering medications. There were no associations between HOMA‐IR and bone parameters in men. Conclusions: Homeostatic Model Assessment of Insulin Resistance was negatively associated with radial cortical vBMD in overweight and obese older women, but not in men. Further studies are needed to clarify sex‐specific associations between insulin resistance and bone health in overweight and obese older adults. [ABSTRACT FROM AUTHOR]

Osteoporosis and osteopenia are increasingly prevalent conditions among older adults. Not only do the fractures associated with poor bone health have significant health consequences for the individual, but also their economic impact is placing increasing financial burden on governments and society. This study aimed to determine the direct economic cost of osteoporosis, osteopenia, and fractures among Australians aged 50 years and older in 2017. This study uses previous Australian data on the incidence and prevalence of osteoporosis and osteopenia together with recent Australian data on health service utilization after fracture to provide an estimate of the economic burden of osteoporosis. A bottom‐up costing approach was used to determine the average direct health care and non‐health care total costs of a fracture, as well as the average community health service costs of managing individuals with osteoporosis or osteopenia. The total direct cost of osteoporosis in Australia in 2017 was estimated to be $3.44 billion (AUD 2017, USD 2.77 billion). Treatment of fractures accounted for 68% of total direct costs, and non‐fracture management of osteoporosis accounted for 32%. Hip fractures accounted for the highest proportion (43%) of the total direct cost of fractures, although fractures at "other" sites accounted for 38.5%. Fractures among individuals aged 70 years and older accounted for 74% of the direct costs (55% and 19% in women and men, respectively). Fracture costs in those with osteopenia accounted for 50% of direct fracture treatment costs. This up‐to‐date cost analysis estimated that costs in 2017 were three times higher than in 2007. These estimates will aid clinicians, policy makers, researchers, and health care organizations to acknowledge the economic importance of reducing osteoporosis‐related fractures and associated costs. This provides a strong public health case to promote bone health that will assist in reducing future fracture‐related costs. © 2018 American Society for Bone and Mineral Research. [ABSTRACT FROM AUTHOR]

Prospective observational studies uniformly link vitamin D deficiency with the incidence of type 2 diabetes mellitus ( T2 DM), yet trials supplementing participants at risk of T2 DM with vitamin D to reduce progression to T2 DM have yielded inconsistent results. Inconsistencies between supplementation trials may be due to insufficient dosing or small sample sizes. Observational studies may also have reported spurious associations due to uncontrolled confounding by lifestyle or genetic factors. Alternatively, observational and intervention studies may not be entirely comparable. Observational studies show an association between higher vitamin D status, which is predominantly derived from sun exposure, and decreased incidence of T2 DM. Trials intervene with vitamin D supplementation, and therefore may be missing alternate causes of the effect of sun exposure, as seen in observational studies. We propose that sun exposure may be the driving force behind the associations seen in observational studies; sun exposure may have additional benefits beyond increasing serum 25-hydroxyvitamin D (25 OHD) levels. We performed an electronic literature search to identify articles that examined associations between sun exposure and T2 DM and/or glucose metabolism. A best evidence synthesis was then conducted using outcomes from analyses deemed to have high methodological quality. Ten eligible full-text articles were identified, yielding 19 T2 DM-related outcomes. The best evidence analysis considered 11 outcomes which were grouped into six outcome types: T2 DM, fasting glucose, glucose tolerance, fasting insulin, insulin secretion and insulin sensitivity. There was moderate evidence to support a role of recreational sun exposure in reducing odds of T2 DM incidence. High-level evidence was lacking; evidence presented for other outcomes was of low or insufficient level. This review highlights significant gaps in research pertaining to sun exposure and T2 DM-related outcomes. Further research is encouraged as we aim to identify novel preventative strategies for T2 DM. [ABSTRACT FROM AUTHOR]

Objectives: To examine whether combined vitamin D and calcium supplementation improves insulin sensitivity, insulin secretion, β-cell function, inflammation and metabolic markers. Design: 6-month randomized, placebo-controlled trial. Participants: Ninety-five adults with serum 25-hydroxyvitamin D [25(OH)D] ≤55 nmol/L at risk of type 2 diabetes (with prediabetes or an AUSDRISK score ≥15) were randomized. Analyses included participants who completed the baseline and final visits (treatment n = 35; placebo n = 45). Intervention: Daily calcium carbonate (1,200 mg) and cholecalciferol [2,000–6,000 IU to target 25(OH)D >75 nmol/L] or matching placebos for 6 months. Measurements: Insulin sensitivity (HOMA2%S, Matsuda index), insulin secretion (insulinogenic index, area under the curve (AUC) for C-peptide) and β-cell function (Matsuda index x AUC for C-peptide) derived from a 75 g 2-h OGTT; anthropometry; blood pressure; lipid profile; hs-CRP; TNF-α; IL-6; adiponectin; total and undercarboxylated osteocalcin. Results: Participants were middle-aged adults (mean age 54 years; 69% Europid) at risk of type 2 diabetes (48% with prediabetes). Compliance was >80% for calcium and vitamin D. Mean serum 25(OH)D concentration increased from 48 to 95 nmol/L in the treatment group (91% achieved >75 nmol/L), but remained unchanged in controls. There were no significant changes in insulin sensitivity, insulin secretion and β-cell function, or in inflammatory and metabolic markers between or within the groups, before or after adjustment for potential confounders including waist circumference and season of recruitment. In a post hoc analysis restricted to participants with prediabetes, a significant beneficial effect of vitamin D and calcium supplementation on insulin sensitivity (HOMA%S and Matsuda) was observed. Conclusions: Daily vitamin D and calcium supplementation for 6 months may not change OGTT-derived measures of insulin sensitivity, insulin secretion and β-cell function in multi-ethnic adults with low vitamin D status at risk of type 2 diabetes. However, in participants with prediabetes, supplementation with vitamin D and calcium may improve insulin sensitivity. Trial Registration: Australian New Zealand Clinical Trials Registry [ABSTRACT FROM AUTHOR]

Ageing, obesity and the metabolic syndrome (MetS) may all contribute to poor muscle health (sarcopenia). This study aimed to determine the cross-sectional associations between MetS (International Diabetes Federation classification) and sarcopenia (revised European Working Group on Sarcopenia in Older People definition) in 84 overweight and obese older adults. Components of sarcopenia included muscle strength (hand grip and leg extension), physical performance (stair climb test and short physical performance battery (SPPB), including gait speed and repeated chair stands time), muscle mass (appendicular lean mass (ALM), dual-energy X-ray absorptiometry), muscle size (peripheral quantitative computed tomography-determined calf and forearm cross-sectional area (CSA)) and muscle quality (muscle density and strength normalised to lean mass). Waist circumference was associated with greater muscle size, but poorer leg extension strength, chair stands and stair climb time, gait speed, SPPB scores and muscle quality measures (all p < 0.05). MetS was positively associated with ALM and forearm muscle CSA, and negatively associated with muscle quality measures and chair stands time (all p < 0.05). MetS is associated with larger muscle size, yet poorer muscle quality in overweight and obese older adults. Assessments of muscle function and quality should be considered for obese older adults and those with MetS. [ABSTRACT FROM AUTHOR]