Search

Objectives To determine characteristics of sarcopenic obesity that are independently associated with bone health and balance in older adults. Study design Cross-sectional study of 168 community-dwelling older adults (mean age 67.7 ± 8.4 years; 55% women). Main outcome measures Appendicular lean mass (ALM), whole-body areal BMD (aBMD) and body fat percentage were assessed by dual-energy X-ray absorptiometry. Peripheral quantitative computed tomography assessed muscle density and cortical volumetric BMD (vBMD), area, thickness, and strength-strain index (SSI) at 66% tibial length. Hand grip strength (dynamometry) and balance path length (computerised posturography) were assessed. Obesity was defined as high body fat percentage. Results Greater lower-leg muscle density was associated with lower balance path length in men (r = −0.36; P < .01) and women (r = −0.40; P = < .01). Obese participants by body fat percentage did not differ to non-obese on bone indices, although a trend towards lower cortical vBMD was observed in obese compared with non-obese men (1041.4 ± 39.8 vs 1058.8 ± 36.1 mg/cm 3 ; P = .051). In multivariable models, ALM was positively associated with all bone parameters in obese women, and with whole-body aBMD, proximal tibial cortical area and SSI in non-obese women, and both non-obese and obese men (all P < .05). Lower-leg muscle density was also positively associated with cortical vBMD (B = 2.91; 95% CI 0.02, 5.80) and area (2.70; 0.06, 5.33) in obese women. Conclusions Amongst components of sarcopenic obesity, higher ALM is a consistent independent predictor of better bone health. Low muscle density may also compromise bone health and balance. Interventions which improve muscle mass and composition may lower fracture risk in sarcopenic obesity. [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]

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]

Asian race, younger age, higher body mass index (BMI) and antiresorptive drugs have all been associated with atypical femur fractures (AFFs). This increased risk of AFF in Asians is important as by 2050, >50% of hip fractures globally will occur in Asia, with an increased demand for antiresorptive drugs being likely. It is also currently unclear whether AFF risk is increased in all Asian subgroups. We therefore aimed to identify the incidence of AFFs in an Australian tertiary hospital, the contribution of ethnic origin to AFF risk, and determine other clinical risk factors for AFF. From January 1, 2009 to December 31, 2017, 97 AFFs (82 complete and 15 incomplete) occurred in 71 individuals in the overall study population of 204,358. Patients with AFF were more likely to be female (88.7% vs 69.1%, p < 0.001) and younger [median (IQR): 74(52–92) years vs 83(75–88) years, p < 0.001] than the "typical" femur fracture group (n = 3330). The cumulative incidence rate of AFF was 4.2 per 100,000 person-years, far lower than for any ICD-10 AM coded "typical" femur fracture (202.9 per 100,000 person-years). Asians were 3.4 (95%CI, 2.1–5.6) times more likely to sustain an AFF than non-Asians, the highest incidence being in those from South East Asian countries (16.6 per 100,000 person years), suggesting differences in risk between Asian countries. In the nested case-control study, bisphosphonate use was an independent association with AFF development. We conclude Asian ethnicity is an important association with AFF in this large Australian cohort. • Incidence of atypical femur fractures is outweighed by osteoporotic femur fractures. • Asian ethnicity is a risk factor for atypical femur fractures. • Antiresorptive drugs, female sex, and younger age were associated with AFFs. [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]

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]