Sex-specific associations between insulin resistance and bone parameters in overweight and obese older adults

The Effect of Carnosine Supplementation on Musculoskeletal Health in Adults with Prediabetes and Type 2 Diabetes: A Secondary Analysis of a Randomized Controlled Trial

BACKGROUND/OBJECTIVES

Type 2 diabetes (T2D) is associated with an increased risk of adverse musculoskeletal outcomes likely due to heightened chronic inflammation, oxidative stress, and advanced glycation end-products (AGE). Carnosine has been shown to have anti-inflammatory, anti-oxidative, and anti-AGE properties. However, no clinical trials have examined the impact of carnosine on musculoskeletal health in adults with prediabetes or T2D.

METHODS

In a randomized, double-blind clinical trial, 49 participants with prediabetes or T2D and without existing musculoskeletal conditions were assigned to receive either 2 g/day carnosine or matching placebo for 14 weeks. Whole-body dual-energy X-ray absorptiometry (DXA) was used to assess body composition, and peripheral quantitative computed tomography (pQCT) was used to assess bone health at the distal and proximal tibia.

RESULTS

Forty-three participants completed this study. Carnosine supplementation had no effect on change in hand grip strength (HGS) or upper-limb relative strength (HGS/lean mass) versus placebo. Change in appendicular lean mass, percentage of body fat, visceral fat area, proximal tibial cortical volumetric bone mineral density (vBMD), distal tibial trabecular vBMD, and stress-strain index did not differ with carnosine compared to placebo. Fourteen weeks of carnosine supplementation did not improve muscle strength, body composition, or bone health in adults with prediabetes or T2D.

CONCLUSIONS

Carnosine supplementation may not be an effective approach for improving musculoskeletal health in adults with prediabetes and T2D without musculoskeletal conditions. However, appropriately powered trials with longer duration are warranted to confirm our findings. The trial was registered at clinicaltrials.gov (NCT02917928).

Association Analysis of Insulin Resistance and Osteoporosis Risk in Chinese Patients with T2DM

Background

To explore the relationship between insulin resistance and osteoporosis risk in Chinese patients with type 2 diabetes mellitus (T2DM).

Methods

A total of 234 T2DM patients were retrospectively analyzed, and their lumbar bone mineral density (BMD) and insulin resistance using C-peptide-based homeostasis model of insulin resistance [HOMA-IR (CP)] were assessed. Univariate and multivariable logistic regression methods were used to evaluate the association between HOMA-IR (CP) and osteoporosis, and subgroup analysis was performed on female and male patients.

Results

After fully adjusting the covariates, the association between HOMA-IR (CP) and osteoporosis was only significant in female patients (P = 0.022); the interaction effect with gender was significant (P for interaction <0.05). Curve fitting showed that the relationship between HOMA-IR (CP) and osteoporosis in women was nonlinear. When HOMA-IR (CP) is <4.00, its effect on osteoporosis was not significant (P = 0.474); when HOMA-IR (CP) is >4.00, the risk of osteoporosis increased significantly, with OR = 26.88 (95% CI: 2.75-262.69, P = 0.005). The relationship between insulin resistance and osteoporosis risk in T2DM patients is significantly affected by gender.

Conclusion

The higher the degree of insulin resistance in female patients, the greater the risk of osteoporosis, but the two are not linearly associated.

Risk Factors for Incident Falls and Fractures in Older Men With and Without Type 2 Diabetes Mellitus: The Concord Health and Ageing in Men Project

BACKGROUND

Type 2 diabetes mellitus (T2DM) increases falls and fracture risk. Our objective was to compare incidence and risk factors for falls and fractures in community-dwelling older men with and without T2DM.

METHODS

A total of 1705 men (471 with T2DM; 1234 without T2DM) aged ≥70 years were assessed at baseline. Men were contacted every 4 months for 6.0 ± 2.2 years to ascertain incident falls and fractures, with the latter being confirmed by radiographic reports. Hip fractures were ascertained via data linkage (follow-up: 8.8 ± 3.6 years). Risk factors for falls and fractures included physical activity and function, body composition, medications, and vision measures.

RESULTS

Men with T2DM had similar fall (incident rate ratio [IRR]: 0.92 [95% confidence interval {CI}: 0.70, 1.12], n = 1246) and fracture rates (hazard ratio [HR]: 0.86 [95% CI: 0.56, 1.32], n = 1326) compared to men without T2DM after adjustment for significant risk factors. In men with T2DM, depression (IRR: 1.87 [95% CI: 1.05, 3.34], n = 333), sulphonylurea usage (IRR: 2.07 [95% CI: 1.30, 3.27]) and a greater number of prescription medications (IRR: 1.13 [95% CI: 1.03, 1.24]) were independently associated with increased fall rates, and higher total hip bone mineral density was independently associated with lower fracture rates (HR: 0.63 [95% CI: 0.47, 0.86], n = 351). Interaction terms demonstrated that better contrast sensitivity was independently associated with lower fracture rates (HR: 0.14 [95% CI: 0.02, 0.87]) in men with T2DM compared to men without T2DM.

CONCLUSION

Fall and fracture rates were similar in men with and without T2DM after adjusting for significant risk factors. Vision assessments including contrast sensitivity measures may improve fracture prediction in older men with T2DM.

Relationship between Insulin Resistance (HOMA-IR), Trabecular Bone Score (TBS), and Three-Dimensional Dual-Energy X-ray Absorptiometry (3D-DXA) in Non-Diabetic Postmenopausal Women

BACKGROUND

Insulin may play a key role in bone metabolism, where the anabolic effect predominates. This study aims to analyze the relationship between insulin resistance and bone quality using the trabecular bone score (TBS) and three-dimensional dual-energy X-ray absorptiometry (3D-DXA) in non-diabetic postmenopausal women by determining cortical and trabecular compartments.

METHODS

A cross-sectional study was conducted in non-diabetic postmenopausal women with suspected or diagnosed osteoporosis. The inclusion criteria were no menstruation for more than 12 months and low bone mass or osteoporosis as defined by DXA. Glucose was calculated using a Hitachi 917 auto-analyzer. Insulin was determined using an enzyme-linked immunosorbent assay (EIA). Insulin resistance was estimated using a homeostasis model assessment of insulin resistance (HOMA-IR). DXA, 3D-DXA, and TBS were thus collected. Moreover, we examined bone parameters according to quartile of insulin, hemoglobin A1C (HbA1c), and HOMA-IR.

RESULTS

In this study, we included 381 postmenopausal women. Women located in quartile 4 (Q4) of HOMA-IR had higher values of volumetric bone mineral density (vBMD) but not TBS. The increase was higher in the trabecular compartment (16.4%) than in the cortical compartment (6.4%). Similar results were obtained for insulin. Analysis of the quartiles by HbA1c showed no differences in densitometry values, however women in Q4 had lower levels of TBS. After adjusting for BMI, statistical significance was maintained for TBS, insulin, HOMA-IR, and HbA1c.

CONCLUSIONS

In non-diabetic postmenopausal women there was a direct relationship between insulin resistance and vBMD, whose effect is directly related to greater weight. TBS had an inverse relationship with HbA1c, insulin, and insulin resistance unrelated to weight. This might be explained by the formation of advanced glycosylation products (AGEs) in the bone matrix, which reduces bone deformation capacity and resistance, as well as increases fragility.