Association between bone microarchitecture and sarcopenia in postmenopausal women with type 2 diabetes

Bone microarchitecture, as assessed using high-resolution peripheral quantitative computed tomography, is adversely affected in postmenopausal women with type 2 diabetes mellitus having sarcopenia/sarcopenic obesity while areal bone mineral density does not differ between those with and without sarcopenia.

Purpose: Type 2 diabetes (T2D) increases the risk of sarcopenia, which independently contributes to bone fragility. We aimed to explore the association between sarcopenia/sarcopenic obesity and bone quality using second-generation high-resolution peripheral quantitative computed tomography (HR-pQCT) in T2D.

Methods: We analyzed the baseline participant characteristics of an ongoing randomized clinical pilot trial (CTRI/2022/02/039978). Postmenopausal women (≥ 50 years) with T2D and high risk of fragility fractures were included. Areal BMD (aBMD), trabecular bone score (TBS), and body composition were measured using DXA. Bone microarchitecture was assessed at distal radius/distal tibia using HR-pQCT. Muscle strength was estimated using dominant handgrip strength (HGS). Sarcopenia was defined as low HGS (< 18.0 kg) and low appendicular skeletal muscle index (ASMI) (< 4.61 kg/m²). Probable sarcopenia was defined as low HGS with normal ASMI. Sarcopenic obesity was classified as co-existence of sarcopenia and obesity (BMI ≥ 25.0 kg/m²).

Results: We recruited 129 postmenopausal women (mean age 64.2 ± 6.7 years). Participants were categorized into four mutually exclusive groups: group A (normal HGS and ASMI, n = 17), group B (probable sarcopenia, n = 77), group C (non-obese sarcopenia, n = 18), and group D (obese sarcopenia, n = 18). The four groups did not differ significantly with regard to baseline characteristics, fracture prevalence, HbA1c, aBMD, and TBS. However, HR-pQCT-derived volumetric BMD and cortical/trabecular microarchitecture were significantly poorer in group C/group D than in group A/group B.

Conclusions: Bone quality rather than bone density (quantity) is adversely affected in T2D postmenopausal women with sarcopenia/sarcopenic obesity, which could increase the fracture risk in this patient sub-population.