Endocrine Abstracts

Sarcopenia is a degenerative loss of skeletal muscle mass, quality, and strength. It increases the risk of falls and fractures, is associated with cardiac and respiratory disease and cognitive impairment and leads to mobility disorders. It decreases quality of life, leads to loss of independence, placement in long-term care and finally death. A variety of indices and parameters can be used to define sarcopenia. According to literature, matrix-GLA-protein (MGP) is associated with bone parameters and cardiovascular risk. We therefore investigated whether uncarboxylated, dephosphorylated MGP (uc-dpMGP) is associated with muscle/fat mass parameters and with sarcopenia defined by dual-energy X-ray absorptiometry (DXA) derived indices and/or hand grip strength (HGS). We analysed data from the BioPersMed cohort (n = 966, 531 females, 435 males, mean age 58 ± 9 years), a prospective elderly cohort of asymptomatic subjects at cardiovascular risk. Uc-dpMGP was measured with IDS-iSYS InaKtif MGP Kit (Immunodiagnostic Systems Holdings PLC, UK). Muscle and fat mass parameters were determined by Lunar iDXA (GE Healthcare GmbH, Austria): ALM: Appendicular lean mass [kg]; LMI: Lean mass index [kg/m²]; FMI: fat mass index [kg/m²]; LESM: lower extremity skeletal muscle mass [kg]; TSM: total skeletal mass [kg]; TSMI: total skeletal mass index [kg/m²]; ALMI^BMI: ALM/BMI. HGS was measured via JAMAR@Hand Dynamometer (Patterson Medical, Ltd, UK). Sarcopenia was defined via HGS, SMI (skeletal muscle mass index), LESMI (lower extremity skeletal muscle mass index), AMMI (appendicular skeletal muscle mass index), ASM (appendicular skeletal muscle mass), ALMI (appendicular lean mass index) and with all parameters. Cut off values: HGS [kg]: males: <27; females: <16 (at the weaker hand); SMI [%]: males: <29.9, females: <23.5; LESMI [kg/m²]: males: 5.1, females: 3.7; ASM [kg]: males: 20, females: 15; AMMI [kg/m²]: males: 7, females: 5.5; ALMI [kg/m²]: males: ≤ 65 years: 7.59, > 65 years: 7.64, females: ≤ 65 years: 5.47, > 65 years: 5.78. ALM (P = 0.004), LMI (P = 0.004), FMI (P <0.001), LESM (P = 0.004), TSM (P = 0.014) and TSMI (P = 0.004) correlated positively and ALMI^BMI (P <0.001) negatively with uc-dpMGP serum levels. Uc-dpMGP serum levels were significantly higher in persons with sarcopenia according to SMI (P = <0.001), HGS (P = 0.008), AMMI (P = 0.011), ASM (P = 0.001) and all parameters (P <0.001). The number of persons with sarcopenia varied between 29 to 224 according to parameters used for characterization. Uc-dpMGP serum levels might be useful as a biomarker in the characterization of sarcopenia. Dependent on the indices used for its definition.