Introduction: Insulin resistance is a well-known hallmark of the metabolic syndrome (MetS), and it detrimentally affects also protein metabolism, favoring to the decline of lean body mass. The aim of the present study was to explore muscle strength (as a functional consequence of sarcopenic obesity) and muscle quality (namely, myosteatosis) in women with and without the Metabolic Syndrome (MetS).
Methods: Study participants were enrolled at the Sapienza University, Rome, Italy. Body composition was assessed through DXA. The Handgrip strength test (HGST) was performed to assess muscle strength using a dynamometer (Dynex, Akern). HGST was normalized to arm lean mass; intramuscular adipose tissue (IMAT) and intramyocellular lipid content (IMCL) were measured by magnetic resonance spectroscopy, and used as indicators of myosteatosis. The MetS was diagnosed according to the NCEP-ATPIII criteria. HOMA-IR was calculated; C-reactive protein (CRP) levels were measured. The International Physical Activity Questionnaire (IPAQ) was administered to assess the physical activity level (PAL).
Results: 54 women (age: 48±14 years, BMI: 37.9±5.4 kg/m2) were included. MetS was diagnosed in 54% of subjects. HGST/arm lean mass was lower in women with the MetS compared to their counterparts without the MetS (6.3±1.8 vs 7.8±1.6, P=0.03). HGST/arm lean mass was negatively associated to HOMA-IR (beta: −0.37, S.E.:0.16, P=0.02), after adjustment for age, body fat, CRP levels, and PAL. IMAT (2655±1710 vs 1614±642 mm2) and IMCL (25.0±21.4 vs 23.1±20.6%) were not different in obese women with the MetS compared to women without the MetS (P>0.05). No association emerged between HGST/arm lean mass and IMAT or IMCL.
Conclusion: Insulin resistance, and not muscle fatty infiltration per se, may play a role in the decline of muscle strength in subjects with obesity, leading to the phenotype of dynapenic obesity.
20 May 2017 - 23 May 2017