Sarcopenic Obesity Among Adults With Facioscapulohumeral Muscular Dystrophy

Abstract

BACKGROUND: Sarcopenic obesity has been observed in people with neuromuscular impairment and is linked to adverse health outcomes; it is unclear, however, if adults with facioscapulohumeral muscular dystrophy (FSHD) develop this condition. PURPOSE: Determine if adults with FSHD meet criteria for sarcopenic obesity (appendicular lean mass index (ALMI) scores of <7.26 kg/m2 or 5.45 kg/m2; % body fat of ≥27% or 38% in men/women). METHODS: Ten FSHD patients (50±11.4 years, 2 females) and ten age/sex-matched controls (47±13.6 years, 2 females) completed one visit, which included a full-body DXA scan. Regional and whole body total mass (g), fat mass (FM, (g, %)), and lean mass (LM, (g, %)) were collected; body mass index (BMI, kg/m2) and sarcopenia measures (appendicular lean mass (sum of arm/leg lean mass, ALM (kg)) and ALM index (ALMI, kg/m2)) were computed. RESULTS: Whole body total mass was similar between cohorts (FSHD: 84.5±12.9 vs. control: 81.8±13.5 kg; p=0.65). A decrease in ALM volume was found in the FSHD group (FSHD: 20.5±4.4 vs. control: 26.5±5.9 kg; p=0.02); similarly, ALMI scores were different between FSHD and controls (FSHD: 6.3±1.2 vs. control: 8.6±1.4 kg/m2; p=0.001). An increase in the proportion of whole body FM to whole body total mass (% body fat) in the FSHD group was observed (FSHD: 40.8±7.0 vs. control: 27.9±7.5%; p=0.001). While mean alterations in ALMI (6.3 ±1.3 kg/m2) and % body fat (40.0 ± 6.4%) among men with FSHD met diagnostic criteria for sarcopenic obesity, this finding was not mirrored among female FSHD counterparts (ALMI: 6.2 ±1.0 kg/m2, % body fat: 44.1 ±11.4%). Whole body LM was 15% lower in FSHD (p=0.05), furthermore, the FSHD group had a reduced proportion of whole body LM to whole body total mass vs. controls (p=0.001), along with lower total arm (p<0.01) and total leg lean mass (p=0.03). Study participants with FSHD did exhibit an increase in total body FM (p<0.01), along with greater total leg fat mass (p<0.001) but not total arm fat mass (p=0.09). CONCLUSIONS: A loss in ALM and increase in FM may lead to sarcopenic obesity in men with FSHD, resulting in a reduced quality of life and longevity.