Body composition and functional restoration in chronical musculoskeletal pain patients

Backgrounds and aims A decrease of the skeletal muscle mass (sarcopenia), from a complex origin, occurs of from the age of 40 years. In the context of physical medicine, most of the studies have been done in older populations, but not in younger populations. Patients A cohort of 600 patients (288 men et 312 women; mean age 42.4 years), included in a restoration program for a chronic and disabilitating musculoskeletal disorder, has been evaluated by a bio-impedance analysis (BIA). Methods For all the patients, were measured: the lean mass, the Fat Mass, the Muscle Mass calculated with the Janssen's equation [1] , the percentage of the muscular mass of over the weight. The presence of a sarcopenia was defined by the value of the percentage accordingly to the Janssen's classification [2] (% inferior to–2DS of the mean value of a referent population). Results The lean mass and the muscle mass were significantly negatively correlated with the age ( P  = 0.001). The mean value of the lean mass was significantly lower in patients 50 to 60 years old than the younger patients, independently from the sex. 13.8% patients had a sarcopenia: 36,1% in the 50 to 60 years old, 28,9% in the 40 to 50 years old, 12% in the 30 to 40 years old. In parallel, it has been found an increase of the fat mass, in function of the sex and of the age ( P  = 0.001). Discussion It is the first study that evaluates the body composition in physical medicine. Our results confirm the decrease of the muscular mass and the increase of the fat mass particularly in patients with an age higher than 50 years. The occurrence of a sarcopenia may influence the process of the retraining in strength and endurance due to the deficit in contractile proteins.