Relación entre la masa muscular, la densidad mineral ósea, la fuerza muscular, la aptitud funcional y la calidad muscular en personas mayores = Relationship between muscle mass, bone mineral density, muscle strength, functional fitness and muscle quality in older people

Abstract

RELATIONSHIP BETWEEN MUSCLE MASS, BONE MINERAL DENSITY, MUSCLE STRENGTH, FUNCTIONAL FITNESS AND MUSCLE QUALITY IN OLDER PEOPLE Introduction: As part of the aging process, older people show a progressive decrease in bone mineral density (BMD), muscle mass, muscle strength and functional fitness. But when this decline exceeds normal levels, two well-known problems that affect the health of older people arise: sarcopenia and osteoporosis. Objective: The aim of this study was to determine the frequency of sarcopenia and osteoporosis in a group of older people from León, Spain. In addition, this study explored the association between muscle mass, BMD, muscle strength, functional fitness and muscle quality (MQ). Materials and Methods: A cross-sectional study was carried out on 83 men and 175 women (mean age 70.9 SD 5.5 years and 71.5 SD 5.2 years, respectively). Lean mass (LM) (total, arms, legs, thighs and appendicular), femur neck BMD (FNBMD) and lumbar spine BMD (LSBMD) were assessed by dual-energy X-ray absorptiometry. The isometric maximum strength of leg extension (IMSLE) and biceps curl were assessed by a load cell. The dynamic maximum strength of biceps curl (DMSBC) and leg extension were measured by one-repetition maximun (1-RM). The mean power measures of leg extension (MPLE) at 40%, 50%, 60%, 70% and 80% 1-RM were assessed with a linear motion transducer. The hand grip strength (HGS) was measured with a Jamar dynamometer. The functional fitness was assessed according to four tests taken from the Senior Fitness Test: Arm curl, Chair stand, Step-in-place, and 8 foot up-and-go (8f-UG). The MQ was defined by dividing each test of muscle strength by the specific muscle mass of upper and lower limbs. The osteoporosis of femur neck (OPFN) and the osteoporosis of lumbar spine XXIV (OPLS) were determined by the T-score of the FNBMD and LSBMD, respectively (<-2.5). The sarcopenia was determined according to the definition of the EWGSOP with the following criteria: appendicular lean mass index (ALMI), HGS and 8F-UG. 643316135 Results: The frequency of sarcopenia was 2.3%, while the OPFN was 11.6% and the OPLS was 22.5%; this last was higher in the women (p = 0.001). Most measurements of LM were correlated with muscle strength of arms and legs; however, in the linear regression analysis after adjustment for age and BMI, the ALMI did not behave as an explanatory variable of HGS in both sexes (important criteria used in the evaluation of sarcopenia). Moreover, the ALMI showed better associations with other tests of strength, especially with the MPLE evaluated up to 70% of 1-RM in women and up to 80% of 1-RM in men. Low performance on each test of SFT battery did not show major associations with the indicators of LM; while the tests of muscle strength and MQ showed higher significant differences in both sexes (p <0.05). The measurements of LM were positively correlated with LSBMD in women and FNBMD in both sexes (p <0.01); with respect to muscle strength, important positive correlations were presented in men between the FN...