BODY COMPOSITION, LOW MUSCLE MASS AND PHYSICAL PERFORMANCE IN MIDDLE AGED AND OLDER WOMEN: A CROSS-SECTIONAL STUDY
Body Composition, Muscle Strength, Physical Functional Performance, Aging, Epidemiology.
Introduction: Among the most clinically significant changes that occur during female aging, hormonal ones stand out, which culminate in important changes in body composition, leading to decreased muscle mass, bone density and increased fat mass. with changes in the pattern of their distribution. These changes cause significant impacts on the musculoskeletal system, reducing muscle strength and impairing the physical performance, functional capacity and health of women from middle age. Objective: To analyze the relationship between body composition, low muscle mass and physical performance in middle-aged and elderly women living in the community. Materials and Methods: This is an observational, analytical, cross-sectional study with an epidemiological nature. The population consisted of women aged 40 to 80 years, residing in the municipalities of Parnamirim and Santa Cruz, state of Rio Grande do Norte. Samples were collected for biochemical dosage, body composition and physical performance evaluations were performed, as well as the collection of sociodemographic, socioeconomic data and information regarding gynecological history and regular practice of physical activity. For statistical analysis, measures of central tendency and dispersion, Student's t-test, ROC curve, chi-square, logistic regression, Pearson correlation and canonical correlation were used, this last one is a multivariate analysis technique that aims to analyze the influence of the independent variable set on the dependent variable set. Results: The anthropometric indexes cut-off points were able to identify the presence of low muscle, except for VAI (visceral adiposity index) (p <0.05). After regression analysis, BAI (body adiposity index), WC (waist circumference), WHR (waist-hip ratio) and RCA (waist-height ratio) were associated with a higher risk of low muscle mass (14.5, 6.2, 1.8 and 5.0 respectively). The first three canonical functions were statistically significant, accounting for 97.54% of the shared variance between the two sets of variables. The first function was the one that best estimated the shared variance, in addition to presenting the highest canonical correlation and redundancy index (% cumulative variance = 82.52, Wilks Lambda = 0.66, canonical correlation = 0.532, p value <0.001). In the first canonical function, an inverse correlation was observed between the CI (conicity index) (-0.59) and the handgrip strength (0.84) and the SPPB (Short Physical Performance Battery )(0.68). While in the second canonical charge it was possible to observe that VAI and CI correlated inversely only with SPPB (0.47). Finally, the third canonical function showed inverse correlations between BAI (0.63), BMI (0.84), WHR (0.67) and CI (0.43) with gait speed (-0.59 and with the SPPB (-0.45) and direct correlation only with the time to sit and stand (0.52). Conclusions: Changes in body composition during the female aging process are associated with low muscle mass and decreased physical performance in middle-aged and elderly women. The cutoff points of the anthropometric indices seem to be effective in identifying low muscle mass, showing that increases in these indices increase the chance of presenting low muscle mass. Moreover, it can be observed that physical performance is significantly influenced by body composition. The results presented have important clinical relevance, since a better understanding about this theme is fundamental to provide scientific support for health care planning in the area of Geriatrics, Women's Health and Physical Therapy