Assessment of body composition, muscle strength, functional capacity in a cohort of Brazilian women aged 20 to 90 years

• Grant number: 23/07761-9
• Support Opportunities: Regular Research Grants
• Field of knowledge: Health Sciences - Medicine - Medical Clinics
• Principal Investigator: Diogo Souza Domiciano
• Grantee: Diogo Souza Domiciano
• Host Institution: Hospital das Clínicas da Faculdade de Medicina da USP (HCFMUSP). Secretaria da Saúde (São Paulo - Estado). São Paulo , SP, Brazil
• Associated researchers: Alan Lins Fernandes ; Camille Pinto Figueiredo ; Thiago Quadrante Freitas ; Valéria de Falco Caparbo
• Associated scholarship(s): 24/02786-6 - Assessment of body composition, muscle strength, functional capacity in a cohort of Brazilian women aged 20 to 90 years, BP.TT

Abstract

Introduction. Aging leads to progressive loss of muscle mass, decreased muscle strength and impairment of functional capacity, a condition known as sarcopenia, which is associated with higher mortality. Concomitantly, there is redistribution of fat and increase in adipose tissue (sarcopenic obesity), which accelerates atherosclerosis. Intramuscular fat infiltration further impairs muscle function and aggravates sarcopenia. Pathogenesis involves increased circulation of inflammatory cytokines, metabolic and hormonal changes, and alterations in the secretion of myokines by skeletal muscle and adipokines by adipose tissue. Since the characteristics of body composition are determined genetically and by environmental factors, large variations in body composition between different populations are expected. However, there are no studies in Brazilian population that consistently evaluated the evolution of physical measures (muscle strength and functional capacity) assessed by standardized tests as a function of age group, as well as their correlation with quantitative measures of lean mass and adipose mass.Objectives. Primary: to establish an age-reference curve of muscle function parameters (muscle strength and functional capacity) in a cohort of healthy Brazilian women between 20 and 90 years old. Secondary: to correlate muscle strength and functional capacity with lean mass (total and appendicular) and adiposity (total and visceral fat) measurements obtained by bone densitometry (DXA); to investigate the association between biomarkers (cytokines, myokines and adipokines) and muscle and fat parameters; and to investigate the impact of intramuscular fat assessed by magnetic resonance imaging (MRI) of the thigh on muscle strength and functional capacity.Methods. A total of 450 healthy Brazilian women aged 20 years and older will be consecutively recruited for the study. Clinical characteristics will be obtained by clinical questionnaire. Body composition (lean mass and fat mass) will be obtained by whole body densitometry (GE Lunar iDXA). Grip strength will be measured with a hand dynamometer (Handgrip) and quadriceps strength will be assessed by the five times sit to stand test (5XSST). Functional capacity will be assessed by gait speed and Short Physical Performance Battery (SPPB). Thigh MRI will be performed to quantify intramuscular fat. Circulating biomarkers will be measured, including cytokines [interleukins IL-6, IL-10, tumor necrosis factor alpha (TNF-±), interferon-gamma (IFN-³)], myokines and neuromuscular junction markers [myostatin, GDF- 15 (growth factor differentiation-15), BNDF (brain derived neurotrophic factor), PIIINP (N-terminal type 3 procollagen)], adipokines (adiponectin, leptin) and hormones [cortisol, dehydroepiandrosterone sulfate (DHEA), IGF-1 (insulin-like growth factor 1)].Statistical analysis. To establish parameters of normality by age group, individuals will be divided into groups by decades (20-29, 30-39, 40-49, 50-59, 60-69, 70-79, 80+ years old). Multiple linear regression models will be constructed to predict lean mass, fat mass, muscle strength and physical capacity as a function of age, weight, and height. Results will be illustrated using scatter plots. The significance level adopted will be p d 0.05. (AU)