INFLUENCE OF VISCERAL FAT AND SUBCUTANEOUS FAT ON MUSCLE MASS IN OLDER ADULTS

• Grant number: 25/18815-8
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: September 01, 2025
• End date: August 31, 2026
• Field of knowledge: Health Sciences - Physiotherapy and Occupational Therapy
• Principal Investigator: Tiago da Silva Alexandre
• Grantee: Ingrid Sant'Ana Guillen
• Host Institution: Centro de Ciências Biológicas e da Saúde (CCBS). Universidade Federal de São Carlos (UFSCAR). São Carlos , SP, Brazil
• Associated research grant: 24/01918-6 - Brain, muscle, bone and adipose tissue interplay: unveiling mechanisms to prevent frailty and promote healthy ageing, AP.TEM

Abstract

Introduction: The global population ageing and the increasing prevalence of obesity are interconnected phenomena that significantly impact public health. Obesity, characterized by the excessive accumulation of body fat, is associated with chronic diseases and adverse outcomes, especially in older adults. Muscle mass, in turn, is essential for the generation of muscle strength, mobility, and metabolism, and its loss is associated with a higher risk of falls, fractures, and death in older adults. Although the relationship between body fat and muscle mass has been studied in the literature, the specific contribution of each type of fat, visceral or subcutaneous, to changes in muscle mass throughout the ageing process is still unclear. Objectives: 1) To analyse whether higher visceral fat is associated with low muscle mass in people aged 40 and over; 2) To analyse whether higher subcutaneous fat is associated with low muscle mass in people aged 40 and over. Methods: This is a cross-sectional study with data from approximately 50,000 UK Biobank participants aged 40 years or older, assessed in 2014. The exposure variables will be: 1) visceral fat, defined as adipose tissue within the abdominal cavity, measured in litres (L); and 2) subcutaneous fat, defined as subcutaneous adipose tissue in the abdomen, also measured in litres (L). The outcome variable will be muscle mass, defined as the total fat-free thigh volume, measured in litres (L), obtained by the sum of the anterior and posterior muscle compartments of the thighs. Both fat types and muscle mass were assessed by magnetic resonance imaging. Linear regression models will be performed to analyse the associations between visceral fat, subcutaneous fat, and muscle mass, adjusted for sociodemographic, behavioral, clinical characteristics, and biochemical measurements. Expected results: Higher amounts of visceral and subcutaneous fat are expected to be associated with lower muscle mass, reinforcing the importance of body composition in the metabolic and functional health of older adults. Therefore, understanding the specific influence of each type of fat on muscle mass can guide more effective strategies for assessing, intervening, and promoting functionality and quality of life in old age.