Muscle Quality and Myosteatosis: Novel Associations With Mortality Risk: The Age, Gene/Environment Susceptibility (AGES)-Reykjavik Study.

• Main Authors: Reinders, Ilse, Murphy, Rachel A, Brouwer, Ingeborg A, Visser, Marjolein, Launer, Lenore, Siggeirsdottir, Kristin, Eiriksdottir, Gudny, Gudnason, Vilmundur, Jonsson, Palmi V, Lang, Thomas F, Harris, Tamara B, Age, Gene/Environment Susceptibility (AGES)-Reykjavik Study
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: eScholarship, University of California 2016
• Subjects: Age; Gene/Environment Susceptibility (AGES)-Reykjavik Study; Thigh; Muscle; Skeletal; Humans; Obesity; Tomography; X-Ray Computed; Body Mass Index; Mortality; Proportional Hazards Models; Risk Factors; Health Behavior; Environment; Age Factors; Health Status; Socioeconomic Factors; Aged; 80 and over; Iceland; Female; Male; Adiposity; Muscle Strength; Gene-Environment Interaction; adipose tissue; aging; computed tomography; mortality risk; muscle composition; strength; and over; Mathematical Sciences; Medical and Health Sciences; Epidemiology
• Online Access: https://escholarship.org/uc/item/5m41n0nx

Muscle composition may affect mortality risk, but prior studies have been limited to specific samples or less precise determination of muscle composition. We evaluated associations of thigh muscle composition, determined using computed tomography imaging, and knee extension strength with mortality risk among 4,824 participants aged 76.4 (standard deviation (SD), 5.5) years from the Age, Gene/Environment Susceptibility (AGES)-Reykjavik Study (2002-2006). Cox proportional hazards models were used to estimate hazard ratios. After 8.8 years of follow-up, there were 1,942 deaths. For men, each SD-increment increase in muscle lean area, muscle quality, and strength was associated with lower mortality risk, with decreases ranging between 11% and 22%. Each SD-increment increase in intermuscular adipose tissue and intramuscular adipose tissue was associated with higher mortality risk (hazard ratio (HR) = 1.13 (95% confidence interval (CI): 1.06, 1.22) and HR = 1.23 (95% CI: 1.15, 1.30), respectively). For women, each SD-increment increase in muscle lean area, muscle quality, and strength was associated with lower mortality risk, with decreases ranging between 12% and 19%. Greater intramuscular adipose tissue was associated with an 8% higher mortality risk (HR = 1.08, 95% CI: 1.01, 1.16). This study shows that muscle composition is associated with mortality risk. These results also show the importance of improving muscle strength and area and lowering muscle adipose tissue infiltration.