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

• Main Authors: Reinders, Ilse, Murphy, Rachel, Brouwer, Ingeborg, Visser, Marjolein, Launer, Lenore, Siggeirsdottir, Kristin, Eiriksdottir, Gudny, Gudnason, Vilmundur, Jonsson, Palmi, Harris, Tamara, Lang, Thomas
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: eScholarship, University of California 2016
• Subjects: adipose tissue; aging; computed tomography; mortality risk; muscle; muscle composition; strength; Adiposity; Age Factors; Aged; 80 and over; Body Mass Index; Environment; Female; Gene-Environment Interaction; Health Behavior; Health Status; Humans; Iceland; Male; Mortality; Muscle Strength; Skeletal; Obesity; Proportional Hazards Models; Risk Factors; Socioeconomic Factors; Thigh; Tomography; X-Ray Computed
• Online Access: https://escholarship.org/uc/item/3bv0g07p

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.