title: Greater Skeletal Muscle Fat Infiltration Is Associated With Higher All-Cause and Cardiovascular Mortality in Older Men.
abstract: BACKGROUND
  Skeletal muscle fat infiltration (myosteatosis) increases with aging, and has been associated with poor metabolic and musculoskeletal health, independent of overall adiposity. Studies examining the relationship of myosteatosis and mortality among older individuals recruited without regard to their health status are sparse.
  
  
  METHODS
  We evaluated the association of peripheral computed tomography measured calf myosteatosis (intermuscular fat and muscle density as a measure of intramuscular fat) with mortality in 1,063 community-dwelling older men. Cox proportional hazards models were used to estimate the risk of mortality independent of potential confounders.
  
  
  RESULTS
  During a mean follow-up of 7.2 years, 317 participants died. After adjustment for potential covariates and additional adjustment for whole body fat, lower skeletal muscle density was associated with increased all-cause mortality and cardiovascular disease mortality (hazard ratio [95% confidence interval] per standard deviation lower skeletal muscle density: 1.24 [1.09-1.41] and 1.46 [1.15-1.86], respectively), and to some extent with noncardiovascular disease mortality (1.18 [1.0-1.38], p = .053). After adjusting for trunk fat in a separate multivariable model, the association between skeletal muscle density and all-cause and cardiovascular disease mortality remained significant (both p < .01), while its association with noncardiovascular disease mortality became of borderline significance (p = .085). No other measures of adiposity, including calf intermuscular fat, were associated with mortality.
  
  
  CONCLUSIONS
  Our study reveals an independent association between skeletal muscle density and mortality in a community-based sample of older, predominantly Caucasian men. Further studies are needed to establish if this association is independent of other ectopic fat depots, and to identify the biological mechanisms underlying this relationship.
authors.affiliation: Department of Epidemiology, Graduate School of Public Health, University of Pittsburgh, Pennsylvania. miljkovici@edc.pitt.edu.
authors.forename: Iva
authors.initials: I
authors.lastname: Miljkovic
authors.affiliation: Department of Epidemiology, Graduate School of Public Health, University of Pittsburgh, Pennsylvania.
authors.forename: Allison L
authors.initials: AL
authors.lastname: Kuipers
authors.affiliation: Department of Epidemiology, Graduate School of Public Health, University of Pittsburgh, Pennsylvania.
authors.forename: Jane A
authors.initials: JA
authors.lastname: Cauley
authors.affiliation: Department of Epidemiology, Graduate School of Public Health, University of Pittsburgh, Pennsylvania.
authors.forename: Tanushree
authors.initials: T
authors.lastname: Prasad
authors.affiliation: Research Service, Veterans Affairs Medical Center, Portland, Oregon.
authors.forename: Christine G
authors.initials: CG
authors.lastname: Lee
authors.affiliation: Center for Chronic Disease Outcomes Research, Veterans Affairs Medical Center, Minneapolis, Minneapolis.
authors.forename: Kristine E
authors.initials: KE
authors.lastname: Ensrud
authors.affiliation: California Pacific Medical Center, San Francisco.
authors.forename: Peggy M
authors.initials: PM
authors.lastname: Cawthon
authors.affiliation: Stanford Prevention Research Center, Department of Medicine, School of Medicine, Stanford University, Palo Alto, CA.
authors.forename: Andrew R
authors.initials: AR
authors.lastname: Hoffman
authors.affiliation: Department of Medicine, Columbia University, New York, New York.
authors.forename: Thuy-Tien
authors.initials: TT
authors.lastname: Dam
authors.affiliation: Department of Radiology, McMaster University, Hamilton, Ontario, Canada.
authors.forename: Christopher L
authors.initials: CL
authors.lastname: Gordon
authors.affiliation: Department of Epidemiology, Graduate School of Public Health, University of Pittsburgh, Pennsylvania.
authors.forename: Joseph M
authors.initials: JM
authors.lastname: Zmuda
mesh_terms: D000273:Adipose Tissue / Q000033:anatomy & histology*; D000368:Aged; D001823:Body Composition; D002318:Cardiovascular Diseases / Q000401:mortality*; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D018482:Muscle, Skeletal / Q000033:anatomy & histology*; D016016:Proportional Hazards Models; D014481:United States / Q000453:epidemiology
keywords: Aging.; Mortality; Muscle density; Skeletal muscle fat infiltration
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