title: The muscle quality index and mortality among males and females.
abstract: The muscle quality index (MQI) was proposed as a measure to quantify age-related alterations in muscle function. It is unknown if the MQI predicts mortality.
  
  
  
  This was a population-based cohort study from the Third National Health and Nutrition Survey (NHANES III; 1988-1994). The MQI was quantified using a timed sit-to-stand test, body mass, and leg length. Vital status was obtained through the National Center for Health Statistics. We fit multivariable-adjusted regression models to estimate the hazard ratio (HR) and 95% confidence interval (CI) between the MQI and mortality.
  
  
  
  During 14.6 years of follow-up, 3299 (73.1%) of 4510 study participants died. Lower MQI was associated with a higher risk of mortality (Ptrend <.001). The multivariable-adjusted HR for mortality was 1.50 (95% CI, 1.15-1.96) for those in the lowest quintile of MQI compared to the highest quintile. The association between MQI and mortality was stronger among males (highest vs. lowest quintile of MQI, HR = 1.37 [95% CI, 1.00-1.87]; Ptrend = .001) compared to females (highest vs. lowest quintile of MQI, HR = 1.27 (95% CI, 0.89-1.83); Ptrend = .044; Pinteraction = .005].
  
  
  
  The MQI predicts mortality and may differ between males and females. Additional research examining the MQI is warranted.
authors.affiliation: Dana-Farber Cancer Institute, Division of Population Sciences, Boston, MA; Department of Biostatistics & Epidemiology, Center for Clinical Epidemiology & Biostatistics, University of Pennsylvania, Philadelphia. Electronic address: justinc_brown@dfci.harvard.edu.
authors.forename: Justin C
authors.initials: JC
authors.lastname: Brown
authors.affiliation: Department of Biostatistics & Epidemiology, Center for Clinical Epidemiology & Biostatistics, University of Pennsylvania, Philadelphia.
authors.forename: Michael O
authors.initials: MO
authors.lastname: Harhay
authors.affiliation: Division of Nephrology, Department of Medicine, Drexel University College of Medicine, Philadelphia, PA.
authors.forename: Meera N
authors.initials: MN
authors.lastname: Harhay
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging / Q000502:physiology*; D015992:Body Mass Index; D005260:Female; D006801:Humans; D015994:Incidence; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D009026:Mortality / Q000639:trends*; D015999:Multivariate Analysis; D018482:Muscle, Skeletal / Q000502:physiology*; D009749:Nutrition Surveys; D018570:Risk Assessment; D055948:Sarcopenia / Q000401:mortality* / Q000503:physiopathology*; D012737:Sex Factors; D016019:Survival Analysis; D014481:United States
keywords: Aging; Mobility; Muscle strength; Physical activity; Physical function