title: Body Composition Remodeling and Mortality: The Health Aging and Body Composition Study.
abstract: BACKGROUND
  Age-related losses of lean mass and shifts to central adiposity are related to functional decline and may predict mortality and/or explain part of the risk of weight loss. To determine how mortality risk is related to shifts in body composition, changes should be considered in the context of overall weight change.
  
  
  METHODS
  Five-year changes in body composition were assessed with computed tomography (cm2) and dual x-ray absorptiometry (kg) in 869 men and 934 women initially aged 70-79 years. All-cause mortality was monitored for up to 12 years (2002-2003 to September 30, 2014), and risk was assessed using sex-specific Cox models.
  
  
  RESULTS
  Both men and women lost weight, visceral fat area, thigh muscle area, lean mass, and fat mass (all p < .01) but gained intermuscular thigh fat area (p < .01). There were 995 deaths. After adjustment for total weight change, demographics, and chronic disease, losing thigh muscle area was associated with higher mortality in both men (1.21, 1.08-1.35) and women (1.18, 1.01-1.37, per 9.0cm2) and was especially strong in normal weight (body mass index < 25kg/m2) individuals and those losing weight. Losing intermuscular thigh fat was protective against mortality only in normal weight (0.66, 0.51-0.86) and weight stable men (0.79, 0.66-0.95, per 3.2cm2). Changes in visceral fat area were not associated with mortality.
  
  
  CONCLUSIONS
  Older adults with greater loss of thigh muscle than expected for overall weight change had a higher mortality risk compared to those with relative thigh muscle preservation, suggesting that conservation of muscle mass is important for survival in old age.
authors: Department of Epidemiology, University of Pittsburgh, Pennsylvania.
authors: Adam J
authors: AJ
authors: Santanasto
authors: Translational Research Institute for Metabolism and Diabetes, Florida Hospital, Sanford Burnham, Orlando.
authors: Bret H
authors: BH
authors: Goodpaster
authors: Sticht Center on Aging, Wake Forest School of Medicine, Winston-Salem, North Carolina.
authors: Stephen B
authors: SB
authors: Kritchevsky
authors: Department of Epidemiology, University of Pittsburgh, Pennsylvania.
authors: Iva
authors: I
authors: Miljkovic
authors: Department of Preventive Medicine, University of Tennessee Health Science Center, Memphis.
authors: Suzanne
authors: S
authors: Satterfield
authors: Department of Epidemiology and Biostatistics, University of California at San Francisco.
authors: Ann V
authors: AV
authors: Schwartz
authors: California Pacific Medical Center Research Institute, San Francisco.
authors: Steven R
authors: SR
authors: Cummings
authors: Department of Epidemiology, University of Pittsburgh, Pennsylvania.
authors: Robert M
authors: RM
authors: Boudreau
authors: Intramural Research Program, National Institute on Aging, Bethesda, Maryland.
authors: Tamara B
authors: TB
authors: Harris
authors: Department of Epidemiology, University of Pittsburgh, Pennsylvania.
authors: Anne B
authors: AB
authors: Newman
mesh_terms: D000273:Adipose Tissue; D000368:Aged; D000375:Aging; D001823:Body Composition; D005260:Female; D006801:Humans; D008297:Male; D009026:Mortality; D018482:Muscle, Skeletal / Q000033:anatomy & histology; D011446:Prospective Studies
keywords: Body composition; Mortality; Muscle; Prospective cohort