title: Gender-Specific Associations in Age-Related Changes in Resting Energy Expenditure (REE) and MRI Measured Body Composition in Healthy Caucasians.
abstract: The effect of gender as well as gender-specific changes of fat free mass (FFM) and its metabolic active components (muscle mass and organ masses [OMs]) and fat mass (FM) on age-related changes in resting energy expenditure (REE) are not well defined. We hypothesized that there are gender differences in (1) the age-specific onset of changes in detailed body composition (2); the onset of changes in body composition-REE associations with age.
  
  
  
  Using a cross-sectional magnetic resonance imaging database of 448 Caucasian participants (females and males) with comprehensive data on skeletal muscle (SM) mass, adipose tissue (AT), OMs, and REE.
  
  
  
  We observed gender-specific differences in the onset of age-related changes in metabolic active components and REE. Declines in body composition and REE started earlier in females than in males for SM (29.4 vs 39.6 years), AT (38.2 vs 49.9 years), OM (34.7 vs 45.7 years), and REE (31.9 vs 36.8 years). The age-related decrease of AT was significantly higher in females than in males (-5.69kg/decade vs -0.59kg/decade). In females adjusted REEmFFM&FM (resting energy expenditure measured adjusted for FFM and FM) and REEmSM/OM/AT (resting energy expenditure measured adjusted for skeletal muscle and organ mass and adipose tissue) decreased by -145 kJ/d/decade and -604.8 kJ/d/ decade after the age of 35.2 respectively 34.3 years. SM was main determinant of REEm in females (R (2) = .67) and males (R (2) = .66) with remaining variance mainly explained by kidney mass (R (2) = .07) in females and liver mass (R (2) = .09) in males.
  
  
  
  We concluded that gender affects the age-related changes in body composition as well as changes in body composition-REE relationship. This trial was registered at linicaltrials.gov as NCT01737034.
authors.affiliation: Institute of Human Nutrition and Food Science, Christian-Albrechts-Universität zu Kiel, Germany.
authors.forename: Corinna
authors.initials: C
authors.lastname: Geisler
authors.affiliation: Institute of Human Nutrition and Food Science, Christian-Albrechts-Universität zu Kiel, Germany.
authors.forename: Wiebke
authors.initials: W
authors.lastname: Braun
authors.affiliation: Institute of Human Nutrition and Food Science, Christian-Albrechts-Universität zu Kiel, Germany.
authors.forename: Maryam
authors.initials: M
authors.lastname: Pourhassan
authors.affiliation: Institute of Human Nutrition and Food Science, Christian-Albrechts-Universität zu Kiel, Germany.
authors.forename: Lisa
authors.initials: L
authors.lastname: Schweitzer
authors.affiliation: Clinic for Diagnostic Radiology, Section Biomedical Imaging, Molecular Imaging North Competence Center CC, Kiel, Germany.
authors.forename: Claus-Christian
authors.initials: CC
authors.lastname: Glüer
authors.affiliation: Institute of Human Nutrition and Food Science, Christian-Albrechts-Universität zu Kiel, Germany. Institute of Nutritional Medicine, Universität Hohenheim, Stuttgart, Germany.
authors.forename: Anja
authors.initials: A
authors.lastname: Bosy-Westphal
authors.affiliation: Institute of Human Nutrition and Food Science, Christian-Albrechts-Universität zu Kiel, Germany. mmueller@nutrfoodsc.uni-kiel.de.
authors.forename: Manfred J
authors.initials: MJ
authors.lastname: Müller
mesh_terms: D000273:Adipose Tissue / Q000000981:diagnostic imaging / Q000378:metabolism; D000328:Adult; D017668:Age of Onset; D000375:Aging / Q000502:physiology*; D001823:Body Composition / Q000502:physiology*; D003430:Cross-Sectional Studies; D004734:Energy Metabolism / Q000502:physiology*; D005260:Female; D005858:Germany / Q000453:epidemiology; D006801:Humans; D007668:Kidney / Q000473:pathology*; D008099:Liver / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000000981:diagnostic imaging / Q000378:metabolism; D009929:Organ Size; D012737:Sex Factors
keywords: Age-specific; Body composition changes; Caucasian; Resting energy expenditure; Sex-specific