title: Higher Leptin and Adiponectin Concentrations Predict Poorer Performance-based Physical Functioning in Midlife Women: the Michigan Study of Women's Health Across the Nation.
abstract: BACKGROUND
  Excess fat mass is a greater contributor to functional limitations than is reduced lean mass or the presence of obesity-related conditions. The impact of fat mass on physical functioning may be due to adipokines, adipose-derived proteins that have pro- or anti-inflammatory properties.
  
  
  METHODS
  Serum samples from 1996 to 2003 that were assayed for leptin, adiponectin, and resistin were provided by 511 participants from the Michigan site of the Study of Women's Health Across the Nation. Physical functioning performance was assessed annually during study visits from 1996 to 2003.
  
  
  RESULTS
  Among this population of Black and White women (mean baseline age = 45.6 years, SD = 2.7 years), all of whom were premenopausal at baseline, higher baseline leptin concentrations predicted longer stair climb, sit-to-rise, and 2-pound lift times and shorter forward reach distance (all p < .01). This relationship persisted after adjustment for age, BMI, percent skeletal muscle mass, race/ethnicity, economic strain, bodily pain, diabetes, knee osteoarthritis, and C-reactive protein. Baseline total adiponectin concentrations did not predict any mobility measures but did predict quadriceps strength; a 1 µg/mL higher adiponectin concentration was associated with 0.64 Nm lower quadriceps strength (p = .02). Resistin was not associated with any of the physical functioning performance measures. Change in the adipokines was not associated with physical functioning.
  
  
  CONCLUSIONS
  In this population of middle-aged women, higher baseline leptin concentrations predicted poorer mobility-based functioning, whereas higher adiponectin concentrations predicted reduced quadriceps strength. These findings suggest that the relationship between the adipokines and physical functioning performance is independent of other known correlates of poor functioning.
authors: Department of Epidemiology and ckarvone@umich.edu.
authors: Carrie A
authors: CA
authors: Karvonen-Gutierrez
authors: Department of Epidemiology and.
authors: Huiyong
authors: H
authors: Zheng
authors: Department of Environmental Health Sciences, University of Michigan School of Public Health, Ann Arbor.
authors: Peter
authors: P
authors: Mancuso
authors: Department of Epidemiology and.
authors: Siobán D
authors: SD
authors: Harlow
mesh_terms: D052242:Adiponectin / Q000097:blood*; D005260:Female; D006801:Humans; D020738:Leptin / Q000097:blood*; D008137:Longitudinal Studies; D008824:Michigan; D008875:Middle Aged; D053580:Muscle Strength / Q000502:physiology; D010809:Physical Fitness / Q000502:physiology*; D011237:Predictive Value of Tests; D052243:Resistin / Q000097:blood; D014481:United States
chemical_list: D052242:Adiponectin; D020738:Leptin; D052243:Resistin
keywords: Adipokine; Adiponectin; Leptin; Obesity; Physical functioning