title: Total insulinlike growth factor 1 and insulinlike growth factor binding protein levels, functional status, and mortality in older adults.
abstract: OBJECTIVE
  To assess the association between total insulinlike growth factor (IGF)-1, IGF binding protein-1 (IGFBP-1), and IGFBP-3 levels and functioning and mortality in older adults.
  
  
  METHODS
  Cohort study.
  
  
  METHODS
  One thousand one hundred twenty-two individuals aged 65 and older without prior cardiovascular disease events participating in the Cardiovascular Health Study.
  
  
  METHODS
  Baseline fasting plasma levels of IGF-1, IGFBP-1, and IGFBP-3 (defined as tertiles, T1-T3) were examined in relationship to handgrip strength, time to walk 15 feet, development of new difficulties with activities of daily living (ADLs), and mortality.
  
  
  RESULTS
  Higher IGFBP-1 predicted worse handgrip strength (P-trend(T1-T3)<.01) and slower walking speed (P-trend(T1-T3)=.03), lower IGF-1 had a borderline significant association with worse handgrip strength (P-trend(T1-T3)=.06), and better grip strength was observed in the middle IGFBP-3 tertile than in the low or high tertiles (P=.03). Adjusted for age, sex, and race, high IGFBP-1 predicted greater mortality (P-trend(T1-T3)<.001, hazard ratio (HR)(T3vsT1)=1.48, 95% confidence interval (CI)=1.15-1.90); this association was borderline significant after additional confounder adjustment (P-trend(T1-T3)=.05, HR(T3vsT1)=1.35, 95% CI=0.98-1.87). High IGFBP-1 was associated with greater risk of incident ADL difficulties after adjustment for age, sex, race, and other confounders (P-trend(T1-T3)=.04, HR(T3vsT1)=1.40, CI=1.01-1.94). Neither IGF-1 nor IGFBP-3 level predicted mortality or incident ADL difficulties.
  
  
  CONCLUSIONS
  In adults aged 65 and older, high IGFBP-1 levels were associated with greater risk of mortality and poorer functional ability, whereas IGF-1 and IGFBP-3 had little association with these outcomes.
authors.affiliation: Department of Epidemiology and Population Health, Albert Einstein College of Medicine, Bronx, New York 10461, USA. rkaplan@aecom.yu.edu
authors.forename: Robert C
authors.initials: RC
authors.lastname: Kaplan
authors.forename: Aileen P
authors.initials: AP
authors.lastname: McGinn
authors.forename: Michael N
authors.initials: MN
authors.lastname: Pollak
authors.forename: Lewis
authors.initials: L
authors.lastname: Kuller
authors.forename: Howard D
authors.initials: HD
authors.lastname: Strickler
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Rohan
authors.forename: XiaoNan
authors.initials: X
authors.lastname: Xue
authors.forename: Stephen B
authors.initials: SB
authors.lastname: Kritchevsky
authors.forename: Anne B
authors.initials: AB
authors.lastname: Newman
authors.forename: Bruce M
authors.initials: BM
authors.lastname: Psaty
mesh_terms: D000203:Activities of Daily Living; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood; D002318:Cardiovascular Diseases / Q000097:blood / Q000453:epidemiology / Q000503:physiopathology; D004797:Enzyme-Linked Immunosorbent Assay; D005215:Fasting; D005260:Female; D005500:Follow-Up Studies; D018737:Hand Strength / Q000502:physiology*; D006801:Humans; D015994:Incidence; D018970:Insulin-Like Growth Factor Binding Protein 1 / Q000097:blood*; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000097:blood*; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D011446:Prospective Studies; D012307:Risk Factors; D015996:Survival Rate / Q000639:trends; D014481:United States / Q000453:epidemiology; D016138:Walking / Q000502:physiology*
chemical_list: D015415:Biomarkers; D018970:Insulin-Like Growth Factor Binding Protein 1; D018972:Insulin-Like Growth Factor Binding Protein 3; D007334:Insulin-Like Growth Factor I