Total insulinlike growth factor 1 and insulinlike growth factor binding protein levels, functional status, and mortality in older adults.
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.
Kaplan
Robert C
RC
Department of Epidemiology and Population Health, Albert Einstein College of Medicine, Bronx, New York 10461, USA. rkaplan@aecom.yu.edu
McGinn
Aileen P
AP
Pollak
Michael N
MN
Kuller
Lewis
L
Strickler
Howard D
HD
Rohan
Thomas E
TE
Xue
XiaoNan
X
Kritchevsky
Stephen B
SB
Newman
Anne B
AB
Psaty
Bruce M
BM
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*
D015415:Biomarkers; D018970:Insulin-Like Growth Factor Binding Protein 1; D018972:Insulin-Like Growth Factor Binding Protein 3; D007334:Insulin-Like Growth Factor I