Free insulin-like growth factor-I and cognitive function in older persons living in community.
BACKGROUND
Increasing evidences from experimental and human studies suggest that the activity of the growth hormone (GH/insulin-like growth factor-I) axis may contribute to the age-related cognitive decline and poor cognition in late life.


OBJECTIVE
The aim of the present study was to evaluate the relationship of total serum free IGF-I and its binding protein-3 with cognitive performance in older persons aged 80 years or older.


METHODS
Data are from baseline evaluation of the ilSIRENTE study (n=353). Cognitive performance was evaluated using five items enclosed in the Minimum Data Set for Home Care assessment form: short-term memory, procedural memory, cognitive skills in daily decision making, verbal expression, comprehension. Free insulin-like growth factor-I (free IGF-I) and IGF-binding protein-3 (IGFBP-3) in blood were measured. Analysis of covariance (ANCOVA) was used to examine the relationship between cognitive impairment and the serum free IGF-I and IGFBP-3 concentrations, after adjustment for potential confounding variables.


RESULTS
After adjustment for potential confounders, which included age, gender, education, cerebrovascular disease, ischemic heart disease, congestive heart failure, hypertension, diabetes, depression, Parkinson diseases, thyroid diseases, smoking status, alcohol abuse, body mass index, and number of medications, individuals with verbal expression problems (n=20) and individuals with comprehension problems (n=24) had a significantly lower serum levels of readily dissociable IGF-I than participants without cognitive impairments. The serum IGFBP-3 presented the same behavior of free IGF-I.


CONCLUSIONS
The present study suggests that among old-old subjects living in the community lower levels of total serum free IGF-I and IGFBP-3 are associated with impairment of cognitive performance. This finding suggests that the GH/IGF-I axis may play an important role in the age-related decline of cognitive performance.
Landi
Francesco
F
Department of Gerontology and Geriatrics, Catholic University of Sacred Heart, 00168, Roma, Italy. francesco_landi@rm.unicatt.it
Capoluongo
Ettore
E
Russo
Andrea
A
Onder
Graziano
G
Cesari
Matteo
M
Lulli
Paola
P
Minucci
Angelo
A
Pahor
Marco
M
Zuppi
Cecilia
C
Bernabei
Roberto
R
D000203:Activities of Daily Living; D000369:Aged, 80 and over; D003071:Cognition / Q000502:physiology*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D018972:Insulin-Like Growth Factor Binding Protein 3; D018969:Insulin-Like Growth Factor Binding Proteins / Q000097:blood; D007334:Insulin-Like Growth Factor I / Q000032:analysis*; D007558:Italy / Q000453:epidemiology; D008297:Male; D008569:Memory Disorders / Q000453:epidemiology; D011446:Prospective Studies; D012111:Residence Characteristics
C515497:IGFBP3 protein, human; D018972:Insulin-Like Growth Factor Binding Protein 3; D018969:Insulin-Like Growth Factor Binding Proteins; D007334:Insulin-Like Growth Factor I