Relationship between serum insulin-like growth factor-1 levels and Alzheimer's disease and vascular dementia.
OBJECTIVE
To determine whether decreased serum insulin-like growth factor-1 (IGF-1) levels could be a risk factor for dementia in older people.


METHODS
Case control study.


METHODS
Showa University Karasuyama Hospital, Tokyo, Japan.


METHODS
A total of 436 Japanese elderly subjects: 106 patients with Alzheimer's disease (AD), 103 patients with vascular dementia (VaD), and 227 age-matched controls without dementia.


METHODS
Serum concentrations of IGF-1 and atherogenic lipoproteins, carotid artery intima-media thickness (IMT), and plaques were determined.


RESULTS
Mini-Mental State Examination (MMSE) scores were positively correlated with serum IGF-1 concentrations as well as mean blood pressure or body mass index and were negatively correlated with age, serum low-density lipoprotein cholesterol and lipoprotein(a) concentrations, and carotid IMT. Serum IGF-1 concentrations had a significant inverse correlation with carotid IMT. Analysis across the IGF-1 quartiles revealed a threshold effect of low IGF-1 on MMSE score in subjects with the IGF-1 levels of 140 ng/mL or less (50% percentile) versus those with IGF-1 levels greater than 140 ng/mL. Multiple logistic regression concerning AD and VaD retained serum IGF-1 concentrations of 140 ng/mL or less and carotid IMT of 0.9 mm or more. Patients with AD and VaD had significantly lower IGF-1 concentrations and greater mean IMT than nondemented controls.


CONCLUSIONS
These results suggest that decreased serum IGF-1 level and the progression of carotid atherosclerosis could play a role as independent risk factors for dementia.
Watanabe
Takuya
T
Department of Biochemistry, Showa University School of Medicine, Tokyo, Japan. watanabemd@med.showa-u.ac.jp
Miyazaki
Akira
A
Katagiri
Takashi
T
Yamamoto
Hideki
H
Idei
Tsunenori
T
Iguchi
Takashi
T
D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000097:blood / Q000175:diagnosis*; D016022:Case-Control Studies; D015140:Dementia, Vascular / Q000097:blood / Q000175:diagnosis*; D003937:Diagnosis, Differential; D005260:Female; D015577:Geriatric Assessment / Q000706:statistics & numerical data; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D007564:Japan; D008055:Lipids / Q000097:blood; D008297:Male; D008609:Mental Status Schedule / Q000706:statistics & numerical data; D008875:Middle Aged; D012307:Risk Factors; D013223:Statistics as Topic
D008055:Lipids; D007334:Insulin-Like Growth Factor I