IGF1 and its binding proteins 3 and 1 are differentially associated with metabolic syndrome in older men.
OBJECTIVE
Circulating IGF1 declines with age, and reduced circulating IGF1 is associated with increased cardiovascular mortality in some but not all studies. The relationship between IGF-binding proteins 3 and 1 (IGFBP3 and IGFBP1) with risk of cardiovascular disease remains unclear. We sought to examine associations between IGF1, IGFBP3 and IGFBP1 with metabolic syndrome in older men.


METHODS
Cross-sectional analysis of 3980 community-dwelling men aged >or=70 years. Methods Morning plasma levels of IGF1, IGFBP3 and IGFBP1 were assayed. Metabolic syndrome was defined according to National Cholesterol Education Program-Adult Treatment Panel III (NCEP-ATPIII) criteria.


RESULTS
For IGF1 and IGFBP3, there was a U-shaped relationship, with middle quintiles possessing the lowest odds ratios (OR) for metabolic syndrome (reference Q1, Q3 IGF1: OR 0.74, 95% confidence intervals 0.57-0.96, Q3 IGFBP3: OR 0.67, 0.51-0.87). Increasing IGFBP1 was associated with reduced risk of metabolic syndrome with a dose-response gradient (reference Q1, OR for Q2 to Q5 IGFBP1: 0.56, 0.33, 0.22 and 0.12 respectively, P<0.001). IGF1 was associated with two, IGFBP1 with four and IGFBP3 with all five components of the metabolic syndrome. The ratio of IGF1/IGFBP3 was not associated with metabolic syndrome.


CONCLUSIONS
In older men, both lower and higher IGF1 and IGFBP3 levels may be metabolically unfavourable. IGFBP1, as a marker of insulin sensitivity, is relevant in the assessment of metabolic syndrome, while the IGF1/IGFBP3 ratio is less informative. Longitudinal follow-up of this cohort would be needed to determine whether these distributions of IGF1, IGFBP3 and IGFBP1 predict incidence of cardiovascular events during male ageing.
Yeap
Bu B
BB
School of Medicine and Pharmacology, University of Western Australia, Perth, Western Australia 6009, Australia. byeap@cyllene.uwa.edu.au
Chubb
S A Paul
SA
Ho
Ken K Y
KK
Setoh
Johnson W S
JW
McCaul
Kieran A
KA
Norman
Paul E
PE
Jamrozik
Konrad
K
Flicker
Leon
L
D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000378:metabolism; D015992:Body Mass Index; D015331:Cohort Studies; D015897:Comorbidity; D006801:Humans; D018970:Insulin-Like Growth Factor Binding Protein 1 / Q000097:blood*; D018972:Insulin-Like Growth Factor Binding Protein 3; D018969:Insulin-Like Growth Factor Binding Proteins / Q000097:blood*; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D008297:Male; D024821:Metabolic Syndrome / Q000453:epidemiology* / Q000378:metabolism*; D011237:Predictive Value of Tests; D012307:Risk Factors
C032231:IGFBP1 protein, human; C515497:IGFBP3 protein, human; D018970:Insulin-Like Growth Factor Binding Protein 1; D018972:Insulin-Like Growth Factor Binding Protein 3; D018969:Insulin-Like Growth Factor Binding Proteins; D007334:Insulin-Like Growth Factor I