title: IGF1 and its binding proteins 3 and 1 are differentially associated with metabolic syndrome in older men.
abstract: 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.
authors.affiliation: School of Medicine and Pharmacology, University of Western Australia, Perth, Western Australia 6009, Australia. byeap@cyllene.uwa.edu.au
authors.forename: Bu B
authors.initials: BB
authors.lastname: Yeap
authors.forename: S A Paul
authors.initials: SA
authors.lastname: Chubb
authors.forename: Ken K Y
authors.initials: KK
authors.lastname: Ho
authors.forename: Johnson W S
authors.initials: JW
authors.lastname: Setoh
authors.forename: Kieran A
authors.initials: KA
authors.lastname: McCaul
authors.forename: Paul E
authors.initials: PE
authors.lastname: Norman
authors.forename: Konrad
authors.initials: K
authors.lastname: Jamrozik
authors.forename: Leon
authors.initials: L
authors.lastname: Flicker
mesh_terms: 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
chemical_list: 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