title: IGF-I/IGFBP-3 ratio: a mechanistic insight into the metabolic syndrome.
abstract: Recent reports suggest that IGF (insulin-like growth factor)-I and IGFBP-3 (IGF-binding protein-3) have independent and opposing mechanistic effects on insulin. The aim of the present study was to assess the relationship between the IGF-I/IGFBP-3 ratio and the metabolic syndrome. We examined 3281 subjects (1463 men and 1818 women, aged 20-49 years), otherwise healthy adults, who participated in NHANES III (Third National Health and Nutrition Examination Survey), which has released measurements of IGF-I and IGFBP-3. Insulin resistance was estimated using the computer HOMA2 (homoeostatic model assessment 2) model. The updated ATP-III (Adult Treatment Panel III) definition of the metabolic syndrome was used. We applied adjusted logistic and linear regression models. After adjusting for age and race, men and women in the lowest quartile of the IGF-I/IGFBP-3 ratio were 3-fold more likely to meet the ATP-III definition of the metabolic syndrome and twice as likely to be insulin-resistant. Mean values of the IGF-I/IGFBP-3 ratio decreased significantly as the number of metabolic syndrome components increased (P<0.0001, as determined by ANOVA). The area under the ROC (receiver operating characteristic) curve for detecting insulin resistance using the IGF-I/IGFBP-3 ratio was 0.760, significantly improving upon either protein alone (P=0.01). In conclusion, the IGF-I/IGFBP-3 ratio is significantly associated with the metabolic syndrome. Calculating the ratio of these two proteins may provide insight into the metabolic syndrome clustering phenomenon.
authors.affiliation: Atherosclerosis Research Unit, Department of Medicine, Karolinska University Hospital, S-171 76 Stockholm, Sweden. jusier@ki.se
authors.forename: Justo
authors.initials: J
authors.lastname: Sierra-Johnson
authors.forename: Abel
authors.initials: A
authors.lastname: Romero-Corral
authors.forename: Virend K
authors.initials: VK
authors.lastname: Somers
authors.forename: Francisco
authors.initials: F
authors.lastname: Lopez-Jimenez
authors.forename: Anders
authors.initials: A
authors.lastname: Mälarstig
authors.forename: Kerstin
authors.initials: K
authors.lastname: Brismar
authors.forename: Anders
authors.initials: A
authors.lastname: Hamsten
authors.forename: Rachel M
authors.initials: RM
authors.lastname: Fisher
authors.forename: Mai-Lis
authors.initials: ML
authors.lastname: Hellénius
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000097:blood; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007333:Insulin Resistance / Q000502:physiology; 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*; D008297:Male; D024821:Metabolic Syndrome / Q000097:blood* / Q000175:diagnosis; D008875:Middle Aged; D015233:Models, Statistical; D055815:Young Adult
chemical_list: D015415:Biomarkers; 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