title: Phosphorylated IGFBP-1 as a non-invasive predictor of liver fat in NAFLD.
abstract: Insulin-like growth factor binding protein 1 (IGFBP-1) is a potentially interesting marker for liver fat in NAFLD as it is exclusively produced by the liver, and insulin is its main regulator. We determined whether measurement of fasting serum phosphorylated IGFBP-1 (fS-pIGFBP-1) helps to predict liver fat compared to routinely available clinical parameters and PNPLA3 genotype at rs738409. Liver fat content (proton magnetic resonance spectroscopy) was measured in 378 subjects (62% women, age 43 [30-54] years, BMI 32.7 [28.1-39.7] kg/m(2), 46% with NAFLD). Subjects were randomized to discovery and validation groups, which were matched for clinical and biochemical parameters and PNPLA3 genotype. Multiple linear regression and Random Forest modeling were used to identify predictors of liver fat. The final model, % Liver Fat Equation', included age, fS-pIGFBP-1, S-ALT, waist-to-hip ratio, fP-Glucose and fS-Insulin (adjusted R(2) = 0.44 in the discovery group, 0.49 in the validation group, 0.47 in all subjects). The model was significantly better than a model without fS-pIGFBP-1 or S-ALT or S-AST alone. Random Forest modeling identified fS-p-IGFBP-1 as one of the top five predictors of liver fat (adjusted R(2) = 0.39). Therefore, measurement of fS-pIGFBP-1 may help in non-invasive prediction of liver fat content.
authors.affiliation: Minerva Foundation Institute for Medical Research, Helsinki, Finland.|Department of Medicine, University of Helsinki and Helsinki University Central Hospital, Helsinki, Finland.
authors.forename: Elina M
authors.initials: EM
authors.lastname: Petäjä
authors.affiliation: Minerva Foundation Institute for Medical Research, Helsinki, Finland.|Systems Immunity University Research Institute and Division of Infection and Immunity, School of Medicine, Cardiff University, Cardiff, United Kingdom.
authors.forename: You
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: United Medix Laboratories, Espoo, Finland.
authors.forename: Marika
authors.initials: M
authors.lastname: Havana
authors.affiliation: HUS Medical Imaging Center, Radiology, University of Helsinki and Helsinki University Central Hospital, Helsinki, Finland.
authors.forename: Antti
authors.initials: A
authors.lastname: Hakkarainen
authors.affiliation: HUS Medical Imaging Center, Radiology, University of Helsinki and Helsinki University Central Hospital, Helsinki, Finland.
authors.forename: Nina
authors.initials: N
authors.lastname: Lundbom
authors.affiliation: United Medix Laboratories, Espoo, Finland.
authors.forename: Jarkko
authors.initials: J
authors.lastname: Ihalainen
authors.affiliation: Minerva Foundation Institute for Medical Research, Helsinki, Finland.|Department of Medicine, University of Helsinki and Helsinki University Central Hospital, Helsinki, Finland.
authors.forename: Hannele
authors.initials: H
authors.lastname: Yki-Järvinen
mesh_terms: D000273:Adipose Tissue / Q000473:pathology*; D000328:Adult; D005260:Female; D006801:Humans; D018970:Insulin-Like Growth Factor Binding Protein 1 / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D065626:Non-alcoholic Fatty Liver Disease / Q000378:metabolism* / Q000473:pathology; D010766:Phosphorylation
chemical_list: D018970:Insulin-Like Growth Factor Binding Protein 1