title: Reproducibility of Retinol Binding Protein 4 and Omentin-1 Measurements over a Four Months Period: A Reliability Study in a Cohort of 207 Apparently Healthy Participants.
abstract: The reliability of single time point measurements of the novel adipokines retinol-binding protein 4 and omentin-1 in the blood has not been evaluated in large samples yet. The present study aimed to assess the amount of biological variation of these two adipokines within individuals. The study sample comprised 207 participants (124 women and 83 men) from Potsdam (Germany) and surrounding areas, with an average age of 56.5 years (SD 4.2). Blood samples were collected from each participant twice, approximately four months apart. Using enzyme linked immunosorbent assays, the concentrations of retinol-binding protein 4 and omentin-1 were determined in EDTA plasma. As indicators of reliability, intraclass correlation coefficients (ICCs) were calculated from the repeated biomarker measurements. The ICCs for repeated retinol-binding protein 4 and omentin-1 measurements were 0.77 (95% CI 0.71, 0.82) and 0.83 (95% CI 0.78, 0.87), respectively, indicating for both adipokines excellent reliability. ICCs were stable across strata according to sex, age, BMI, and blood pressure. Thus, for epidemiological studies it seems reasonable to rely on concentrations of retinol-binding protein 4 and omentin-1 in samples from a single time point if repeated measurements are not available.
authors.affiliation: Department of Molecular Epidemiology, German Institute of Human Nutrition Potsdam-Rehbruecke, Nuthetal, Germany; German Center for Diabetes Research (DZD), Neuherberg, Germany.
authors.forename: Clemens
authors.initials: C
authors.lastname: Wittenbecher
authors.affiliation: Research Group Cardiovascular Epidemiology, German Institute of Human Nutrition Potsdam-Rehbruecke, Nuthetal, Germany.
authors.forename: Romina
authors.initials: R
authors.lastname: di Giuseppe
authors.affiliation: Department for Clinical Chemistry and Pathobiochemistry, Otto-von-Guericke-University Magdeburg, Magdeburg, Germany.
authors.forename: Ronald
authors.initials: R
authors.lastname: Biemann
authors.affiliation: Research Group Cardiovascular Epidemiology, German Institute of Human Nutrition Potsdam-Rehbruecke, Nuthetal, Germany.
authors.forename: Juliane
authors.initials: J
authors.lastname: Menzel
authors.affiliation: Research Group Cardiovascular Epidemiology, German Institute of Human Nutrition Potsdam-Rehbruecke, Nuthetal, Germany.
authors.forename: Maria
authors.initials: M
authors.lastname: Arregui
authors.affiliation: Department for Clinical Chemistry and Pathobiochemistry, Otto-von-Guericke-University Magdeburg, Magdeburg, Germany.
authors.forename: Juliane
authors.initials: J
authors.lastname: Hoffmann
authors.affiliation: Department of Epidemiology, German Institute of Human Nutrition Potsdam-Rehbruecke, Nuthetal, Germany.
authors.forename: Krasimira
authors.initials: K
authors.lastname: Aleksandrova
authors.affiliation: Department of Epidemiology, German Institute of Human Nutrition Potsdam-Rehbruecke, Nuthetal, Germany.
authors.forename: Heiner
authors.initials: H
authors.lastname: Boeing
authors.affiliation: Department for Clinical Chemistry and Pathobiochemistry, Otto-von-Guericke-University Magdeburg, Magdeburg, Germany.
authors.forename: Berend
authors.initials: B
authors.lastname: Isermann
authors.affiliation: Department of Molecular Epidemiology, German Institute of Human Nutrition Potsdam-Rehbruecke, Nuthetal, Germany; German Center for Diabetes Research (DZD), Neuherberg, Germany.
authors.forename: Matthias B
authors.initials: MB
authors.lastname: Schulze
authors.affiliation: Research Group Cardiovascular Epidemiology, German Institute of Human Nutrition Potsdam-Rehbruecke, Nuthetal, Germany; Institute of Social Medicine, Epidemiology, and Health Economics, Charité University Medical Center, Berlin, Germany.
authors.forename: Cornelia
authors.initials: C
authors.lastname: Weikert
mesh_terms: D000328:Adult; D000368:Aged; D015415:Biomarkers; D015331:Cohort Studies; D016207:Cytokines / Q000097:blood*; D005260:Female; D058851:GPI-Linked Proteins / Q000097:blood; D005858:Germany; D064368:Healthy Volunteers; D006801:Humans; D037102:Lectins / Q000097:blood*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D054839:Retinol-Binding Proteins, Plasma
chemical_list: D015415:Biomarkers; D016207:Cytokines; D058851:GPI-Linked Proteins; C432397:ITLN1 protein, human; D037102:Lectins; C101326:RBP4 protein, human; D054839:Retinol-Binding Proteins, Plasma