title: Reliability of serum metabolite concentrations over a 4-month period using a targeted metabolomic approach.
abstract: Metabolomics is a promising tool for discovery of novel biomarkers of chronic disease risk in prospective epidemiologic studies. We investigated the between- and within-person variation of the concentrations of 163 serum metabolites over a period of 4 months to evaluate the metabolite reliability expressed by the intraclass-correlation coefficient (ICC: the ratio of between-person variance and total variance). The analyses were performed with the BIOCRATES AbsoluteIDQ™ targeted metabolomics technology, including acylcarnitines, amino acids, glycerophospholipids, sphingolipids and hexose in 100 healthy individuals from the European Prospective Investigation into Cancer and Nutrition (EPIC)-Potsdam study who had provided two fasting blood samples 4 months apart. Overall, serum reliability of metabolites over a 4-month period was good. The median ICC of the 163 metabolites was 0.57. The highest ICC was observed for hydroxysphingomyelin C14:1 (ICC = 0.85) and the lowest was found for acylcarnitine C3:1 (ICC = 0). Reliability was high for hexose (ICC = 0.76), sphingolipids (median ICC = 0.66; range: 0.24-0.85), amino acids (median ICC = 0.58; range: 0.41-0.72) and glycerophospholipids (median ICC = 0.58; range: 0.03-0.81). Among acylcarnitines, reliability of short and medium chain saturated compounds was good to excellent (ICC range: 0.50-0.81). Serum reliability was lower for most hydroxyacylcarnitines and monounsaturated acylcarnitines (ICC range: 0.11-0.45 and 0.00-0.63, respectively). For most of the metabolites a single measurement may be sufficient for risk assessment in epidemiologic studies with healthy subjects.
authors.affiliation: Department of Epidemiology, German Institute of Human Nutrition Potsdam-Rehbruecke, Nuthetal, Germany. anna.floegel@dife.de
authors.forename: Anna
authors.initials: A
authors.lastname: Floegel
authors.forename: Dagmar
authors.initials: D
authors.lastname: Drogan
authors.forename: Rui
authors.initials: R
authors.lastname: Wang-Sattler
authors.forename: Cornelia
authors.initials: C
authors.lastname: Prehn
authors.forename: Thomas
authors.initials: T
authors.lastname: Illig
authors.forename: Jerzy
authors.initials: J
authors.lastname: Adamski
authors.forename: Hans-Georg
authors.initials: HG
authors.lastname: Joost
authors.forename: Heiner
authors.initials: H
authors.lastname: Boeing
authors.forename: Tobias
authors.initials: T
authors.lastname: Pischon
mesh_terms: D005260:Female; D006801:Humans; D008297:Male; D055432:Metabolomics; D008875:Middle Aged; D015203:Reproducibility of Results; D044967:Serum