title: Influence of DNA extraction methods on relative telomere length measurements and its impact on epidemiological studies.
abstract: Measurement of telomere length is widely used in epidemiologic studies. Insufficient standardization of the measurements processes has, however, complicated the comparison of results between studies. We aimed to investigate whether DNA extraction methods have an influence on measured values of relative telomere length (RTL) and whether this has consequences for epidemiological studies. We performed four experiments with RTL measurement in quadruplicate by qPCR using DNA extracted with different methods: 1) a standardized validation experiment including three extraction methods (magnetic-particle-method EZ1, salting-out-method INV, phenol-chloroform-isoamyl-alcohol PCI) each in the same 20 samples demonstrated pronounced differences in RTL with lowest values with EZ1 followed by INV and PCI-isolated DNA; 2) a comparison of 307 samples from an epidemiological study showing EZ1-measurements 40% lower than INV-measurements; 3) a matching-approach of two similar non-diseased control groups including 143 pairs of subjects revealed significantly shorter RTL in EZ1 than INV-extracted DNA (0.844 ± 0.157 vs. 1.357 ± 0.242); 4) an association analysis of RTL with prevalent cardiovascular disease detected a stronger association with INV than with EZ1-extracted DNA. In summary, DNA extraction methods have a pronounced influence on the measured RTL-values. This might result in spurious or lost associations in epidemiological studies under certain circumstances.
authors.affiliation: Division of Genetic Epidemiology, Department of Medical Genetics, Molecular and Clinical Pharmacology, Medical University of Innsbruck, Innsbruck, Austria.
authors.forename: Julia
authors.initials: J
authors.lastname: Raschenberger
authors.affiliation: Division of Genetic Epidemiology, Department of Medical Genetics, Molecular and Clinical Pharmacology, Medical University of Innsbruck, Innsbruck, Austria.
authors.forename: Claudia
authors.initials: C
authors.lastname: Lamina
authors.affiliation: Division of Genetic Epidemiology, Department of Medical Genetics, Molecular and Clinical Pharmacology, Medical University of Innsbruck, Innsbruck, Austria.
authors.forename: Margot
authors.initials: M
authors.lastname: Haun
authors.affiliation: Division of Genetic Epidemiology, Department of Medical Genetics, Molecular and Clinical Pharmacology, Medical University of Innsbruck, Innsbruck, Austria.
authors.forename: Barbara
authors.initials: B
authors.lastname: Kollerits
authors.affiliation: Division of Genetic Epidemiology, Department of Medical Genetics, Molecular and Clinical Pharmacology, Medical University of Innsbruck, Innsbruck, Austria.
authors.forename: Stefan
authors.initials: S
authors.lastname: Coassin
authors.affiliation: Division of Genetic Epidemiology, Department of Medical Genetics, Molecular and Clinical Pharmacology, Medical University of Innsbruck, Innsbruck, Austria.
authors.forename: Eva
authors.initials: E
authors.lastname: Boes
authors.affiliation: Department of Internal Medicine I, Paracelsus Medical University/Salzburger Landeskliniken, Salzburg, Austria.
authors.forename: Ludmilla
authors.initials: L
authors.lastname: Kedenko
authors.affiliation: Division of Genetic Epidemiology, Institute for Medical Biometry and Statistics, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany.
authors.forename: Anna
authors.initials: A
authors.lastname: Köttgen
authors.affiliation: Division of Genetic Epidemiology, Department of Medical Genetics, Molecular and Clinical Pharmacology, Medical University of Innsbruck, Innsbruck, Austria.
authors.forename: Florian
authors.initials: F
authors.lastname: Kronenberg
mesh_terms: D000328:Adult; D004247:DNA / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification*; D016172:DNA Fingerprinting / Q000379:methods; D016021:Epidemiologic Studies; D005260:Female; D006801:Humans; D008297:Male; D016615:Telomere / Q000737:chemistry / Q000235:genetics*; D059505:Telomere Homeostasis / Q000235:genetics*
chemical_list: D004247:DNA