| Author |
Berg, Stéphanie M. Moor, Marleen H. M. McGue, Matt Pettersson, Erik Terraccia, Antonio Verweij, Karin J. H. Amin, Najaf Derringer, Jaime Esko, Tõnu Grootheest, Gerard Hansell, Narelle K. Huffman, Jennifer Konte, Bettina Lahti, Jari Lucia, Michelle Matteson, Lindsay K. Viktorin, Alexander Wouda, Jasper Agrawal, Arpana Allik, Jüri Bierut, Laura Broms, Ulla Campbell, Harry Smith, George Davey Eriksson, Johan G. Ferrucci, Luigi Franke, Barbera Fox, Jean Paul Geus, Eco J. C. Giegling, Ina Gow, Alan J. Grucza, Richard Hartmann, Annette M. Heath, Andrew C. Heikkilä, Kauko Iaco, William G. Janzing, Joost Jokela, Markus Kiemeney, Lambertus Lehtimäki, Terho Madden, Pamela A. F. Magnusson, Patrik K. E. rthstone, Kate Nutile, Teresa Ouwens, Klaasjan G. Palotie, Aar Pattie, Alison Pesonen, Anu Katriina Polasek, Ozren Pulkkinen, Lea Pulkki Råback, Laura Raitakari, Olli T. Realo, Anu Rose, Richard J. Ruggiero, Daniela Seppälä, Ilkka Slutske, Wendy S. Smyth, David C. Sorice, Rossella Starr, John M. Sutin, Angelina R. Tanaka, Toshiko Verhagen, Josine Vermeulen, Sita Vuoksimaa, Eero Widen, Elisabeth Willemsen, Gonneke Wright, Margaret J. Zgaga, Lina Rujescu, Dan Metspalu, Andres Wilson, James F. Ciullo, Marina Hayward, Caroline Rudan, Igor Deary, Ian J. Räikkönen, Katri Arias Vasquez, Alejandro Costa, Paul T. Keltikangas Järvinen, Liisa Duijn, Cornelia M. Penninx, Brenda W. J. H. Krueger, Robert F. Evans, David M. Kaprio, Jaakko Pedersen, Nancy L. Martin, Nicholas G. Boomsma, Dorret I. |
| Abstract |
Mega- or meta-analytic studies (e.g. genome-wide association studies) are increasingly used in behavior genetics. An issue in such studies is that phenotypes are often measured by different instruments across study cohorts, requiring harmonization of measures so that more powerful fixed effect meta-analyses can be employed. Within the Genetics of Personality Consortium, we demonstrate for two clinically relevant personality traits, Neuroticism and Extraversion, how Item-Response Theory (IRT) can be applied to map item data from different inventories to the same underlying constructs. Personality item data were analyzed in >160,000 individuals from 23 cohorts across Europe, USA and Australia in which Neuroticism and Extraversion were assessed by nine different personality inventories. Results showed that harmonization was very successful for most personality inventories and moderately successful for some. Neuroticism and Extraversion inventories were largely measurement invariant across cohorts, in particular when comparing cohorts from countries where the same language is spoken. The IRT-based scores for Neuroticism and Extraversion were heritable (48 and 49 %, respectively, based on a meta-analysis of six twin cohorts, total N = 29,496 and 29,501 twin pairs, respectively) with a significant part of the heritability due to non-additive genetic factors. For Extraversion, these genetic factors qualitatively differ across sexes. We showed that our IRT method can lead to a large increase in sample size and therefore statistical power. The IRT approach may be applied to any mega- or meta-analytic study in which item-based behavioral measures need to be harmonized. |
