Evidence of a unique and common genetic etiology between the CAR and the remaining part of the diurnal cycle : a study of 14 year-old twins

Authors: Ouellet-Morin, Isabelle; Brendgen, Mara Rosemarie; Girard, Alain; Lupien, Sonia; Dionne, Ginette; Vitaro, Frank; Boivin, Michel
Abstract: Introduction: By and large, studies have reported moderate contributions of genetic factors to cortisol secreted in the early morning and even smaller estimates later in the day. In contrast, the cortisol awakening response (CAR) has shown much stronger heritability estimates, which prompted the hypothesis that the etiology of cortisol secretion may vary according to the time of day. A direct test of this possibility has, however, not yet been performed. Objective: To describe the specific and common etiology of the CAR, awakening level and cortisol change from morning to evening in an agehomogenous sample of twin adolescents. Methods: A total of 592 participants of the Québec Newborn Twin Study, a population-based 1995-1998 cohort of families with twins in Canada, have collected saliva at awakening, 30 minutes later, at the end of afternoon and in the evening over four collection days. Results: Multivariate Cholesky model showed both specific and common sources of variance between the CAR, awakening and cortisol diurnal change. The CAR had the strongest heritability estimates, which, for the most part, did not overlap with the other indicators. Conversely, similar magnitudes of genetic and environmental contributions were detected at awakening and for diurnal change, which partially overlapped. Conclusion: Our study unraveled differences between the latent etiologies of the CAR and the rest of the diurnal cycle, which may contribute to identify regulatory genes and environments and detangle how these indicators each relate to physical and mental health.
Document Type: Article de recherche
Issue Date: 8 January 2016
Open Access Date: 8 January 2017
Document version: AM
Permalink: http://hdl.handle.net/20.500.11794/13587
This document was published in: Psychoneuroendocrinology, Vol. 66, 91–100 (2016)
Pergamon Press
Alternative version: 10.1016/j.psyneuen.2015.12.022
Collection:Articles publiés dans des revues avec comité de lecture

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