title: Associations between hippocampal morphology, diffusion characteristics, and salivary cortisol in older men.
abstract: High, unabated glucocorticoid (GC) levels are thought to selectively damage certain tissue types. The hippocampus is thought to be particularly susceptible to such effects, and though findings from animal models and human patients provide some support for this hypothesis, evidence for associations between elevated GCs and lower hippocampal volumes in older age (when GC levels are at greater risk of dysregulation) is inconclusive. To address the possibility that the effects of GCs in non-pathological ageing may be too subtle for gross volumetry to reliably detect, we analyse associations between salivary cortisol (diurnal and reactive measures), hippocampal morphology and diffusion characteristics in 88 males, aged ∼73 years. However, our results provide only weak support for this hypothesis. Though nominally significant peaks in morphology were found in both hippocampi across all salivary cortisol measures (standardised β magnitudes<0.518, puncorrected>0.0000003), associations were both positive and negative, and none survived false discovery rate correction. We found one single significant association (out of 12 comparisons) between a general measure of hippocampal diffusion and reactive cortisol slope (β=0.290, p=0.008) which appeared to be driven predominantly by mean diffusivity but did not survive correction for multiple testing. The current data therefore do not clearly support the hypothesis that elevated cortisol levels are associated with subtle variations in hippocampal shape or microstructure in non-pathological older age.
authors.affiliation: Centre for Cognitive Ageing and Cognitive Epidemiology, University of Edinburgh, UK; Department of Psychology, University of Edinburgh, UK; Scottish Imaging Network, A Platform for Scientific Excellence (SINAPSE) Collaboration, Edinburgh, UK.
authors.forename: Simon R
authors.initials: SR
authors.lastname: Cox
authors.affiliation: Centre for Cognitive Ageing and Cognitive Epidemiology, University of Edinburgh, UK; Scottish Imaging Network, A Platform for Scientific Excellence (SINAPSE) Collaboration, Edinburgh, UK; Department of Neuroimaging Sciences, Centre for Clinical Brain Sciences, University of Edinburgh, UK. Electronic address: M.Valdes_Hernan@ed.ac.uk.
authors.forename: Maria Del Carmen
authors.initials: MDC
authors.lastname: Valdés Hernández
authors.affiliation: School of Computing, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, South Korea.
authors.forename: Jaeil
authors.initials: J
authors.lastname: Kim
authors.affiliation: Centre for Cognitive Ageing and Cognitive Epidemiology, University of Edinburgh, UK; Scottish Imaging Network, A Platform for Scientific Excellence (SINAPSE) Collaboration, Edinburgh, UK; Department of Neuroimaging Sciences, Centre for Clinical Brain Sciences, University of Edinburgh, UK.
authors.forename: Natalie A
authors.initials: NA
authors.lastname: Royle
authors.affiliation: Centre for Cognitive Ageing and Cognitive Epidemiology, University of Edinburgh, UK; Department of Psychology, University of Edinburgh, UK.
authors.forename: Sarah E
authors.initials: SE
authors.lastname: MacPherson
authors.affiliation: Centre for Cognitive Ageing and Cognitive Epidemiology, University of Edinburgh, UK; Scottish Imaging Network, A Platform for Scientific Excellence (SINAPSE) Collaboration, Edinburgh, UK; Edinburgh Delirium Research Group, Geriatric Medicine, University of Edinburgh, UK.
authors.forename: Karen J
authors.initials: KJ
authors.lastname: Ferguson
authors.affiliation: Centre for Cognitive Ageing and Cognitive Epidemiology, University of Edinburgh, UK; Scottish Imaging Network, A Platform for Scientific Excellence (SINAPSE) Collaboration, Edinburgh, UK; Department of Neuroimaging Sciences, Centre for Clinical Brain Sciences, University of Edinburgh, UK.
authors.forename: Susana
authors.initials: S
authors.lastname: Muñoz Maniega
authors.affiliation: Centre for Cognitive Ageing and Cognitive Epidemiology, University of Edinburgh, UK; Scottish Imaging Network, A Platform for Scientific Excellence (SINAPSE) Collaboration, Edinburgh, UK; Department of Neuroimaging Sciences, Centre for Clinical Brain Sciences, University of Edinburgh, UK.
authors.forename: Devasuda
authors.initials: D
authors.lastname: Anblagan
authors.affiliation: Department of Neuroimaging Sciences, Centre for Clinical Brain Sciences, University of Edinburgh, UK; Department of Computer Science, Lagos State University, Lagos, Nigeria.
authors.forename: Benjamin S
authors.initials: BS
authors.lastname: Aribisala
authors.affiliation: Centre for Cognitive Ageing and Cognitive Epidemiology, University of Edinburgh, UK; Scottish Imaging Network, A Platform for Scientific Excellence (SINAPSE) Collaboration, Edinburgh, UK; Department of Neuroimaging Sciences, Centre for Clinical Brain Sciences, University of Edinburgh, UK.
authors.forename: Mark E
authors.initials: ME
authors.lastname: Bastin
authors.affiliation: School of Computing, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, South Korea.
authors.forename: Jinah
authors.initials: J
authors.lastname: Park
authors.affiliation: Centre for Cognitive Ageing and Cognitive Epidemiology, University of Edinburgh, UK.
authors.forename: John M
authors.initials: JM
authors.lastname: Starr
authors.affiliation: Centre for Cognitive Ageing and Cognitive Epidemiology, University of Edinburgh, UK; Department of Psychology, University of Edinburgh, UK.
authors.forename: Ian J
authors.initials: IJ
authors.lastname: Deary
authors.affiliation: Centre for Cognitive Ageing and Cognitive Epidemiology, University of Edinburgh, UK; Edinburgh Delirium Research Group, Geriatric Medicine, University of Edinburgh, UK.
authors.forename: Alasdair M J
authors.initials: AMJ
authors.lastname: MacLullich
authors.affiliation: Centre for Cognitive Ageing and Cognitive Epidemiology, University of Edinburgh, UK; Scottish Imaging Network, A Platform for Scientific Excellence (SINAPSE) Collaboration, Edinburgh, UK; Department of Neuroimaging Sciences, Centre for Clinical Brain Sciences, University of Edinburgh, UK.
authors.forename: Joanna M
authors.initials: JM
authors.lastname: Wardlaw
mesh_terms: D000368:Aged; D006624:Hippocampus / Q000000981:diagnostic imaging*; D006801:Humans; D006854:Hydrocortisone / Q000032:analysis*; D008279:Magnetic Resonance Imaging; D008297:Male; D009929:Organ Size / Q000502:physiology; D012463:Saliva / Q000737:chemistry
chemical_list: D006854:Hydrocortisone
keywords: 3D shape analysis; Ageing; Brain; Cortisol; Hippocampus; MRI