Hippocampal volume and depressive symptoms: A population-based neuroimaging study

Abstract

In clinical samples, depression was reported to be associated with hippocampal volume loss. We sought to examine this in a population-based setting. Design: Cross-sectional study derived from the Mayo Clinic population-based Study of Aging in Olmsted County, Minnesota. Participants: cognitively normal subjects who had Magnetic Resonance Imaging (MRI) of the head and documented measures of depression constituted the sample for this study. Each MRI scan was graded for hippocampal volume, ventricular size, and white matter hyperintensity (WMH) severity, using a visual analog grading scale. Hippocampal and ventricular size were graded on 3D T1 weighted images while WMH was graded on FLAIR images. Depression was measured by using Beck Depressive Inventory (BDI-II). Statistical analysis: non-parametric rank based Spearman correlation was used to examine the association between the BDI score and hippocampal volume as well as ventricular volume and WMH. Data were available on 185 cognitively normal individuals with a mean (SD) age of 79 (5.5) years. 84 of them (45.4%) were females. The BDI score ranged from 0 to 20 (a score of ≤ 13 is normal, 14 to 20 is indicative of mild depression, 21 to 30 is moderate and > 30 severe depression). After adjusting for age, sex and education, there was no correlation between BDI score and hippocampal volume (r = 0.12, p = 0.1), BDI and ventricular volume (r = -0.03, p = 0.7), BDI and WMH (r = -0.05, p = 0.5). No participant had a BDI score indicative of moderate or severe depression. In cognitively normal elderly persons, we did not observe a significant association between mild depressive symptoms and hippocampal volume loss in a population-based setting. Study supported by: The National Institutes of Health (K01 MH68351, U01 AG06786, K01 AG028573, R02 AR30582, and R01NS33978), Bethesda, MD; Robert H. and Clarice Smith and Abigail Van Buren Alzheimer's Disease Research Program and the Harold Amos Medical Faculty Development Program.