Hemoglobin concentration is associated with the hippocampal volume in community-dwelling adults

Background: This study examined whether the hemoglobin concentration is correlated with the hippocampal volume using voxel-based morphometry (VBM).Methods: This cross-sectional study included 1923 community dwellers, aged 40-89 years, from the sixth wave of the National Institute for Longevity Sciences, Longitudinal Study of Aging. The hemoglobin levels were determined through blood examination. The regional cortical volumes were evaluated using three-dimensional T1 weighted magnetic resonance images. Following preprocessing with a statistical parametric mapping software, a VBM analysis of covariance design was implemented to identify the regional gray matter volumes related to hemoglobin concentration, while adjusting for age, sex, education, body mass index, depressive symptoms, alcohol consumption status, smoking status, medical history, and the estimated glomerular filtration rate.Results: VBM analysis revealed a significantly positive correlation between the hemoglobin concentration and gray matter volume in the bilateral anterior hippocampus and the amygdala clusters as well as in the cingulate and middle temporal gyri, cerebellum, and superior sagittal and transverse sinuses.Conclusions: The hemoglobin concentration could be positively associated with the hippocampal volume among community-dwelling middle-aged and older adults, which highlights the importance of monitoring the hemoglobin concentration in older adults to decrease the possibility of neurodegeneration.