Red Cell Distribution Width, Anemia, and Brain Volumetric Outcomes Among Middle-Aged Adults

Article type: Research Article

Authors: Beydoun, May A.^{a; *} | Hossain, Sharmin^a | MacIver, Peter H.^{a; b} | Srinivasan, Dhivya^c | Beydoun, Hind A.^d | Maldonado, Ana I.^{a; b} | Katzel, Leslie I.^{e; f} | Davatzikos, Christos^c | Gullapalli, Rao P.^g | Seliger, Stephen L.^h | Erus, Guray^c | Evans, Michele K.^a | Zonderman, Alan B.^a | Waldstein, Shari R.^{b; e; f}

Affiliations: [a] Laboratory of Epidemiology and Population Sciences, NIA/NIH/IRP, Baltimore, MD, USA | [b] Department of Psychology, University of Maryland, Baltimore County, Catonsville, MD, USA | [c] Artificial Intelligence in Biomedical Imaging Lab, Center for Biomedical Image Computing and Analytics (CBICA), Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA | [d] Department of Research Programs, Fort Belvoir Community Hospital, Fort Belvoir, VA, USA | [e] Geriatric Research Education and Clinical Center, Baltimore VA Medical Center, Baltimore, MD, USA | [f] Division of Gerontology & Geriatric Medicine, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, USA | [g] Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore, MD, USA | [h] Division of Nephrology, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, USA

Correspondence: [*] Correspondence to: May A. Beydoun, PhD, NIH Biomedical Research Center, National Institute on Aging, IRP, 251 Bayview Blvd., Suite 100, Room #: 04B118, Baltimore, MD 21224, USA. Fax: +1 410 558 8236; E-mail: baydounm@mail.nih.gov.

Abstract: Background:Anemia and red cell distribution width (RDW) have been linked to poor cognitive performance, pending studies of underlying mechanisms. Objective:We examined cross-sectional relationships of initial RDW status (v1), RDW change (δ), and anemia with brain structural magnetic resonance imaging (sMRI) markers, including global and cortical brain and hippocampal and white matter lesion (WML) volumes, 5–6 years later. Methods:Data were used from three prospective visits within the Healthy Aging in Neighborhoods of Diversity Across the Life Span (HANDLS) study with complete v1 (2004–2009) and v2 (2009–2013) exposures and ancillary sMRI data at vscan (2011–2015, n = 213, mean v1 to vscan time: 5.7 years). Multivariable-adjusted linear regression models were conducted, overall, by sex, by race, and within non-anemics, correcting for multiple testing with q-values. Results:In minimally adjusted models (socio-demographics and follow-up time), anemiav1 and RDWv1 were consistently associated with smaller bilateral hippocampal volumes overall, and among females (q < 0.05), without significant sex differences. RDWv1 was related to smaller select regional cortical brain gray and white matter volumes in hematological measure-adjusted models; anemiav1 was associated with larger WML volumes only among whites. Conclusion:In summary, baseline anemia and RDW were consistently associated with smaller bilateral hippocampal volumes, particularly among females, while anemia was linked to larger WML volume among Whites. In hematological measure-adjusted models, baseline RDW was linked to smaller regional gray and white matter volumes. Pending studies with sMRI repeats, randomized controlled trials are needed, demonstrating associations of anemia and elevated RDW with reduced brain volumes and cognitive dysfunction.

Keywords: Aging, anemia, brain volumes, hippocampus, red cell distribution width, white matter lesion

DOI: 10.3233/JAD-201386

Journal: Journal of Alzheimer's Disease, vol. 81, no. 2, pp. 711-727, 2021