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

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 v_scan (2011–2015, n = 213, mean v₁ to v_scan 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), anemia_v1 and RDW_v1 were consistently associated with smaller bilateral hippocampal volumes overall, and among females (q < 0.05), without significant sex differences. RDW_v1 was related to smaller select regional cortical brain gray and white matter volumes in hematological measure-adjusted models; anemia_v1 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.