ABO blood type, factor VIII,

and incident cognitive

impairment in the REGARDS

cohort

Kristine S. Alexander, PhD, MCR,
Neil A. Zakai, MD, MSc,
Sarah Gillett, PhD,

Leslie A. McClure, PhD,
Virginia Wadley, PhD,
Fred Unverzagt, PhD and

Mary Cushman, MD, MSc

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Correspondence to Dr. Cushman: mary.cushman@uvm.edu

Published online before print September 10, 2014,
doi: 10.1212/WNL.0000000000000844Neurology 10.1212/WNL.0000000000000844

Abstract
Full Text (PDF)

ABSTRACT

Objective: To assess the relationships among ABO group, factor VIII (FVIII),
and incident cognitive impairment in a large, prospective cohort study of
black and white adults in the United States using a nested case-control design.

Methods: Incident cognitive impairment was defined using cognitive domain
tests over a mean follow-up of 3.4 years. ABO blood group was measured by
genotyping in a nested case-control sample of 495 cases with cognitive
impairment and 587 controls.

Results: Those with blood group AB and those with higher FVIII had an
increased risk of cognitive impairment, adjusting for age, race, region, and
sex (respective odds ratios 1.82, 95% confidence interval [CI] 1.15–2.90;
and 1.24, 95% CI 1.10–1.38 for 40 IU/dL higher FVIII). Mean FVIII was
higher in those with blood type AB (142 IU/dL; 95% CI 119–165) compared
with O (104 IU/dL; 95% CI 101–107), and FVIII mediated 18% of the
association between AB group and incident cognitive impairment
(95% CI for mediation −30% to 68%).

Conclusions: Blood group AB and higher FVIII were associated
with increased incidence of cognitive impairment in this prospective
study. The association of blood group AB with incident cognitive
impairment was not significantly mediated by FVIII levels.