Researchers, led by Jiao Wang, explored if anemia was associated with cognitive decline and risk of dementia, and if levels of inflammation affected any identified associations. The study, published in the Journal of Alzheimer’s Disease, noted some previous studies have concluded anemia was associated with poor cognitive function and increased dementia risk, while others have not.
Overall, the investigators suggested their findings supported an association between anemia and increased dementia risk and poor cognitive performance—especially in the processing speed domain. Additionally, they suggested high inflammation levels, assessed via C-reactive protein (CRP), potentially exacerbated the association between anemia and dementia.
Anemia, Inflammation Linked to Dementia, Cognitive Decline
The researchers reviewed 207,203 patients aged >60 years and without baseline dementia from the UK Biobank database. Anemia was defined as hemoglobin <13 g/dL for males and <12 g/dL for females. Inflammation was rated high or low based on median CRP levels, with a threshold of 1.50 mg/L. A subgroup of 18,211 participants completed global and domain-specific cognitive assessments. Analyses included linear mixed-effects, Cox regression, and Laplace regression models.
According to the report, anemia was associated with more rapid declines in global cognition (β= −0.08; 95% CI, −0.14 to −0.01) and processing speed (β= −0.10; 95% CI −0.19 to −0.01). Over a median follow-up of 9.76 years (interquartile range, 7.55-11.39 years), 6272 patients developed dementia.
Authors estimated patients with anemia had an increased risk of dementia (hazard ratio [HR], 1.57; 95% CI, 1.38-1.78), and their dementia onset was accelerated by 1.53 years (95% CI, 1.08-1.97). Patients with both anemia and high inflammation levels had a further heightened risk of dementia (HR, 1.89; 95% CI, 1.60-2.22), with a significant association between anemia and CRP and dementia risk (P-interaction=.032).
Given their findings, the study’s authors suggested “our results emphasize the importance of early detection and prevention of anemia to slow down the progression of cognitive function in older adults.”