Association Between Anemia and Dementia: A Nationwide, Populationbased Cohort Study in Taiwan.

Abstract

In addition to the traditional risk predictors, whether anemia is an early biomarker of dementia, needs to be confirmed. This population-based cohort study aimed to investigate the dementia risk in patients with newly diagnosed anemia using data from the Taiwan National Health Insurance Research Database. All newly diagnosed anemia patients (n = 26,343) with no history of stroke hospitalization, central nervous disease other than dementia, psychiatric disorders, traumatic brain injury, major operations, or blood loss diseases, were enrolled. A group of non-anemic controls, 1:4 matched with anemic patients on the basis of demographics and comorbidities, was also included. A competing risk analysis was used to evaluate the dementia risk in anemic patients compared to that of their matched controls. The adjusted subdistribution hazard ratio (SHR) of dementia risk in anemic patients was 1.14 (95% confidence interval [CI]: 1.08~1.21, p<0.001). Patients with iron supplements tended to exhibit a lower dementia risk (adjusted SHR: 0.84; 95% CI: 0.75~0.94, p=0.002) compared to patients without iron supplement. A subgroup analysis showed that a positive association between dementia and anemia existed in females, those aged 70 years and older, and patients without hypertension, diabetes, or hyperlipidemia. The present population-based cohort study identified that newly diagnosed anemia is a risk factor for dementia and also that iron supplementation was able to reduce the risk of dementia in people with iron deficiency anemia.