The association between hemoglobin level and risk of developing dementia.

BackgroundHemoglobin levels are key indicators of health and may be associated with dementia risk. This study examined this association in a Korean population, stratified by sex.ObjectiveThis study aimed to evaluate the association between hemoglobin levels and the incidence of all-cause and subtype-specific dementia in a nationwide Korean cohort and to determine whether these associations differed by sex.MethodsFrom the National Health Insurance Service-National Health Screening Cohort, 316,542 adults aged ≥40 years were followed from 2004-2005 until 2019. Hemoglobin levels were divided into sex-specific quintiles. Dementia was defined by International Classification of Diseases, 10th Revision codes and prescriptions for anti-dementia medications. Risks of all-cause, Alzheimer's, and vascular dementia were analyzed using Cox proportional hazards models.ResultsCompared to the reference group (4th quintile), both the lower and higher hemoglobin quintiles were associated with an increased all-cause dementia risk (adjusted HR 1.16 [95% CI, 1.11-1.22] for Q1 and 1.07 [95% CI, 1.02-1.13] for Q5). Alzheimer's risk rose only in the lower quintiles, while vascular dementia risk rose at both extremes. These associations were stronger in women.ConclusionsAbnormal hemoglobin levels, particularly in women, were linked to an increased risk of dementia. Managing hemoglobin levels and correcting anemia may help prevent dementia.