Anemia was associated with higher levels of Alzheimer disease (AD) blood biomarkers and a markedly increased long-term risk of dementia, with the highest risk observed when low hemoglobin coexisted with elevated neurodegenerative markers. In a population-based cohort from the Swedish National Study on Aging and Care in Kungsholmen, 2,282 dementia-free adults aged 60 years or older (median age 72.2 years; 61.6% women) were followed for a mean of 9.3 years, during which 362 individuals (15.9%) developed dementia. Hemoglobin levels measured at baseline, with anemia defined by World Health Organization criteria (blood hemoglobin level of 12 g/dL or less for females and 13 g/dL or less for males), showed strong cross-sectional associations with key AD-related blood biomarkers, including phosphorylated tau 217 (p-tau217), neurofilament light chain (NfL), and glial fibrillary acidic protein (GFAP), indicating greater tau pathology, neuroaxonal injury, and astroglial activation among anemic individuals. Longitudinal analyses demonstrated that anemia was associated with a 66% higher risk of incident dementia after adjustment for confounders. Importantly, joint exposure analyses revealed a synergistic effect: participants with both anemia and elevated biomarker levels had substantially higher risks, such as more than a threefold increase among those with anemia and high NfL (HR 3.64). These findings suggest that anemia may contribute to or exacerbate neurodegenerative processes, and highlight hemoglobin as a clinical marker that may enhance dementia risk stratification when combined with emerging AD biomarkers. Source: https://jamanetwork.com/
