Compared with individuals with a normal hemoglobin level, those with anemia had higher baseline levels of p-tau217 (β, 0.22; 95% CI, 0.15-0.30), NfL (β, 0.25; 95% CI, 0.19-0.31), and GFAP (β, 0.08; 95% CI, 0.03-0.12) and showed a higher risk of developing dementia (hazard ratio [HR], 1.66; 95% CI, 1.21-2.28) during follow-up. This evidence concerns the gene GFAP and dementia.