Individuals with low haemoglobin levels, especially those with elevated concentrations of Alzheimer’s disease (AD) biomarkers, are at greater risk of developing dementia, as suggested in new research.
In an analysis of data from the Swedish National Study on Aging and Care in Kungsholmen (SNAC-K), WHO-defined anaemia was associated with a 66-percent higher risk of dementia (adjusted hazard ratio [aHR], 1.66, 95 percent confidence interval [CI], 1.21–2.28) over 16 years of follow-up. [JAMA Netw Open 2026;9:e264029]
Anaemia was also associated with increased baseline levels of phosphorylated tau 217 (p-tau217) (β, 0.22, 95 percent CI, 0.15–0.30), neurofilament light chain (NfL) (β, 0.25, 95 percent CI, 0.19–0.31), and glial fibrillary acidic protein (GFAP) (β, 0.08, 95 percent CI, 0.03–0.12).
“Co-occurrence of low haemoglobin and elevated AD blood biomarkers was associated with further amplified dementia risk,” the investigators said.
For instance, the risk of dementia was more than threefold higher among individuals with both anaemia and high NfL vs those with normal haemoglobin levels and low NfL (aHR, 3.64, 95 percent CI, 2.39–5.56). This was also observed for anaemia combined with high p-tau217 or GFAP levels, although an additive interaction was only seen between anaemia and elevated NfL levels, the investigators noted.
“Overall, our findings expand previous knowledge of the anaemia-dementia association by suggesting an interplay between anaemia and neuropathology—as measured by blood biomarkers—in dementia development,” they added.
In a linked commentary, Dr Frank Wolters from Erasmus MC–University Medical Centre Rotterdam, Rotterdam, the Netherlands, noted that the biomarker-level observations in the study provide novel evidence connecting haemoglobin directly to AD. [JAMA Netw Open 2026;9:e267758]
“Although the cross-sectional design in this respect did not allow for formal mediation analyses, results point at least toward a joint role of Alzheimer pathology and anaemia, in line with earlier observations linking haemoglobin to plasma amyloid-β,” Wolters wrote. [Atherosclerosis 2022;348:44-50]
“In order to move findings from observation to effective intervention, mechanistic insight is mandatory. Such insights could come from observational studies on anaemia and its causes, including use of repeated measures of haemoglobin and emulated target trials, as well as from small physiological trials,” he added.
A total of 2,282 SNAC-K participants (median age 72.2 years, 61.6 percent female, 36.2 percent had university education) were included in the study. Of these, 8.7 percent had anaemia, defined as blood haemoglobin level of ≤12 g/dL for females and ≤13 g/dL for males.
Compared with participants with normal haemoglobin levels, those with anaemia were more likely to be older, male, and had a lower educational level and more chronic diseases. The incidence rate of dementia during follow-up was higher among participants with anaemia (4.37 vs 1.65 per 100 person-years).