Anaemia triples dementia risk, study finds

Anaemia in later life is linked to Alzheimer’s-related blood changes and a higher dementia risk, a study suggests.

Anaemia is a condition marked by low haemoglobin, the protein in red blood cells that carries oxygen around the body.

The findings suggest anaemia may not only be a risk factor for dementia, but could also interact with key neurodegenerative processes, meaning the gradual damage or loss of brain cells.

In this large cohort study of 2,282 adults aged 60 and over who were free of dementia, researchers analysed blood samples alongside long-term cognitive outcomes.

Participants were followed for an average of 9.3 years, during which 15.9 per cent developed dementia.

People with anaemia showed significantly higher levels of key Alzheimer’s-related blood biomarkers at the start of the study, including phosphorylated tau 217, known as p-tau217, neurofilament light chain and glial fibrillary acidic protein.

Anaemia was associated with a 66 per cent higher risk of developing dementia compared with normal haemoglobin levels.

The risk was even more pronounced when anaemia coexisted with raised biomarkers, with some groups showing more than a threefold increase in dementia risk.

The study drew on data from a well-established population-based ageing cohort, with repeated follow-ups and robust diagnostic criteria for dementia.

Researchers used advanced statistical models to assess both biomarker associations and long-term dementia risk.

These findings suggest a potential biological pathway linking reduced oxygen-carrying capacity to neurodegeneration.

Reduced haemoglobin may contribute to cerebral hypoxia, where the brain gets less oxygen, which has been proposed as a mechanism that could speed up cell injury and harmful protein build-up.

The results highlight anaemia as a potentially modifiable risk factor in dementia prevention strategies.

Future research is needed to determine whether treating anaemia can directly lower dementia risk or slow disease progression.

Nonetheless, the study adds to evidence that wider health factors such as anaemia may play a more central role in neurodegenerative disease than previously recognised.