Quick Facts

• Adults with anemia showed 66% higher risk of developing dementia over 9.3 years compared to those with normal hemoglobin
• Study tracked 2,282 dementia-free adults aged 60 and older, with 362 developing dementia during follow-up
• Anemic participants had elevated brain biomarkers linked to Alzheimer’s disease and neurodegeneration

Adults with anemia face a 66% higher risk of developing dementia compared to those with normal hemoglobin levels, according to new research published in JAMA Network Open.

The study followed 2,282 dementia-free adults aged 60 and older for an average of 9.3 years. Researchers found that 362 participants developed dementia during the follow-up period. Among participants with baseline anemia, the dementia incidence rate reached 4.37 cases per 100 person-years, compared to just 1.65 cases per 100 person-years in those with normal hemoglobin.

Only 8.7% of participants had anemia at the study’s start, yet this group showed significantly higher levels of phosphorylated tau 217, neurofilament light chain, and glial fibrillary acidic protein. These blood biomarkers indicate Alzheimer’s disease pathology and brain cell damage.

The risk climbed even higher when anemia occurred alongside elevated brain biomarkers. Participants with both anemia and high neurofilament light chain levels showed nearly four times greater dementia risk, with an adjusted hazard ratio of 3.64.

“Our findings suggest that anemia is a relevant risk factor for dementia,” said Dr. Martina Valletta, the study’s lead author from Karolinska Institute. “Because anemia is relatively easy to detect with routine blood tests and, in many cases, treatable, it could represent a potentially modifiable target in dementia prevention strategies.”

The associations proved stronger in men than women. Valletta explained that women naturally have lower hemoglobin levels throughout life and may develop physiologic adaptation. Men typically develop anemia later, usually with chronic disease.

The brain’s high oxygen demand makes it vulnerable when hemoglobin levels drop. Hemoglobin carries oxygen through the bloodstream, and low levels may subject the brain to chronic stress.

Valletta emphasized the study’s observational nature limits conclusions about treatment. “We cannot conclude that treating anemia will directly prevent dementia. This remains an open question for future research,” she said.

The findings align with previous research showing anemia’s association with cognitive decline. A meta-analysis of five population studies found individuals with anemia had 46% higher dementia risk.

Experts recommend testing anyone with memory problems for anemia. Iron deficiency represents just one factor – vitamin B12, vitamin C, folate, and protein intake all support healthy red blood cell production.

The research suggests anemia deserves attention during cognitive assessments, especially in older adults with memory concerns. While anemia doesn’t diagnose Alzheimer’s disease, it may provide a clinically relevant signal for dementia risk assessment.

Read more: This Common Deficiency May Raise Dementia Risk By 66%, Study Finds