Blood test marker linked to higher dementia risk in large study

A study of nearly 370,000 adults found that a common blood inflammation marker, the neutrophil-to-lymphocyte ratio (NLR), is linked to a higher risk of developing dementia later in life. Researchers analyzed health records from two large cohorts, finding elevated NLR was independently associated with increased dementia risk, with a 7% higher risk in one group and 21% in another. The association was strongest among female and Hispanic participants, though the observational data shows correlation, not causation. The findings support the "inflammaging" theory, where chronic low-grade inflammation may contribute to neurodegeneration. NLR is already measured in routine bloodwork, and while not a standalone diagnostic tool, consistently elevated levels may warrant discussion with a doctor.