Neutrophils, a type of white blood cell circulating in the bloodstream, act as some of the body's first responders to infection and inflammation. When the immune system is activated, their numbers can rise quickly, altering the balance between neutrophils and other immune cells. Doctors can measure this balance using a standard lab value called the neutrophil to lymphocyte ratio (NLR). This number is routinely calculated from a complete blood count, a common test used to detect infections and assess immune health. New research from NYU Langone Health suggests that this simple measurement may do more than reflect current illness. It could also help identify people at higher risk of developing Alzheimer's disease and related dementias, even before any symptoms appear. The study examined NLR data from nearly 400,000 patients across two large healthcare systems.…