New blood tests designed to detect Alzheimer’s disease long before symptoms emerge have generated interest among those concerned about dementia. However, medical experts caution that these tests are not yet ready for routine use in people without cognitive symptoms, and emphasize that lifestyle changes remain the most effective method to reduce risk.
The U.S. Food and Drug Administration has approved four blood tests to aid clinicians in diagnosing Alzheimer’s in patients already showing signs of cognitive impairment. These tests help distinguish Alzheimer’s from other forms of dementia and can facilitate early access to medications that may modestly slow disease progression. Despite this, some individuals without symptoms are seeking these tests, even though they are neither approved nor recommended for asymptomatic populations.
Dr. Nicholas Ashton of Banner Health, a nonprofit health system in the United States, advises that these tests should be limited to research settings for people without symptoms. Instead, he suggests focusing on managing preventable risk factors. A large study led by New York University’s Optimal Aging Institute found that individuals who reached middle age without high blood pressure, diabetes, or smoking lived nearly 13 years longer without dementia compared to those with all three conditions by their 50s. The study’s senior author, Prof. Josef Coresh, urged a proactive approach to controlling these risks, emphasizing that even delaying illness onset can have significant benefits.
Mark Yost, a 60-year-old from Phoenix, Arizona, reflects the concerns of many who have witnessed Alzheimer's in family members. Though symptom-free, he sought out testing to understand his risk and ways to possibly prevent or slow any decline. Alzheimer’s pathology is linked to abnormal accumulations of amyloid and tau proteins in the brain, which develop over decades before symptoms appear. Blood tests measuring phosphorylated tau 217 (p-tau217) show promise in identifying those at higher risk, with one study associating elevated levels of this protein with a 38% chance of developing cognitive impairment within five years. However, a positive test indicates increased risk—not a definitive diagnosis—as many older adults with high amyloid do not develop symptoms. False positives also remain a concern.
Yost participated in a Banner Health blood test study and was informed his p-tau217 level was intermediate, suggesting some amyloid presence but not to a degree currently considered worrisome. While uncertain, he continues to engage in brain-healthy activities such as regular exercise and mental stimulation through hobbies.
Beyond testing, research supports lifestyle interventions to preserve cognition. A major clinical trial demonstrated that regular moderate exercise, resistance training, and adherence to the MIND diet—which emphasizes leafy greens, berries, whole grains, poultry, and fish—can slow cognitive decline in at-risk older adults. Additional recommendations include maintaining adequate sleep, addressing hearing loss, avoiding social isolation, and engaging in mentally stimulating activities.
The NYU study reinforces the link between cardiovascular health and brain health. High blood pressure, diabetes, and smoking can damage brain blood vessels and contribute to inflammation, accelerating cognitive decline. Even individuals carrying the APOE4 gene, which raises Alzheimer’s risk, may benefit from managing these risk factors. Prof. Coresh highlighted the importance of early and sustained blood pressure control for protecting brain function.
While current Alzheimer’s blood tests offer promise for early identification, experts advise patience. Ongoing clinical trials are examining whether treatments now used for Alzheimer’s might be effective in pre-symptomatic individuals—potentially shifting future testing strategies. For now, adopting healthy lifestyle habits remains the best approach to reducing dementia risk.