New blood tests that can detect markers of Alzheimer's disease years before symptoms appear are becoming available, but medical professionals stress that these tests are not yet recommended for individuals without cognitive concerns. Instead, experts advocate for proactive lifestyle interventions to lower the overall risk of dementia.
The U.S. Food and Drug Administration has cleared several blood tests designed to help doctors diagnose Alzheimer's disease in patients experiencing memory problems or other cognitive symptoms. These tests can aid in faster diagnosis, potentially allowing individuals with early-stage Alzheimer's to access treatments that may modestly slow disease progression. However, dementia specialists caution that these tests are not approved or recommended for people who are not experiencing symptoms.
"The worried well should not be getting those tests" outside of a research setting, stated Nicholas Ashton, a testing expert at Arizona's Banner Health. He emphasized that focusing on potentially preventable brain health risks is a more beneficial strategy.
A significant study indicated that individuals who reached middle age without conditions such as high blood pressure, diabetes, and a history of smoking lived nearly 13 years longer without dementia compared to those with all three issues in their 50s. "Be aggressive," advised Dr. Josef Coresh of NYU Langone Health, the study's senior author. He added that even delaying the onset of these conditions yields substantial benefits.
Alzheimer's disease is characterized by abnormal forms of two proteins: beta-amyloid, which can form plaques in the brain, and tau tangles, which contribute to neuron damage and symptoms. Blood tests measuring a form of tau called p-tau217 have shown promise in reflecting amyloid buildup in symptomatic individuals. For those without symptoms, a study found that older adults with very high p-tau217 levels had a 38% risk of developing cognitive impairment within five years.
However, Ashton noted that a positive test result is a risk factor, not a definitive prediction of developing Alzheimer's. Many older adults with high amyloid levels never experience cognitive decline, and some positive results can be false positives. Mark Yost, 60, who participated in a blood test study, received an "intermediate" result, indicating a potential for some amyloid buildup but not a "worrisome elevated" level. He described the uncertainty as disappointing but is focusing on brain-healthy habits like exercise and engaging in mentally stimulating activities.
A large trial last year demonstrated that healthier lifestyle choices could slow age-related cognitive decline in older adults at increased risk for dementia. Recommended habits include moderate-intensity exercise four times a week, resistance training twice weekly, and adhering to the MIND diet, which prioritizes leafy greens, berries, whole grains, poultry, and fish.
Dementia experts also recommend sufficient sleep, avoiding social isolation, addressing hearing loss, and engaging in mental and physical exercise. Middle age is considered a critical period for adopting these habits.
The NYU study reinforces the connection between heart health and brain health. Researchers analyzed health records of over 12,000 people tracked since their mid-50s. High blood pressure, Type 2 diabetes, and smoking can damage the brain's blood vessels and promote inflammation. Individuals without these three conditions in middle age fared best, but avoiding even one or two of them showed benefits. The study also suggested that even individuals with the APOE4 gene, a known risk factor for Alzheimer's, could benefit from a healthier middle age.
Further research is ongoing to determine if current Alzheimer's drugs could be effective for people before symptoms manifest, which might influence future recommendations for blood testing.