A simple blood test could one day help identify people at risk of Alzheimer’s long before memory problems begin, according to new research published in The Lancet. Scientists found that certain changes in the blood may reveal early warning signs of the condition in otherwise healthy middle-aged adults.

The study examined more than 1,300 adults in the United States with an average age of 61. Researchers discovered that a small group showed higher levels of proteins linked to Alzheimer’s. These individuals performed less well in tests involving memory, attention and thinking speed, and their abilities appeared to decline more quickly over time.

Experts say the findings could open the door to earlier action. Identifying people at risk before symptoms appear may encourage healthier lifestyles, including regular exercise, better sleep, avoiding smoking and addressing hearing problems. Such steps could help delay the onset of memory decline.

A separate study in the same journal found that a newer type of brain scan was more effective at detecting early changes associated with Alzheimer’s than current methods. Researchers believe this could improve the identification of people most likely to develop symptoms in the future.

However, specialists caution that these tests are not yet suitable for routine community-wide screening and should be used alongside other assessments.