A new genetic test can predict the age a person is likely to develop Alzheimer's and calculate a person's risk of developing the disease in a particular year, according to a study published Tuesday in PLOS Medicine. “For any given individual, for a given age and genetic information, we can calculate your ‘personalized’ annualized risk for developing [Alzheimer's]," study co-author Rahul Desikan says in a press release. The polygenic hazard score test was created using genetic data from 70,000 people and is based on 31 genetic markers, the Guardian reports. Scientists behind the study found that thousands of small genetic variations can add up to a substantial risk for Alzheimer's.
People the test ranked in the top 10% for risk of Alzheimer's were more than three times as likely to develop the disease during the study. They developed Alzheimer's 11 years before those in the lowest 10% for risk (84 years old vs. 95 years old, on average). There's currently no treatment for Alzheimer's, but experts believe that when one is found, it will have to be administered very early on, the Telegraph reports. This new test could help doctors identify patients for treatment before it's too late. But one expert not involved in the study says genetics is only one part of determining Alzheimer's risk; exercise, diet, and mental activity level all play a part. (Sleeping late may be an early warning sign of dementia.)