Scientists have found that variations in a gene involved in the brain’s waste-removal system can influence whether poor sleep accelerates changes associated with Alzheimer’s years before symptoms appear. The team analyzed 13 common AQP4 gene variants alongside participants’ self-reported sleep patterns, brain scans, and cognitive test results. They found that individuals with certain genetic variants experienced faster grey matter loss when they reported shorter sleep durations. Loss of grey matter is considered an early indicator of structural brain changes that may contribute to Alzheimer’s disease. She explained that the same genetic variant could appear either protective or harmful depending on an individual’s sleep habits, making sleep one of the few risk factors people can actively improve.