Outdoor light at night, referred to as light pollution, has been associated with some human health issues, but for the first time a study links light pollution to Alzheimer’s disease. Researchers at Rush University Medical Center wrote in Frontiers in Neuroscience that nightly light pollution—a modifiable environmental condition—may influence risk of Alzheimer’s. They reached their conclusion by grouping medical data with light pollution intensity. The study shows nighttime light intensity is associated with greater Alzheimer’s prevalence than any other risk factor examined for those younger than sixty-five. Authors say simple changes can be made to reduce exposure to light at night, such as adding blackout curtains or sleeping with an eye mask