Should soccer balls come with a health warning? Many experts are asking this question now that new evidence suggests a popular move—“heading” the ball—could increase the risk of developing brain diseases such as dementia, The Herald reports. Previously, researchers had shown professional soccer players were more at risk of developing Alzheimer’s disease than regular people—and more likely to die of neurodegenerative diseases. A new analysis of those results shows defenders, who head the ball most often, are almost five times more likely to develop a brain disease than the average person. Forwards, offensive players most responsible for scoring goals, suffered significantly less risk and goalkeepers, who almost never head the ball, had risks comparable to average people, researchers report in JAMA Neurology this week. The research also shows athletes who played professionally for more than 15 years, regardless of position, were at higher risk of developing brain diseases.