Heading a soccer ball can damage mental health. Researchers found that ex-football players are three and a half times more likely to die of dementia. They looked at the deaths of over 7,600 ex-players and the deaths of 23,000 people who did not play football. They found that the ex-players had a lot more brain injuries.

Football associations in the UK requested the research after a player died in 2002. Doctors said he died after "repeated minor brain traumas". A researcher said ex-players were more likely to suffer from diseases like Alzheimer's. He said they were less likely to die of diseases like heart disease and lung cancer.