A study by the University of Oulu and the University of Eastern Finland found that people who developed Alzheimer's disease before the age of 65 accumulated a wide range of health problems, particularly during the five years preceding diagnosis. Compared with matched controls, they were more likely to experience depression, dizziness, headaches, traumatic brain injuries, epilepsy, cerebrovascular disorders, thyroid diseases and problems related to heavy alcohol use. Tinnitus and hearing loss were already more common six to 10 years before diagnosis.