Britons fear developing Alzheimer's disease more than any other health condition associated with old age, according to the Alzheimer's Society.
But few realise that simple lifestyle changes could cut their chances of getting the illness.
Some 37 per cent of people fear developing dementia but 62 per cent believe their lifestyle does not impact on their chance of developing dementia.
Neil Hunt, chief executive of the Alzheimer's Society, said: "Dementia is a devastating disease. It begins with memory problems but gradually robs older people of their ability to dress, speak, eat or do virtually anything for themselves.
"One in three older people will end their lives with dementia, so these fears are very real for thousands of people in the UK.
"The good news is that people can fight their fears by following our Be Headstrong challenge."
Be Headstrong offers tips on warding off dementia. Lifestyle factors and changes to reduce the risk of the disease include not smoking, eating less saturated fat, exercising regularly, leading an active social life and getting regular blood pressure and cholesterol checks.