What is Alzheimer's disease? Accounting for between 50 per cent and 70 per cent of all dementias worldwide, Alzheimer's disease is the most common form of dementia. It is a physical brain disease characterised by the impairment of brain functions such as impaired memory, language, thinking and behaviour. It is a progressive disease caused by the gradual degeneration of brain cells. Alzheimer’s disease can broadly be categorised into two areas: Sporadic Alzheimer’s disease can affect adults at any age, but occurs most often after age 65. This is the most common form of Alzheimer’s disease and affects people who may or may not have a family history of the disease. Familial Alzheimer’s disease is a much less common form in which the disease is passed directly from one generation to another.1 Causes of Alzheimer's Disease Although the causes of Alzheimer’s disease are still not yet fully understood, scientists are starting to gain a greater understanding of the risk factors that increase the likelihood of developing the disease. These include age, family history, heart health and lifestyle factors, such as diet or physical activity. AgeThe greatest risk factor for developing Alzheimer ’s disease is advancing age. Studies have shown that the occurrence of Alzheimer’s increases from about the age of 65. Around 1 in 4 Australians over the age of 85 have some form of Dementia.Family HistoryPeople with a first degree relative, such as a parent or a sibling, who has developed Alzheimer’s disease, have an increased risk of developing the disease. This risk is higher if two or more first degree relatives have been affected. Heart health and lifestyle factorsAlthough there are no definitive protective factors for dementia, there is now a growing body of evidence that suggests that there are several lifestyle factors that could reduce the risk of developing dementia. These include: Maintaining a level of physical activityAdopting a healthy dietMaintaining a socially active lifestyleStaying mentally activeManaging your cholestorol levels or blood glucose levels if you have cardiovascular disease or diabetes Symptoms of Alzheimer's Alzheimer’s Australia. Alzheimer’s disease (Help Sheet). Available at: http://www.fightdementia.org.au/understanding-‐dementia/alzheimers-‐disease.aspx. Accessed March 2013.