Many diseases have specific causes – for example a virus causes measles. Although it is not currently understood why people develop dementia, there are many factors which have been suggested to be linked to the development of the condition. Some are risk factors, whilst others appear to be protective.
Risk factors are characteristics or factors that appear to have some relationship to the development of a disease. If these risk factors are present, there is an increased chance, but not a certainty, that the disease will develop. For example, not everyone who smokes develops heart disease and not everyone with heart disease has been a smoker. However, smoking is a strong risk factor for heart disease.
Risk factors can include family background or exposures to a substance or product. Going back to the example of smoking: a person who smokes has a greater risk of developing heart disease than someone who does not smoke. Some risk factors can be modified, for example lowering blood pressure reduces the risk of a stroke; other risk factors cannot be modified, for example age or family history.
Age and a strong family history of dementia are risk factors with a strong link to dementia. Excessive alcohol consumption, head injury, and risk factors for heart disease such as high blood pressure, diabetes, smoking and being overweight also seem to increase the risk of getting dementia.
It seems that people who keep their brains active may be at less risk of developing dementia. Reading, engaging in a hobby such as playing bridge or chess, or doing crosswords and word puzzles may help to reduce risk.
Am I at risk of developing dementia? – Alzheimer’s Society factsheet
ADI’s policy brief for dementia risk factors (PDF)