What are the risk factors for dementia? Researchers have discovered several important factors that affect our risk of developing dementia. These include age and genetics, but also medical conditions and lifestyle choices. A person’s risk of developing dementia depends upon a combination of all of these risk factors. Some of them, such as age or the genes we have inherited from our parents, are beyond our control. Others are things we can change, such as our lifestyle choices – for example, whether we smoke and how much we exercise. Different dementia risk factors also seem to be important at different stages in our lives. For example, many studies show that staying in education beyond the age of 16 seems to reduce your risk of dementia in later life. Ageing Age is the strongest known risk factor for dementia. Whilst it is possible to develop the condition earlier – at least 1 in 20 people with dementia developed it at age under 65 (see factsheet 440, What is young-onset dementia?) – the chances of developing dementia rise significantly as we get older. Above the age of 65, a person’s risk of developing Alzheimer’s disease or vascular dementia doubles roughly every 5 years. It is estimated that dementia affects one in 14 people over 65 and one in six over 80. Gender Women are more likely to develop Alzheimer’s disease than men. This is the case even if we allow for the fact that women on average live longer. The reasons for this are still unclear. It has been suggested that Alzheimer’s disease in women is linked to a lack of the hormone oestrogen after the menopause. However, controlled trials of hormone replacement therapy (HRT, which replaces female hormones) have not been shown to reduce the risk of developing Alzheimer’s. The age at which HRT is started, however, may affect the outcome. HRT (prescribed mainly to help with symptoms of the menopause) is not recommended as a way for women to help reduce their risk of dementia. For most dementias other than Alzheimer’s disease, men and women have much the same risk. For vascular dementia, men are actually at slightly higher risk than women. This is because men are more prone to stroke and heart disease, which can cause vascular and mixed dementia. Ethnicity There is some evidence that people from certain ethnic communities are at higher risk of dementia than others. For example, South Asian people (from countries such as India and Pakistan) seem to develop dementia – particularly vascular dementia – more often than white Europeans. South Asians are well known to be at a higher risk of stroke, heart disease and diabetes, and this is thought to explain the higher dementia risk. Similarly, people of African or African-Caribbean origin seem to develop dementia more often. They are known to be more prone to diabetes and stroke. All of these effects are probably down to a mix of differences in diet, smoking, exercise and genes Medical conditions and diseases Cardiovascular factors There is very strong evidence that conditions that damage the heart, arteries or blood circulation all significantly affect a person’s chances of developing dementia. These are known as cardiovascular risk factors. The main ones for dementia are: type 2 diabetes – in mid-life or later life high blood pressure – in mid-life high total blood cholesterol levels – in mid-life obesity – in mid-life.