Risk factors for dementia

Because the frequency of Alzheimer’s disease (AD) and other dementias increases according to advancing age, the importance of dementia is recognized more in the society where the aged occupy a larger part of the population. Although the cause or risk factor for dementia has not been fully elucidated, the elucidation of risk factors may provide a useful tool for the prevention of dementia. Risk factors are divided into 3 groups, including age, genetic factors and environmental factors. Age is an uncontrollable factor which greatly influences the incidence of dementias. However, the research on genetic or environmental risk is essential to resolve important clinical issues and to suggest sites for therapeutic intervention. In this article, I will describe some aspects of genetic and environmental risk factors of dementia, especially the radiation effect after the atomic bomb.