Epidemiology and etiology of Alzheimer's disease

One of the consequences of the worldwide population aging phenomenon is the increasing number of the neurodegenerative diseases, with Alzheimer's disease, as the most predominant one. The prevalence and etiology of Alzheimer's varies in different regions of the world, due to the structure of the aged populations in different countries. The social and economic burdens of geriatric diseases in the decade of the "demographic transition", have engaged the health systems in a serious challenge. Thus, it seems essential to identify the developing factors for neurodegenerative diseases in each country. In this review, the etiology of Alzheimer's disease has been investigated in different populations, also the possible factors that may explain the risk of developing Alzheimer’s in the future (such as vascular risk factors and depression) as well as protective factors that may reduce the risk of incidence (such as social, physical and cognitive activities, diet rich in polyunsaturated fatty acids and antioxidants, and controlled vascular risk factors). Studies have shown that beginning education in early life and being engaged with entertaining mental activities during adulthood, while trying to maintain on good vascular health or optimal controlling vascular diseases can be preventive strategies against Alzheimer’s disease.