Global prevalence and incidence of Alzheimer’s disease and mild cognitive impairment

Abstract

Alzheimer’s disease (AD) is the most prevalent cause of dementia worldwide. AD is characterized histopathologically by senile plaques composed of amyloid β-peptide (Aβ) and neurofibrillary tangles consisting of aggregated tau protein. AD onset is preceded by mild cognitive impairment (MCI) where it is supposed that oligomers start to damage synapses. In a world with a rising number of people aged 65 and older, MCI and AD have become a public health problem. Therefore, the aim of this review is to collect the current knowledge on MCI and AD epidemiology, highlighting the social and biological factors that produce regional differences in their prevalence. To achieve this goal, we have searched original articles, meta-analysis publications and reviews published since 2010 on epidemiology. As expected, the epidemiological data show divergent values between countries, age and sexes. Factors such as genetic polymorphisms, cardiovascular diseases, diabetes and educational level are changing AD and MCI rates through the last decades. Even though the efforts done to collect population data, further studies need to be performed around the world. Studding the evolution of AD prevalence by ages from normal cognitive status to severe stages of AD will be crucial to foresee economic expenses in the future.