UC Irvine

Our understanding of the epidemiology of Alzheimer disease (AD) has advanced rapidly during the past decade. Community (population) studies in many countries have confirmed that the prevalence of AD (and of vascular dementia) rises exponential fashion at least between ages 65 and 85, doubling with every 5 years of age; comparison of population studies between different countries has shown age-specific prevalence rates to be similar within a factor of two among countries as diverse as China, Japan, Great Britain, France, Italy, and the United States. From these population studies other demographic factors, including gender (women may be more susceptible to AD than men), poor education, and perhaps certain occupations have emerged as important putative risk factors. Moreover, case-control and longitudinal studies have confirmed the importance of family history as a major risk factor, and other, somewhat unexpected risk factors, such as head trauma and coronary artery disease, have been identified. From these findings, together with current knowledge of molecular, genetic, and pathological features of AD, a picture emerges of the interaction over time of these risk factors with the biological factors that lead to the development of the Alzheimer process.