Heterogeneity in Alzheimer’s Disease: Implications for Epidemiology

Summary

It is well established that Alzheimer’s is a heterogeneous disease. The heterogeneity in the disease is expressed in several domains, such as the types and patterns of clinical symptoms, the genetic underpinnings, neuropathological indices, and responses to pharmacological treatments and interventions. Much of the information published on Alzheimer’s disease has been developed from highly selected patient groups. In the U.S., these patient groups are often Caucasian, middle class research volunteers. These patient groups do not represent the population of the country or the universe of people with Alzheimer’s disease, and therefore there are important potential limits to the generalizability of the findings obtained. The demographic changes that are already underway, and will accelerate in the next decades in many countries in the world, will add new dimensions to the heterogeneity of the disease. Ultimately, to understand and to defeat the disease, we must understand the new cohorts of people with the disease, their genetic, environmental and social characteristics and the interactions of those characteristics. Furthermore, if we are to enlist participants in research and develop educational programs and useful and used services, then it is necessary to address a long list of social and behavioral research questions. These questions will have to be investigated against the backdrop of the anticipated changes in the demographic and cultural profiles of the people with the disease. One drug treatment, one behavioral approach, or one model for service programs will not be adequate to address the needs of all people with Alzheimer’s disease. It is clear that a single size will not fit all.