Latinos develop symptoms of Alzheimer's disease earlier

U.S. Latinos develop symptoms of Alzheimer's disease earlier, on average, than white non-Latino people, according to a study in the May issue of Archives of Neurology.

Although Latino people are a geographic and genetically diverse group, some reports suggest that they may differ from Anglo (white non-Latino) individuals in several Alzheimer's disease (AD) characteristics, according to background information in the article. Differences shown in previous studies include a higher prevalence of Alzheimer's in both Caribbean and Mexican-American Latino people and an increased incidence of Alzheimer's in the Latino populations of New York City and Houston, compared with Anglos. This study compares the age at which Alzheimer's symptoms first appear between Latino and Anglo subjects evaluated through the National Institute on Aging-sponsored Alzheimer's Disease Centers (ADC) program.

Christopher M. Clark, M.D., of the University of Pennsylvania, Philadelphia, and colleagues at five Alzheimer's Disease Centers (three east coast and two west coast centers) conducted a two phase study to compare the age of onset of Alzheimer's disease symptoms of U.S. mainland Latino individuals with age of symptom onset in Anglo individuals. The first phase of the study, a retrospective database analysis, found that the mean (average) age at symptom onset for 366 Latino patients with a clinical diagnosis of Alzheimer's was 68.8 years compared with 73.5 years for 2,823 Anglo patients and was consistent for the east coast centers (individuals of predominately Caribbean origin) and the west coast centers (individuals of predominately Mexican origin).

In the second phase of the study, 119 Latinos and 55 Anglo patients with probable or possible Alzheimer's disease were evaluated using a number of standardized assessment tests for severity of dementia and psychiatric symptoms. In addition, information on each patient, including birthplace, migration history, years of education and the age of the onset of Alzheimer's symptoms was obtained from a knowledgeable informant, usually a spouse or adult child. In this phase of the study, the researchers found that Latinos had a mean age of symptom onset that was 6.8 years earlier than Anglo individuals evaluated at the same clinic. There was no difference in the age of symptom onset between the Latinos evaluated at the east and west coast centers, although there were differences in the countries of origin.

"…the findings in this study indicate that Latino individuals, the largest and fastest growing minority group in the mainland United States, appear to have an earlier age of AD symptom onset compared with Anglo individuals with a similar educational level," the authors conclude. "The factors responsible for this remain to be identified, but the observation has a potential impact on both the burden of dementia care carried by this population group and the dementia-related diagnostic and educational efforts directed toward the Latino population. From the individual patient and family standpoint as well as a public health perspective, it is important to identify modifiable factors that contribute to the symptomatic expression of AD in this significant minority group."