Alzheimer disease and other dementias are more common in black individuals than in white individuals. According to the Alzheimer's Association, in the population aged 71 years and older, black persons are almost twice as likely as white persons to have Alzheimer disease and other dementias (21.3% of blacks vs 11.2% of whites). The number of Hispanic persons studied in this age group was too small to determine the prevalence of dementia in this population.
The following risk factors for Alzheimer-type dementia have been identified:
APOE 4 genotype
Traumatic brain injury
Some studies have reported a higher risk for Alzheimer-type dementia in women than in men; other studies, however, including the Aging, Demographics, and Memory Study, found no difference in risk between men and women. Almost two thirds of Americans with Alzheimer disease are women.
Although more than 90% of Alzheimer-type dementia cases are sporadic (ie, not inherited), familial forms are recognized. Familial clustering represents approximately 15%-25% of late-onset cases and most often involves late-onset dementia. In familial clustering, at least two of the affected individuals are third-degree relatives or closer.
For more on the etiology and epidemiology of Alzheimer disease, read here.
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Cite this: Helmi L. Lutsep. Fast Five Quiz: Dementia - Medscape - Oct 17, 2018.