Alzheimer's, Dementia & Mental Health
Mild Cognitive Impairment nor Alzheimer's Show
Racial Discrimination in Shortening Life
Older African-Americans and whites both have reduced
survival with cognitive impairment and it's about equal
June 8, 2009 - Alzheimer's disease and its
precursor, mild cognitive impairment, appear to be associated with an
increased risk of death among both white and African American older
adults, according to a report in the June issue of Archives of
Neurology, one of the JAMA/Archives journals.
Alzheimer's disease has earlier been found to
reduce life expectancy and has emerged as a leading cause of death in
the United States.
"Data from two national surveys suggest that life
expectancy among patients with Alzheimer's disease may be greater for
African Americans than for whites," the authors write.
"However, not all surveys have reported this
difference. Furthermore, in these surveys, the diagnosis of Alzheimer's
disease is not based on a uniform clinical evaluation but derived from
medical records, increasing the likelihood of substantial variation in
the quality of diagnostic classifications."
Robert S. Wilson, Ph.D., and colleagues at Rush
University Medical Center, Chicago, studied 1,715 older adults (average
age 80.1, 52.5 percent African American) from four adjacent
neighborhoods in Chicago.
Each participant had a clinical evaluation that
included medical history, a neurological examination and cognitive
(thinking, learning and memory) function testing.
Based on these evaluations, an experienced
physician diagnosed 296 (17.3 percent) of the participants with
Alzheimer's disease, 597 (34.8 percent) with mild cognitive impairment
and 20 (1.2 percent) with other forms of dementia, while 802 (46.8
percent) had no cognitive impairment.
During up to 10 years of follow-up (average
observation period, 4.7 years) 634 individuals died (37 percent),
including 25.8 percent of those without cognitive impairment, 40.4
percent of those with mild cognitive impairment, 59.1 percent of those
with Alzheimer's disease and 60 percent of those with other forms of
dementia.
"Compared with people without cognitive impairment,
risk of death was increased by about 50 percent among those with mild
cognitive impairment and was nearly three-fold greater among those with
Alzheimer's disease," the authors write.
"These effects were seen among African Americans
and whites and did not differ by race."
Among individuals with mild cognitive impairment,
risk of death increased as cognitive impairment became more severe,
another association that did not differ by race. A similar association
between disease severity and survival was seen among patients with
Alzheimer's disease, although that effect was slightly stronger for
African Americans than for whites.
"Overall, these results do not suggest strong
racial differences in survival for persons with mild cognitive
impairment and Alzheimer's disease," the authors conclude.
Editor's Note: This research was supported
by grants from the National Institute on Aging and by a grant from the
National Institute of Environmental Health Sciences.