Race May Affect Alzheimer's Survival
Study Shows Latinos and African-Americans With Alzheimer's Disease Live Longer Than Whites
Nov. 14, 2007 -- Race may be an independent predictor of survival among
people diagnosed with Alzheimer's disease, with Latinos and blacks living
longer than whites.
The findings from a study involving nearly 31,000 patients treated at more
than 30 Alzheimer's centers across the country revealed that, compared with
whites, Latinos were 40% and African-Americans were 15% less likely to die
during the study period.
The ethnic differences were seen even after researchers accounted for other
factors known to influence survival, including education level and age at
Researcher Kala Mehta, DSc, who is an epidemiologist at the University of
California, San Francisco, says she went into the study expecting to find that
whites live longer than the other ethnic groups studied following an Alzheimer's diagnosis.
"That was our original hypothesis, but it wasn't what we found," she
Alzheimer's, Race, and Survival
The study is one of the largest ever to examine the impact of ethnicity on
Alzheimer's disease outcomes.
But because it included only patients treated at Alzheimer's disease
centers, the findings may not be an accurate indicator of what is happening
with the Alzheimer's population at large, Mehta says.
"It is possible that these ethnic differences persist, but we can't say
that from this study," she says.
Four out of five (81%) of the study participants were white, 12% were
African-American, 4% were Latino, 1.5% were Asian, and 0.5% were American
The patients were followed for an average of 2.4 years, and they had a
median survival of 4.8 years since their first visit to an Alzheimer's disease
Autopsy results from 3,000 patients revealed no significant differences in
Alzheimer's disease progression at death by racial group.
But while Asians and American Indians lived about as long as whites with
Alzheimer's disease, Latinos and African-Americans lived significantly
Mehta says the reasons for this remain a mystery.
"Our goal is to try to understand the racial differences with a view
toward improving the health of all people with Alzheimer's disease," she
Reasons for Survival Difference Unclear
American Academy of Neurology spokesman David Knopman, MD, tells WebMD that
he too was surprised by the study findings.
He says they may point to a genetic difference between the races linked to
Alzheimer's survival or they may be driven by cultural differences between the
studied ethnic groups.
Whites are more likely to be treated at Alzheimer's centers than blacks and
Latinos. Because of this, white patients attending such centers may also be
more likely to have other health problems that could affect survival, Knopman
Knopman is a professor of neurology at the Mayo Clinic in Rochester,
"We need more studies to tell us what is going on here," he says.
"But one encouraging message from this research is that blacks and Latinos
do not seem to be at a disadvantage when it comes to Alzheimer's disease
outcomes. That is a very positive finding."