Lifelong depression may increase risk of vascular dementia; Study
also finds late-life depression may signal
Alzheimer's disease
OAKLAND, Calif., May 9,
2012 – Depressive symptoms that occur in
both midlife and late life are associated
with an increased risk of developing
vascular dementia, while symptoms that occur
in late life only are more likely to be
early signs of Alzheimer's disease,
according to University of California at San
Francisco and Kaiser Permanente researchers.
The study, which appears
in the current issue of the Archives of
General Psychiatry, is the first to examine
whether midlife or late-life depression is
more likely to lead to either Alzheimer's
disease or vascular dementia in the long
term.
The researchers explain
that vascular dementia, the second most
common type of dementia, develops when
impaired blood flow to parts of the brain
deprives cells of nutrients and oxygen.
"People who had
depressive symptoms in both midlife and late
life were much more likely to develop
vascular dementia, while those who had
depressive symptoms in late life only were
more likely to develop Alzheimer's disease,"
said the study's lead author Deborah E.
Barnes, PhD, MPH, with the UCSF Departments
of Psychiatry and Epidemiology &
Biostatistics and the San Francisco Veterans
Affairs Medical Center.
"The findings have
important public health implications because
they raise hope that adequate treatment of
depression in midlife may reduce dementia
risk, particularly vascular dementia, later
in life," added Rachel Whitmer, PhD, a
research scientist at the Kaiser Permanente
Northern California Division of Research and
the principal investigator of the study.
UCSF and Kaiser
Permanente investigators examined the
association between depressive symptoms and
dementia over the course of 45 years in a
longitudinal study of more than 13,000
long-term members of the Kaiser Permanente
Northern California integrated care delivery
system.
The study population
consisted of members who participated in a
voluntary health examination called the
Multiphasic Health Checkup in San Francisco
and Oakland during 1964-1973 when they were
40-55 years old.
Participants were
evaluated for depressive symptoms in midlife
as part of the Multiphasic Health Checkup
and again in late life between 1994-2000.
Between 2003-2009, 3,129 participants were
diagnosed with dementia.
Though more research is
needed, the findings suggest that depression
that begins in late life may be an early
symptom of Alzheimer's disease, while
chronic depression over the life course may
reflect a long-term process of changes to
blood flow in the brain associated with
increased risk of vascular dementia.