MONDAY, May 7 (HealthDay News) -- People who suffer depression
when they're middle-aged or elderly may also have an higher risk of
dementia later, a new study suggests.
Researchers evaluated long-term data from more than 13,000
people in California. They found that depressive symptoms occurred
in about 14 percent of participants in midlife only, while about
9.2 percent of cases of depression developed in late life only.
Just over 4 percent of people in the study had depression that
stretched over midlife and late life.
Over six years of follow-up, 22.5 percent of the participants
were diagnosed with dementia. The study found that 5.5 percent of
the participants developed Alzheimer's disease and 2.3 percent
developed vascular dementia, which is caused by brain damage
resulting from impaired blood flow to the brain.
According to the research team, people with late-life depression
were twice as likely to get Alzheimer's disease and those with both
midlife
and late-life depression had a more than threefold increased
risk of vascular dementia.
The research team was led by Deborah Barnes, of the University
of California, San Francisco, and the San Francisco Veterans
Affairs Medical Center. Writing in the May issue of the
Archives of General Psychiatry, they say the findings suggest that depression extending throughout the lifespan might raise odds for dementia, especially vascular dementia. In many cases, depression occurring for the first time in late life may reflect an early stage of dementia, especially in the case of Alzheimer's disease.
The study was only able to find an association between
depression and Alzheimer's risk; it could not prove
cause-and-effect.
More than 5 million people in the United States have Alzheimer's
disease and the health care costs of the condition were about $172
billion in 2010, according to background information in the
study.
"Prevalence and costs of Alzheimer's disease and other dementias are projected to rise dramatically during the next 40 years unless a prevention or a cure can be found. Therefore, it is critical to gain a greater understanding of the key risk factors and etiologic [causal] underpinnings of dementia," the researchers wrote.
More information
The U.S. National Institute of Neurological Disorders and Stroke
has more about
dementia.