Diabetes and depression
are each hard on the brain, and having both conditions may significantly raise
the risk of dementia, according
to new research.
"What this argues for is, we need to do a better job of both
identifying diabetes and depression and then really treating them once
identified," said study researcher Dr. Dimitry Davydow, an associate
professor of psychiatry and behavioral sciences at the University of Washington
School of Medicine in Seattle.
His team looked at dementia risk among 2.4 million people in
Denmark, age 50 and older, who had depression, type 2 diabetes or both, and compared them with people
who had neither condition.
The researchers also took into account pre-existing medical
conditions, such as cerebral vascular problems, complications such as kidney problems and other ailments.
"Even after taking those into account, diabetes itself raised
the risk of dementia by 15 percent, depression by 83 percent and the two
together by 107 percent," Davydow said.
Read: Diabetes ups dementia risk
Type 2 diabetes and major depression increasingly common
The association was especially strong in people younger than 65.
In that age group, "a quarter of the cases [of dementia] were attributed
to depression and diabetes," he said.
In Western populations, type 2 diabetes and major depression are
increasingly common. And as many as 20 percent of people with diabetes, which
is rapidly increasing in younger groups, also have depression, the researchers
said in background notes with the study.
"To our knowledge, this is the first study to look at this
issue in this way," Davydow said. The findings were published online April
15 in JAMA Psychiatry.
The study points out a complicated link between depression,
diabetes and dementia, but does not establish a direct cause-and-effect
"There is lots of evidence that those who struggle with
depression are more likely to develop chronic medical problems like diabetes
and heart disease and high
blood pressure," Davydow said.
"They are less likely to take medications if they are
depressed. Those who have diabetes are more likely to suffer from
depression," he added.
Moreover, diabetes makes it more likely that plaque will develop
in blood vessels, which can lead to strokes and dementia, Davydow said.
Read: Dementia rises with diabetes and
Lifestyle choices can assist in managing both depression and
Diabetes and depression each threaten brain health, said Dr.
Charles Reynolds III, of the University of Pittsburgh Medical Center, and
author of a commentary accompanying the study.
Both ''pose threats to vascular health, thereby impeding
maintenance of healthy brain aging and functioning, and posing a risk for
cognitive decline," he said.
Reynolds urged those who have a combination of diabetes and
depression to get treatment for both in order to protect their brain.
Read: Type 2 diabetes may raise dementia risk
such as increasing physical activity, will also benefit the management of both
conditions," he added.
The research team - led by Davydow and the study's recently
deceased first author, Dr. Wayne Katon - followed the study participants from
2007 through 2013. All patients were dementia-free at the start.
The researchers said nearly 20 percent of participants had a diagnosis of depression, about 9
percent had diabetes, and nearly 4 percent had both.
Over the study period, more than 59,600 men and women (2.4
percent) got dementia - at age 81, on average. Of those, 26 percent had only
depression, 11 percent had only type 2 diabetes and nearly 7 percent had both.
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