By Kathleen Fackelmann, USA TODAY
Loneliness may put people at risk of an Alzheimer's-like dementia, a study reported Monday.
"People who described themselves as lonely were twice as likely to develop dementia," says researcher Robert Wilson of the Rush University Medical Center in Chicago.
Other studies have found that people who are unmarried and socially isolated are at higher risk for dementia, including Alzheimer's. But this study is one of the first to show a link between loneliness — or the feelings of disconnection from other people — and a higher risk of developing dementia late in life, says Laurel Coleman, a spokeswoman for the Alzheimer's Association and a geriatrician in Portland, Maine.
Wilson and his colleagues studied 823 people who were about 80 years old and had no sign of dementia at the start of the study. The team gave the recruits a loneliness quiz and tested them annually for signs of memory loss and confusion, two key signs of dementia and Alzheimer's.
During the four-year study, 76 people developed an Alzheimer's-like dementia, Wilson says. The risk of developing dementia increased about 51% for each one-point increase on the loneliness scale. People with the highest scores had 2.1 times the risk of developing dementia, a group of conditions that destroy brain cells and lead to mental confusion. Alzheimer's is the most common form of dementia.
Autopsies were performed on 90 people who died during the study. The researchers found no link between loneliness and the development of the abnormal brain deposits that are the hallmark of Alzheimer's.
That finding suggests loneliness might be triggering dementia through a novel mechanism — one that doesn't lead to a brain riddled with deposits, Wilson says.
One theory is that people who are lonely over long periods of time might have higher levels of damaging stress hormones. The elevated stress hormones might lead to an accelerated aging of the brain — and perhaps to dementia, Wilson says.
Other research suggests lonely people are at risk of other health problems such as cancer and high blood pressure, says John Cacioppo of the University of Chicago. Still, he says, the new finding, which appears in February's Archives of General Psychiatry, must be verified by additional research.
The findings didn't change much when the team factored in markers of social isolation, such as infrequent participation in social events. That means that people who have a small number of good friends might be better off than those with a busy social schedule but chronic feelings of loneliness, Wilson says.
But lonely people often benefit from signing up for a new class or activity, Coleman says. Research shows that such activities might protect aging brain cells. And seniors who are out and about are more likely to make new friends, which might lessen feelings of loneliness, she says.