Loneliness—the unpleasant feeling of emptiness or desolation—can creep in and cause suffering to people at any age. But it can be especially debilitating to older adults and may predict serious health problems and even death, says a new study by University of San Francisco researchers.

The team analyzed data in the Health and Retirement Study, a nationally representative study by the National Institute on Aging conducted on 1,604 older adults between 2002 and 2008. The research, published earlier this month in the Archives of Internal Medicine, focused specifically on the question of loneliness and its impact.

"In our typical medical model, we don't think of subjective feelings as affecting health," says co-author Dr. Carla Perissinotto, professor in the UCSF Division of Geriatrics. "It's intriguing to find that loneliness is independently associated with an increased rate of death and functional decline."

The team's analysis found that loneliness doesn't necessarily correlate with living alone. The study found 43 percent of surveyed older adults felt lonely, yet only 18 percent lived alone.

"We are interested in identifying the different factors that cause adults to become functionally impaired and ultimately at risk for nursing home admission," Perissinotto says. "The aging of our population and the greater odds of institutionalization make it important for us to think about all the factors that are putting elders in danger, including social and environmental risks."

Researchers at UCSF focused on death and a decrease in the ability to perform daily activities, such as upper extremity tasks, climbing stairs, and walking.

People who identified themselves as lonely had an adjusted risk ratio of 1.59, or a statistically significant 59 percent greater risk of decline. For death, the hazard ratio was 1.45, or a 45 percent greater risk of death.

"This is one of those outcomes you don't want to see because it was terrible to find out it was actually true," Perissinotto says.

Perissinotto and her colleagues believe the impact of loneliness on an elderly patient is different from the effects of depression. While depression is linked with a lack of enjoyment, energy, and motivation, loneliness can be felt in people who are fully functional.

As the baby boomer population continues to expand, Perissinotto says she hopes to be able to integrate social and medical services for elderly patients more comprehensively—and be more mindful of what kinds of social interventions they require.

"Asking about chronic diseases is not enough," she says. "There's much more going on in people's homes and their communities that is affecting their health. If we don't ask about it, we are missing a very important and independent risk factor."