Loneliness and dementia

HD Lighthouse Contributing Editor's Comment: As part of our effort to add to the information in the HDL Triad, the Lighthouse also monitors studies that identify variables that slow the aging process and prevent Alzheimer's.

A research team from Rush University Medical Center in Chicago has added to their already excellent work on factors associated with dementia. And this time instead of correlating potential risk variables with Alzheimer's in a sample of people, they have a longitudinal study which followed people over time. They found that people who felt lonely were more likely to develop Alzheimer's than those that didn't. This is a major variable and has effects that are independent from what was happening in the brain and from the individual's social networks.

The take home message is that our connections with caring friends and family members help keep us healthy. We all need to value and nourish our relationships. If friends have fallen away through time and circumstances, we should take the time to make new ones. If we don't have family or if there is an estrangement that can't be repaired, our friends can be our family.

-- Marsha L. Miller, Ph.D.
Posted to the HDL: 10 Feb 2007

Robert S. Wilson, Ph.D., senior neuropsychologist in the Rush Alzheimer's Disease Center and professor in the Departments of Neurological Sciences and Psychology at Rush University Medical Center.

(Chicago) - Lonely individuals may be twice as likely to develop the type of dementia linked to Alzheimer's disease in late life as those who are not lonely, according to a study by researchers at the Rush Alzheimer's Disease Center. The study is published in the February issue of Archives of General Psychiatry.

Previous studies have shown that social isolation, or having few interactions with others, is associated with an increased risk of dementia and cognitive decline. However, little was know about the emotional isolation, which refers to feeling alone rather than being alone.

Robert S. Wilson, PhD, and his colleagues, analyzed the association between loneliness and Alzheimer's disease in 823 older adults over a four year period. Participants underwent evaluations that included questionnaires to assess loneliness, classifications of dementia and Alzheimer's disease, and testing of their thinking, learning and memory abilities. Loneliness was measured on a scale of one to five, with higher scores indicating more loneliness. The data was collected between November 2000 and May 2006.

At the first examination, participants' average loneliness score was 2.3. During the study period, 76 individuals developed dementia that met criteria for Alzheimer's disease. Risk for developing Alzheimer's disease increased approximately 51 percent for each point on the loneliness score, so that a person with a high loneliness score (3.2) had about 2.1 times greater risk of developing Alzheimer's disease than a person with a low score (1.4). The findings did not change significantly when the researchers factored in markers of social isolations, such as a small network and infrequent social activities.

According to Wilson, loneliness is a risk factor for Alzheimer's disease, not an early sign of the disease. Autopsies were performed on 90 individuals who died during the study. Loneliness during life was not related to any of the hallmark brain changes associated with Alzheimer's disease, including nerve plaques and tangles, or tissue damaged by lack of blood flow.

"Humans are very social creatures. We need healthy interactions with others to maintain our health," said Wilson. The results of our study suggest that people who are persistently lonely may be more vulnerable to the deleterious effects of age-related neuropathology."

The mechanism that does link dementia and loneliness is unclear. Wilson encourages more study to look at how negative emotions cause changes in the brain.

"If loneliness is causing changes in the brain, it is quite possible that medications or changes in behavior could lessen the effects of these negative emotions and reduce the risk of Alzheimer's disease," said Wilson.

The researchers are extremely grateful for the remarkable dedication and altruism of the volunteers participating in the Rush Memory and Aging Project. The research was supported by grants from the Illinois Department of Public Health and the National Institutes on Aging, which leads the Federal effort to support and conduct basic, clinical, and social and behavioral studies on aging and on Alzheimer's disease.

Friends rock!

Context

Social isolation in old age has been associated with risk of developing dementia, but the risk associated with perceived isolation, or loneliness, is not well understood.

Objective:

To test the hypothesis that loneliness is associated with increased risk of Alzheimer disease (AD).

Design

Longitudinal clinicopathologic cohort study with up to 4 years of annual in-home follow-up.

Participants

A total of 823 older persons free of dementia at enrollment were recruited from senior citizen facilities in and around Chicago, Ill. Loneliness was assessed with a 5-item scale at baseline (mean +/- SD, 2.3 +/- 0.6) and annually thereafter. At death, a uniform postmortem examination of the brain was conducted to quantify AD pathology in multiple brain regions and the presence of cerebral infarctions.

Main Outcome Measures

Clinical diagnosis of AD and change in previously established composite measures of global cognition and specific cognitive functions.

Results

During follow-up, 76 subjects developed clinical AD. Risk of AD was more than doubled in lonely persons (score 3.2, 90th percentile) compared with persons who were not lonely (score 1.4, 10th percentile), and controlling for indicators of social isolation did not affect the finding. Loneliness was associated with lower level of cognition at baseline and with more rapid cognitive decline during follow-up. There was no significant change in loneliness, and mean degree of loneliness during the study was robustly associated with cognitive decline and development of AD. In 90 participants who died and in whom autopsy of the brain was performed, loneliness was unrelated to summary measures of AD pathology or to cerebral infarction.

Conclusion

Loneliness is associated with an increased risk of late-life dementia but not with its leading causes.

Source: Archives of General Psychiatry 2007 Feb;64(2):234-40.

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