Loneliness Could Boost
Alzheimer's Risk

HealthDay News 6feb2007

Being lonely may increase the risk of developing Alzheimer's disease later in life, new research suggests.

Researchers at the Rush University Medical Center in Chicago assessed loneliness and dementia in 823 people, averaging almost 81 years of age, for up to four years. At the start of the study, the participants' overall average loneliness score was 2.3 on a scale from 1 (lowest) to 5.

Seventy-six people developed Alzheimer's disease during the course of the study, which is published in the February issue of the journal Archives of General Psychiatry.

According to the researchers, each point of increase on the loneliness score was associated with about a 51 percent increased risk of developing Alzheimer's.

This would mean that a person with a high loneliness score (3.2) would be about 2.1 times more likely to develop Alzheimer's than someone with a low score (1.4), they said.

Autopsies performed on 90 people who died during the study revealed that loneliness in life was not related to any of the characteristic brain changes -- such as nerve plaques and tangles -- that are associated with Alzheimer's disease.

So, the actual mechanism linking loneliness and Alzheimer's is unclear, the researchers said. It's unlikely that Alzheimer's actually causes the loneliness, they said.

"In human beings, loneliness has been associated with impaired social skills. Thus, neural systems underlying social behavior might be less elaborated in lonely persons and, as a result, be less able to compensate for other neural systems compromised by age-related neuropathy," the study authors wrote.

SOURCE: JAMA/Archives journals, news release, Feb. 5, 2007

source:  6feb2007

ABSTRACT

Loneliness and Risk of Alzheimer Disease

Archives of General Psychiatry v.64, n.2, February 2007

Robert S. Wilson, PhD; Kristin R. Krueger, PhD; Steven E. Arnold, MD; Julie A. Schneider, MD; Jeremiah F. Kelly, MD; Lisa L. Barnes, PhD; Yuxiao Tang, PhD; David A. Bennett, MD

Arch Gen Psychiatry. 2007;64:234-240.

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.

Author Affiliations:
Rush Alzheimer's Disease Center (Drs Wilson, Krueger, Schneider, Kelly, Barnes, and Bennett), Rush Institute for Healthy Aging (Dr Tang), and Departments of Neurological Sciences (Drs Wilson, Schneider, Barnes, and Bennett), Behavioral Sciences (Drs Wilson, Krueger, and Barnes), Pathology (Dr Schneider), and Internal Medicine (Drs Kelly and Tang), Rush University Medical Center, Chicago, Ill; and Center for Neurobiology and Behavior, and Department of Psychiatry, University of Pennsylvania, Philadelphia (Dr Arnold).

source:  6feb2007