A new study examined if self-reported loneliness was associated with a build-up of cortical amyloid levels in the brain — a marker of preclinical Alzheimer disease.
Alzheimer disease (AD) is a process that moves through preclinical, mild cognitive impairment, and dementia stages before it leads to progressive neuropsychiatric, cognitive, and functional declines.
Although loneliness has been associated with cognitive and functional decline and an increased risk of AD dementia, a link between loneliness and preclinical Alzheimer’s has not been established.
In the new study, published online by JAMA Psychiatry, Nancy J. Donovan, M.D., of Brigham and Women’s Hospital and Harvard Medical School, Boston, and coauthors addressed if their could be an association between between loneliness and Alzheimer’s.
To do this, they used brain imaging technology to measure cortical amyloid levels in the brain and a loneliness scale to indicate levels of loneliness.
The study included 43 women and 36 men with an average age of about 76. Of the participants, 22 (28 percent) were carriers of a genetic risk factor and 25 (32 percent) were in the amyloid-positive group based on volume in imaging. The participants’ average loneliness score was 5.3 on a scale of three to 12.
The authors report higher cortical amyloid levels were associated with greater loneliness after controlling for age, sex, genetic risk factors, socioeconomic status, depression, anxiety, and social network.
Participants in the amyloid-positive group were 7.5 times more likely to be classified as lonely then non-lonely compared with individuals in the amyloid-negative group.
The association between high amyloid levels and loneliness also was stronger in genetic carriers than in non-carriers, according to the results.
Limitations of the study include the demographic profile of the participants who had high intelligence and educational attainment but limited racial and socioeconomic diversity. The participants also had better mental and physical health.
The finding suggests that a linkage appears to be present between loneliness and brain changes associated with pre-Alzheimers among normal adults.
As such, study authors believe the study presents evidence for loneliness as a neuropsychiatric symptom relevant to preclinical AD.
“This work will inform new research into the neurobiology of loneliness and other socioemotional changes in late life and may enhance early detection and intervention research in AD,” the study concludes.