Behind the headlines: Is loneliness linked to Alzheimer's?

Loneliness might increase the chance of developing Alzheimer's disease, writes Sanjay Tanday

What is the story?
People who are lonely in their old age are more likely to develop Alzheimer’s disease than those with a more active social life, according to media reports.

US researchers found that lonely people were twice as likely to develop the type of dementia linked to Alzheimer’s in later life than people who experienced little loneliness, say the papers.

A five-point scale was used to measure loneliness, with higher scores indicating more loneliness. The researchers concluded that loneliness appeared to be a risk factor for Alzheimer’s, but not an early sign of the disease.

However, the exact mechanism that links dementia and loneliness is unclear.

What is the research?
The reports are based on a US cohort study of 823 people aged on average 81 years that examined the association between loneliness and Alzheimer’s disease over four years.

Participants filled in an annual questionnaire to assess loneliness. A five-point scale was used to rate each statement in the questionnaire, with higher scores indicating greater loneliness.

The questionnaire included statements specifically designed to assess the emotional loneliness of the individual, such as  ‘I miss having people around’.

Social network size was identi-fied using standard questions about the number of children, family and friends each person had and how often they interacted with them.

Frequency of participation in social activity was assessed using a six-statement questionnaire scored using a five-point scale.

Annual tests to assess the cog-nitive function of the individuals were also carried out. These in-cluded memory tests, word list recognition and verbal fluency.

During the course of the study, 76 individuals developed dementia that met the criteria for Alzheimer’s. Those that developed Alzheimer’s had an average loneliness score of 2.5, compared with 2.2 in those that did not develop the disease.

The risk of developing Alz-heimer’s increased by 51 per cent for each point on the loneliness score. For example, a person with a loneliness score of 3.2, was twice as likely to develop Alzheimer’s as a person with a score of 1.4.

Autopsies were performed on the 90 individuals who died during the study. Loneliness was not found to be related to any of the hallmark brain changes associated with Alzheimer’s, including nerve plaques and tangles.

What do the researchers say?
Lead researcher Dr Robert Wilson, senior neuropsychologist from Rush University Medical Centre in Chicago, said: ‘The findings of the study are important because they indicate that feeling alone is related to risk of Alzheimer’s even after controlling for the extent of social activity and the size of social networks.’

The implication for GPs and carers of the elderly is that in old age, the quality of social attachments and the quantity of social interactions are important in helping to maintain physical and emotional well being, said Dr Wilson.

‘If loneliness is causing changes in the brain, it is possible that medications could lessen the effects of these negative emotions and reduce the risk of Alzheimer’s disease,’ he said.

However, further research needs to be done into how negative emotions cause changes in the brain, added Dr Wilson.

What do other experts say?
North London GP Dr Steve Iliffe, who has a special interest in dementia and Alzheimer’s disease, said GPs should not read too much into the research at this stage.

‘Loneliness is also associated with depression, and depression may also be a risk factor for dementia,’ he said.

‘There is no effective preventive treatment for dementia, so we need not look too hard for dementia until it starts to cause problems for individuals and their families.’

What the papers said

“Alzheimer’s is a lonely disease” 

“Loneliness link with Alzheimer’s” 

“Lonely people more likely to develop Alzheimer’s”

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