Social relationships are essential to aging well; research has shown an association between lack of social engagement and increased risk of dementia.
A new study by investigators from Brigham and Women’s Hospital found that higher brain amyloid-β in combination with lower social engagement in elderly men and women was associated with greater cognitive decline over three years.
The results of the study were published last month in the American Journal of Geriatric Psychiatry.
“Social engagement and cognitive function are related to one another and appear to decline together,” said senior author Nancy Donovan, MD, chief of the Division of Geriatric Psychiatry at the Brigham.
“This means that social engagement may be an important marker of resilience or vulnerability in older adults at risk of cognitive impairment.”
The investigators sampled 217 men and women enrolled in the Harvard Aging Brain Study, a longitudinal observational study looking for early neurobiological and clinical signs of Alzheimer’s disease.
The participants, aged 63-89, were cognitively normal, but some individuals showed high levels of amyloid-β protein, a pathologic hallmark of Alzheimer’s disease detected with neuroimaging techniques.
The investigators used standard questionnaires and examinations to assess participants’ social engagement (including activities such as spending time with friends and family and doing volunteer work) and cognitive performance at baseline and three years later.
Social engagement was particularly relevant to cognition in participants with evidence of Alzheimer’s disease brain changes.
The researchers report that, among cognitively normal older adults with high levels of amyloid-β, those who had lower social engagement at baseline showed steeper cognitive decline than those who were more socially engaged.
This association was not observed in those with low amyloid-β.
Donovan and her team used a standard measure of social engagement that did not capture all the intricacies of digital communication or the qualitative aspects of relationships.
They reported that a more contemporary and comprehensive assessment of social engagement could be a valuable outcome measure in future clinical trials of Alzheimer’s disease.
The team cited that future studies with follow-up periods longer than three years may further gauge cognitive decline over time and help untangle the complex mechanisms of Alzheimer’s disease progression.
“We want to understand the breadth of this issue in older people and how to intervene to protect high-risk individuals and preserve their health and well-being,” said Donovan.
Dementia is an irreversible progressive disease that has no effective treatment1.
A recent study has shown that 35.6 million people worldwide suffer from dementia, and this number is predicted to double by 2030 and more than triple by 20502.
China had the largest number of persons with dementia in 2010 with 9.19 million3.
Additionally, the increasing prevalence of dementia may lead to a sharp rise in the social and economic burdens of the disease.
The total worldwide societal cost of dementia was estimated to be $315 billion in 2005 and $422 billion in 2009, indicating an increase of 34% between 2005 and 2009.
The societal costs of dementia in China were $41 billion, leading China to become the country with the third-highest societal costs of dementia following the United States and Japan.
China, as the largest developing country, will face grave challenges in preventing and controlling dementia.
Accordingly, the risk factors of dementia must be considered.
Notably, fewer studies have examined the association between social engagement (SE) and the risk for the onset of dementia, and the findings have been inconsistent.
SE refers to the maintenance of social connections and participation in social activities7. A few prospective studies of older adults have indicated that the risks of cognitive decline and dementia are increased in individuals who are isolated, lack physical activity and have poor social networks and support8–15.
A longitudinal study from the Kungsholmen Project16 showed that engagement in social and leisure activities in late life might decrease the risk of dementia in older adults because participation in productive or social activities could potentially sustain individuals’ senses of self-efficacy and thus improve the health statuses of older adults.
Additionally, engaging in intellectually challenging activities may promote or enhance cognitive performance.
The Envejecer en Leganes study17 showed that good social relationships with friends and relatives might generate continued mental stimulation and better cognitive strategies in late life.
Similar results were obtained from Dutch8 and Swedish10 studies on the elderly. However, these findings are in contrast with the results of previous studies20,21 showing that social relationships are not associated with an decreased risk of dementia or Alzheimer disease (AD) in the elderly.
In addition to these controversies, most epidemiological studies documenting the association between SE and incident dementia have examined only one baseline measurement of SE and related this measure to the subsequent dementia risk. Conversely, these studies have rarely investigated changes in SE after the baseline.
This type of investigation is important because many people change their SE level throughout life, and these changes may affect the risk of dementia.
To the best of our knowledge, only one study has evaluated the association between changes in SE from midlife to late life and the risk of dementia with a focus on old men22. Saczynski et al.22 indicated that only decreasing SE from midlife to late life was associated with an increased risk of dementia, whereas increasing SE was not associated with a reduced risk of dementia among Japanese-American men.
The objective of this study is to examine the association of SE and changes in SE with the risk of dementia in a cohort during a 9-year follow-up.
The sample was derived from the Chinese Longitudinal Healthy Longevity Survey (CLHLS).
More information: Kelsey D. Biddle et al, Social Engagement and Amyloid-β-Related Cognitive Decline in Cognitively Normal Older Adults, The American Journal of Geriatric Psychiatry (2019). DOI: 10.1016/j.jagp.2019.05.005
Journal information: American Journal of Geriatric Psychiatry
Provided by Brigham and Women’s Hospital