Social isolation, cognitive reserve, and cognition in healthy older people

In the paper

“This model suggested that people who are less socially isolated had better CAMCOG scores and the model explained about 17% of the variance in CAMCOG scores.”

In the paper

“Some participants had improved on their CAMCOG scores at follow-up.”

In the paper

“Social isolation was significantly associated with comprehension, but not with orientation, expression, memory, attention and calculation, praxis, abstract thinking, and perception.”

In the paper

“When each aspect of the cognitive reserve measure was separated in moderation analyses, we found that education and cognitive activity did not moderate the association, but occupational complexity did.”

In the paper

“We also found that the relationship between social isolation and cognition is moderated by cognitive reserve longitudinally, but not cross-sectionally.”

In the paper

“Further analysis shows that the association of social isolation with cognitive change was significant in individuals with low occupational complexity, but not high occupational complexity.”

In the paper

“The finding that social isolation is associated with cognitive function at baseline and two year follow-up is consistent with previous studies that assess these relationships using baseline [25] and longitudinal data [26–28].”

In the paper

“Participants with missing data on the measures used at baseline (N = 146) and follow-up (N = 700) were also excluded.”

In the paper

“Cognitive reserve is a theoretical concept that may account for the role of social isolation and its association with cognitive outcomes in later life.”

• Also stated in: § Introduction · plain

  “Cognitive reserve is a theoretical concept that can account for the differences observed in late-life cognitive trajectories.”

• Also stated in: § Introduction · hedged

  “The theory suggests that individuals differ in their degree of resilience against age-related brain pathology and hence may show differences in cognitive function in relation to an equivalent level of pathology [8, 9].”

What the sources say

• Not checked yetcites [8] Y Stern, 2002, What is cognitive reserve? Theory and research application of the reserve concept, Journal of the International Neuropsychological Society source
• Not checked yetcites [9] Y Stern, 2012, Cognitive reserve in ageing and Alzheimer's disease, The Lancet Neurology source

In the paper

“These differences are linked to the ability of an individual to recruit protective mechanisms associated with cognitive abilities built up over the lifespan, and actively compensate for damage caused by pathology [10].”

What the sources say

• Not checked yetcites [10] Y Stern, 2009, Cognitive reserve, Neuropsychologia source

In the paper

“Cognitive function was assessed using the Cambridge Cognitive Examination (CAMCOG) [33]. The CAMCOG is a standardised measure that consists of 67 items, assessing cognitive function along eight subscales”

What the sources say

• Not checked yetcites [33] M Roth, 1986, A standardised instrument for the diagnosis of mental disorder in the elderly with special reference to the early detection of dementia, The British Journal of Psychiatry source

In the paper

“One reason for inconsistency in reported findings may be a lack of consideration of underlying mechanisms that could influence this relationship.”

In the paper

“Including these indicators in measures of isolation reduces the validity of findings, as they do not necessarily reflect isolation.”

In the paper

“This has important implications for interventions that may target social isolation to improve cognitive function.”

In the paper

“Sensory problems (hearing and eyesight) at baseline were also controlled for as these problems may reduce an individual’s ability to be socially engaged and hence contribute to an increased level of social isolation [38, 39].”

In the paper

“People aged 65 and over were randomly sampled from general practice lists between 2011 and 2013.”

In the paper

“The LSNS-6 was also normally distributed at baseline (skewness of -.13 and kurtosis of 2.61).”

In the paper

“This may reduce or delay the extent of impairment experienced and protect against the expression of pathological processes [11].”

What the sources say

• Not checked yetcites [11] KL Siedlecki, 2009, Construct validity of cognitive reserve in a multiethnic cohort: The Northern Manhattan Study, Journal of the International Neuropsychological Society source

In the paper

“Variation in approaches to assessing and defining social isolation and cognitive outcomes may contribute to inconsistency and complicate the interpretation of empirical findings.”

In the paper

“Being unable to complete such tasks may indicate limitations in physical ability and mobility, which may influence ability to be socially engaged, and hence increase level of social isolation [40].”

What the sources say

• Not checked yetcites [40] CF Mendes de Leon, 2003, Social engagement and disability in a community population of older adults: the New Haven EPESE, American Journal of Epidemiology source

In the paper

“as were people living in an institution (N = 95) as it is considered that the experience of social isolation will differ between community and residential settings.”

In the paper

“which are established covariates of late-life cognition [35–37].”

What the sources say

• Not checked yetcites [35] LL Barnes, 2003, Gender, cognitive decline, and risk of AD in older persons, Neurology source
• Not checked yetcites [36] S Tervo, 2004, Incidence and risk factors for mild cognitive impairment: a population-based three-year follow-up study of cognitively healthy elderly subjects, Dementia and Geriatric Cognitive Disorders source
• Not checked yetcites [37] RS Tilvis, 2004, Predictors of cognitive decline and mortality of aged people over a 10-year period. The Journals of Gerontology Series A, Biological Sciences and Medical Sciences source

In the paper

“The authors reported a moderating effect for delayed recall, but not for immediate recall or verbal fluency [27].”

What the sources say

• Not checked yetcites [27] A Shankar, 2013, Social isolation and loneliness: relationships with cognitive function during 4 years of follow-up in the English Longitudinal Study of Ageing, Psychosomatic Medicine source

In the paper

“The theory suggests that individuals differ in their degree of resilience against age-related brain pathology and hence may show differences in cognitive function in relation to an equivalent level of pathology [8, 9].”

What the sources say

• Not checked yetcites [8] Y Stern, 2002, What is cognitive reserve? Theory and research application of the reserve concept, Journal of the International Neuropsychological Society source
• Not checked yetcites [9] Y Stern, 2012, Cognitive reserve in ageing and Alzheimer's disease, The Lancet Neurology source

In the paper

“These experiences may create a buffer against cognitive decline by enhancing brain processes such as neural connectivity and hence cognitive ability.”

What the sources say

• Not checked yetcites [11] KL Siedlecki, 2009, Construct validity of cognitive reserve in a multiethnic cohort: The Northern Manhattan Study, Journal of the International Neuropsychological Society source

In the paper

“Interviews were conducted by research assistants who had completed training provided by staff at the co-ordinating centre in Cambridge and participants could choose whether they wanted their interview conducted in English or Welsh.”

In the paper

“Participants were stratified by age to ensure a representative sample across two age groups (65–74 and ≥75).”

In the paper

“Finally, the participants’ ability to complete daily tasks alone (such as housework, getting dressed, getting up and down stairs, carrying things, etc.) at baseline was controlled for.”

In the paper

“CAMCOG scores were normally distributed at baseline (skewness of -.84 and kurtosis of 4.48) and follow-up (skewness of -1.16 and kurtosis of 5.44).”

In the paper

“Education alone is not a comprehensive indication of cognitive reserve and it is suggested that multiple proxy indicators representing reserve at different stages of life are preferable [30, 31].”

What the sources say

• Not checked yetcites [30] C Opdebeeck, 2016, Cognitive reserve and cognitive function in healthy older people: a meta-analysis, Aging, Neuropsychology, and Cognition source
• Not checked yetcites [31] A Tucker, 2011, Cognitive reserve in aging, Current Alzheimer Research source

In the paper

“Social isolation was measured in CFAS-Wales using the Lubben Social Network Scale–6 (LSNS-6) [34]. The LSNS-6 is a standardised measure of social isolation”

What the sources say

• Not checked yetcites [34] J Lubben, 2006, Performance of an abbreviated version of the Lubben Social Network Scale among three European community-dwelling older adult populations, The Gerontologist source

In the paper

“This might then protect the individual against the effects of disease pathology in the first instance, and also compensate for damage and recruit alternative neural pathways when required.”

What the sources say

• Not checked yetcites [11] KL Siedlecki, 2009, Construct validity of cognitive reserve in a multiethnic cohort: The Northern Manhattan Study, Journal of the International Neuropsychological Society source

In the paper

“Having a range of good social connections has been identified as an important aspect of successful ageing [12] and is associated with lower mortality rates [13, 14], better health outcomes [15, 16], and higher reported wellbeing [17, 18] and quality of life [19, 20].”

What the sources say

• Not checked yetcites [13] J Holt‐Lunstad, 2012, Social relationships and mortality, Social and Personality Psychology Compass source
• Not checked yetcites [14] A Steptoe, 2013, Social isolation, loneliness, and all-cause mortality in older men and women, Proceedings of the National Academy of Sciences source
• Not checked yetcites [15] EY Cornwell, 2009, Social disconnections, perceived isolation, and health among older adults, Journal of Health and Social Behavior source
• Not checked yetcites [16] D Umberson, 2010, Social relationships and health a flashpoint for health policy, Journal of Health and Social Behavior source
• Not checked yetcites [17] SC Olesen, 2011, Community participation and mental health during retirement in community sample of Australians, Aging & Mental Health source
• Not checked yetcites [18] W Tomaszewski, 2013, Living environment, social participation and wellbeing in older age: the relevance of housing and local area disadvantage, Journal of Population Ageing source

In the paper

“A score of ≤12 may be taken to indicate the presence of social isolation [34].”

What the sources say

• Not checked yetcites [34] J Lubben, 2006, Performance of an abbreviated version of the Lubben Social Network Scale among three European community-dwelling older adult populations, The Gerontologist source

In the paper

“Inconsistency in results assessing the relationship between social isolation and cognitive function may be attributed to conceptual and methodological challenges associated with defining and measuring social isolation.”

In the paper

“In contrast, being isolated would not provide this stimulation and hence may not build reserve.”

In the paper

“Findings suggest that maintaining a socially active lifestyle in later life may enhance cognitive reserve and benefit cognitive function.”

In the paper

“Given that depression is also associated with cognitive impairment, people with an AGECAT classification of depression (N = 333) were also excluded”

In the paper

“Several covariates were controlled for in the analyses, including age (years), gender, and education (years) at baseline”

In the paper

“Studies that acquire samples through participants responding to advertised studies may be more at risk of bias to a ‘self-selected’ sample that are more engaged in social and community activities, and hence are not isolated.”

In the paper

“Interventions to reduce social isolation in older people may benefit cognitive function both directly and indirectly through building cognitive reserve.”

In the paper

“In addition, the education measure in the present study is a relatively crude index and only considers the number of years of education.”

In the paper

“This approach is preferable as it accounts for the variance in reserve built at different stages of life [30, 31].”

What the sources say

• Not checked yetcites [30] C Opdebeeck, 2016, Cognitive reserve and cognitive function in healthy older people: a meta-analysis, Aging, Neuropsychology, and Cognition source
• Not checked yetcites [31] A Tucker, 2011, Cognitive reserve in aging, Current Alzheimer Research source

In the paper

“For example, an individual with a poor education and low occupational complexity may compensate for this through good social relationships [27].”

What the sources say

• Not checked yetcites [27] A Shankar, 2013, Social isolation and loneliness: relationships with cognitive function during 4 years of follow-up in the English Longitudinal Study of Ageing, Psychosomatic Medicine source

In the paper

“For instance, participation in social activities has been associated with better health among participants from low socio-economic groups [42].”

What the sources say

• Not checked yetcites [42] Z Heritage, 2008, Impact of social ties on self-reported health in France: Is everyone affected equally?, BMC Public Health source

In the paper

“However, we excluded participants with poor cognitive function or dementia at baseline which reduces the risk of reverse causation.”

In the paper

“Participants in CFAS-Wales were sampled from general practice registers and approached to participate, giving a representative sample of older people, including those who are extremely isolated.”

In the paper

“This measure of education is much more sensitive.”

In the paper

“Such individuals are likely to receive less cognitive stimulation through social contact, resulting in lower cognitive reserve and hence poorer cognitive function [8, 9].”

What the sources say

• Not checked yetcites [8] Y Stern, 2002, What is cognitive reserve? Theory and research application of the reserve concept, Journal of the International Neuropsychological Society source
• Not checked yetcites [9] Y Stern, 2012, Cognitive reserve in ageing and Alzheimer's disease, The Lancet Neurology source

In the paper

“This has important implications for interventions, suggesting that targeting isolation may be beneficial for cognitive health.”

In the paper

“Social isolation may be detrimental to cognitive function as isolated individuals experience less social contact with others.”

In the paper

“However, the authors of this study assessed three sub-domains of cognition, and found that education moderated the association between isolation and cognition for delayed recall, but not for verbal fluency or immediate recall [27].”

What the sources say

• Not checked yetcites [27] A Shankar, 2013, Social isolation and loneliness: relationships with cognitive function during 4 years of follow-up in the English Longitudinal Study of Ageing, Psychosomatic Medicine source

In the paper

“Shankar and colleagues [27] measure education based on the highest qualification obtained, and classify participant’s educational level as either low (no formal qualifications) or high.”

What the sources say

• Not checked yetcites [27] A Shankar, 2013, Social isolation and loneliness: relationships with cognitive function during 4 years of follow-up in the English Longitudinal Study of Ageing, Psychosomatic Medicine source

In the paper

“However, the contribution of each of these components of the cognitive reserve score may vary considerably across participants.”

In the paper

“It is possible that social isolation may be prodromal to poor cognitive function [45].”

What the sources say

• Not checked yetcites [45] LL Barnes, 2004, Social resources and cognitive decline in a population of older African Americans and whites, Neurology source

In the paper

“This is inconsistent with a previous study by Shankar and colleagues [27] which reported that education did moderate this association.”

What the sources say

• Not checked yetcites [27] A Shankar, 2013, Social isolation and loneliness: relationships with cognitive function during 4 years of follow-up in the English Longitudinal Study of Ageing, Psychosomatic Medicine source

In the paper

“These individual differences may not be adequately reflected in the measure.”