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Cited by 227Dementia and Cognitive Impairment ResearchHealth disparities and outcomesAging and Gerontology Research

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

Open access
Evans, Isobel E. M., Llewellyn, David J., Matthews, Fiona E., Woods, Robert T., Brayne, Carol, Clare, Linda, on behalf of the CFAS-Wales research team·2018·PLOS ONE
DOI 10.1371/journal.pone.0201008PMC PMC6097646
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Abstract

There is evidence to suggest that social isolation is associated with poor cognitive health, although findings are contradictory. One reason for inconsistency in reported findings may be a lack of consideration of underlying mechanisms that could influence this relationship. Cognitive reserve is a theoretical concept that may account for the role of social isolation and its association with cognitive outcomes in later life. Therefore, we aimed to examine the relationship between social isolation and cognition in later life, and to consider the role of cognitive reserve in this relationship. Baseline and two year follow-up data from the Cognitive Function and Ageing Study-Wales (CFAS-Wales) were analysed. Social isolation was assessed using the Lubben Social Network Scale-6 (LSNS-6), cognitive function was assessed using the Cambridge Cognitive Examination (CAMCOG), and cognitive reserve was assessed using a proxy measure of education, occupational complexity, and cognitive activity. Linear regression modelling was used to assess the relationship between social isolation and cognition. To assess the role of cognitive reserve in this relationship, moderation analysis was used to test for interaction effects. After controlling for age, gender, education, and physically limiting health conditions, social isolation was associated with cognitive function at baseline and two year follow-up. Cognitive reserve moderated this association longitudinally. Findings suggest that maintaining a socially active lifestyle in later life may enhance cognitive reserve and benefit cognitive function. This has important implications for interventions that may target social isolation to improve cognitive function.

AI snapshot

Written from the paper’s full text.

TL;DR

In CFAS-Wales, social isolation was associated with poorer cognitive function at baseline and with cognitive change over two years, and cognitive reserve moderated the longitudinal association. Occupational complexity drove the moderation, with isolation linked to cognitive change only among those with low occupational complexity.

Key findings

  • Social isolation was associated with cognition at baseline after full adjustment (B = .04, 95% CI .02–.07, p < .001; adjusted R² = .17) and with two-year cognitive change (B = .05, 95% CI .01–.10, p = .03; adjusted R² = .05), suggesting less isolated people had better CAMCOG scores and less decline.
  • At baseline, 601 of 2,224 participants (27.02%) were classified as socially isolated by LSNS-6 ≤12; isolated participants were older, more likely to be men, had poorer CAMCOG scores, fewer years of education, less cognitive activity, and lower cognitive reserve scores.
  • Cognitive reserve did not moderate the cross-sectional association (.01; 95% CI −.01–.04), but it did moderate the longitudinal association (.05; 95% CI .10–0). Post-hoc analyses showed occupational complexity significantly moderated the association (−.05; 95% CI −.10–−.01), while education (−.04; 95% CI −.08–.01) and cognitive activity (−.01; 95% CI −.06–.03) did not.
  • Social isolation was associated with cognitive change in the low occupational complexity group (.08; 95% CI 0–.15) but not the high occupational complexity group (.03; 95% CI −.02–.09). Baseline gender interaction was significant (p = .04), with the association significant for women but not men; longitudinal gender interaction was not significant (p = .13).

Methods

  • Longitudinal analysis of the Cognitive Function and Ageing Study–Wales (CFAS-Wales), a population-based cohort aged 65+ sampled from general practice lists in rural and urban Wales, with baseline interviews in 2011–2013 and two-year follow-up in 2013–2015. Final samples were 2,224 for cross-sectional and 1,524 for longitudinal analyses after exclusions.
  • Social isolation was measured with the Lubben Social Network Scale-6 (LSNS-6; ≤12 indicating isolation), cognition with the Cambridge Cognitive Examination (CAMCOG), and cognitive reserve with a weighted composite of education, occupational complexity, and cognitive activity.
  • Linear regression assessed baseline cognition and standardized two-year cognitive change; moderation analyses tested interactions between social isolation and cognitive reserve, adjusting for age, gender, education (except in reserve models), sensory limitations, and help with daily activities, using Stata 15.0.

Limitations

  • Stated: social isolation may be prodromal to poor cognitive function, though participants with baseline cognitive impairment or dementia were excluded to reduce reverse causation.
  • Stated: very little cognitive change occurred over two years, and some participants improved on CAMCOG, limiting the validity of longitudinal analyses; the two-year follow-up may be insufficient to observe cognitive change.
  • Stated/evident: the cognitive reserve composite may not adequately reflect individual differences in how much each component contributes, and education was measured only as years of education, a relatively crude index. Also evident: many participants were excluded for missing follow-up data, and those excluded were older and had poorer baseline cognition, education, cognitive activity, occupational complexity, and higher isolation.

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Integrity signals

Registry

Crossref · 10.1371/journal.pone.0201008

Cites

47 of 47 references verified0 citation errors · 0 not checkable

Statistics

Claims the paper makes

0 of 52 cited sources checked · 0 supported · 0 flagged

  • Findingown data

    Social isolation was significantly associated with cognition at baseline, adjusted R2 = .02, F(1, 2222) = 35.99, p < .001.

    “Social isolation was significantly associated with cognition, adjusted R2 = .02, F(1, 2222) = 35.99, p < .001.”
    Quote in the paperSubstantial claim
  • Findingown data

    Cognitive reserve moderated the association between social isolation and cognitive function longitudinally.

    “Cognitive reserve moderated this association longitudinally.”
    Quote in the paperSubstantial claim
  • Findingown data

    Social isolation was significantly associated with orientation (cross-sectional CAMCOG).

    “Social isolation was significantly associated with orientation, expression, praxis, and perception, but not with comprehension, memory, attention and calculation, or abstract thinking.”
    Quote in the paperSubstantial claim
  • Findingown data

    After adjusting for all covariates, the association between social isolation and cognition at baseline remained significant, adjusted R2 = .17, F(7, 2216) = 64.67, p < .001.

    “After adjusting for all covariates, the association remained significant, adjusted R2 = .17, F(7, 2216) = 64.67, p < .001.”
    Quote in the paperSubstantial claim
  • Findingown data

    After controlling for age, gender, education, and physically limiting health conditions, social isolation was associated with cognitive function at baseline and two year follow-up.

    “After controlling for age, gender, education, and physically limiting health conditions, social isolation was associated with cognitive function at baseline and two year follow-up.”
    Quote in the paperSubstantial claim
  • May combine two claims. 25
  • Classified as probably not a substantial claim. 43

  • May combine two claims.

    Findingown data

    People who are less socially isolated had better CAMCOG scores, and the model explained about 17% of the variance in CAMCOG scores.

    “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.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

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

    “Some participants had improved on their CAMCOG scores at follow-up.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Social isolation was not significantly associated with orientation, expression, memory, attention and calculation, praxis, abstract thinking, and perception (longitudinal CAMCOG).

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

  • May combine two claims.

    Findingown data

    Education and cognitive activity did not moderate the association between social isolation and cognition, but occupational complexity did.

    “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.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    The relationship between social isolation and cognition is moderated by cognitive reserve longitudinally, but not cross-sectionally.

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

  • May combine two claims.

    Findingown data

    The association of social isolation with cognitive change was significant in individuals with low occupational complexity, but not high occupational complexity.

    “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.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingcitation

    Social isolation is associated with cognitive function at baseline and at two-year follow-up.

    “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].”
    Quote in the paperSubstantial claim

  • Classified as probably not a substantial claim.

    Study design and conductnone given

    Participants with missing data on the measures used at baseline and follow-up were excluded.

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

  • Classified as probably not a substantial claim. May combine two claims.

    Premisecitation

    Cognitive reserve is a theoretical concept that can account for differences in late-life cognitive trajectories and may account for the role of social isolation in cognitive outcomes.

    “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].”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [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 in the free run.

    • cites [9] Y Stern, 2012, Cognitive reserve in ageing and Alzheimer&apos;s disease, The Lancet Neurology source

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Premisecitation

    These differences are linked to the ability to recruit protective mechanisms associated with cognitive abilities built up over the lifespan and to compensate for damage caused by pathology.

    “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].”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [10] Y Stern, 2009, Cognitive reserve, Neuropsychologia source

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Study design and conductcitation

    Cognitive function was assessed using the CAMCOG, a standardised measure.

    “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”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [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

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S2 (checkable), S4 (based).

    Interpretationnone given

    A lack of consideration of underlying mechanisms may be one reason for inconsistency in reported findings.

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

  • Classified as probably not a substantial claim.

    Interpretationreasoning

    Including indicators such as being unmarried, living alone, or social support in measures of isolation reduces the validity of findings, as they do not necessarily reflect isolation.

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

  • Classified as probably not a substantial claim.

    Interpretationreasoning

    Interventions that target social isolation may improve cognitive function.

    “This has important implications for interventions that may target social isolation to improve cognitive function.”
    Quote in the paperSubstantial claim

  • Classified as probably not a substantial claim.

    Study design and conductreasoning

    Analyses also controlled for sensory problems (hearing and eyesight) at baseline.

    “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].”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductown data

    Participants were randomly sampled from general practice lists.

    “People aged 65 and over were randomly sampled from general practice lists between 2011 and 2013.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductown data

    The LSNS-6 was normally distributed at baseline.

    “The LSNS-6 was also normally distributed at baseline (skewness of -.13 and kurtosis of 2.61).”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim. May combine two claims.

    Premisecitation

    This may reduce or delay the extent of impairment experienced and protect against the expression of pathological processes.

    “This may reduce or delay the extent of impairment experienced and protect against the expression of pathological processes [11].”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [11] KL Siedlecki, 2009, Construct validity of cognitive reserve in a multiethnic cohort: The Northern Manhattan Study, Journal of the International Neuropsychological Society source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S2 (checkable).

    Interpretationreasoning

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

    “Variation in approaches to assessing and defining social isolation and cognitive outcomes may contribute to inconsistency and complicate the interpretation of empirical findings.”
    Quote in the paperNot a substantial claim
    • The authors state this as an assumption: There is no consistent definition of social isolation used within the literature, and this inconsistency is reflected in the measures selected to assess social isolation.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Being unable to complete daily tasks may indicate limitations in physical ability and mobility, which may influence ability to be socially engaged, and hence increase level of social isolation.

    “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].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [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

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Study design and conductreasoning

    People living in an institution were excluded.

    “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.”
    Quote in the paperSubstantial claim
    • The authors state this as an assumption: The experience of social isolation differs between community and residential settings.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Age, gender, and education are established covariates of late-life cognition.

    “which are established covariates of late-life cognition [35–37].”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [35] LL Barnes, 2003, Gender, cognitive decline, and risk of AD in older persons, Neurology source

      Not checked in the free run.

    • cites [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 in the free run.

    • cites [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

      Not checked in the free run.

  • Classified as probably not a substantial claim. May combine two claims.

    Premisecitation

    One previous study reported a moderating effect of education on the association between social isolation and cognitive function for delayed recall, but not for immediate recall or verbal fluency.

    “The authors reported a moderating effect for delayed recall, but not for immediate recall or verbal fluency [27].”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [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

      Not checked in the free run.

  • Classified as probably not a substantial claim. May combine two claims.

    Premisecitation

    Individuals differ in their degree of resilience against age-related brain pathology and may show differences in cognitive function in relation to an equivalent level of pathology.

    “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].”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [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 in the free run.

    • cites [9] Y Stern, 2012, Cognitive reserve in ageing and Alzheimer&apos;s disease, The Lancet Neurology source

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Premisecitation

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

    “These experiences may create a buffer against cognitive decline by enhancing brain processes such as neural connectivity and hence cognitive ability.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [11] KL Siedlecki, 2009, Construct validity of cognitive reserve in a multiethnic cohort: The Northern Manhattan Study, Journal of the International Neuropsychological Society source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductnone given

    Interviews were conducted by research assistants who had completed training provided by staff at the co-ordinating centre in Cambridge.

    “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.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductreasoning

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

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

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductown data

    Analyses controlled for participants' ability to complete daily tasks alone at baseline.

    “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.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductown data

    CAMCOG scores were normally distributed at baseline and follow-up.

    “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).”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S2 (checkable). May combine two claims.

    Premisecitation

    Education alone is not a comprehensive indication of cognitive reserve, and multiple proxy indicators representing reserve at different stages of life are preferable.

    “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].”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [30] C Opdebeeck, 2016, Cognitive reserve and cognitive function in healthy older people: a meta-analysis, Aging, Neuropsychology, and Cognition source

      Not checked in the free run.

    • cites [31] A Tucker, 2011, Cognitive reserve in aging, Current Alzheimer Research source

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Study design and conductcitation

    Social isolation was measured using the LSNS-6, a standardised measure.

    “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”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [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

      Not checked in the free run.

  • Classified as probably not a substantial claim. May combine two claims.

    Premisecitation

    This may protect against the effects of disease pathology and compensate for damage and recruit alternative neural pathways when required.

    “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.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [11] KL Siedlecki, 2009, Construct validity of cognitive reserve in a multiethnic cohort: The Northern Manhattan Study, Journal of the International Neuropsychological Society source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Having a range of good social connections is associated with lower mortality rates, better health outcomes, higher reported wellbeing and quality of life.

    “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].”
    Quote in the paperNot a substantial claim0 of 6 sources checked
    • cites [13] J Holt‐Lunstad, 2012, Social relationships and mortality, Social and Personality Psychology Compass source

      Not checked in the free run.

    • cites [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 in the free run.

    • cites [15] EY Cornwell, 2009, Social disconnections, perceived isolation, and health among older adults, Journal of Health and Social Behavior source

      Not checked in the free run.

    • cites [16] D Umberson, 2010, Social relationships and health a flashpoint for health policy, Journal of Health and Social Behavior source

      Not checked in the free run.

    • cites [17] SC Olesen, 2011, Community participation and mental health during retirement in community sample of Australians, Aging & Mental Health source

      Not checked in the free run.

    • cites [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

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Premisecitation

    A score of ≤12 on the LSNS-6 may be taken to indicate the presence of social isolation.

    “A score of ≤12 may be taken to indicate the presence of social isolation [34].”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [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

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Interpretationreasoning

    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.

    “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.”
    Quote in the paperSubstantial claim
    • The authors state this as an assumption: There is no consistent definition of social isolation used within the literature, and this inconsistency is reflected in the measures selected to assess social isolation.

  • Classified as probably not a substantial claim. May combine two claims.

    Interpretationreasoning

    Being isolated would not provide this stimulation and hence may not build reserve.

    “In contrast, being isolated would not provide this stimulation and hence may not build reserve.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationown data

    Maintaining a socially active lifestyle in later life may enhance cognitive reserve and benefit cognitive function.

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

  • Classified as probably not a substantial claim.

    Study design and conductreasoning

    People with an AGECAT classification of depression were excluded.

    “Given that depression is also associated with cognitive impairment, people with an AGECAT classification of depression (N = 333) were also excluded”
    Quote in the paperSubstantial claim
    • The authors state this as an assumption: Depression is associated with cognitive impairment.

  • Classified as probably not a substantial claim.

    Study design and conductown data

    Analyses controlled for age, gender, and education at baseline.

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

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisenone given

    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.

    “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.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationreasoning

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

    “Interventions to reduce social isolation in older people may benefit cognitive function both directly and indirectly through building cognitive reserve.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: Some aspects of early- and mid-life reserve, such as education or occupational complexity, cannot be modified in later life.
    • Rests on an assumption: Other aspects of reserve, such as social activity, can be modified in later life and can contribute to building reserve and reducing poor cognitive function.

  • Classified as probably not a substantial claim. May combine two claims.

    Study design and conductnone given

    The education measure in the present study is a relatively crude index and only considers the number of years of education.

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

  • Probably not a substantial claim: may not pass S2 (checkable).

    Interpretationcitation

    This approach is preferable as it accounts for the variance in reserve built at different stages of life.

    “This approach is preferable as it accounts for the variance in reserve built at different stages of life [30, 31].”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [30] C Opdebeeck, 2016, Cognitive reserve and cognitive function in healthy older people: a meta-analysis, Aging, Neuropsychology, and Cognition source

      Not checked in the free run.

    • cites [31] A Tucker, 2011, Cognitive reserve in aging, Current Alzheimer Research source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    An individual with a poor education and low occupational complexity may compensate for this through good social relationships.

    “For example, an individual with a poor education and low occupational complexity may compensate for this through good social relationships [27].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [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

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Participation in social activities has been associated with better health among participants from low socio-economic groups.

    “For instance, participation in social activities has been associated with better health among participants from low socio-economic groups [42].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [42] Z Heritage, 2008, Impact of social ties on self-reported health in France: Is everyone affected equally?, BMC Public Health source

      Not checked in the free run.

  • May combine two claims.

    Study design and conductreasoning

    We excluded participants with poor cognitive function or dementia at baseline which reduces the risk of reverse causation.

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

  • May combine two claims.

    Study design and conductreasoning

    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.

    “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.”
    Quote in the paperSubstantial claim

  • Classified as probably not a substantial claim.

    Interpretationreasoning

    This measure of education is much more sensitive.

    “This measure of education is much more sensitive.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationcitation

    Isolated individuals are likely to receive less cognitive stimulation through social contact, resulting in lower cognitive reserve and hence poorer cognitive function.

    “Such individuals are likely to receive less cognitive stimulation through social contact, resulting in lower cognitive reserve and hence poorer cognitive function [8, 9].”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [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 in the free run.

    • cites [9] Y Stern, 2012, Cognitive reserve in ageing and Alzheimer&apos;s disease, The Lancet Neurology source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S2 (checkable).

    Interpretationreasoning

    Targeting isolation may be beneficial for cognitive health.

    “This has important implications for interventions, suggesting that targeting isolation may be beneficial for cognitive health.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationreasoning

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

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

  • May combine two claims.

    Premisecitation

    Shankar and colleagues found that education moderated the association between isolation and cognition for delayed recall, but not for verbal fluency or immediate recall.

    “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].”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [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

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Shankar and colleagues measure education based on the highest qualification obtained, and classify educational level as low or high.

    “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.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [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

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductreasoning

    The contribution of each of these components of the cognitive reserve score may vary considerably across participants.

    “However, the contribution of each of these components of the cognitive reserve score may vary considerably across participants.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    It is possible that social isolation may be prodromal to poor cognitive function.

    “It is possible that social isolation may be prodromal to poor cognitive function [45].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [45] LL Barnes, 2004, Social resources and cognitive decline in a population of older African Americans and whites, Neurology source

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Premisecitation

    Shankar and colleagues reported that education did moderate the association between isolation and cognition.

    “This is inconsistent with a previous study by Shankar and colleagues [27] which reported that education did moderate this association.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [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

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing).

    Study design and conductreasoning

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

    “These individual differences may not be adequately reflected in the measure.”
    Quote in the paperNot a substantial claim
57 of 57

  • The authors state this as an assumption.

    The association between social connections and cognition is less well understood than other lifestyle factors that may build cognitive reserve.

    “Compared to other lifestyle factors that may build cognitive reserve, the association between social connections and cognition is less well understood.”

  • The authors state this as an assumption.

    There is no consistent definition of social isolation used within the literature, and this inconsistency is reflected in the measures selected to assess social isolation.

    “There is no consistent definition used within the literature and this inconsistency is reflected in the measures selected to assess social isolation.”

  • The authors state this as an assumption.

    Previous work suggests that cognitive reserve may be important in the association between social isolation and cognitive function, but this has not been explored.

    “Although previous work suggests that cognitive reserve may be important in this association, to our knowledge, this has not been explored.”

  • The authors state this as an assumption.

    The experience of social isolation differs between community and residential settings.

    “as it is considered that the experience of social isolation will differ between community and residential settings.”

  • The authors state this as an assumption.

    Depression is associated with cognitive impairment.

    “Given that depression is also associated with cognitive impairment”

  • The paper relies on this without support.

    Some aspects of early- and mid-life reserve, such as education or occupational complexity, cannot be modified in later life.

    “Although some aspects of early- and mid- life reserve cannot be modified in later life, such as education or occupational complexity, there are other aspects of reserve that can be modified, such as social activity, to contribute to building reserve and reducing poor cognitive function in later life.”

  • The paper relies on this without support.

    Other aspects of reserve, such as social activity, can be modified in later life and can contribute to building reserve and reducing poor cognitive function.

    “Although some aspects of early- and mid- life reserve cannot be modified in later life, such as education or occupational complexity, there are other aspects of reserve that can be modified, such as social activity, to contribute to building reserve and reducing poor cognitive function in later life.”
7 of 7

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

  • The importance of social isolation in later life and the benefits of having a wide social network and engagement in frequent social activity on cognitive function are reinforced by the present findings.

    “This further reinforces the importance of social isolation in later life and the benefits of having a wide social network and engagement in frequent social activity on cognitive function (Evans et al., 2018).”

    From Living alone and cognitive function in later life (2019) · cites this paper as Evans et al., 2018

Statistics recomputed

Every reported test result, recomputed from its test statistic and degrees of freedom. A result shows as not adding up only once an independent check has confirmed it.

  • Not confirmedF(6, 1090) = 35.85reported p = .1 · recomputed p < .001

    “F(6, 1090) = 35.85, p = .10”

  • Not confirmedF(8, 2215) = 57.23reported p = .04 · recomputed p < .001

    “F(8, 2215) = 57.23, p = .04”

  • Not confirmedF(6, 759) = 11.57reported p = .02 · recomputed p < .001

    “F(6, 759) = 11.57, p = .02”

  • Not confirmedF(6, 751) = 4.65reported p = .39 · recomputed p < .001

    “F(6, 751) = 4.65, p = .39”

  • Not confirmedF(8, 1515) = 10.75reported p = .13 · recomputed p < .001

    “F(8, 1515) = 10.75, p = .13”

  • ConsistentF(1, 2222) = 35.99reported p < .001 · recomputed p < .001

    “F(1, 2222) = 35.99, p < .001”

  • ConsistentF(7, 2216) = 64.67reported p < .001 · recomputed p < .001

    “F(7, 2216) = 64.67, p < .001”

  • ConsistentF(6, 1120) = 38.41reported p < .001 · recomputed p < .001

    “F(6, 1120) = 38.41, p < .001”

  • ConsistentF(1, 1522) = 8.92reported p = .003 · recomputed p = .003

    “F(1, 1522) = 8.92, p = .003”

  • ConsistentF(7, 1516) = 11.95reported p < .001 · recomputed p < .001

    “F(7, 1516) = 11.95, p < .001”

10 of 10

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Self-check results appear here once an independent check has confirmed them.

Cites

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Related

Authors
Evans, I. E. M., Llewellyn, D. J., Matthews, F. E., Woods, R. T., Brayne, C., Clare, L., & on behalf of the CFAS-Wales research team
Affiliations
  • University of Exeter (GB)
  • University of Cambridge (GB)
  • Australian National University (AU)
Corresponding author
Evans, Isobel E. M.
ORCID
Venue
PLOS ONE
Publisher
Public Library of Science (PLoS)
Published
2018-08-17
Volume
13
Issue
8
Pages
e0201008
ISSN
1932-6203 (ISSN-L)
DOI
10.1371/journal.pone.0201008
PMC
PMC6097646
OpenAlex
W2885562630
Semantic Scholar
0eb1f8c6e94aa5029d0a29d2e7657b7f06c5e0d3
Cited by
227
References
47
Citations by year
2026: 13 · 2025: 35 · 2024: 41 · 2023: 30 · 2022: 31 · 2021: 44 · 2020: 15 · 2019: 16 · 2018: 1
FWCI
14.71
Type
journal article
Language
en
Open access
Licence
Locations
  • PLoS ONE (publishedVersion, cc-by)
  • Europe PMC (PubMed Central) (publishedVersion, cc-by)
  • PubMed Central (publishedVersion, cc-by)
  • PubMed (publishedVersion)
  • RePEc: Research Papers in Economics (submittedVersion)
  • DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion)
  • Figshare (submittedVersion)
  • Figshare (submittedVersion, cc-by)
  • Repository@Hull (Worktribe) (University of Hull) (submittedVersion, cc-by)
  • Open Research Exeter (University of Exeter) (submittedVersion, cc-by)
  • Bangor University Research Portal (Bangor University) (submittedVersion, cc-by)
  • Newcastle University ePrints (Newcastle Univesity) (cc-by)
Funders
Alzheimer's Society (AS-DTC-2014-027)
Topics
  • Health Sciences › Medicine › Psychiatry and Mental health › Dementia and Cognitive Impairment Research
  • Social Sciences › Health › Health disparities and outcomes
  • Social Sciences › Psychology › Neuropsychology and Physiological Psychology › Aging and Gerontology Research
Keywords
social isolation, cognitive reserve, cognitive function, older adults, cognitive aging, Lubben Social Network Scale, occupational complexity, educational attainment, cognitive activity, social networks
MeSH terms
Cognitive Aging, Healthy Aging, Aged, Aged, 80 and over, Cognition, Female, Follow-Up Studies, Humans, Male, Social Isolation, Wales, Linear Models, Cognitive Reserve

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Claims read by deepseek-v4.1-flash under definition version 3 (extract-v3) on 2026-10-09.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-10-09.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

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