Social health and cognitive change in old age: the role of brain reserve

OBJECTIVE: Individual aspects of social health (SH; e.g. network, engagement, support) have been linked to cognitive health. However, their combined effect, and the role of the structural properties of the brain (brain reserve, BR) remain unclear. We investigated the interplay of SH and BR on cognitive change in older adults. METHODS: Within the Swedish National study on Aging and Care-Kungsholmen, 368 dementia-free adults aged ≥60 years with baseline brain magnetic resonance imaging were followed over 12 years to assess cognitive change. A measure of global cognition was computed at each of the five waves of assessment by averaging domain-specific Z-scores for episodic memory, perceptual speed, semantic memory, letter and category fluency. An SH composite score was computed at baseline by combining leisure activities and social network. BR was proxied by total brain tissue volume (TBTV). Linear mixed models (adjusted for sociodemographic, vascular, and genetic factors) were used to estimate cognitive trajectories in relation to SH, TBTV. Interaction analysis and stratification were used to examine the interplay between SH and TBTV. RESULTS: Moderate-good SH (n=245; vs. poor; β-slope=0.01 [95% CI 0.002, 0.02]; p=0.018) and moderate-to-large TBTV (n=245; vs. small; β-slope=0.03 [95% CI 0.02, 0.04]; p<0.001) were separately associated with slower cognitive decline. In stratified analysis, moderate-good SH was associated with higher cognitive levels (but not change) only in participants with moderate-to-large TBTV (β-intercept=0.21 [95%CI 0.06; 0.37], p<0.01; interaction SH*TBTV p<0.05). INTERPRETATION: Our findings highlight the interplay between social health and brain reserve that likely unfolds throughout the entire life course to shape old-age cognitive outcomes. This article is protected by copyright. All rights reserved

Social health and change in cognitive capability among older adults:findings from four European longitudinal studies

Introduction: In this study we examine whether social health markers measured at baseline are associated with differences in cognitive capability and in the rate of cognitive decline over an 11-to-18-year period among older adults and compare results across studies. Methods: We applied an integrated data analysis approach to 16,858 participants (mean age 65 years; 56% female) from the National Survey for Health and Development (NSHD), the English Longitudinal Study of Aging (ELSA), the Swedish National Study on Aging and Care in Kungsholmen (SNAC-K), and the Rotterdam Study. We used multilevel models to examine social health in relation to cognitive capability and the rate of cognitive decline. Results: Pooled estimates show distinct relationships between markers of social health and cognitive domains e.g., a large network size (≥6 people vs none) was associated with higher executive function (0.17 SD[95%CI:0.0, 0.34], I2=27%) but not with memory (0.08 SD[95%CI: -0.02, 0.18], I2=19%). We also observed pooled associations between being married or cohabiting, having a large network size and participating in social activities with slower decline in cognitive capability, however estimates were close to zero e.g., 0.01SD/year [95%CI: 0.01 to 0.02] I2=19% for marital status and executive function. There were clear study-specific differences: results for average processing speed were the most homogenous and results for average memory were the most heterogenous. Conclusion: Overall, markers of good social health have a positive association with cognitive capability. However, we found differential associations between specific markers of social health and cognitive domains and differences between studies. These findings highlight the importance of examining between study differences and considering context specificity of findings in developing and deploying any intervention

Social Health and Change in Cognitive Capability among Older Adults: Findings from Four European Longitudinal Studies

INTRODUCTION: In this study we examine whether social health markers measured at baseline are associated with differences in cognitive capability and in the rate of cognitive decline over an 11-to-18-year period among older adults and compare results across studies. METHODS: We applied an integrated data analysis approach to 16,858 participants (mean age 65 years; 56% female) from the National Survey for Health and Development (NSHD), the English Longitudinal Study of Aging (ELSA), the Swedish National Study on Aging and Care in Kungsholmen (SNAC-K), and the Rotterdam Study. We used multilevel models to examine social health in relation to cognitive capability and the rate of cognitive decline. RESULTS: Pooled estimates show distinct relationships between markers of social health and cognitive domains e.g., a large network size (≥6 people vs none) was associated with higher executive function (0.17 SD[95%CI:0.0, 0.34], I2=27%) but not with memory (0.08 SD[95%CI: -0.02, 0.18], I2=19%). We also observed pooled associations between being married or cohabiting, having a large network size and participating in social activities with slower decline in cognitive capability, however estimates were close to zero e.g., 0.01SD/year [95%CI: 0.01 to 0.02] I2=19% for marital status and executive function. There were clear study-specific differences: results for average processing speed were the most homogenous and results for average memory were the most heterogenous. CONCLUSION: Overall, markers of good social health have a positive association with cognitive capability. However, we found differential associations between specific markers of social health and cognitive domains and differences between studies. These findings highlight the importance of examining between study differences and considering context specificity of findings in developing and deploying any interventions

Social connections and risk of incident mild cognitive impairment, dementia, and mortality in 13 longitudinal cohort studies of ageing

INTRODUCTION: Previous meta-analyses have linked social connections and mild cognitive impairment, dementia, and mortality. However, these used aggregate data from North America and Europe and examined a limited number of social connection markers. METHODS: We used individual participant data (N = 39271, Mage  = 70.67 (40-102), 58.86% female, Meducation  = 8.43 years, Mfollow-up  = 3.22 years) from 13 longitudinal ageing studies. A two-stage meta-analysis of Cox regression models examined the association between social connection markers with our primary outcomes. RESULTS: We found associations between good social connections structure and quality and lower risk of incident mild cognitive impairment (MCI); between social structure and function and lower risk of incident dementia and mortality. Only in Asian cohorts, being married/in a relationship was associated with reduced risk of dementia, and having a confidante was associated with reduced risk of dementia and mortality. DISCUSSION: Different aspects of social connections - structure, function, and quality - are associated with benefits for healthy aging internationally. HIGHLIGHTS: Social connection structure (being married/in a relationship, weekly community group engagement, weekly family/friend interactions) and quality (never lonely) were associated with lower risk of incident MCI. Social connection structure (monthly/weekly friend/family interactions) and function (having a confidante) were associated with lower risk of incident dementia. Social connection structure (living with others, yearly/monthly/weekly community group engagement) and function (having a confidante) were associated with lower risk of mortality. Evidence from 13 longitudinal cohort studies of ageing indicates that social connections are important targets for reducing risk of incident MCI, incident dementia, and mortality. Only in Asian cohorts, being married/in a relationship was associated with reduced risk of dementia, and having a confidante was associated with reduced risk of dementia and mortality

Associations between social connections and cognition: a global collaborative individual participant data meta-analysis

International audienceBackground Poor social connections (eg, small networks, infrequent interactions, and loneliness) are modifiable risk factors for cognitive decline. Existing meta-analyses are limited by reporting aggregate responses, a focus on global cognition, and combining social measures into single constructs. We aimed to investigate the association between social connection markers and the rate of annual change in cognition (ie, global and domain-specific), as well as sex differences, using an individual participant data meta-analysis.Methods We harmonised data from 13 longitudinal cohort studies of ageing in North America, South America, Europe, Africa, Asia, and Australia. Studies were eligible for inclusion if they had baseline data for social connection markers and at least two waves of cognitive scores. Follow-up periods ranged from 0 years to 15 years across cohorts. We included participants with cognitive data for at least two waves and social connection data for at least one wave. We then identified and excluded people with dementia at baseline. Primary outcomes were annual rates of change in global cognition and cognitive domain scores over time until final follow-up within each cohort study analysed by use of an individual participant data meta-analysis. Linear mixed models within cohorts used baseline social connection markers as predictors of the primary outcomes. Effects were pooled in two stages using random-effects meta-analyses. We assessed the primary outcomes in the main (partially adjusted) and fully adjusted models. Partially adjusted models controlled for age, sex, and education; fully adjusted models additionally controlled for diabetes, hypertension, smoking, cardiovascular risk, and depression.Findings Of the 40 006 participants in the 13 cohort studies, we excluded 1392 people with dementia at baseline. 38 614 individual participants were included in our analyses. For the main models, being in a relationship or married predicted slower global cognitive decline (b=0•010, 95% CI 0•000-0•019) than did being single or never married; living with others predicted slower global cognitive (b=0•007, 0•002-0•012), memory (b=0•017, 0•006-0•028), and language (b=0•008, 0•000-0•015) decline than did living alone; and weekly interactions with family and friends (b=0•016, 0•006-0•026) and weekly community group engagement (b=0•030, 0•007-0•052) predicted slower memory decline than did no interactions and no engagement. Never feeling lonely predicted slower global cognitive (b=0•047, 95% CI 0•018-0•075) and executive function (b=0•047, 0•017-0•077) decline than did often feeling lonely. Degree of social support, having a confidante, and relationship satisfaction did not predict cognitive decline across global cognition or cognitive domains. Heterogeneity was low (I²=0•00-15•11%) for all but two of the significant findings (association between slower memory decline and living with others [I²=58•33%] and community group engagement, I²=37•54-72•19%), suggesting robust results across studies.Interpretation Good social connections (ie, living with others, weekly community group engagement, interacting weekly with family and friends, and never feeling lonely) are associated with slower cognitive decline

A variant at chromosome 9p21 is associated with recurrent myocardial infarction and cardiac death after acute coronary syndrome: The GRACE Genetics Study

Recent genetic studies identified the rs1333049 variant on chromosome 9p21 as a major susceptibility locus for coronary artery disease and myocardial infarction (MI). Here, we evaluated whether this variant also contributes to recurrent MI or cardiac death following an acute coronary syndrome (ACS).status: publishe