Increased prevalence of loneliness and associated risk factors during the COVID-19 pandemic: findings from the Canadian Longitudinal Study on Aging (CLSA)

Social Isolation, Physical Activity, and Subsequent Changes in Cognition Among Middle- and Older-Aged Adults: Results From the Canadian Longitudinal Study on Aging

OBJECTIVE

The objectives of this study were to a) evaluate associations between social isolation and change in cognition over a 3-year period, and b) evaluate whether physical activity mediates the association between social isolation and cognition change.

METHODS

Using baseline and follow-up 1 data from the Canadian Longitudinal Study on Aging, latent change score models, incorporating direct and indirect pathways, were constructed to estimate the indirect effect of social isolation on cognitive change through physical activity. Multigroup models were constructed based on age group (45-65 versus 65+ years) and sex to allow for varying estimates across age and sex. The final analytic sample included 51,338 participants.

RESULTS

Indirect effects of social isolation on cognition through physical activity were evident in men and women 65+ years old for memory change ( = -0.005 [99.9% confidence interval = -0.007 to -0.002], p < .001 in both groups) and in male adults 65+ years old for executive function change ( = -0.01 [99.9% confidence interval = -0.02 to -0.006], p < .001). Statistically significant indirect effects were not observed for adults between 45 and 65 years old.

CONCLUSIONS

Social isolation is associated with diminished physical activity, and in turn, diminished physical activity is associated with decline in memory in older women and men, with larger declines in executive function in older men. Public health initiatives to promote physical activity-perhaps incorporating social interaction-among older adults experiencing social isolation could be one way to mitigate the negative impact of social isolation on cognitive health.

Association of Loneliness with Functional Connectivity MRI, Amyloid-β PET, and Tau PET Neuroimaging Markers of Vulnerability for Alzheimer's Disease

Background

Loneliness has been declared an "epidemic" associated with negative physical, mental, and cognitive health outcomes such as increased dementia risk. Less is known about the relationship between loneliness and advanced neuroimaging correlates of Alzheimer's disease (AD).

Objective

To assess whether loneliness was associated with advanced neuroimaging markers of AD using neuroimaging data from Framingham Heart Study (FHS) participants without dementia.

Methods

In this cross-sectional observational analysis, we used functional connectivity MRI (fcMRI), amyloid-β (Aβ) PET, and tau PET imaging data collected between 2016 and 2019 on eligible FHS cohort participants. Loneliness was defined as feeling lonely at least one day in the past week. The primary fcMRI marker was Default Mode Network intra-network connectivity. The primary PET imaging markers were Aβ deposition in precuneal and FLR (frontal, lateral parietal and lateral temporal, retrosplenial) regions, and tau deposition in the amygdala, entorhinal, and rhinal regions.

Results

Of 381 participants (mean age 58 [SD 10]) who met inclusion criteria for fcMRI analysis, 5% were classified as lonely (17/381). No association was observed between loneliness status and network changes. Of 424 participants (mean age 58 [SD = 10]) meeting inclusion criteria for PET analyses, 5% (21/424) were lonely; no associations were observed between loneliness and either Aβ or tau deposition in primary regions of interest.

Conclusions

In this cross-sectional study, there were no observable associations between loneliness and select fcMRI, Aβ PET, and tau PET neuroimaging markers of AD risk. These findings merit further investigation in prospective studies of community-based cohorts.

Correlates and trajectories of loneliness among community-dwelling older adults during the COVID-19 pandemic: A Canadian longitudinal study

The COVID-19 pandemic provided a unique opportunity to examine the contributions of social interaction and other non-social factors to loneliness among older adults in the context of confinement measures constraining opportunities for in-person social interactions. This study aims to identify groups of individuals with heterogeneous trajectories of loneliness during the COVID-19 pandemic and to explore the sociodemographic, health, psychological and social interaction-related factors associated with these trajectories. In this 12-month longitudinal study, 614 community-dwelling individuals aged 60+ years completed telephone-based interviews on four occasions between May 2020 and May 2021. Loneliness was evaluated using the three-item version of the UCLA Loneliness Scale. Multilevel modelling assessed average changes in loneliness over time. Group-based trajectory modelling was performed to identify distinct trajectories of loneliness over time. Multinomial logistic regressions were conducted to explore the predictors of these trajectories. On average, there was a curvilinear change in loneliness that tracked the stringency of the COVID-19-related confinement measures. In this convenience sample, three heterogeneous trajectories were identified: a stable-low (17.2%), a fluctuating-moderate (48.8%) and a sustained-elevated (34.0%) trajectory. Participants in the sustained-elevated loneliness trajectory were more likely to live alone and experience elevated psychological distress and greater COVID-19 perceived health threat compared to those in the stable-low trajectory. Participants in the fluctuating-moderate loneliness group were more likely to have multimorbidity, experience greater psychological distress, and have less frequent in-person interactions than the stable-low loneliness group. Assessing the combination of sociodemographic, health, psychological and social factors may help identify individuals at higher risk for chronic loneliness.