Emotional support (giving or receiving) and risk of incident dementia: The Ohsaki Cohort 2006 Study

Utilization of Japanese long-term care-related data including Kaigo-DB: An analysis of current trends and future directions

Despite high expectations from the government and researchers regarding data utilization, comprehensive analysis of long-term care (LTC)-related data use has been limited. This study reviewed the use of LTC-related data, including Kaigo-DB, in Japan after 2020. There was an increase in studies using LTC-related data in Japan between 2020 and 2021, followed by a stabilization period. The national government provided 13.5% of this data (6.5% from Kaigo-DB), while prefectures and municipalities contributed 85.2%, and facilities provided 1.3%. The linked data used in 90.4% of the studies primarily consisted of original questionnaire or interview surveys (34.6%) and medical claims (34.0%). None of the studies based on Kaigo-DB utilized linked data. In terms of study design, cohort studies were the most common (84.6%), followed by descriptive (5.1%), cross-sectional (3.2%), and case-control studies (1.3%). Among the 138 individual-based analytical descriptive studies, the most frequently used LTC-related data as an exposure was LTC services (26.8%), and the most common data used as an outcome was LTC certification or care need level (43.5%), followed by the independence degree of daily living for the older adults with dementia (18.1%). To enhance the use of LTC-related data, especially the valuable national Kaigo-DB, insights can be gleaned from how researchers effectively utilize municipal and prefectural data. Streamlining access to Kaigo-DB and enabling its linkage with other datasets are promising for future research in this field.

Association of community-level social capital with dementia: A multilevel nine-year longitudinal study using data from the Japan Gerontological Evaluation Study

BACKGROUND

Individual-level social capital prevents cognitive decline. However, a few studies have focused on the effects of community-level social capital on dementia. Therefore, we investigated the association between community-level social capital and dementia onset based on longitudinal study data on older adults in Japan.

METHODS

We used longitudinal data from the Japan Gerontological Evaluation Study, obtained over nine years (2010-2019). In total, 35,921 physically and cognitively independent individuals (16,848 males and 19,073 females) aged ≥65 years and nested within 308 communities in seven municipalities participated in the study. Dementia onset was assessed using the public long-term care insurance registration. Social capital was assessed using three dimensions: civic participation, social cohesion, and reciprocity. We performed a two-level multilevel survival analysis stratified by sex, calculated hazard ratios (HRs), and 95% confidence intervals (CIs).

RESULTS

During the follow-up, 6245 (17.4%) dementia onset cases were identified. The cumulative incidence of dementia was 16.2% in males and 18.4% in females. After adjusting for covariates, individual-level civic participation was associated with a lower incidence of dementia in both males and females (HR, 0.84; 95% CI, 0.77-0.92; HR, 0.78; 95% CI, 0.73-0.84). Community-level civic participation and social cohesion were associated with a lower incidence of dementia among females (HR, 0.96; 95% CI, 0.93-0.99; HR, 0.93; 95% CI, 0.88-0.98) and cross-level interaction on social cohesion among females (HR, 0.95; 95% CI, 0.90-0.99).

CONCLUSIONS

Living in a community with high civic participation and social cohesion is associated with a lower incidence of dementia among older females. Therefore, promoting civic participation and social cohesion in the community may be a useful population-based strategy to delay or prevent the onset of dementia.

Functional social support and cognitive function in middle- and older-aged adults: a systematic review of cross-sectional and cohort studies

BACKGROUND

Intact cognitive function is crucial for healthy aging. Functional social support is thought to protect against cognitive decline. We conducted a systematic review to investigate the association between functional social support and cognitive function in middle- and older-aged adults.

METHODS

Articles were obtained from PubMed, PsycINFO, Sociological Abstracts, CINAHL, and Scopus. Eligible articles considered any form of functional social support and cognitive outcome. We narratively synthesized extracted data by following the Synthesis Without Meta-Analysis (SWiM) guidelines and assessed risk of bias using the Newcastle-Ottawa Scale (NOS).

RESULTS

Eighty-five articles with mostly low risk-of-bias were included in the review. In general, functional social support-particularly overall and emotional support-was associated with higher cognitive function in middle- and older-aged adults. However, these associations were not all statistically significant. Substantial heterogeneity existed in the types of exposures and outcomes evaluated in the articles, as well as in the specific tools used to measure exposures and outcomes.

CONCLUSIONS

Our review highlights the role of functional social support in the preservation of healthy cognition in aging populations. This finding underscores the importance of maintaining substantive social connections in middle and later life.

SYSTEMATIC REVIEW REGISTRATION

Rutter EC, Tyas SL, Maxwell CJ, Law J, O'Connell ME, Konnert CA, Oremus M. Association between functional social support and cognitive function in middle-aged and older adults: a protocol for a systematic review. BMJ Open;10(4):e037301. https://doi.org/10.1136/bmjopen-2020-037301.

Altruistic Social Activity, Depressive Symptoms, and Brain Regional Gray Matter Volume: Voxel-Based Morphometry Analysis from 8695 Old Adults

Altruistic social activity, such as giving support to others, has shown protective benefits on dementia risk and cognitive decline. However, the pathological mechanism is unclear. In the present study, we investigated the association between altruistic social activity and brain regional gray matter. Furthermore, to explore the psychological interplay in altruistic social activity, we tested mediating effect of depressive symptoms on brain regional gray matter. We performed a cross-sectional Voxel-Based Morphology (VBM) analysis including 8695 old adults (72.9±6.1 years) from Japan Prospective Studies Collaboration for Aging and Dementia (JPSC-AD) Cohort. We measured altruistic social activities by self-report questionnaire, depressive symptoms by Geriatric Depression Scale (GDS)-short version. We employed the whole-brain VBM method to detect relevant structural properties related to altruistic social activity. We then performed multiple regression models to detect the mediating effect of depressive symptoms on particular brain regional gray matter volume while adjusting possible physical and social lifestyle covariables. We found that altruistic social activity is associated with larger gray matter volume in posterior insula, middle cingulate gyrus, hippocampus, thalamus, superior temporal gyrus, anterior orbital gyrus, and middle occipital gyrus. Depressive symptoms mediated over 10% on altruistic social activity and hippocampus volume, over 20% on altruistic social activity and cingulate gyrus volume. Our results indicated that altruistic social activity might preserve brain regional gray matter where are sensitive to aging and cognitive decline. Meanwhile, this association may be explained by indirect effect on depressive symptoms, suggesting that altruistic social activity may mitigate the neuropathology of dementia.