Good social connections are proposed to positively influence the course of cognitive decline by stimulating cognitive reserve and buffering harmful stress-related health effects. Prior meta-analytic research has uncovered links between social connections and the risk of poor health outcomes such as mild cognitive impairment, dementia, and mortality. These studies have primarily used aggregate data from North America and Europe with limited markers of social connections. Further research is required to explore these associations longitudinally across a wider range of social connection markers in a global setting.

We examined the associations between social connection structure, function, and quality and the risk of our primary outcomes (mild cognitive impairment, dementia, and mortality).

Individual participant-level data were obtained from 13 longitudinal studies of ageing from across the globe. We conducted survival analysis using Cox regression models and combined estimates from each study using two-stage meta-analysis. We examined three social constructs: connection structure (living situation, relationship status, interactions with friends/family, community group engagement), function (social support, having a confidante) and quality (relationship satisfaction, loneliness) in relation to the risks of three primary outcomes (mild cognitive impairment, dementia, and mortality). In our partially adjusted models, we included age, sex, and education and in fully adjusted models used these variables as well as diabetes, hypertension, smoking, cardiovascular risk, and depression.

In our fully adjusted models we observed: a lower risk of mild cognitive impairment was associated with being married/in a relationship (vs. being single), weekly community group engagement (vs. no engagement), weekly family/friend interactions (vs. not interacting), and never feeling lonely (vs. often feeling lonely); a lower risk of dementia was associated with monthly/weekly family/friend interactions and having a confidante (vs. no confidante); a lower risk of mortality was associated with living with others (vs. living alone), yearly/monthly/weekly community group engagement, and having a confidante.

Good social connection structure, function, and quality are associated with reduced risk of incident MCI, dementia, and mortality. Our results provide actionable evidence that social connections are required for healthy ageing.

Octogenarians of today are better educated, and physically and cognitively healthier, than earlier born cohorts. Less is known about time trends in mental health in this age group. We aimed to study time trends in the prevalence of depression and psychotropic drug use among Swedish 85-year-olds.

We derived data from interviews with 85-year-olds in 1986–1987 (N = 348), 2008–2010 (N = 433) and 2015–17 (N = 321). Depression diagnoses were made according to the Diagnostic and Statistical Manual of Mental Disorders. Symptom burden was assessed with the Montgomery-Åsberg Depression Rating Scale (MADRS). Information on psychotropic drug use, sociodemographic, and health-related factors were collected during the interviews.

The prevalence of major depression was lower in 2015–2017 (4.7%, p < 0.001) and 2008–2010 (6.9%, p = 0.010) compared to 1986–1987 (12.4%). The prevalence of minor depression was lower in 2015–2017 (8.1%) compared to 2008–2010 (16.2%, p = 0.001) and 1986–1987 (17.8%, p < 0.001). Mean MADRS score decreased from 8.0 in 1986–1987 to 6.5 in 2008–2010, and 5.1 in 2015–2017 (p < 0.001). The reduced prevalence of depression was not explained by changes in sociodemographic and health-related risk factors for depression. While psychoactive drug use was observed in a third of the participants in each cohort, drug type changed over time (increased use of antidepressants and decreased use of anxiolytics and antipsychotics).

The prevalence of depression in octogenarians has declined during the past decades. The decline was not explained by changes in known risk factors for depression. The present study cannot answer whether changed prescription patterns of psychoactive drugs have contributed to the decline.

To determine the accuracy of 12 previously validated short versions of the Geriatric Depression Scale (GDS) to detect major depressive disorder (MDD) in a high-risk population with and without global cognitive impairment.

Cross-sectional study.

Five hospitals, Western Sweden.

Older adults (age ≥70 years, n = 60) assessed at a home visit 1 year after hospital care in connection with suicide attempt.

Depression symptoms were rated using the established 15-item GDS. Eleven short GDS versions identified by a recent systematic review were derived from this administered version. Receiver operating characteristic curves and area under the curve (AUC) for the identification of MDD diagnosed according to Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, were obtained for each version. The Youden Index optimal criterion was used to determine the appropriate cutoffs. Analyses were repeated after stratification by cognitive status (Mini Mental State Examination score ≤24 and >24) for the best performing GDS short versions and the established 15-item GDS.

The 7-item GDS according to Broekman et al. (2011), with a cutoff 3, was the most accurate among the 12 short versions (AUC 0.90, 95% confidence interval 0.80–1.00), identifying MDD with sensitivity 88% and specificity 81%. The cutoff score remained consistent in the presence of global cognitive impairment, which was not the case for the standardized 15-item GDS.

The Broekman 7-item GDS had high accuracy to detect MDD in this prospective clinical cohort at high risk for MDD. Further testing of GDS short versions in diverse settings is required.