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.

Olfactory dysfunction and depression are common in later life, and both have been presented as risk factors for dementia. Our purpose was to investigate the associations between these two risk factors and determine if they had an additive effect on dementia risk.

Olfactory function was assessed using the Brief Smell Identification Test (BSIT), and depression was classified using a combination of the 15-item Geriatric Depression Scale (GDS) score and current antidepressant use. Cross-sectional associations between depression and olfactory function were examined using correlations. Cox regression analyses were conducted to examine the longitudinal relationship between olfaction and depression and incident dementia across 12-years of follow-up.

Participants were 780 older adults (aged 70–90 years; 56.5% female) from the Sydney Memory and Ageing Study (MAS) without a diagnosis of dementia at baseline.

Partial correlation revealed a nonsignificant association between baseline depression and olfactory function after accounting for covariates (r = −.051, p = .173). Cox regression showed that depression at baseline (hazard ratio = 1.706, 95% CI 1.185–2.456, p = .004) and lower BSIT scores (HR = .845, 95%CI .789–.905, p < .001) were independently associated with a higher risk of incident dementia across 12 years. Entering both predictors together improved the overall predictive power of the model.

Lower olfactory identification scores and depressive symptoms predict incident dementia over 12 years. The use of BSIT scores and depression in conjunction provides a greater ability to predict dementia than either used alone. Assessment of olfactory function and depression screening may provide clinical utility in the early detection of dementia.

Computerised neuropsychological assessments (CNAs) are proposed as an alternative method of assessing cognition to traditional pencil-and-paper assessment (PnPA), which are considered the “gold standard” for diagnosing dementia. However, limited research has been conducted with culturally and linguistically diverse (CALD) individuals. This study investigated the suitability of PnPAs and CNAs for measuring cognitive performance in a heterogenous sample of older, Australian CALD English-speakers compared to a native English-speaking background (ESB) sample.

Participants were 1037 community-dwelling individuals aged 70–90 years without a dementia diagnosis from the Sydney Memory and Ageing Study (873 ESB, 164 CALD). Differences in the level and pattern of cognitive performance in the CALD group were compared to the ESB group on a newly developed CNA and a comprehensive PnPA in English, controlling for covariates. Multiple hierarchical regression was used to identify the extent to which linguistic and acculturation variables explained performance variance.

CALD participants’ performance was consistently poorer than ESB participants on both PnPA and CNA, and more so on PnPA than CNA, controlling for socio-demographic and health factors. Linguistic and acculturation variables together explained approximately 20% and 25% of CALD performance on PnPA and CNA respectively, above demographics and self-reported computer use.

Performances of CALD and ESB groups differed more on PnPAs than CNAs, but caution is needed in concluding that CNAs are more culturally-appropriate for assessing cognitive decline in older CALD individuals. Our findings extend current literature by confirming the influence of linguistic and acculturation variables on cognitive assessment outcomes for older CALD Australians.

This study aimed to investigate psychometric properties and enhance precision of the 16-item Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE-16) up to interval-level scale using Rasch methodology.

Partial Credit Rasch model was applied to the IQCODE-16 scores using longitudinal data spanning 10 years of biennial follow-up.

Community-dwelling older adults aged 70–90 years and their informants, living in Sydney, Australia, participated in the longitudinal Sydney Memory and Ageing Study (MAS).

The sample included 400 participants of the MAS aged 70 years and older, 109 out of those were diagnosed with dementia 10 years after the baseline assessment.

The IQCODE-16.

Initial analysis indicated excellent reliability of the IQCODE-16, Person Separation Index (PSI) = 0.92, but there were four misfitting items and local dependency issues. Combining locally dependent items into four super-items resulted in the best Rasch model fit with no misfitting or locally dependent items, strict unidimensionality, strong reliability, and invariance across person factors such as participants’ diagnosis and relationship to their informants, as well as informants’ age and sex. This permitted the generation of conversion algorithms to transform ordinal scores into interval data to enhance precision of measurement.

The IQCODE-16 demonstrated strong reliability and satisfied expectations of the unidimensional Rasch model after minor modifications. Ordinal-to-interval transformation tables published here can be used to increase accuracy of the IQCODE-16 without altering its current format. These findings could contribute to enhancement of precision in assessing clinical conditions such as cognitive decline in older people.