Most previous studies of frailty trajectories in older adults focus on the average trajectory and ignore death. Longitudinal quantile analysis of frailty trajectories permits the definition of reference curves, and the application of mortal cohort inference provides more realistic estimates than models that ignore death. Using data from individuals aged 65 or older (n = 25 446) from the Survey of Health, Ageing, and Retirement in Europe (SHARE) from 2004 to 2020, we derived repeated values of the Frailty Index (FI) based on the accumulation of health deficits. We applied weighted Generalized Estimating Equations to estimate the quantiles of the FI trajectory, adjusting for sample attrition due to death, sex, education, and cohort. The FI quantiles increased with age and progressed faster for those with the highest level of frailty (⁠ $β^a0.9$ = 0.0229, p < .001; $β^a0.5$ = 0.0067, p < .001; H₀: $βa0.5=βa0.9$⁠, p < .001). Education was consistently associated with a slower progression of the FI in all quantiles (⁠ $β^ae0.1$ = −0.0001, p < .001; $β^ae0.5$ =−0.0004, p < .001; $β^ae0.9$ = −0.0003, p < .001) but sex differences varied across the quantiles. Women with the highest level of frailty showed a slower progression of the FI than men when considering death. Finally, no cohort effects were observed for the FI progression. Quantile FI trajectories varied by age, sex, education, and cohort. These differences could inform the practice of interventions aimed at older adults with the highest level of frailty.

Dispersion in cognitive test performance within a single testing session is proposed as an early marker of poor brain health. Existing research, however, has not investigated factors that may explain individual differences in cognitive dispersion. We investigate the extent to which the Big Five personality traits are associated with cognitive dispersion in older adulthood. To promote transparency and reliability, we applied preregistration and conceptual replication via coordinated analysis. Drawing data from seven longitudinal studies of aging (N_total = 33,581; M_age range = 56.4–71.2), cognitive dispersion scores were derived from cognitive test results. Independent linear regression models were fit in each study to examine personality traits as predictors of dispersion scores, adjusting for mean cognitive performance and sociodemographics (age, sex, education). Results from individual studies were synthesized using random effects meta-analyses. Synthesized results revealed that openness was positively associated with cognitive dispersion, 0.028, 95% CI [0.003, 0.054]. There was minimal evidence for associations between cognitive dispersion and the other personality traits in independent analyses or meta-analyses. Mean cognitive scores were negatively associated with cognitive dispersion across the majority of studies, while sociodemographic variables were not consistently associated with cognitive dispersion. Higher levels of openness were associated with greater cognitive dispersion across seven independent samples, indicating that individuals higher in openness had more dispersion across cognitive tests. Further research is needed to investigate mechanisms that may help to explain the link between openness and cognitive dispersion, as well as to identify additional individual factors, beyond personality traits, that may be associated with cognitive dispersion.

Ageing has been related to the onset of disability and dependency in older adults. There is a need to better understand the disability and dependency trajectories of older adults and their relationship with socio-demographic characteristics and institutional or cultural context. This study analyses the role of age, sex, education and self-perceived health in disability, dependency and death transitions, addressing the heterogeneity across European countries and inconsistencies when using different measures of disability. Multi-state models were adjusted to evaluate the role of risk and protective factors in the transitions to disability, dependency and death. Difficulties in performing activities of daily living (ADLs) assess disability and dependency states. Data were from the Survey of Health, Ageing and Retirement in Europe conducted in 2004–2013, considering individuals aged 65 and older at baseline from Austria, Belgium, Denmark, France, Germany, Italy, the Netherlands, Spain, Sweden and Switzerland. The results showed that transitions to disability and dependency varied with age, sex, education and self-perceived health. The probability of transition to disability and dependency states increases until the age of 70 for all countries. However, there was heterogeneity in the disability and dependency trajectories with ageing between men and women. In most countries, women live with difficulties and may need help for longer than men. Care policies should consider sex differences to decrease the burden of care of informal caregivers, particularly in countries where care systems are absent or partially developed and a high level of family obligations to care needs exist.

Objectives: To assess the heterogeneity of transitions toward dependency in older adults and to explore the robustness of results to different operationalizations of dependency. Method: Using data from people aged 60 years and older from a national representative study in Uruguay (Encuesta Longitudinal de Protección Social, N = 5071), we fitted multinomial regressions adjusted by sociodemographic and health characteristics to model transitions into dependency and death. We used a harder operationalization with basic activities of daily living (Katz-dependency) and Comprehensive-dependency with basic, instrumental, and advanced activities. Results: Increasing age (RRR = 1.08, CI = [1.05; 1.12], p < .001) and having comorbidities (RRR = 2.16, CI = [1.31; 3.57], p = .003) increased the risk of transition from nondependent to dependent using Katz-dependency. Women with at least two chronic conditions have increased risk of Comprehensive-dependency (RRR = 1.79, CI = [1.15; 2.80], p = .010). Discussion: Inconsistencies in findings emerged when evaluating transitions into dependency with the different measures, which may have social care implications.

Cross-sectional studies have shown improvements in cognition in later-born cohorts. However, it remains unclear whether these cohort effects extend beyond cognitive levels and are also detectable in the rate of age-related cognitive decline. Additionally, evidence is scarce on the presence and consistency of cohort effects throughout different segments of the distribution of cognitive trajectories. This study evaluates the existence and variability of cohort effects across the entire distribution of aging-related trajectories of verbal fluency. With this purpose, we develop sex and education-adjusted longitudinal norms of verbal fluency using data from 9 waves of the English Longitudinal Study of Aging (ELSA) by fitting quantile mixed models. The effect of age was modeled using splines to assess birth cohort effects, after grouping individuals in 5-year groups from 1920 to 1950 according to their age at study entry. To test for possible cohort effects across the 10th, 50th, and 90th quantiles, the coefficients associated with the splines were allowed to vary among cohorts. Our results suggest that, consistently across longitudinal quantiles, decline in verbal fluency across age is less pronounced for later-born individuals (p < .001), supporting the hypothesis of cohort effects. Additionally, we also found that quantiles of verbal fluency at any age are shifted upwards in later-born cohorts compared to those in earlier-born cohorts. These results enhance our understanding of cognitive decline in older adults by demonstrating that cohort effects on cognition are observable both cross-sectionally and longitudinally, affecting the entire range of verbal fluency trajectories.

Intrinsic capacity (IC) is a composite that includes five different domains related to a person’s capacities: sensory, locomotion, vitality, psychological and cognitive. IC represents part of a global effort to promote healthy ageing, one aspect of which is healthy cognitive functioning. This study aimed to elucidate the association of IC and cognitive decline in older adults. Using data from the English Longitudinal Study of Ageing (ELSA, wave 6), IC composite was derived through z-score and item-response theory (IRT) methods in a sample of cognitively normal older adults ( n = 731, aged 70.1 ± 6.77 years). Global cognition (GC) was derived by categorizing Mini-mental State Examination scores obtained in the same population 4–5 years later (ELSA-HCAP, 2018). After algorithm selection, GC categories were regressed on IC scores, demographic and lifestyle covariates. The IRT algorithm showed better model fit and strong associations with age, sex and education. Lower IC was associated with higher likelihood of developing mild cognitive impairment (MCI) 4 to 5 years after IC assessment. Increased age and lower education were also strong predictors of GC, whereas no significant effects were found for sex, physical activity, or number of comorbidities in the fully adjusted model. Although bivariate regressions showed that reduced moderate or vigorous physical activity and increased number of comorbidities are associated with higher odds of developing later MCI, the lack of associations between these covariates and GC in the fully adjusted model suggests a possible mediation effect on IC. No study had previously explored the association of IC on later cognitive impairment. Results agree with previous evidence associating low IC to females, older ages and lower education. Further research to reveal possible underlying mechanisms explaining this association is needed to improve our understanding and relevance of IC for healthy ageing.