Cognitive Ageing in Great Britain in the New Century: Cohort Differences in Episodic Memory

The progression of cognitive impairment and its influencing factors in older adults based on longitudinal item response theory

BACKGROUND

Understanding the development of cognitive impairment and its influencing factors in older adults is crucial for formulating early intervention strategies.

PURPOSE

To identify the early dimensions of cognitive impairment and provide a comprehensive description of the trajectories of cognitive decline in older adults prior to death.

METHODS

Based on the data of 9883 older adults in the Chinese Longitudinal Healthy Longevity Survey from 2002 to 2018, a longitudinal item response theory (Longitudinal IRT) model including covariates was applied to estimate the following parameters. The items in which older adults encountered obstacles first had the least difficulty parameters (δ). The earlier the information curve of an item is lifted, the more information it provides in the early stages of cognitive impairment. Regression coefficient (β) represents the relative rate of cognitive decline. The cognitive impairment values estimated from the Longitudinal IRT were fitted to a mixed-effects model to examine cognitive impairment trajectories.

RESULTS

'Draw the figure on B Card' (δ = -0.816) was the most challenging item, followed by 'recalling 'clothes" (δ = 0.348) and 'recalling 'apples" (δ = 0.419), while 'name the 'pen" (δ = 4.402) was the simplest instruction for the old adults. The curves of the items in the recall dimension began to rise in the early stages of cognitive impairment. Cognitive impairment of older adults who were women (β = 0.061), elder (β = 0.111), smokers (β = 0.060), living in rural areas (β = 0.052), not participating in organised social activities (β = 0.092), suffering from hypertension (β = 0.022), hyperglycaemia (β = 0.035), dyslipidaemia (β = 0.314), low education levels (β = 0.128), manual labourers (β = 0.027), and eventual development of dementia (β = 0.212) exhibited a more accelerated progression. These individuals also had poorer cognitive trajectories.

CONCLUSION

Recall is the earliest dimension of cognitive impairment. The subjects who were women, elder, smokers, living in rural areas, not participating in organised social activities, suffering from hypertension, hyperglycaemia, dyslipidaemia, low education, manual labourers, and eventually development of dementia, had a faster descending speed and poorer trajectories.

Modeling Risk Factors for Intraindividual Variability: A Mixed-Effects Beta-Binomial Model Applied to Cognitive Function in Older People in the English Longitudinal Study of Ageing

Cognitive functioning in older age profoundly impacts quality of life and health. While most research on cognition in older age has focused on mean levels, intraindividual variability (IIV) around this may have risk factors and outcomes independent of the mean value. Investigating risk factors associated with IIV has typically involved deriving a summary statistic for each person from residual error around a fitted mean. However, this ignores uncertainty in the estimates, prohibits exploring associations with time-varying factors, and is biased by floor/ceiling effects. To address this, we propose a mixed-effects location scale beta-binomial model for estimating average probability and IIV in a word recall test in the English Longitudinal Study of Ageing. After adjusting for mean performance, an analysis of 9,873 individuals across 7 (mean = 3.4) waves (2002-2015) found IIV to be greater at older ages, with lower education, in females, with more difficulties in activities of daily living, in later birth cohorts, and when interviewers recorded issues potentially affecting test performance. Our study introduces a novel method for identifying groups with greater IIV in bounded discrete outcomes. Our findings have implications for daily functioning and care, and further work is needed to identify the impact for future health outcomes.

Life Course Socioeconomic Position and Cognitive Aging Trajectories: A Cross-National Cohort Study in China and England

Background and Objectives

Cross-national research on cognitive aging inequality has largely concentrated on Western countries. It is unclear whether socioeconomic position (SEP) has similar effects on cognitive decline in emerging economies. We compared the association between life course SEP and cognitive function trajectories between China and England, the largest nation under state socialism and one of the oldest capitalist countries.

Research Design and Methods

This cross-cohort study examined participants aged 50 years and older from the China Health and Retirement Longitudinal Study (n = 12,832) and the English Longitudinal Study of aging (n = 8,875). Cognition z-scores were derived using comparable measures of memory and time orientation on 4 occasions. Life course SEP was self-reported by participants at baseline. Seven- to 8-year trajectories of cognition z-scores were estimated using latent growth curve modeling. Country- and gender-specific associations between childhood/adolescent deprivation, education, material wealth, and home ownership were evaluated in relation to model intercept (baseline level) and linear slope (annual rate of change) of cognition.

Results

After multivariable adjustment, education was positively associated with the greatest differences in baseline cognition across country and gender. Education was further linked to a slower rate of cognitive decline (z-score units per year); but compared with those with low education, Chinese men (b = 0.032) and women (b = 0.065) with high education had significantly slower declines than English men (b = -0.004) and women (b = 0.010) with high education.

Discussion and Implications

Despite substantial between-cohort differences in downstream and upstream determinants of dementia, education provided the greatest benefits to cognitive aging in England but particularly in China.

Lower grip strength and insufficient physical activity can increase depressive symptoms among middle-aged and older European adults: a longitudinal study

Objectives

The present study aimed to identify the gender-specific trajectories of grip strength using group-based trajectories, explore the interaction between grip strength and physical activity on depression, and investigate the association of physical activity with the change in depression by different grip strength groups among middle-aged and older European adults.

Methods

A total of 14,098 participants aged 50 years or older from the Survey of Health, Ageing and Retirement in Europe 2007–2019 were included in this study. Group-based trajectory modeling was used to identify the low, middle and high group of grip strength by gender. Generalized estimated equations were fitted to analyze the interaction effect. The data of wave 2-wave 5 and wave 2-wave 7 were chosen to conduct sensitivity analyses.

Results

Significant interactions between grip strength group and physical inactivity were found (x²_interaction = 11.16, P = 0.004). Significant interactions between physical inactivity and time on depression were identified in low (x²_interaction = 27.83, P < 0.001) and moderate (x²_interaction = 23.67, P < 0.001) grip strength, but a similar result was not found in high grip strength (x²_interaction = 4.39, P = 0.495). Participants in the physical inactivity group had higher depression scores in the low and moderate grip strength groups. Sensitivity analyses yield almost similar results.

Conclusions

Grip strength and physical inactivity interact with depression. Lower grip strength and insufficient physical activity can increase depressive symptoms. People with lower grip strength and physical inactivity should pay special attention to the prevention of depression.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12877-022-03392-x.

Gender differences in the association of depression trajectories with executive and memory functions: Evidence from the longitudinal study of the Survey of Health, Ageing and Retirement in Europe (2004-2017)

Gender differences in depression trajectories and their effects on cognitive function are poorly understood. This article aims to identify depression trajectories in both genders and further explore the association of depression trajectories with executive and memory functions by gender. A total 3990 participants aged 50 years or older with repeated measurements from waves 1 to 7 (wave 3 excluded) of the Study of the Survey of Health, Ageing and Retirement in Europe (SHARE) were included. Group-based trajectory modeling (GBTM) was conducted to identify the optimal number of depression trajectories. Generalized estimating equation (GEE) models were used to examine the relation of depression trajectories to cognitive function after stratification by gender. Three distinct depression trajectories were identified in both genders, but the patterns of trajectories among genders were nonidentical. The trajectories of depression in males were characterized by non-low, moderate, persistent-depressive symptoms but with an unstable trend, while in females, they were characterized by non-low, moderate, persistent-depressive symptoms and with a worsening trend. The prevalence of persistent high depression in women (20.08%) was higher than that in men (3.13%). Moderate and persistent high depression trajectories were negatively associated with episodic memory (β = -0.53 and -0.72, respectively, p < 0.001) and verbal fluency in females (β = -0.96 and -1.47, p=0.01 and < 0.001, respectively). Older women had a greater frequency of developing depression than older men. Gender differences in depression trajectories existed. Moderate and persistent high depression trajectories exerted a negative effect on some domains of cognitive impairment only in females.

Social Contact Mode and 15-Year Episodic Memory Trajectories in Older Adults With and Without Hearing Loss: Findings from the English Longitudinal Study of Ageing

OBJECTIVES

Frequent social contact benefits cognition in later life although evidence is lacking on the potential relevance of the modes chosen by older adults, including those living with hearing loss, for interacting with others in their social network.

METHOD

11,418 participants in the English Longitudinal Study of Ageing provided baseline information on hearing status and social contact mode and frequency of use. Multilevel growth curve models compared episodic memory (immediate and delayed recall) at baseline and longitudinally in participants who interacted frequently (offline only or offline and online combined), compared to infrequently, with others in their social network.

RESULTS

Frequent offline (B=0.23; SE=0.09) and combined offline and online (B=0.71; SE=0.09) social interactions predicted better episodic memory after adjustment for multiple confounders. We observed positive, longitudinal associations between combined offline and online interactions and episodic memory in participants without hearing loss (B=0.50, SE=0.11) but not with strictly offline interactions (B=0.01, SE=0.11). In those with hearing loss, episodic memory was positively related to both modes of engagement (offline only: B=0.79, SE=0.20; combined online and offline: B=1.27, SE=0.20). Sensitivity analyses confirmed the robustness of these findings.

DISCUSSION

Supplementing conventional social interactions with online communication modes may help older adults, especially those living with hearing loss, sustain, and benefit cognitively from, personal relationships.

Sex differences and the role of education in cognitive ageing: analysis of two UK-based prospective cohort studies

BACKGROUND

Previous studies have shown an excess risk of Alzheimer's disease and related dementias among women. Education is thought to have a causal association with dementia onset. We aimed to investigate the role of education in influencing sex differences in cognitive ageing.

METHODS

We analysed data from two prospective cohort studies in the UK; the English Longitudinal Study of Ageing (ELSA) and the Whitehall II study, to assess sex differences in cognitive performance and cognitive decline by birth cohort (birth year 1930-38, 1939-45, or 1946-55), before and after adjustment for education, and by high and low education level. Memory was assessed using immediate recall, for which data were available from all waves of the ELSA (2002-14) and Whitehall II (1997-2015) studies. Fluency was assessed using a semantic fluency test based on an animal naming task, with data available from all waves of the Whitehall II study and waves one to five (2002-10) and wave seven (2014) of the ELSA study. Cognitive scores were standardised separately in each study based on the mean and SD of the corresponding test among participants aged 50-59 years with secondary education.

FINDINGS

15 924 participants were included from the two studies. In pooled analyses, women had better memory scores than men in all birth cohorts, irrespective of adjustment for education (eg, at age 60 years, birth cohort 1930-38, mean difference between sexes [male scores minus female scores] -0·25 SDs [95% CI -0·32 to -0·19] after adjustment for education), and in both education level groups. Memory decline was faster in men than in women (at age 60 years, birth cohort 1946-55, mean difference in 13-year change -0·15 SDs [-0·20 to -0·09]; after adjustment for education -0·14 SDs [-0·20 to -0·08]). Men had better fluency scores than women in earlier birth cohorts and in the low education group (at age 60 years, birth cohort 1930-38, mean difference 0·20 SDs [95% CI 0·05 to 0·36]); but women had better fluency scores than men in later birth cohorts and in the high education group (at age 60 years, birth cohort 1946-55, mean difference -0·17 SDs [-0·24 to -0·10]). No sex differences were observed for fluency decline.

INTERPRETATION

Our findings suggest that decreasing disparities between sexes in education, due to secular increases in educational opportunities, could attenuate sex differences in dementia risk and cognitive decline in the future.

FUNDING

National Institute on Aging, National Institutes of Health; UK Medical Research Council; British Heart Foundation; and National Institute for Health Research.

Schizophrenia polygenic risk predicts general cognitive deficit but not cognitive decline in healthy older adults

There has been a long argument over whether schizophrenia is a neurodegenerative disorder associated with progressive cognitive impairment. Given high heritability of schizophrenia, ascertaning if genetic susceptibility to schizophrenia is also associated with cognitive decline in healthy people would support the view that schizophrenia leads to an accelerated cognitive decline. Using the population representative sample of 6817 adults aged >50 years from the English Longitudinal Study of Ageing, we investigated associations between the biennial rate of decline in cognitive ability and the schizophrenia polygenic score (SZ-PGS) during the 10-year follow-up period. SZ-PGS was calculated based on summary statistics from the Schizophrenia Working Group of the Psychiatric Genomics Consortium. Cognition was measured sequentially across four time points using verbal memory and semantic fluency tests. The average baseline verbal memory was 10.4 (SD = 3.4) and semantic fluency was 20.7 (SD = 6.3). One standard deviation (1-SD) increase in SZ-PGS was associated with lower baseline semantic fluency (β = -0.25, 95%CI = -0.40 to -0.10, p = 0.002); this association was significant in men (β = -0.36, 95%CI = -0.59 to -0.12, p = 0.003) and in those who were aged 60-69 years old (β = -0.32, 95%CI = -0.58 to -0.05, p = 0.019). Similarly, 1-SD increase in SZ-PGS was associated with lower verbal memory score at baseline in men only (β = -0.12, 95%CI = -0.23 to -0.01, p = 0.040). However, SZ-PGS was not associated with a greater rate of decline in these cognitive domains during the 10-year follow-up. Our findings highlight that while genetic susceptibility to schizophrenia conveys developmental cognitive deficit, it is not associated with an ongoing cognitive decline, at least in later life. These results do not support the neo-Kraepelinian notion of schizophrenia as a genetically determined progressively deteriorating brain disease.

Longitudinal Association Between Hearing Loss, Vision Loss, Dual Sensory Loss, and Cognitive Decline

BACKGROUND/OBJECTIVES

To better understand the role of sensory loss as a potentially modifiable risk factor for cognitive decline, this study examined cognitive decline in relation to single modality hearing or vision loss and dual sensory loss.

DESIGN

Longitudinal secondary data analysis.

SETTING

The Health and Retirement Study (HRS) and its supplement: The Aging, Demographics, and Memory Study (ADAMS).

PARTICIPANTS

Individuals aged 73 and older (N = 295).

MEASUREMENTS

Hearing loss was defined by an inability to hear sounds of 25 dB at frequencies between 0.5 and 4.0 kHz in either ear. Vision loss was defined as having corrected binocular vision worse than 20/40. Dual sensory loss was defined as having both hearing and vision loss. We used one time point of hearing and vision data objectively measured in ADAMS Wave C (June 2006-May 2008) and five waves of cognitive function data measured by the HRS version of the Telephone Interview for Cognitive Status in HRS (2006-2014). Multilevel mixed models were used.

RESULTS

Among the participants, 271 completed a hearing assessment and 120 had hearing loss; 292 completed a vision assessment and 115 had vision loss; 52 had dual sensory loss. Older adults with hearing loss had a significantly faster rate of cognitive decline as they aged compared to those with normal hearing (β = -0.16, P < .05). No significant association was found between vision loss and the rate of cognitive decline (β = -0.06, P = .41). Older adults who had dual sensory loss likewise had a significantly faster rate of cognitive decline as they age (β = -0.23, P < .05) compared to those with no sensory loss.

CONCLUSION

Older adults with hearing loss and dual sensory loss have faster rates of cognitive decline than those with normal sensory function.

Assessing the Long-Term Impact of Concussion upon Cognition: A 5-Year Prospective Investigation

OBJECTIVE

Jockeys have high rates of concussion, with 5% of jockeys receiving at least one concussion annually. The impact of acute concussion upon cognition is well understood, but less is known about the long-term effects of concussion upon cognition. Our aim was to assess the impact of concussion upon jockeys who had provided pre-concussion assessments of cognition using a prospective design.

METHOD

In this study, over a 5-year period, we assessed the cognitive performance of jockeys with ≥1 medically diagnosed concussion (MDC; n = 17, months since concussion, M = 29.18), against those who had not been concussed (NC; n = 41). Jockeys who had not been concussed in the preceding 6 months completed four computer-based cognitive assessments from the CogSport battery.

RESULTS

Unlike the majority of the small existing literature, there was no difference (p ≥ .05) between the MDC and NC groups after controlling for age and baseline performance. Additionally, we used a measure of reliable change to assess for clinically meaningful decrements from baseline in each test and composite score 5 years later. None of the jockeys in the MDC group recorded significant decrements on any CogSport measure from baseline (z > -1.65).

CONCLUSIONS

The findings suggest that the presence of concussion does not result in persistent decrements in cognitive performance and that when findings are considered collectively, assessing factors beyond medically diagnosed concussion (e.g., chronic stress, undiagnosed concussion) may improve the interpretation of our current findings.

Trajectories of cognitive function and their determinants in older people: 12 years of follow-up in the Chinese Longitudinal Healthy Longevity Survey

BACKGROUND

Cognitive decline in advanced age is closely related to dementia. The trajectory of cognitive function in older Chinese is yet to be fully investigated. We aimed to investigate the trajectories of cognitive function in a nationally representative sample of older people living in China and to explore the potential determinants of these trajectories.

METHODS

This study included 2,038 cognitively healthy persons aged 65-104 years at their first observation in the Chinese Longitudinal Healthy Longevity Survey from 2002 to 2014. Cognitive function was measured using the Chinese version of the Mini-Mental State Examination (MMSE). Group-based trajectory modeling was used to identify potential heterogeneity of longitudinal changes over the 12 years and to investigate associations between baseline predictors of group membership and these trajectories.

RESULTS

Three trajectories were identified according to the following types of changes in MMSE scores: slow decline (14.0%), rapid decline (4.5%), and stable function (81.5%). Older age, female gender, having no schooling, a low frequency of leisure activity, and a low baseline MMSE score were associated with the slow decline trajectory. Older age, body mass index (BMI) less than 18.5 kg/m2, and having more than one cardiovascular disease (CVD) were associated with the rapid decline trajectory.

CONCLUSION

Three trajectories of cognitive function were identified in the older Chinese population. The identified determinants of these trajectories could be targeted for developing prevention and intervention strategies for dementia.

Cardiovascular risk factors and memory decline in middle-aged and older adults: the English Longitudinal Study of Ageing

BACKGROUND

We investigated the association between trajectories of verbal episodic memory and burden of cardiovascular risk factors in middle-aged and older community-dwellers.

METHODS

We analysed data from 4372 participants aged 50-64 and 3005 persons aged 65-79 years old from the English Longitudinal Study of Ageing who were repeatedly evaluated every 2 years and had six interviews of a 10-year follow-up. We measured the following baseline risk factors: diabetes, hypertension, smoking, physical inactivity and obesity to derive a cardiovascular risk factor score (CVRFs). Adjusted linear mixed effect regression models were estimated to determine the association between number of CVFRs and six repeated measurements of verbal memory scores, separately for middle-aged and older adults.

RESULTS

CVRFs was not significantly associated with memory at baseline. CVFRs was significantly associated with memory decline in middle-aged (50-64y), but not in older (65-79y) participants. This association followed a dose-response pattern with increasing number of CVFRs being associated with greater cognitive decline. Comparisons between none versus some CVRFs yielded significant differences (p < 0.05).

CONCLUSIONS

Our findings confirm that the effect of cumulative CVRFs on subsequent cognitive deterioration is age-dependent. CVRFs are associated with cognitive decline in people aged 50-64 years, but not in those aged ≥65 years. Although modest, the memory decline associated with accumulation of cardiovascular risk factors in midlife may increase the risk of late-life dementia.

Hearing Impairment, Loneliness, Social Isolation, and Cognitive Function: Longitudinal Analysis Using English Longitudinal Study on Ageing

OBJECTIVE

This study examines the relationships between hearing impairment and cognitive function among older adults, and whether that association is mediated by loneliness and social isolation.

METHODS

Data were drawn from English Longitudinal Study of Ageing (ELSA) wave two (2004/2005) until wave seven (2014/2015). The study sample consisted of 8,199 individuals aged 50 years or older. Cognitive function was measured using episodic memory. We performed analysis using a generalized structural equation modeling (GSEM) technique.

RESULTS

GSEM analysis shows that the direct effect of hearing impairment on episodic memory was negative and significant (β = -0.29, p <0.001). Loneliness and social isolation mediated that effect. Hearing impairment was positively associated with loneliness (β = 0.10, p <0.001) and social isolation (β = 0.04, p <0.001). Loneliness (β = -0.08, p <0.001) and social isolation (β = -0.09, p = 0.001) were significantly associated with lower memory scores.

CONCLUSION

The link between hearing impairment and episodic memory was partly mediated by loneliness and social isolation. Interventions to improve the social networks of older adults with hearing impairment are likely to be beneficial in preventing cognitive decline. Thus, the importance of maintaining social relationships among older adults, especially those with hearing impairment is highlighted.

Associations Between Self-Reported Sensory Impairment and Risk of Cognitive Decline and Impairment in the Health and Retirement Study Cohort

Objectives

We aimed to determine whether self-assessed single (hearing or visual) and dual sensory (hearing and visual) impairments are associated with cognitive decline and incident possible cognitive impairment, no dementia (CIND) and probable dementia.

Method

Data were drawn from the 1996–2014 surveys of the Health and Retirement Study (HRS), involving 19,618 respondents who had no probable dementia and who were aged 50 years or older at the baseline. We used linear mixed models to test the association between self-assessed sensory impairment and cognitive decline followed by a Cox proportional hazard model to estimate the relative risk of incident possible CIND and probable dementia associated with the presence of sensory impairment.

Results

Respondents with self-assessed single and dual sensory impairment performed worse in cognitive tests than those without sensory impairment. The fully adjusted incidence of developing possible CIND was 17% higher for respondents with hearing impairment than those without hearing impairment. Respondents with visual impairment had 35% and 25% higher risk for developing possible CIND and probable dementia, respectively, than those without visual impairment. Respondents with dual sensory impairment at baseline were 38% and 26% more likely to develop possible CIND and probable dementia, respectively, than those with no sensory impairment.

Discussion

Self-assessed sensory impairment is independently associated with cognitive decline and incident possible CIND and probable dementia. Further studies are needed to identify the mechanism underlying this association and to determine whether treatment of sensory impairment could ameliorate cognitive decline and delay the onset of dementia among older adults.

Lateral ventricle volume trajectories predict response inhibition in older age-A longitudinal brain imaging and machine learning approach

Objective

In a three-wave 6 yrs longitudinal study we investigated if the expansion of lateral ventricle (LV) volumes (regarded as a proxy for brain tissue loss) predicts third wave performance on a test of response inhibition (RI).

Participants and methods

Trajectories of left and right lateral ventricle volumes across the three waves were quantified using the longitudinal stream in Freesurfer. All participants (N = 74;48 females;mean age 66.0 yrs at the third wave) performed the Color-Word Interference Test (CWIT). Response time on the third condition of CWIT, divided into fast, medium and slow, was used as outcome measure in a machine learning framework. Initially, we performed a linear mixed-effect (LME) analysis to describe subject-specific trajectories of the left and right LV volumes (LVV). These features were input to a multinomial logistic regression classification procedure, predicting individual belongings to one of the three RI classes. To obtain results that might generalize, we evaluated the significance of a k-fold cross-validated f1-score with a permutation test, providing a p-value that approximates the probability that the score would be obtained by chance. We also calculated a corresponding confusion matrix.

Results

The LME-model showed an annual ∼ 3.0% LVV increase. Evaluation of a cross-validated score using 500 permutations gave an f1-score of 0.462 that was above chance level (p = 0.014). 56% of the fast performers were successfully classified. All these were females, and typically older than 65 yrs at inclusion. For the true slow performers, those being correctly classified had higher LVVs than those being misclassified, and their ages at inclusion were also higher.

Conclusion

Major contributions were: (i) a longitudinal design, (ii) advanced brain imaging and segmentation procedures with longitudinal data analysis, and (iii) a data driven machine learning approach including cross-validation and permutation testing to predict behaviour, solely from the individual’s brain “signatures” (LVV trajectories).

Trajectories of allostatic load among older Americans and Britons: longitudinal cohort studies

BACKGROUND

Difference in life expectancy between males and females has been suggested to rest on sex difference in physiological dysregulation. But allostatic load, a physiological index, has not been carefully examined for an extended period beyond middle age. We aim to draw longitudinal trajectories of allostatic load in a national sample of older Americans and Britons; also to examine sex-based trajectories and factors behind their differences.

METHODS

We studied men and women aged ≥50 years participating in the Health and Retirement Study Waves 8-11, 2006-2012 (N = 15,583 person-years) and the English Longitudinal Study of Ageing Waves 2, 4 and 6, 2004-2012 (N = 14,765 person-years). Because of the difference in provenance, we included different number of biomarkers to calculate allostatic load in HRS and ELSA. In HRS we used 8 biomarkers (systolic and diastolic blood pressure, haemoglobin A1c, high-density lipoprotein, total cholesterol, waist circumference, cystatin C, and C-reactive protein), while ELSA allostatic load was constructed from 10 biomarkers (systolic and diastolic blood pressure, haemoglobin A1c, high-density lipoprotein, total cholesterol, waist circumference, BMI, triglyceride, fibrinogen and C-reactive protein). A growth curve model was fitted to repeated observations of allostatic load, demographic characteristics, socioeconomic position, comorbidities and health behaviours (smoking, drinking, and physical exercise). To account for attrition, a joint model was applied.

RESULTS

The analysis showed that allostatic load increases linearly with age in the U.S. However, there are different levels for males and females. In England allostatic load follows such different paths that their trajectories cross in later life.

CONCLUSIONS

Sex-based trajectories of allostatic load showed distinct female advantage and are mostly consistent with female advantage in life expectancy.

Cataract surgery and age-related cognitive decline: A 13-year follow-up of the English Longitudinal Study of Ageing

BACKGROUND

Visual impairment has been associated with lower cognitive ability among older adults, yet little is known about whether improving visual function with cataract surgery would be associated with slower cognitive decline. This study aimed to assess whether trajectories of cognitive decline differed before and after cataract surgery and compare those trajectories between older adults with cataract surgery and without cataract.

METHODS AND FINDINGS

Data were drawn from the English Longitudinal Study of Ageing (ELSA) Wave 1 (2002/03) until Wave 7 (2014/15). The study population consisted of 2,068 individuals who underwent cataract surgery between Wave 2 and Wave 6 as the treatment group and 3,636 individuals with no cataract as the control group. We included only respondents who took part in a minimum three waves. Propensity score matching method was used to match the individuals in the treatment group with those in the control group. After we put an "artificial" intervention point for the individuals in the control group at the point that the matched person has cataract surgery, spline method was used to identify differences in cognitive trajectories pre- and post-cataract surgery. In the treatment group, we found that cataract surgery was positively associated with episodic memory scores after controlling for the potential covariates (β = 4.23, p<0.001). Episodic memory scores declined with older age, but the decline in episodic memory scores was slower after cataract surgery (β = -0.05, p<0.001) than before cataract surgery (β = -0.1, p<0.001). Although the episodic memory among respondents in the control group before intervention (β = -0.08, p<0.001) declined slower than those in the intervention group (β = -0.1, p<0.001), the declines in episodic memory scores were similar in both groups after the intervention (control: β = -0.05, p<0.001; intervention: β = -0.05, p<0.001).

CONCLUSIONS

Cataract surgery may have a positive impact on trajectories of cognitive decline in later life. Further research is required to identify the mechanism to explain the association between cataract surgery and cognitive ageing, and whether early intervention towards vision correction results in a reduction in dementia risk.

Dementia across local districts in England 2014 to 2015

BACKGROUND

The number of older people needing dementia care is projected to rise rapidly, and local districts are now charged with responding to this need. But evidence on local area factors of dementia is scarce. We studied the odds of dementia prevalence and its individual risk factors enriched with area factors.

MATERIALS AND METHODS

This study analysed objectively assigned dementia prevalence in people aged 60 and over living in community in England, drawing data from the English Longitudinal Study of Ageing 2014 to 2015 and local districts statistics using multilevel logistic models. Dementia status is ascertained using a modified version of the Telephone Interview for Cognitive Status. A number of individual risk factors were considered including social determinants, internet use, social connections, and health behaviours; 2 contextual factors were included: the index of multiple deprivation and land use mix.

RESULTS

The prevalence of dementia by this method is 8.8% (95% confidence interval 7.7%-9.2%) in older adults in England. Maps of dementia prevalence across districts showed prevalent areas. In the full model, no area characteristics were significant in predicting dementia prevalence. Education, social connections, internet use, and moderate to vigorous physical activity showed protective associations.

CONCLUSION

Dementia in older adults in England is largely predicted by individual characteristics, although some districts have a large share of their population with dementia. Given the health and social care costs associated with dementia, differential interventions and support to districts and to groups of individuals defined by these characteristics seem warranted.

Visual and hearing impairments are associated with cognitive decline in older people

INTRODUCTION

highly prevalagent hearing and vision sensory impairments among older people may contribute to the risk of cognitive decline and pathological impairments including dementia.This study aims to determine whether single and dual sensory impairment (hearing and/or vision) are independently associated with cognitive decline among older adults and to describe cognitive trajectories according to their impairment pattern.

MATERIAL AND METHODS

we used data from totals of 13,123, 11,417 and 21,265 respondents aged 50+ at baseline from the Health and Retirement Study (HRS), the English Longitudinal Study of Ageing (ELSA) and the Survey of Health, Ageing and Retirement in Europe (SHARE), respectively. We performed growth curve analysis to identify cognitive trajectories, and a joint model was used to deal with attrition problems in longitudinal ageing surveys.

RESULTS

respondents with a single sensory impairment had lower episodic memory score than those without sensory impairment in HRS (β = -0.15, P < 0.001), ELSA (β = -0.14, P < 0.001) and SHARE (β = -0.26, P < 0.001). The analysis further shows that older adults with dual sensory impairment in HRS (β = -0.25, P < 0.001), ELSA (β = -0.35, P < 0.001) and SHARE (β = -0.68, P < 0.001) remembered fewer words compared with those with no sensory impairment. The stronger associations between sensory impairment and lower episodic memory levels were found in the joint model which accounted for attrition.

CONCLUSIONS

hearing and/or vision impairments are a marker for the risk of cognitive decline that could inform preventative interventions to maximise cognitive health and longevity. Further studies are needed to investigate how sensory markers could inform strategies to improve cognitive ageing.

Health care utilisation amongst older adults with sensory and cognitive impairments in Europe

Worldwide, the high prevalence of multiple chronic conditions amongst older population has led to increased utilisation of health care and rising associated costs, becoming a major public health concern. Hearing, vision and cognitive disorders are common chronic conditions amongst older Europeans and recent studies have documented its high co-occurrence. While it has been shown separately that suffering either mental disorders or sensory (hearing and vision) impairments is associated with higher health care utilisation, the association between health care utilisation and the interaction of these conditions has received little attention in the literature. Therefore, using four waves of the Survey of Health, Ageing and Retirement in Europe (SHARE), this study applies the correlated random effects method to the negative binomial and finite mixture models to analyse the extent to which the interaction of cognitive and sensory impairments is associated with health care use. We found that individuals with cognitive impairment tend to have more hospitalisations. The finite mixture approach indicates a positive association between sensory impairment and the number of hospitalisations amongst low users of health care. Additionally, our findings suggest a positive association between suffering both impairments at the same time and the number of doctor and GP visits.

When Did Old Age Stop Being Depressing? Depression Trajectories of Older Americans and Britons 2002-2012

OBJECTIVE

This study aims to investigate the implications of the heterogeneous cohort composition on depression trajectories of older adults in the United States and England.

METHODS

Using growth curve models to identify depressive symptom trajectories and data spanning six waves over 10 years (2002-2012) from the U.S. Health Retirement Study and the English Longitudinal Study of Ageing, community-dwelling Americans and Britons aged 50 years and older were studied. Depressive symptoms were measured using the eight-item Center for Epidemiologic Studies Depression Scale.

RESULTS

The sample included 11,919 respondents (7,095 women [59.53%]) in the United States and 10,606 respondents (5,802 women [54.7%]) in England aged 50 and older. Older cohorts were shown to have higher depressive symptoms than younger cohorts in the United States and England. The trajectories of depression of older cohorts, particularly those of the prewar cohorts in both countries and the war cohort in England, followed a U-shape. Conversely, the trajectories of depression of the younger cohort, particularly those of the postwar cohorts in both countries and the war cohort in the United States, took an inverted U-shape.

CONCLUSION

The trajectories of depression in later life between cohorts took different shapes. This finding may lead to the development of more cost-effective policies for treating depression in later life.

Trajectories of Verbal Episodic Memory in Middle-Aged and Older Adults: Evidence from the English Longitudinal Study of Ageing

OBJECTIVES

To identify distinct latent groups of baseline levels and age-related decline in verbal episodic memory in middle-aged and older adults, and to identify factors associated with these trajectories.

DESIGN

Longitudinal study of six data collections over a period of 10 years.

SETTING

Population-based cohort in England.

PARTICIPANTS

9,515 community-dwelling adults aged 50-79 years.

MEASUREMENTS

Six repeated measurements of immediate and delayed recall of 10 words over 10-year follow-up. Group-based trajectory modeling was used to identify patterns of baseline levels and subsequent decline in memory in two age categories (50-64 and 65-79 years), and to investigate associations between trajectories and baseline predictors of group membership (gender, education, household wealth, marital status, smoking and physical activity) and time-varying covariates (depressive symptoms and number of chronic conditions).

RESULTS

Four trajectories were identified and labelled according to baseline status and decline in memory: very low/decline (9.8%), low/stable (40.2%), average/stable (39.5%) and good/stable (10.5%) in the younger group, and very low/rapid decline (15.7%), low/decline (32.0%), average/stable (38.8%), and good/stable (13.5%) in older participants. In people with stable or declining trajectories, a higher number of depressive symptoms and the presence of cardiovascular diseases were associated with worse memory. Female sex, younger age, and higher education, wealth and physical activity were consistently associated with more favourable trajectories.

CONCLUSIONS

We identified four memory trajectories. Factors known to be associated with cognitive reserve (such as education, wealth and physical activity) were associated with better memory function while depressive symptoms and cardiovascular disease were associated with poorer memory. This suggests that interventions to reduce depressive symptoms and better manage cardiovascular risk factors and disease in midlife may help prevent or delay future memory decline.

Trajectories of the healthy ageing phenotype among middle-aged and older Britons, 2004-2013

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Women had a wider distribution of the healthy ageing phenotype than men had.

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Women started at higher levels and then declined more steeply, leading to crossover in the trajectories of the healthy ageing phenotype.

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Social gradients in the healthy ageing phenotype were significant.

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Smoking and physical activity were strongly associated with the trajectories.

Objectives

Since the ageing population demands a response to ensure older people remain healthy and active, we studied the dynamics of a recently proposed healthy ageing phenotype. We drew the phenotype’s trajectories and tested whether their levels and rates of change are influenced by health behaviours, comorbidities and socioeconomic positions earlier in the life course.

Design and outcomes

The English Longitudinal Ageing Study, a prospective, nationally representative sample of people aged ≥50 years, measured a set of eight biomarkers which make up the outcome of the healthy ageing phenotype three times over nearly a decade (N₂₀₀₄ = 5009, N₂₀₀₈ = 5301, N₂₀₁₃ = 4455). A cluster of health behaviours, comorbidities and socioeconomic positions were also measured repeatedly. We assessed the phenotype’s distribution non-parametrically, then fitted linear mixed models to phenotypic change and further examined time interactions with gender and socioeconomic position. We ran additional analyses to test robustness.

Results

Women had a wider distribution of the healthy ageing phenotype than men had. The phenotype declined annually by −0.242 (95% confidence interval [CI]: −0.352, −0.131). However, there was considerable heterogeneity in the levels and rates of phenotypic change. Women started at higher levels, then declined more steeply by −0.293 (CI: −0.403, −0.183) annually, leading to crossover in the trajectories. Smoking and physical activity assessed on the Allied Dunbar scale were strongly associated with the trajectories.

Conclusion

Though marked by secular decline, the trajectories of the healthy ageing phenotype showed distinct socioeconomic gradients. The trajectories were also susceptible to variations in health behaviours, strengthening the case for serial interventions to attain healthy and active ageing.