Cohort profile: The Dynamic Analyses to Optimize Ageing (DYNOPTA) project

Study protocol for development and validation of a single tool to assess risks of stroke, diabetes mellitus, myocardial infarction and dementia: DemNCD-Risk

INTRODUCTION

Current efforts to reduce dementia focus on prevention and risk reduction by targeting modifiable risk factors. As dementia and cardiometabolic non-communicable diseases (NCDs) share risk factors, a single risk-estimating tool for dementia and multiple NCDs could be cost-effective and facilitate concurrent assessments as compared with a conventional single approach. The aim of this study is to develop and validate a new risk tool that estimates an individual's risk of developing dementia and other NCDs including diabetes mellitus, stroke and myocardial infarction. Once validated, it could be used by the public and general practitioners.

METHODS AND ANALYSIS

Ten high-quality cohort studies from multiple countries were identified, which met eligibility criteria, including large representative samples, long-term follow-up, data on clinical diagnoses of dementia and NCDs, recognised modifiable risk factors for the four NCDs and mortality data. Pooled harmonised data from the cohorts will be used, with 65% randomly allocated for development of the predictive model and 35% for testing. Predictors include sociodemographic characteristics, general health risk factors and lifestyle/behavioural risk factors. A subdistribution hazard model will assess the risk factors' contribution to the outcome, adjusting for competing mortality risks. Point-based scoring algorithms will be built using predictor weights, internally validated and the discriminative ability and calibration of the model will be assessed for the outcomes. Sensitivity analyses will include recalculating risk scores using logistic regression.

ETHICS AND DISSEMINATION

Ethics approval is provided by the University of New South Wales Human Research Ethics Committee (UNSW HREC; protocol numbers HC200515, HC3413). All data are deidentified and securely stored on servers at Neuroscience Research Australia. Study findings will be presented at conferences and published in peer-reviewed journals. The tool will be accessible as a public health resource. Knowledge translation and implementation work will explore strategies to apply the tool in clinical practice.

The Impact of Smoking and Obesity on Disability-Free Life Expectancy in Older Australians

BACKGROUND

Smoking and obesity are 2 modifiable risk factors for disability. We examine the impact of smoking and obesity on disability-free life expectancy (DFLE) at older ages, using 2 levels of disability.

METHOD

We used the DYNOPTA dataset, derived by harmonizing and pooling risk factors and disability outcomes from 5 Australian longitudinal aging studies. We defined mobility disability as inability to walk 1 km, and more severe (activities of daily living [ADL]) disability by the inability to dress or bathe. Mortality data for the analytic sample (N = 20 401; 81.2% women) were obtained from Government Records via data linkage. We estimated sex-specific total life expectancy, DFLE, and years spent with disability by Interpolated Markov Chain (IMaCh) software for each combination of smoking (never vs ever), obesity (body mass index ≥30 vs 18.5 to <30), and education (left school age 14 or younger vs age 15 or older).

RESULTS

Compared to those without either risk factor, high educated nonobese smokers at age 65 lived shorter lives (men and women: 2.5 years) and fewer years free of mobility disability (men: 2.1 years; women: 2.0 years), with similar results for ADL disability. Obesity had the largest effect on mobility disability in women; high educated obese nonsmoking women lived 1.3 years less than nonsmoking, not obese women but had 5.1 years fewer free of mobility disability and 3.2 fewer free of ADL disability. Differences between risk factor groups were similar for the low educated.

CONCLUSIONS

Our findings suggest eliminating obesity would lead to an absolute reduction of disability, particularly in women.

Structuring a conceptual model for cost-effectiveness analysis of frailty interventions

BACKGROUND

Frailty is a major health issue which impacts the life of older people, posing a significant challenge to the health system. One of the key emerging areas is the development of frailty interventions to halt or reverse the progression of the condition. In many countries, economic evidence is required to inform public funding decisions for such interventions, and cost-effectiveness models are needed to estimate long-term costs and effects. Such models should capture current clinical understanding of frailty, its progression and its health consequences. The objective of this paper is to present a conceptual model of frailty that can be used to inform the development of a cost-effectiveness model to evaluate frailty interventions.

METHODS

After critical analysis of the clinical and economic literature, a Delphi study consisting of experts from the disciplines of clinical medicine and epidemiology was undertaken to inform the key components of the conceptual model. We also identified relevant databases that can be used to populate and validate the model.

RESULTS

A list of significant health states/events for which frailty is a strong independent risk factor was identified (e.g., hip fracture, hospital admission, delirium, death). We also identified a list of important patient attributes that may influence disease progression (e.g., age, gender, previous hospital admissions, depression). A number of large-scale relevant databases were also identified to populate and validate the cost-effectiveness model. Face validity of model structure was confirmed by experts.

DISCUSSION AND CONCLUSIONS

The proposed conceptual model is being used as a basis for developing a new cost-effectiveness model to estimate lifetime costs and outcomes associated with a range of frailty interventions. Using an appropriate model structure, which more accurately reflects the natural history of frailty, will improve model transparency and accuracy. This will ultimately lead to better informed public funding decisions around interventions to manage frailty.

Review of methodologies of cohort studies of older people

This paper describes a cohort study in terms of its design, the research questions answered by cohort studies, common analytic techniques and the strengths and limitations of this type of study. We also describe the main cohort studies of older populations, many of which are available for secondary data analysis.

Frailty prevalence in Australia: Findings from four pooled Australian cohort studies

OBJECTIVE

To examine frailty prevalence in Australian older adults.

METHODS

Frailty was measured using a modified Fried Frailty Phenotype (FFP) in a combined cohort of 8804 Australian adults aged ≥65 years (female 86%, median age 80 (79-82) years) from the Dynamic Analyses to Optimise Ageing Project and the North West Adelaide Health Study.

RESULTS

Using the FFP, 21% of participants were frail while a further 48% were prefrail. Chi-squared testing of frailty among four age groups (65-69, 70-74, 75-79 and 80-84 years) for sex, and marital status revealed that frailty was significantly higher for women (approximately double that of men), increased significantly with advancing age for both sexes, and was significantly higher for women who were widowed, divorced or never married.

CONCLUSION

If frailty could be prevented or reversed, it would have an impact on a larger number of older people.

A Cost-Effectiveness Model for Frail Older Persons: Development and Application to a Physiotherapy-Based Intervention

INTRODUCTION

The clinical importance of frailty is increasing. Existing economic evaluations of interventions to manage frailty have limited time horizons, but even in older populations there may be important longer-term differences in costs and outcomes. This paper reports on the development of a cost-effectiveness model to predict publicly funded health and aged care costs and quality-adjusted life years (QALYs) over the remaining lifetime of frail Australians and a model-based cost-utility analysis of a physiotherapy-based intervention for frail individuals.

METHODS

A cohort-based state transition (Markov) model was developed to predict costs and QALYs over the remaining lifetime of a frail population. Frailty is defined using the phenotypic definition of frailty, and the model comprises health states that describe frailty status, residential status, the experience of bone fractures and depression, and death. Model input parameters were estimated and calibrated using the Dynamic Analyses to Optimise Ageing dataset, supplemented with data from the published literature.

RESULTS

The cost-effectiveness model was subject to a range of validation approaches, which did not negate the validity of the model. The evaluated physiotherapy-based frailty intervention has an expected incremental cost per QALY gained of Australian $8129 compared to usual care, but there is a probability of 0.3 that usual care is more effective and less costly than the intervention.

DISCUSSION

Frailty reduces quality of life, is costly to manage and it's prevalence is increasing, but new approaches to managing frailty need to demonstrate value for money. The value of the reported cost-effectiveness model is illustrated through the estimation of all important costs and effects of a physiotherapy-based frailty intervention, which facilitates comparisons with funding decisions for other new technologies in Australia.

Maelstrom Research guidelines for rigorous retrospective data harmonization

Background

It is widely accepted and acknowledged that data harmonization is crucial: in its absence, the co-analysis of major tranches of high quality extant data is liable to inefficiency or error. However, despite its widespread practice, no formalized/systematic guidelines exist to ensure high quality retrospective data harmonization.

Methods

To better understand real-world harmonization practices and facilitate development of formal guidelines, three interrelated initiatives were undertaken between 2006 and 2015. They included a phone survey with 34 major international research initiatives, a series of workshops with experts, and case studies applying the proposed guidelines.

Results

A wide range of projects use retrospective harmonization to support their research activities but even when appropriate approaches are used, the terminologies, procedures, technologies and methods adopted vary markedly. The generic guidelines outlined in this article delineate the essentials required and describe an interdependent step-by-step approach to harmonization: 0) define the research question, objectives and protocol; 1) assemble pre-existing knowledge and select studies; 2) define targeted variables and evaluate harmonization potential; 3) process data; 4) estimate quality of the harmonized dataset(s) generated; and 5) disseminate and preserve final harmonization products.

Conclusions

This manuscript provides guidelines aiming to encourage rigorous and effective approaches to harmonization which are comprehensively and transparently documented and straightforward to interpret and implement. This can be seen as a key step towards implementing guiding principles analogous to those that are well recognised as being essential in securing the foundational underpinning of systematic reviews and the meta-analysis of clinical trials.

Data Resource Profile: Cross-national and cross-study sociodemographic and health-related harmonized domains from SAGE plus ELSA, HRS and SHARE (SAGE+, Wave 1)

Four longitudinal studies were included in this rigorous harmonization process: the Study on global AGEing and adult health (SAGE); English Longitudinal Study on Ageing (ELSA); US Health and Retirement Study (HRS); and Survey of Health, Ageing and Retirement in Europe (SHARE). An ex-post harmonized process was applied to nine health-related thematic domains (socio-demographic and economic, health states, overall self-report of health and mental state, health examinations, physical and mental performance tests, risk factors, chronic conditions, social network and subjective well-being) for data from the 2004 wave of each study. Large samples of adults aged 50 years and older were available from each study: SAGE, n = 18 886; ELSA, n = 9181; HRS, n = 19 303; and SHARE, n = 29 917. The microdata, along with further details about the harmonization process and all metadata, are available through the World Health Organization (WHO) data archive at [http://apps.who.int/healthinfo/systems/surveydata/index.php/catalog]. Further information and enquiries can be made to [sagesurvey@who.int] or the corresponding author. The data resource will continue to be updated with data across additional waves of these surveys and new waves.

The influence of smoking, sedentary lifestyle and obesity on cognitive impairment-free life expectancy

BACKGROUND

Smoking, sedentary lifestyle and obesity are risk factors for mortality and dementia. However, their impact on cognitive impairment-free life expectancy (CIFLE)has not previously been estimated.

METHODS

Data were drawn from the DYNOPTA dataset which was derived by harmonizing and pooling common measures from five longitudinal ageing studies. Participants for whom the Mini-Mental State Examination was available were included (N¼8111,48.6% men). Data on education, sex, body mass index, smoking and sedentary lifestyle were collected and mortality data were obtained from Government Records via data linkage.Total life expectancy (LE), CIFLE and years spent with cognitive impairment (CILE)were estimated for each risk factor and total burden of risk factors.

RESULTS

CILE was approximately 2 years for men and 3 years for women, regardless of age. For men and women respectively, reduced LE associated with smoking was 3.82and 5.88 years, associated with obesity was 0.62 and 1.72 years and associated with being sedentary was 2.50 and 2.89 years. Absence of each risk factor was associated with longer LE and CIFLE, but also longer CILE for smoking in women and being sedentary in both sexes. Compared with participants with no risk factors, those with 2þ had shorter CIFLE of up to 3.5 years depending on gender and education level.

CONCLUSIONS

Population level reductions in smoking, sedentary lifestyle and obesity increase longevity and number of years lived without cognitive impairment. Years lived with cognitive impairment may also increase.

Cohort Profile Update: Australian Longitudinal Study on Women's Health

In 1996 the Australian Longitudinal Study on Women's Health recruited a nationally representative sample of more than 40,000 women in three age cohorts, born in 1973-78, 1946-51 and 1921-26. At least six waves of 3-yearly surveys have been completed. Although the focus remains on factors affecting the health and well-being of women and their access to and use of health services across urban, rural and remote areas of Australia, the study has now been considerably expanded by linkage to other health data sets. For most women who have ever participated in the study, linked records are now available for: government-subsidized non-hospital services (e.g. all general practitioner visits); pharmaceutical prescriptions filled; national death index, including codes for multiple causes of death; aged care assessments and services; cancer registries; and, for most states and territories, hospital admissions and perinatal data. Additionally, a large cohort of women born in 1989-95 have been recruited. The data are available to approved collaborators, with more than 780 researchers using the data so far. Full details of the study materials and data access procedures are available at [http://www.alswh.org.au/].

Examination of the association between mental health, morbidity, and mortality in late life: findings from longitudinal community surveys

BACKGROUND

Physical health has been demonstrated to mediate the mental health and mortality risk association. The current study examines an alternative hypothesis that mental health mediates the effect of physical health on mortality risk.

METHODS

Participants (N = 14,019; women = 91%), including eventual decedents (n = 3,752), were aged 70 years and older, and drawn from the Dynamic Analyses to Optimise Ageing (DYNOPTA) project. Participants were observed on two to four occasions, over a 10-year period. Mediation analysis compared the converse mediation of physical and mental health on mortality risk.

RESULTS

For men, neither physical nor mental health was associated with mortality risk. For women, poor mental health reported only a small effect on mortality risk (Hazard Risk (HR) = 1.01; p < 0.001); more substantive was the risk of low physical health (HR = 1.04; p < 0.001). No mediation effects were observed.

CONCLUSIONS

Mental health effects on mortality were fully attenuated by physical health in men, and partially so in women. Neither mental nor physical health mediated the effect of each other on mortality risk for either gender. We conclude that physical health is a stronger predictor of mortality risk than mental health.

The utility of estimating population-level trajectories of terminal wellbeing decline within a growth mixture modelling framework

PURPOSE

Mortality-related decline has been identified across multiple domains of human functioning, including mental health and wellbeing. The current study utilised a growth mixture modelling framework to establish whether a single population-level trajectory best describes mortality-related changes in both wellbeing and mental health, or whether subpopulations report quite different mortality-related changes.

METHODS

Participants were older-aged (M = 69.59 years; SD = 8.08 years) deceased females (N = 1,862) from the dynamic analyses to optimise ageing (DYNOPTA) project. Growth mixture models analysed participants' responses on measures of mental health and wellbeing for up to 16 years from death.

RESULTS

Multi-level models confirmed overall terminal decline and terminal drop in both mental health and wellbeing. However, modelling data from the same participants within a latent class growth mixture framework indicated that most participants reported stability in mental health (90.3 %) and wellbeing (89.0 %) in the years preceding death.

CONCLUSIONS

Whilst confirming other population-level analyses which support terminal decline and drop hypotheses in both mental health and wellbeing, we subsequently identified that most of this effect is driven by a small, but significant minority of the population. Instead, most individuals report stable levels of mental health and wellbeing in the years preceding death.

Statistical approaches to harmonize data on cognitive measures in systematic reviews are rarely reported

OBJECTIVES

To identify statistical methods for harmonization, the procedures aimed at achieving the comparability of previously collected data, which could be used in the context of summary data and individual participant data meta-analysis of cognitive measures.

STUDY DESIGN AND SETTING

Environmental scan methods were used to conduct two reviews to identify (1) studies that quantitatively combined data on cognition and (2) general literature on statistical methods for data harmonization. Search results were rapidly screened to identify articles of relevance.

RESULTS

All 33 meta-analyses combining cognition measures either restricted their analyses to a subset of studies using a common measure or combined standardized effect sizes across studies; none reported their harmonization steps before producing summary effects. In the second scan, three general classes of statistical harmonization models were identified (1) standardization methods, (2) latent variable models, and (3) multiple imputation models; few publications compared methods.

CONCLUSION

Although it is an implicit part of conducting a meta-analysis or pooled analysis, the methods used to assess inferential equivalence of complex constructs are rarely reported or discussed. Progress in this area will be supported by guidelines for the conduct and reporting of the data harmonization and integration and by evaluating and developing statistical approaches to harmonization.

Cohort Profile: Hong Kong Department of Health Elderly Health Service Cohort

The Department of Health Elderly Health Service Cohort in Hong Kong was set up to promote understanding of ageing in a global context, to exploit the role of Hong Kong as a sentinel for populations currently experiencing very rapid economic development, to provide a developed non-Western 'social laboratory' where empirically derived hypotheses can be tested and to leverage the different patterns of common chronic diseases between East and West to generate novel hypotheses about their determinants. The initial cohort enrolled from July 1998 to the end of December 2001 includes 66 820 people aged 65 years or older, forming about 9% of the population of this age. A comprehensive health assessment was made at enrollment and then repeated regularly on an ongoing basis. The health assessment included a comprehensive assessment of lifestyle, social circumstances, physical health and mental health, including an assessment of cognition and depressive symptoms. Health services use and deaths have been obtained by record linkage and confirmed, where necessary, by telephone interview. Currently, the data are not publicly available; we would welcome collaborations and research proposals.

An examination of the effects of intra and inter-individual changes in wellbeing and mental health on self-rated health in a population study of middle and older-aged adults

PURPOSE

Self-rated health is frequently used as an indicator of health and quality of life in epidemiological studies. While the association between self-rated health and negative mental health is well established, associations with indictors of positive wellbeing are less clear. Data from the Dynamic Analyses to Optimise Ageing (DYNOPTA) project were used to compare the effects of vitality and mental health on self-rated health.

METHODS

Participants (n = 40,712) provided information on vitality, mental health and self-rated health, were aged 45-95 years at baseline, and were followed between 1 and 10 years (M = 5.6; SD = 2.9).

RESULTS

In comparison with mental health, multi-level modelling indicated between- and within-person change in vitality was more strongly associated with self-rated health. Bivariate dual change score modelling of the cross-lagged associations between vitality and self-rated health indicated vitality to be a stronger predictor of change in self-rated health. Self-rated health was unrelated to change in vitality.

CONCLUSION

Vitality accounted for most of the mental health effect on self-rated health and was identified as a significant predictor of change in self-rated health over a 10-year period. Promoting wellbeing and psychological functioning may have significant protective effects on negative health outcomes throughout the adult lifespan and into late life.

COSMIC (Cohort Studies of Memory in an International Consortium): an international consortium to identify risk and protective factors and biomarkers of cognitive ageing and dementia in diverse ethnic and sociocultural groups

BACKGROUND

A large number of longitudinal studies of population-based ageing cohorts are in progress internationally, but the insights from these studies into the risk and protective factors for cognitive ageing and conditions like mild cognitive impairment and dementia have been inconsistent. Some of the problems confounding this research can be reduced by harmonising and pooling data across studies. COSMIC (Cohort Studies of Memory in an International Consortium) aims to harmonise data from international cohort studies of cognitive ageing, in order to better understand the determinants of cognitive ageing and neurocognitive disorders.

METHODS/DESIGN

Longitudinal studies of cognitive ageing and dementia with at least 500 individuals aged 60 years or over are eligible and invited to be members of COSMIC. There are currently 17 member studies, from regions that include Asia, Australia, Europe, and North America. A Research Steering Committee has been established, two meetings of study leaders held, and a website developed. The initial attempts at harmonising key variables like neuropsychological test scores are in progress.

DISCUSSION

The challenges of international consortia like COSMIC include efficient communication among members, extended use of resources, and data harmonisation. Successful harmonisation will facilitate projects investigating rates of cognitive decline, risk and protective factors for mild cognitive impairment, and biomarkers of mild cognitive impairment and dementia. Extended implications of COSMIC could include standardised ways of collecting and reporting data, and a rich cognitive ageing database being made available to other researchers. COSMIC could potentially transform our understanding of the epidemiology of cognitive ageing, and have a world-wide impact on promoting successful ageing.

Gender differences in the trajectories of late-life depressive symptomology and probable depression in the years prior to death

BACKGROUND

Gender differences in depression are well established. Whether these differences persist into late life and in the years preceding death is less clear. There is a suggestion that there is no increased likelihood of depression in late life, but that there is an increase in depressive symptomology, particularly with proximity to death. We compared trajectories of probable depression and depressive symptomology between men and women over age and distance-to-death metrics to determine whether reports of depressive symptoms are more strongly related to age or mortality.

METHODS

Participants (N = 2,852) from the Dynamic Analyses to Optimise Ageing (DYNOPTA) project had a mean age of 75 years (SD = 5.68 years) at baseline and were observed for up to 16 years prior to death. Multi-level regression models estimated change in depressive symptomology and probable depression over two time metrics, increasing age, and distance-to-death.

RESULTS

Increases in depressive symptomology were reported over increasing age and in the years approaching death. Only male participants reported increased probable depression in the years preceding death. Models that utilized distance-to-death metrics better represented changes in late-life depression, although any changes in depression appear to be accounted for by co-varying physical health status.

CONCLUSIONS

As death approaches, there are increases in the levels of depressive symptomology even after controlling for socio-demographic and health covariates. In line with increases in suicide rates in late life, male participants were at greater risk of reporting increases in depressive symptomology.

Alcohol, hospital admissions, and falls in older adults: a longitudinal evaluation

BACKGROUND

There are limited data on the impacts of alcohol use in older adults. We aimed to evaluate self-reported hospital admissions and falls against current Australian alcohol consumption guidelines.

METHODS

We conducted a longitudinal analysis of data from five Australian cohort studies. The study comprised 16,785 people aged 65 years or older at baseline. Alcohol consumption was categorized using Australian guidelines in standard (10 g) drinks per day as "abstinent," "low-risk" (>0 ≤2), "long-term risk" (>2 ≤4), or "short-term risk" (>4). Separate generalized estimating equations for men and women, controlling for key demographic, and health variables (depression, diabetes, circulatory and musculoskeletal conditions) were used to examine the relationship of alcohol consumption with hospitalization and falls against a reference category of low-risk consumption.

RESULTS

Most participants were in the low (10,369, 62%) or abstinent (5,488, 33%) categories. Among women, all alcohol groups had greater odds of admission than low-risk users; among men, only the abstinent group had increased odds. For both genders, depression, diabetes, circulatory and musculoskeletal conditions all increased the odds of admission. For both genders, the unadjusted model showed that abstainers had increased odds of falling, with depression, diabetes, and for women, musculoskeletal conditions also associated with falls in the adjusted model.

CONCLUSION

These outcomes suggest that older women in particular could benefit from targeted alcohol consumption messages or interventions. In relation to falls, other health conditions appear better targets for intervention than alcohol use.

Alcohol and smoking consumption behaviours in older Australian adults: prevalence, period and socio-demographic differentials in the DYNOPTA sample

PURPOSE

Alcohol consumption and tobacco use are key risk factors for chronic disease and health burden across the adult lifespan. We estimate the prevalence of alcohol consumption and smoking by age and time period in adults from mid to old age.

METHODS

Participants (n = 50,652) were drawn from the Dynamic Analyses to Optimise Ageing (DYNOPTA) project and were compared with Australian National Health Survey data. Alcohol and smoking consumption DYNOPTA data were weighted to the estimated resident population of the sampling frame for each contributing study according to age and sex distributions within major statistical regions.

RESULTS

Comparisons in the rates of smoking and alcohol consumption between DYNOPTA and other national surveys were comparable. Males were more likely to be (RRR = 2.12) or have been smokers (RRR = 2.97), whilst females were more likely to be non-drinkers (RRR = 2.52). Period effects were also identified; higher prevalence rates in consumption of alcohol (RRR = 3.21) and smoking (RRR = 1.67) for those contributing studies from the early 1990's, in comparison with those studies from the latter half of the decade, were reported.

CONCLUSIONS

Over a decade, prevalence rates for high-risk consumption of alcohol and current smoking behaviour declined and suggest the possible impact of government health policy, with targeted-health policies, that included bans on public smoking, and a toughening of legislation against alcohol-related crime.

Stability and change in level of probable depression and depressive symptoms in a sample of middle and older-aged adults

BACKGROUND

Findings from studies investigating depression in adults in late life are mixed due to a lack of large longitudinal studies with the power necessary to yield reliable estimates of stability or change. We examined the long-term stability of probable depression and depressive symptomology over a 13-year period in the Dynamic Analyses to Optimize Ageing (DYNOPTA) project.

METHODS

Community-living participants (N = 35,200) were aged 45-103 at baseline, predominantly female (79%), partnered (73%), and educated to secondary school only (61%) and followed for up to 13 years.

RESULTS

At baseline, increased age was associated with lower prevalence of probable depression and depressive symptomology. Over time, prevalence of probable depression was stable while levels of depressive symptomology reported a small decline. However, this finding was not consistent for all age groups; there was evidence for increasing levels of depressive symptomology, but not probable depression, as individuals aged. This effect was particularly notable among males aged 70 plus years.

CONCLUSIONS

These results answer important questions relating to the longitudinal prevalence of probable depression and depressive symptomology in a sample of older Australians. These findings have policy implications for mental health service provision for older adults.

Correlates of subjective health across the aging lifespan: understanding self-rated health in the oldest old

OBJECTIVES

To examine the determinants of self-rated health (SRH) in different age groups of older adults, including the oldest old.

METHODS

Variables assessing physical health, difficulty with self-care, depressive symptoms, and cognitive impairment were pooled and harmonized from three Australian longitudinal studies of ageing (N = 5,222). The association of these with SRH was examined in older adults aged 60 to 64 years, 65 to 74 years, 75 to 84 years, and 85 years and older.

RESULTS

SRH was not associated with cognitive impairment or difficulty with self-care in the oldest old, and its association with physical health was diminished compared with younger groups. Depression showed a significant relationship in all age groups, conferring an approximately fourfold increase in the likelihood of poorer SRH.

DISCUSSION

As old age progresses, self-reports of poor health become most closely related to psychological symptoms. This explains some of the paradoxes of past literature and offers important insights for health professionals working with the oldest old.

Positive components of mental health provide significant protection against likelihood of falling in older women over a 13-year period

BACKGROUND

In late life, falls are associated with disability, increased health service utilization and mortality. Physical and psychological risk factors of falls include falls history, grip strength, sedative use, stroke, cognitive impairment, and mental ill-health. Less understood is the role of positive psychological well-being components. This study investigated the protective effect of vitality on the likelihood of falls in comparison to mental and physical health.

METHODS

Female participants were drawn from the Dynamic Analyses to Optimise Ageing (DYNOPTA) harmonization project. Participants (n = 11,340) were aged 55-95 years (Mean = 73.68; SD = 4.31) at baseline and observed on up to four occasions for up to 13 years (Mean = 5.30; SD = 2.53).

RESULTS

A series of random intercept logistic regression models consistently identified vitality's protective effects on falls as a stronger effect in the reduction of the likelihood of falls than the effect of mental health. Vitality is a significant predictor of falls likelihood even after adjusting for physical health, although the size of effect is substantially explained by its covariance with mental and physical heath.

CONCLUSIONS

Vitality has significant protective effects on the likelihood of falls. In comparison with mental health, vitality reported much stronger protective effects on the likelihood to fall in comparison with the risk associated with poor mental health in a large sample of older female adults. Both physical health and mental health account for much of the variance in vitality, but vitality still reports a protective effect on the likelihood of falls.

A simple measure with complex determinants: investigation of the correlates of self-rated health in older men and women from three continents

Background

Self-rated health is commonly employed in research studies that seek to assess the health status of older individuals. Perceptions of health are, however, influenced by individual and societal level factors that may differ within and between countries. This study investigates levels of self-rated health (SRH) and correlates of SRH among older adults in Australia, United States of America (USA), Japan and South Korea.

Methods

Cross-sectional data were drawn from large surveys of older respondents (≥ 65 years) in Australia (n = 7,355), USA (n = 10,358), Japan (n = 3,541) and South Korea (n = 3,971), collected between 2000 and 2006. Harmonized variables were developed to represent socioeconomic, lifestyle and health indicators. We then assessed whether these variables, and their potentially different impact in different countries, could account for cross-national differences in levels of SRH.

Results

SRH differed significantly between countries, with older Koreans reporting much poorer health than those in the other three nations. This was not the result of biases in response patterns (for example central versus extreme tendency). Health-related correlates of SRH were similar across countries; those with more medical conditions, functional limitations or poor mental health gave poorer ratings. After accounting for the differential impact of determinants in different national contexts, Australians reported better SRH than other nations.

Conclusions

We conclude that when examining correlates of SRH, the similarities are greater than the differences between countries. There are however differences in levels of SRH which are not fully accounted for by the health correlates. Broad generalizations about styles of responding are not helpful for understanding these differences, which appear to be country, and possibly cohort specific. When using SRH to characterize the health status of older people, it is important to consider earlier life experiences of cohorts as well as national and individual factors in later life. Further research is required to understand the complex societal influences on perceptions of health.

Alcohol use and depression from middle age to the oldest old: gender is more important than age

BACKGROUND

Alcohol use disorders are associated with other mental health disorders in young adults, but there are few data on alcohol use and mental health outcomes in older adults, particularly the oldest old. This study examines the relationship between alcohol consumption and depressive symptoms.

METHODS

Data were collected from the Dynamic Analyses to Optimise Ageing (DYNOPTA) project, which has pooled nine Australian longitudinal studies. Alcohol consumption was classified using standard drinks (10 g alcohol)/day as: abstinent, low risk (<0-≤ 2 standard drinks), long-term risk (>2-≤ 4) and short-term risk (>4). Probable depression was classified from harmonized scores on various standard instruments (e.g. Centre for Epidemiological Studies Depression scale).

RESULTS

Overall, 39,104 (86%) participants contributed data. Alcohol classification at baseline showed 7,526 abstinent, 28,112 low risk, 2,271 long-term risk, and 1,195 short-term risk participants. Age ranged from 45 to 103 year (median 60). Using generalized estimating equations (GEE), there were significant gender by alcohol and gender by age interactions, so the analysis was split by gender. Among males, the abstinent and short-term risk groups had increased likelihood of depression: in females the abstinent, long- and short-term risk groups had increased odds of depression. Increased odds of depression was also associated with former and current smoking, younger age-group, not being partnered, leaving school before age 15 and increasing levels of health-impaired walking, dressing, or bathing.

CONCLUSION

The impact of alcohol use differs by gender, nevertheless those using higher levels of alcohol or who smoke should be screened for depression and may benefit from interventions.

A Multistate Life Table Analysis of Union Regimes in the United States: Trends and Racial Differentials, 1970-2002

We estimate trends and racial differentials in marriage, cohabitation, union formation and dissolution (union regimes) for the period 1970-2002 in the United States. These estimates are based on an innovative application of multistate life table analysis to pooled survey data. Our analysis demonstrates (1) a dramatic increase in the lifetime proportions of transitions from never-married, divorced or widowed to cohabiting; (2) a substantial decrease in the stability of cohabiting unions; (3) a dramatic increase in mean ages at cohabiting after divorce and widowhood; (4) a substantial decrease in direct transition from never-married to married; (5) a significant decrease in the overall lifetime proportion of ever marrying and re-marrying in the 1970s to 1980s but a relatively stable pattern in the 1990s to 2000-2002; and (6) a substantial decrease in the lifetime proportion of transition from cohabiting to marriage. We also present, for the first time, comparable evidence on differentials in union regimes between four racial groups.

Deriving prevalence estimates of depressive symptoms throughout middle and old age in those living in the community

BACKGROUND

There is considerable debate about the prevalence of depression in old age. Epidemiological surveys and clinical studies indicate mixed evidence for the association between depression and increasing age. We examined the prevalence of probable depression in the middle aged to the oldest old in a project designed specifically to investigate the aging process.

METHODS

Community-living participants were drawn from several Australian longitudinal studies of aging that contributed to the Dynamic Analyses to Optimise Ageing (DYNOPTA) project. Different depression scales from the contributing studies were harmonized to create a binary variable that reflected "probable depression" based on existing cut-points for each harmonized scale. Weighted prevalence was benchmarked to the Australian population which could be compared with findings from the 1997 and 2007 National Surveys of Mental Health and Well-Being (NSMHWB).

RESULTS

In the DYNOPTA project, females were more likely to report probable depression. This was consistent across age levels. Both NSMHWB surveys and DYNOPTA did not report a decline in the likelihood of reporting probable depression for the oldest old in comparison with mid-life.

CONCLUSIONS

Inconsistency in the reports of late-life depression prevalence in previous epidemiological studies may be explained by either the exclusion and/or limited sampling of the oldest old. DYNOPTA addresses these limitations and the results indicated no change in the likelihood of reporting depression with increasing age. Further research should extend these findings to examine within-person change in a longitudinal context and control for health covariates.

Understanding ageing in older Australians: the contribution of the Dynamic Analyses to Optimise Ageing (DYNOPTA) project to the evidence base and policy

AIM

To describe the Dynamic Analyses to Optimise Ageing (DYNOPTA) project and illustrate its contributions to understanding ageing through innovative methodology, and investigations on outcomes based on the project themes. DYNOPTA provides a platform and technical expertise that may be used to combine other national and international datasets.

METHODS

The DYNOPTA project has pooled and harmonised data from nine Australian longitudinal studies to create the largest available longitudinal dataset (n= 50652) on ageing in Australia.

RESULTS

A range of findings have resulted from the study to date, including methodological advances, prevalence rates of disease and disability, and mapping trajectories of ageing with and without increasing morbidity. DYNOPTA also forms the basis of a microsimulation model that will provide projections of future costs of disease and disability for the baby boomer cohort.

CONCLUSION

DYNOPTA contributes significantly to the Australian evidence base on ageing to inform key social and health policy domains.

Evaluating a Dichotomized Measure of Self-Reported Hearing Loss Against Gold Standard Audiometry

Objectives: To evaluate a harmonized binary measure of self-reported hearing loss against gold standard audiometry in an older adult population. Method: Seven nationally representative population-based studies were harmonized and pooled ( n = 23,001). Self-report items were recoded into a dichotomous format. Audiometric hearing loss was defined by averaged pure-tone thresholds greater than 25-decibel hearing level in the better ear. We compared age and sex stratified prevalence rates of hearing loss estimated by self-report and audiometric measures. Results: Overall, 56% of men and 43% of women had audiometric hearing loss. There were moderate associations between self-reported and audiometric hearing loss. However, prevalence based on self-report was overestimated for adults aged below 70 years and underestimated for adults aged above 75. Discussion: Self-report of hearing loss is insensitive to age effects and does not provide a reliable basis for estimating prevalence of age-related hearing loss, although may indicate perceived hearing disability.

Age and gender differences in physical capability levels from mid-life onwards: the harmonisation and meta-analysis of data from eight UK cohort studies

Using data from eight UK cohorts participating in the Healthy Ageing across the Life Course (HALCyon) research programme, with ages at physical capability assessment ranging from 50 to 90+ years, we harmonised data on objective measures of physical capability (i.e. grip strength, chair rising ability, walking speed, timed get up and go, and standing balance performance) and investigated the cross-sectional age and gender differences in these measures. Levels of physical capability were generally lower in study participants of older ages, and men performed better than women (for example, results from meta-analyses (N = 14,213 (5 studies)), found that men had 12.62 kg (11.34, 13.90) higher grip strength than women after adjustment for age and body size), although for walking speed, this gender difference was attenuated after adjustment for body size. There was also evidence that the gender difference in grip strength diminished with increasing age,whereas the gender difference in walking speed widened (p<0.01 for interactions between age and gender in both cases). This study highlights not only the presence of age and gender differences in objective measures of physical capability but provides a demonstration that harmonisation of data from several large cohort studies is possible. These harmonised data are now being used within HALCyon to understand the lifetime social and biological determinants of physical capability and its changes with age.

Multiple imputation was an efficient method for harmonizing the Mini-Mental State Examination with missing item-level data

OBJECTIVE

The Mini-Mental State Examination (MMSE) is used to estimate current cognitive status and as a screen for possible dementia. Missing item-level data are commonly reported. Attention to missing data is particularly important. However, there are concerns that common procedures for dealing with missing data, for example, listwise deletion and mean item substitution, are inadequate.

STUDY DESIGN AND SETTING

We used multiple imputation (MI) to estimate missing MMSE data in 17,303 participants who were drawn from the Dynamic Analyses to Optimize Aging project, a harmonization project of nine Australian longitudinal studies of aging.

RESULTS

Our results indicated differences in mean MMSE scores between those participants with and without missing data, a pattern consistent over age and gender levels. MI inflated MMSE scores, but differences between those imputed and those without missing data still existed. A simulation model supported the efficacy of MI to estimate missing item level, although serious decrements in estimation occurred when 50% or more of item-level data were missing, particularly for the oldest participants.

CONCLUSIONS

Our adaptation of MI to obtain a probable estimate for missing MMSE item level data provides a suitable method when the proportion of missing item-level data is not excessive.

Age-based testing for driver's license renewal: potential implications for older Australians

OBJECTIVES

To investigate the effect of age-based testing (ABT) for driver's license renewal policies on older Australians.

DESIGN

Secondary data analysis of a pooled dataset.

SETTING

Community-based samples drawn from three Australian states.

PARTICIPANTS

Five thousand two hundred six adults aged 65 to 103 from the Dynamic Analyses to Optimise Ageing (DYNOPTA) project.

MEASUREMENTS

Self-reported driving status, age-based testing (ABT) for driver's license renewal status, demographics, medical conditions, Mini-Mental State Examination (MMSE), and visual acuity.

RESULTS

After accounting for significant demographic and health covariates, logistic regression analyses revealed that older adults required to undergo ABT were between 2.2 (95% confidence interval (CI)=1.35-3.57, P=.001) and 1.5 (95% CI=1.18-1.92, P=.001) times as likely to report not driving. Similar proportions of drivers with cognitive or visual impairments were found regardless of ABT status.

CONCLUSION

Required ABT for license renewal was associated with lower rates of driving. The proportion of drivers with probable cognitive or visual impairments was similar in those who had ABT and those who did not. Future investigation of the effect of current ABT policies on crash rates and the potential to use other scientifically designed ABT strategies is therefore needed.

Estimates of probable dementia prevalence from population-based surveys compared with dementia prevalence estimates based on meta-analyses

Background

National data on dementia prevalence are not always available, yet it may be possible to obtain estimates from large surveys that include dementia screening instruments. In Australia, many of the dementia prevalence estimates are based on European data collected between 15 and 50 years ago. We derived population-based estimates of probable dementia and possible cognitive impairment in Australian studies using the Mini-Mental State Examination (MMSE), and compared these to estimates of dementia prevalence from meta-analyses of European studies.

Methods

Data sources included a pooled dataset of Australian longitudinal studies (DYNOPTA), and two Australian Bureau of Statistics National Surveys of Mental Health and Wellbeing. National rates of probable dementia (MMSE < 24) and possible cognitive impairment (24-26) were estimated using combined sample weights.

Results

Estimates of probable dementia were higher in surveys than in meta-analyses for ages 65-84, but were similar at ages 85 and older. Surveys used weights to account for sample bias, but no adjustments were made in meta-analyses. Results from DYNOPTA and meta-analyses had a very similar pattern of increase with age. Contrary to trends from some meta-analyses, rates of probable dementia were not higher among women in the Australian surveys. Lower education was associated with higher prevalence of probable dementia. Data from investigator-led longitudinal studies designed to assess cognitive decline appeared more reliable than government health surveys.

Conclusions

This study shows that estimates of probable dementia based on MMSE in studies where cognitive decline and dementia are a focus, are a useful adjunct to clinical studies of dementia prevalence. Such information and may be used to inform projections of dementia prevalence and the concomitant burden of disease.

Comparing modelled predictions of neonatal mortality impacts using LiST with observed results of community-based intervention trials in South Asia

Background There is an increasing body of evidence from trials suggesting that major reductions in neonatal mortality are possible through community-based interventions. Since these trials involve packages of varying content, determining how much of the observed mortality reduction is due to specific interventions is problematic. The Lives Saved Tool (LiST) is designed to facilitate programmatic prioritization by modelling mortality reductions related to increasing coverage of specific interventions which may be combined into packages.

Methods To assess the validity of LiST outputs, we compared predictions generated by LiST with observed neonatal mortality reductions in trials of packages which met inclusion criteria but were not used as evidence inputs for LiST.

Results Four trials, all from South Asia, met the inclusion criteria. The neonatal mortality rate (NMR) predicted by LiST matched the observed rate very closely in two effectiveness-type trials. LiST predicted NMR reduction was close (absolute difference <5/1000 live births) in a third study. The NMR at the end of the fourth study (Shivgarh, India) was overestimated by 39% or 16/1000 live births.

Conclusions These results suggest that LiST is a reasonably reliable tool for use by policymakers to prioritize interventions to reduce neonatal deaths, at least in South Asia and where empirical data are unavailable. Reasons for the underestimated reduction in one trial likely include the inability of LiST to model all effective interventions.

Toward an integrative science of life-span development and aging

The study of aging demands an integrative life-span developmental framework, involving interdisciplinary collaborations and multiple methodological approaches for understanding how and why individuals change, in both normative and idiosyncratic ways. We highlight and summarize some of the issues encountered when conducting integrative research for understanding aging-related change, including, the integration of results across different levels of analysis; the integration of theory, design, and analysis; and the synthesis of results across studies of aging. We emphasize the necessity of longitudinal designs for understanding development and aging and discuss methodological issues that should be considered for achieving reproducible research on within-person processes. It will be important that current and future studies permit opportunities for quantitative comparison across populations given the extent to which historical shifts and cultural differences influence life-span processes and aging-related outcomes.