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.NHMRC (National Health and Medical Research Council of Australia

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.NHMRC (National Health and Medical Research Council of Australia

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.NHMRC (National Health and Medical Research Council of Australia

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

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. 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.The Australian data on which this research is based were drawn from several Australian longitudinal studies including: the Australian Longitudinal Study of Ageing (ALSA), the Australian Longitudinal Study of Women’s Health (ALSWH) and the Personality And Total Health Through Life Study (PATH). These studies were pooled and harmonized for the Dynamic Analyses to Optimize Ageing (DYNOPTA) project. DYNOPTA was funded by a National Health and Medical Research Council (NHMRC) grant (# 410215)

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.This work was supported by a National Health and Medical Research Council grant # 410215 and by the Australian Research Council Centre of Excellence in Population Ageing Research (CE110001029). K.J.A is funded by NHMRC Fellowship #1002560. C.J. is funded by the AXA Research Fund

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.This work was supported by a National Health and Mental Medical Research Council grant (#410215); the Australian Research Council Centre of Excellence in Population Ageing Research (project #CE110001029 to Richard A. Burns); and an NHMRC Fellowship (#1002560 to Kaarin J. Anstey)

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 harmonised from three Australian longitudinal studies of ageing (n=5,222). The association of these with SRH was examined in older adults aged 60-64 years, 65-74 years, 75-84 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.National Health and Medical Research Council (NHMRC); Australian Research Council Centre of Excellence in Population Ageing Research (CEPAR

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