Socioeconomic Impacts on Healthy Ageing in the US, England, China and Japan

Background and Aims Healthy ageing has become a popular topic worldwide. So far, a consensus definition of healthy ageing has not been reached. Socioeconomic position (SEP) is an important determinant of healthy ageing. Previous studies have indicated that people in advantaged SEPs are more likely to achieve healthy ageing than people in disadvantaged SEPs. However, only rare studies have compared the magnitude of socioeconomic inequalities in healthy ageing across countries. This thesis aims to conduct a cross-country comparison of socioeconomic inequalities in healthy ageing in the US, England, China and Japan. Data Sources The data are from the Health and Retirement Study (HRS), the English Longitudinal Study of Ageing (ELSA), the China Health and Retirement Longitudinal Study (CHARLS) and the Japanese Study of Ageing and Retirement (JSTAR). The analysis includes 10305 HRS respondents (waves 7–12, 2004–2014), 6590 ELSA respondents (waves 1–7, 2002–2015), 5930 CHARLS respondents (waves 1, 2 and 4, 2011–2015) and 1935 JSTAR respondents (waves 1–3, 2007–2011) aged 60 years or more at baseline. Methods A healthy ageing index (HAI) was created as the main outcome. Education, income, wealth and occupation were included as the main exposures. Data harmonisation was conducted. A two-fold fully conditional specification algorithm was employed to deal with missing data in socioeconomic indicators and covariates (Chapter 2). Pearson’s r and Cronbach’s α were calculated to check the HAI’s test-retest reliability and internal consistency respectively. A Receiver Operating Characteristic curve analysis and a Cox proportional hazards model were applied to test the HAI’s predictive performance on mortality risks (Chapter 3). Multilevel modelling was applied to assess the longitudinal relationships between SEPs and the HAI, allowing for random slopes and intercepts. Socioeconomic rank scores were derived and the slope indices of inequality were calculated to compare the magnitude of inequalities in healthy ageing by education, income and wealth across countries (Chapter 4). Path analysis was used to assess the mediating effects of occupation, income, wealth, smoking and drinking on the relationship between education and healthy ageing. The total, direct and indirect effects of education, occupation, income and wealth on healthy ageing were also calculated (Chapter 5). Results Japanese and English participants achieved healthier ageing than American and Chinese participants. A positive socioeconomic gradient in healthy ageing existed in all countries. The socioeconomic inequality in healthy ageing was relatively small in Japan. In China, the inequality in healthy ageing, especially by education, is daunting. Education was a universally influential socioeconomic predictor of healthy ageing, and is likely to be an independent predictor of healthy ageing among the ageing population across all countries. There were complex pathways from education to healthy ageing in the four countries. The positive effects on healthy ageing of improving education should not be neglected. Wealth inequality in healthy ageing was greater in England than in any other country. Wealth was more influential than income in predicting inequalities in healthy ageing in the US, England and Japan, while income was more influential than wealth in China. Labour force non-participation (e.g. retirement, disability) had negative effects on healthy ageing in the US. Chinese people in paid and stable work were healthier than those in unpaid farming work in later life. Implications This research provides sufficient theoretical and methodological guidelines for the development of well-suited assessments of healthy ageing in the area of public health. These guidelines will be useful for policymakers to capture key elements of healthy ageing when developing ageing policies for older people’s health, social participation and security. This research also provided a unique opportunity to conduct a multinational comparison of socioeconomic impacts on healthy ageing between Western and Asian countries, which has never been done before. Identifying influential socioeconomic indicators of healthy ageing in each country is instructive for exploring universal and country-specific public health practices to support healthy ageing in both Western and Asian countries

Privacy-preserving Sanitization in Data Sharing

In the era of big data, the prospect of analyzing, monitoring and investigating all sources of data starts to stand out in every aspect of our life. The benefit of such practices becomes concrete only when analysts or investigators have the information shared from data owners. However, privacy is one of the main barriers that disrupt the sharing behavior, due to the fear of disclosing sensitive information. This dissertation describes data sanitization methods that disguise the sensitive information before sharing a dataset and our criteria are always protecting privacy while preserving utility as much as possible. In particular, we provide solutions for tasks that require different types of shared data. In the case of sharing partial content of a dataset, we consider the problem of releasing a database under retention restrictions such that the auditing job can still be carried out. While obeying a retention policy often results in the wholesale destruction of the audit log in existing solutions, our framework allows to expire data at a fine granularity and supports audit queries on a database with incompleteness. Secondly, in the case of sharing the entire dataset, we solve the problem of untrusted system evaluation using released database synthesis under differential privacy. Our synthetic database accurately preserves the core performance measures of a given query workload, and satisfies differential privacy with crucial extensions to multi-relation databases. Lastly, in the case of sharing derived information from the data source, we focus on distributing results of network modeling under differential privacy. Our mechanism can safely output estimated parameters of the exponential random graph model, by employing a decomposition of the estimation problem into two steps: getting private sufficient statistics first and then estimating the model parameters. We show that our privacy mechanism provides provably less error than common baselines and our redesigned estimation algorithm offers better accuracy

Bidirectional association between depressive symptoms and mild cognitive impairment over 20 years: Evidence from the health and retirement study in the United States

BACKGROUND: Research examining the association between depressive symptoms and mild cognitive impairment (MCI) has yielded conflicting results. This study aimed to examine the bidirectional association between depressive symptoms and MCI, and the extent to which this bidirectional association is moderated by gender and education. METHODS: Data come from the US Health and Retirement Study over a 20-year period (older adults aged ≥50 years). Competing-risks regression is employed to examine the association between baseline high-risk depressive symptoms and subsequent MCI (N = 9317), and baseline MCI and subsequent high-risk depressive symptoms (N = 9428). Interactions of baseline exposures with gender and education are tested. RESULTS: After full adjustment, baseline high-risk depressive symptoms were significantly associated with subsequent MCI (SHR = 1.20, 95%CI 1.08–1.34). Participants with baseline MCI are more likely to develop subsequent high-risk depressive symptoms than those without baseline MCI (SHR = 1.16, 95%CI 1.01–1.33). Although gender and education are risk factors for subsequent depression and MCI, neither moderates the bidirectional association. LIMITATIONS: Items used to construct the composite cognitive measure are limited; selection bias due to missing data; and residual confounding. CONCLUSIONS: Our study found a bidirectional association between depressive symptoms and MCI. High-risk depressive symptoms are related to a higher risk of subsequent MCI; and MCI predicts subsequent high-risk depression. Though neither gender nor education moderated the bidirectional association, public health interventions crafted to reduce the risk of depression and MCI should pivot attention to older women and those with less formal education

The Association between Subjective Cognitive Decline and Trajectories of Objective Cognitive Decline: Do Social Relationships Matter?

Objectives : We examine the association between subjective cognitive decline (SCD) and the trajectories of objective cognitive decline (OCD); and the extent to which this association is moderated by social relationships. Methods : Data come from waves 10 (2010) through 14 (2018) of the Health and Retirement Study, a nationally representative panel survey of individuals aged 50 and above in the United States. OCD is measured using episodic memory, and overall cognition. SCD is assessed using a baseline measure of self-rated memory. Social relationships are measured by social network size and perceived positive and negative social support. Growth curve models estimate the longitudinal link between SCD and subsequent OCD trajectories and the interactions between SCD and social relationship variables on OCD. Results : SCD is associated with subsequent OCD. A wider social network and lower perceived negative support are linked to slower decline in memory, and overall cognition. None of the social relationship variables, however, moderate the link between SCD and future OCD. Conclusion : Knowing that SCD is linked to subsequent OCD is useful because at SCD stage, deficits are more manageable relative to those at subsequent stages of OCD. Future work on SCD and OCD should consider additional dimensions of social relationships

Online decentralized tracking for nonlinear time-varying optimal power flow of coupled transmission-distribution grids

The coordinated alternating current optimal power flow (ACOPF) for coupled transmission-distribution grids has become crucial to handle problems related to high penetration of renewable energy sources (RESs). However, obtaining all system details and solving ACOPF centrally is not feasible because of privacy concerns. Intermittent RESs and uncontrollable loads can swiftly change the operating condition of the power grid. Existing decentralized optimization methods can seldom track the optimal solutions of time-varying ACOPFs. Here, we propose an online decentralized optimization method to track the time-varying ACOPF of coupled transmission-distribution grids. First, the time-varying ACOPF problem is converted to a dynamic system based on Karush-Kuhn-Tucker conditions from the control perspective. Second, a prediction term denoted by the partial derivative with respect to time is developed to improve the tracking accuracy of the dynamic system. Third, a decentralized implementation for solving the dynamic system is designed based on only a few information exchanges with respect to boundary variables. Moreover, the proposed algorithm can be used to directly address nonlinear power flow equations without relying on convex relaxations or linearization techniques. Numerical test results reveal the effectiveness and fast-tracking performance of the proposed algorithm.Comment: 18 pages with 15 figure

Comparing relationships between health-related behaviour clustering and episodic memory trajectories in the United States of America and England: a longitudinal study

BACKGROUND: Health-related behaviours (HRBs) cluster within individuals. Evidence for the association between HRB clustering and cognitive functioning is limited. We aimed to examine and compare the associations between three HRB clusters: "multi-HRB cluster", "inactive cluster" and "(ex-)smoking cluster" (identified in previous work based on HRBs including smoking, alcohol consumption, physical activity and social activity) and episodic memory trajectories among men and women, separately, in the United States of America (USA) and England. METHODS: Data were from the waves 10-14 (2010-2018) of the Health and Retirement Study in the USA and the waves 5-9 (2010-2018) of the English Longitudinal Study of Ageing in England. We included 17,750 US and 8,491 English participants aged 50 years and over. The gender-specific HRB clustering was identified at the baseline wave in 2010, including the multi-HRB (multiple positive behaviours), inactive and ex-smoking clusters in both US and English women, the multi-HRB, inactive and smoking clusters in US men, and only the multi-HRB and inactive clusters in English men. Episodic memory was measured by a sum score of immediate and delayed word recall tests across waves. For within country associations, a quadratic growth curve model (age-cohort model, allowing for random intercepts and slopes) was applied to assess the gender-stratified associations between HRB clustering and episodic memory trajectories, considering a range of confounding factors. For between country comparisons, we combined country-specific data into one pooled dataset and generated a country variable (0 = USA and 1 = England), which allowed us to quantify between-country inequalities in the trajectories of episodic memory over age across the HRB clusters. This hypothesis was formally tested by examining a quadratic growth curve model with the inclusion of a three-way interaction term (age × HRB clustering × country). RESULTS: We found that within countries, US and English participants within the multi-HRB cluster had higher scores of episodic memory than their counterparts within the inactive and (ex-)smoking clusters. Between countries, among both men and women within each HRB cluster, faster declines in episodic memory were observed in England than in the USA (e.g., b England versus the USA for men: multi-HRB cluster = -0.05, 95%CI: -0.06, -0.03, b England versus the USA for women: ex-smoking cluster = -0.06, 95%CI: -0.07, -0.04). Additionally, the range of mean memory scores was larger in England than in the USA when comparing means between two cluster groups, including the range of means between inactive and multi-HRB cluster for men (b England versus the USA = -0.56, 95%CI: -0.85, -0.27), and between ex-smoking and multi-HRB cluster for women (b England versus the USA = -1.73, 95%CI: -1.97, -1.49). CONCLUSIONS: HRB clustering was associated with trajectories of episodic memory in both the USA and England. The effect of HRB clustering on episodic memory seemed larger in England than in the USA. Our study highlighted the importance of being aware of the interconnections between health behaviours for a better understanding of how these behaviours affect cognitive health. Governments, particularly in England, could pay more attention to the adverse effects of health behaviours on cognitive health in the ageing population

Mental and physical health changes around transitions into unpaid caregiving in the UK: a longitudinal, propensity score analysis

BACKGROUND: The health of unpaid caregivers is poorer, on average, than in non-caregivers. There has been little focus on how health changes when becoming a caregiver and whether this varies by age, gender, and caregiving intensity. We aimed to investigate the mental and physical health changes involved with becoming a caregiver and whether these associations varied by gender, caregiving intensity, or age. METHODS: This study used data from the UK Household Longitudinal Study (2009–20) to examine mental and physical health changes around the transition to becoming a caregiver in adults aged 16 years and older. We included adults with information on care, complete covariates needed for matching, and at least one measure of health before or after becoming a caregiver (or matched non-caregiver). Health was measured via General Health Questionnaire-12 (GHQ-12, psychological distress) and 12-item Short Form Survey (SF-12, physical and mental functioning). We applied piecewise growth curve modelling with propensity score matching to model trajectories of mental and physical health for caregivers and matched non-caregivers. Analyses were stratified by age group, gender, and caregiving intensity. FINDINGS: Sample sizes varied from 3025 (GHQ-12 analyses in early adulthood) to 5785 (SF-12 analyses in early mid-adulthood). Psychological distress increased during transition to caregiving for all ages, particularly in those younger than 64 years, those providing care for 20 h or more per week, and for someone living within the household. Mental health functioning worsened during caregiving transition for those aged 30–64 years, those providing 20 h or more per week, and for those caring for someone within the household. Physical health functioning did not change but there was evidence of lower levels of functioning before caregiving. Changes in mental and physical health upon transition to caregiving did not differ by gender. INTERPRETATION: Our findings highlight the importance of early identification of and support for caregivers, including younger caregivers. This is important to break the cycle of caregiving and future care need. Health services staff, including general practitioners and hospital discharge teams, are well positioned for early identification of caregivers. We also encourage particular support for the mental health of caregivers and particularly those who become caregivers at a younger age. FUNDING: The UK Economic and Social Research Council

Educational gradients in all-cause mortality in two cohorts in the Czech Republic during the early stage of the postcommunist transition

Objectives: We investigated whether social gradient in all-cause mortality in the Czech Republic changed during the postcommunist transition by comparing two cohorts, recruited before and after the political changes in 1989. Methods: Participants (aged 25–64 years) in two population surveys (n=2530 in 1985, n=2294 in 1992) were followed up for mortality for 15 years (291 and 281 deaths, respectively). Education was classified into attainment categories and years of schooling (both continuous and in tertiles). Cox regression was used to estimate HR of death by educational indices in each cohort over a 15-year follow-up. Results: All three educational variables were significantly associated with reduced risk of death in both cohorts when men and women were combined; for example, the adjusted HRs of death in the highest versus lowest tertile of years of schooling were 0.65 (95% CI 0.47 to 0.89) in 1985 and 0.67 (95% CI 0.48 to 0.93) in 1992. Adjustment for covariates attenuated the gradients. In sex-specific analysis, the gradient was more pronounced and statistically significant in men. There were no significant interactions between cohort and educational indices. Conclusions: The educational gradient in mortality did not differ between the two cohorts (1985 vs 1992), suggesting no major increase in educational inequality during the early stage of postcommunist transition. Further research is needed to understand trends in health inequalities during socioeconomic transitions

The associations of physical incapacity and wealth with remaining in paid employment after age 60 in five middle-income and high-income countries

Previous studies on health and socio-economic determinants of later-life labour force participation have mainly come from high-income European countries and the United States of America (USA). Findings vary between studies due to different measures of socio-economic status and labour force outcomes. This study investigated longitudinal associations of physical incapacity and wealth with remaining in paid employment after age 60 in middle- and high-income countries. Using harmonised cohort data in the USA, England, Japan, Mexico and China (N = 32,132), multilevel logistic regression was applied for main associations. The age-related probabilities of remaining in paid employment by physical incapacity and wealth were estimated using marginal effects. This study found that physical incapacity predicted lower odds of remaining in paid employment in each country. Wealth was associated with higher odds of remaining in paid employment in the USA, England and Japan, but not in Mexico. Probabilities of remaining in paid employment were high in Mexico but low in China. The absolute difference in the probability of remaining in paid employment between the richest and the poorest groups was greater in the USA than that in any other country. In the USA, England and Japan, the inverse association between physical incapacity and remaining in paid employment could be partially compensated by wealth only when physical incapacity was not severe. National policies, including considering older adults’ changing capacities for job placement and prioritising the provision of supportive services for socio-economically disadvantaged older adults, developing pathways for informal workers to access social security and pension coverage, and encouraging employers to hire socio-economically disadvantaged older workers and enhancing their employability, could be facilitated. Future studies, such as exploring health and socio-economic determinants of remaining in part-time and full-time paid employment separately in more countries, and the moderating effects of relevant policies on these associations, are needed

Risk of depressive symptoms before and after the first hospitalisation for cancer: Evidence from a 16-year cohort study in the Czech Republic

Background: Whether depression risk starts increasing before cancer diagnosis, and whether cancer is an independent risk factor for depression, remain unclear. We aimed to quantify the risk of depressive symptoms before and after the first hospitalisation for cancer (as a proxy for cancer diagnosis) amongst patients with cancer. Methods: We linked cohort data with national hospitalisation records in the Czech Republic. We followed 1056 incident cancer cases for up to 15 years before and 15 years after the first hospitalisation for cancer. Depressive symptoms were measured using the Centre for Epidemiological Studies-Depression (CES-D) scale. We used multilevel ordered logistic regression to assess the relationship between follow-up years (pre- and post-hospitalisation) and depressive symptoms amongst incident cancer cases. Propensity Score Matching was employed to match each case with a cancer-free control, to test the independent effect of cancer on depressive symptoms over time. Results: Per one year of follow-up (whether pre- or post- hospitalisation) was associated with 1.07 (1.05–1.10) times more likely to have high severity of depressive symptoms amongst patients with cancer. The probability of having high severity of depressive symptoms increased from 25% at five years before hospitalisation to 33% at 7.5 years after hospitalisation. In parallel analyses amongst matched cancer-free controls, the risk of depressive symptoms had no significant changes during follow-up. Limitations: Stratified analyses based on cancer types and stages of malignancy were infeasible. Conclusions: The excess risk of depressive symptoms was apparent five years prior to the first hospitalisation for cancer. Using cancer-free matched controls, we confirmed that cancer was an independent predictor of depressive symptoms