Socioeconomic Status and Health Across the Life Course: Progress and Prospects

Examining factors contributing to the socioeconomic inequalities in handgrip strength among older adults in India: a decomposition analysis

The purpose of this study was to examine (a) the socioeconomic status (SES)-related inequalities associated with handgrip strength (HGS); and (b) the extent to which several demographic, health, and behavioral factors contributed to such SES disparities in HGS among older adults in India. Data were drawn from the 2017-2018 wave 1 of the Longitudinal Ageing Study of India (LASI). The study sample included 27,707 older adults (13,199 men and 14,508 women) aged 60 years and older. HGS was assessed using a handheld Smedley's Hand Dynamometer with a cut-off of 19.5 kg for men and 12.5 kg for women. Bivariate analysis showed the weighted percentage distribution of weak HGS across respondent characteristics. Multivariate logistic regression assessed factors linked to weak HGS. The concentration curve and index (CCI) was used to determine the inequalities in the prevalence of weak HGS by wealth index scores. Wagstaff's decomposition approach was used to test the contribution of each explanatory variable to weak HGS. Around 9% of older adults in this study reported a weak HGS. It was significantly higher among those aged 80 or older (19.21%) and males (15.55%). Weak HGS was concentrated among older adults from poor SES (CCI: 0.05, p < 0.001). A higher percentage of wealth-based inequality in weak HGS was explained by being underweight (38.83%), belonging to the richest wealth quintile (27.95%), and having a higher subjective social status (32.20%). Moreover, about 23.29% of the inequality in weak HGS was explained by Western region and 22.54% by female gender. Additionally, having a secondary level of education explained a higher percentage (22.09%) of inequality, followed by current working status (- 20.68%). Rural residence (13.08%), limitations in instrumental activities of daily living (IADL) (12.21%), and engagement in yoga-related activities (11.55%) explained a higher percentage of wealth-based inequalities. The findings provide evidence of significant SES-related inequalities in HGS and the contribution of various demographic, health, and behavioral factors to such inequality. As such, public health policies and programs focusing on reducing the burden of disability must consider the contribution of social and economic equity to the preservation of muscle strength among older adults.

Cognitive Disparities: The Impact of the Great Depression and Cumulative Inequality on Later-Life Cognitive Function

Population aging has driven a spate of recent research on later-life cognitive function. Greater longevity increases the lifetime risk of memory diseases that compromise the cognitive abilities vital to well-being. Alzheimer's disease, thought to be the most common underlying pathology for elders' cognitive dysfunction (Willis and Hakim 2013), is already the sixth leading cause of death in the United States (Alzheimer's Association 2016). Understanding social determinants of pathological cognitive decline is key to crafting interventions, but evidence is inconclusive for how social factors interact over the life course to affect cognitive function. I study whether early-life exposure to the Great Depression is directly associated with later-life cognitive function, influences risky behaviors over the life course, and/or accumulates with other life-course disadvantages. Using growth curve models to analyze the Health and Retirement Study, I find that early-life exposure to the Great Depression is associated with fluid cognition, controlling for intervening factors-evidence for a critical period model. I find little support for a social trajectory model. Disadvantage accumulates over the life course to predict worse cognitive function, providing strong evidence for a cumulative inequality model.

Pathways of Health and Human Capital from Adolescence into Young Adulthood

Social inequalities in health and human capital are core concerns of sociologists, but little research examines the developmental stage when such inequalities are likely to emerge-the transition to adulthood. With new data and innovative statistical methods we conceptually develop, and empirically operationalize, pathways of physical health and human capital accumulation from adolescence into young adulthood, using an autoregressive cross-lagged structural equation model. Results reveal that pathways of health and human capital accumulate at differential rates across the transition to adulthood; evidence of cross-lagged effects lend support for both social causation and health selection hypotheses. We then apply this model to assess the presence of social inequality in metabolic syndrome-the leading risk factor of cardiovascular disease in the U.S. Findings document social stratification of cardiovascular health that is robust to both observed and unobserved social and health selection mechanisms. We speculate that this social stratification will only increase as this cohort ages.

Cancer patient age and family caregiver bereavement outcomes

PURPOSE

This study drew on life course theory to argue that the strains of cancer caregiving and bereavement are modified by the age of the patient. We expected that caregivers of middle-aged patients would be more distressed than caregivers of older patients.

METHODS

This panel study conducted 199 interviews with family caregivers of advanced cancer patients; first following diagnosis and again shortly after the patient's death.

RESULTS

Among caregivers of middle-aged patients (40-59), grief mediated the relationship between baseline caregiving and bereavement depressed mood, with grief increasing risk of depression in bereavement. Among caregivers of young-old patients (60-79), grief had a suppressor effect on the relationship between caregiving and bereavement depressed mood, showing greater distress during caregiving than at bereavement.

CONCLUSIONS

Caregiving for middle-aged cancer patients may increase the risk for severe grief and depression, whereas caregivers of young-old cancer patients appeared to experience relief at bereavement. After bereavement, continued observation may be warranted for caregivers of a middle-aged patient; grief, added to the ongoing demands of their lives (which may include those left behind by a middle-aged patient), may put such caregivers at risk for greater psychological and emotional distress.

Theoretical foundations for the measurement of environmental factors and their impact on participation among people with disabilities

The ascendance of the World Health Organization's International Classification of Functioning, Disability and Heath (ICF) as the global standard for describing and characterizing aspects of disability has refocused attention on the role that environmental factors (EFs) have on the health and participation of people with disabilities, both as individuals and as a group. There has been a rise in the development of instruments designed to measure EFs alone and in relation to participation. Some instrument developers have used the ICF as a theoretical base for instrument development and to substantiate content validity claims. We contend that this is a misapplication of the ICF. There is a need to step back and reexamine the role that environmental theories can play in developing a conceptually driven approach to measuring the interaction between EFs and participation. For this review, we draw on the fields of social, community, and developmental psychology; disability studies; gerontology; public health; and rehabilitation. We discuss different approaches to the measurement of EFs. We suggest that given the complex nature of EFs and their influence on participation, there is a need for a fresh approach to EF measurement. The thoughtful application of theories and the use of advanced psychometric, measurement, and e-technologies and data visualization methods may enable researchers and clinicians to better quantify, document, and communicate the dynamic interrelationship between EFs and participation and health outcomes for people with disabilities at the individual, group, and population levels.

Determinants of tooth loss and chewing ability in mid- and late life in three Swedish birth cohorts

The aim of the research presented is to determine the influence of socio-economic factors in childhood and mid-life on multiple tooth loss and chewing problems in mid- and late life in three Swedish birth cohorts (1903–1910, 1911–1920 and 1921–1925). Longitudinal national Swedish surveys were used for the analysis. Participants were interviewed in mid-life in 1968 and later in life (77–99 years of age) in 2002. Childhood socio-economic positions (SEP) did not result in different odds of multiple tooth loss and chewing problems in mid- and late life, but persons with higher mid-life SEP had lower odds. Persons born into the 1921–1925 birth cohort had significantly lower odds of multiple tooth loss in late life than the 1903–1910 birth cohort. Women had higher odds of losing multiple teeth than men in late life but not mid-life. Neither gender nor childhood and mid-life SEP predicted chewing problems late in life, but older people with multiple tooth loss had higher odds of chewing difficulty than those with mainly natural teeth. Childhood conditions may contribute to multiple tooth loss in mid-life, which subsequently contributes to multiple tooth loss in late life. Tooth loss in late life is strongly associated with difficulty chewing hard food. Prevalence of multiple tooth loss is higher in women than in men in late life but not in mid-life.

A life course perspective on socioeconomic inequalities in health: a critical review of conceptual frameworks

Social scientists and public health researchers have long known that social position is related to health and that socioeconomic inequalities in health persist in later life. Increasingly, a life course perspective is adopted to understand the socioeconomic position (SEP)-health dynamic. This paper critically reviews the conceptual perspectives underlying empirical research seeking to better understand socioeconomic inequalities in health in the context of the life course. I comment on the contributions of this work, but also its limitations. In particular, I note the emphasis on understanding the mechanisms linking SEP to health, to the exclusion of research on the institutional and structural factors associated with socioeconomic inequalities over the life course. I also critique the relative absence of gender in this work, and how, by not linking individual experiences to the social policy contexts that shape resources and opportunities, the proximal, rather than the structural or institutional determinants of health are emphasized. I suggest that moving forward, a return to some of the key tenets of life course theory, including contributions from the comparative welfare states literature, may better inform life course analyses of socioeconomic inequalities in health. Specific suggestions for life scholarship are discussed.

Social Resources and Change in Functional Health: Comparing Three Age Groups

This study examined the mediating and moderating role of social resources on the association between age and change in functional health for three age groups of older adults. Data were provided by those in their 60s, 80s, and 100s who participated in the first two phases of the Georgia Centenarian study. Analyses confirmed the study's hypothesis that social resources moderated the relationship between age group and change in functional health; in particular, centenarians who experienced the greatest decline in IADLs scored the highest on social resources at time 1. No evidence was found for mediation by social resources or a directional influence by either level of social resources or functional health on change in the other resource. Evidence from this study challenges researchers and service providers to consider the heterogeneity in resources among older adults.

Rising U.S. income inequality and the changing gradient of socioeconomic status on physical functioning and activity limitations, 1984-2007

This study examines the interactive contextual effect of income inequality on health. Specifically, we hypothesize that income inequality will moderate the relationships between individual-level risk factors and health. Using National Health Interview Survey data 1984-2007 (n = 607,959) and U.S. Census data, this paper estimates the effect of the dramatic increase in income inequality in the U.S. over the past two decades on the gradient of socioeconomic status on two measures of health (i.e., physical functioning and activity limitations). Results indicate that increasing income inequality strengthens the protective effects of family income, employment, college education, and marriage on these two measures of health. In contrast, high school education's protective effect (relative to less than a high school education) weakens in the context of increasing income inequality. In addition, we find that increasing income inequality exacerbates men's disadvantages in physical functioning and activity limitations. These findings shed light on research about growing health disparities in the U.S. in the last several decades.

Composition and decomposition in US gender-specific self-reported health disparities, 1984-2007

Variance function regression models and demographic decomposition methods are applied to identify two dimensions of changes in health disparities (SES-demographic effects vs. compositional effects, between-group disparities vs. within-group disparities) in the US from 1984 to 2007. Using National Health Interview Survey data on self-reported health, we find that disparities in men's health increased, while those of women decreased, for the whole period. Widening men's health disparities are largely driven by increases in the effects of SES-demographic statuses on within-group disparities. These increases are moderated by increasing levels of men's college attainment. But decreasing middle and upper income attainment and a decreasing employment rate further increase men's health disparities. For women, the effects of SES-demographic statuses on health disparities also increased over time. This, however, was outweighed by increases in women's college attainment, middle and upper income attainment, and employment rate. The result is overall declining self-reported health disparities for women.

Age differences and changes in resources essential to aging well: a comparison of sexagenarians, octogenarians, and centenarians

THIS STUDY EXAMINED CHANGE OVER TIME IN FIVE RESOURCES ASSESSED BY THE DUKE OARS MULTIDISCIPLINARY FUNCTIONAL ASSESSMENT QUESTIONNAIRE: social, economic, mental, physical, and functional resources. Two hundred and one participants in the Georgia Centenarian Study provided data for this longitudinal study: 70 sexagenarians, 63 octogenarians, and 68 centenarians. Those in their 60s and 80s were followed up within 60 months; due to mortality attrition, centenarians were followed up within 20 months. Centenarians experienced the lowest levels of resources relative to those in their 80s and 60s. Over time they primarily experienced loss in activities of daily living, highlighting that the ability to maximize gains and mitigate losses over time for older adults is highly associated with various resources essential to well-being. Findings suggest that older adults'-especially the very old-resources should be concurrently assessed in a multidimensional analysis by researchers and practitioners who work with older adults in various settings.

Integrating the international classification of functioning, disability, and health model into massage therapy research, education, and practice

Without an increase in clearly defined and clinically significant outcomes research in massage therapy (MT), the practice is in jeopardy of remaining on the fringes of accepted and utilized therapeutic care. This reality will slow the integration of MT into routine preventive, rehabilitative, curative, and supportive care. The International Classification of Functioning, Disability, and Health (ICF) developed by the World Health Organization is a comprehensive model of functioning and disability that provides a universal taxonomy of human functioning that is recognized globally. Integration of the ICF model into MT research, education, and practice would provide a foundation for a common language, particularly in regard to examining outcomes of MT.Here, we review the dynamic and respected ICF model as it applies to massage research, outcomes dissemination, education, and practice, with these specific objectives:To describe the specific domains of the ICF modelTo apply the described ICF domains to current massage practice and researchTo discuss how integration of the ICF model enhances communication and translation among those within and to those outside the MT fieldThe ICF model is ideal for application to MT interests because it works outside the typical focus on pathology or a specific organ system. Instead, the ICF focuses on impairment or limitations in functioning associated with health conditions. The ICF also highlights and incorporates the complex interactions of environment and personal factors and the impact that those factors exert on the domains of body structure, activity, and participation. This interaction has unique implications for MT practitioners, researchers, and clients/patients. Furthermore, the ICF model provides a framework for classifying outcomes, which is a critical aspect of clinical research.

Ethnicity and changing functional health in middle and late life: a person-centered approach

OBJECTIVES

Following a person-centered approach, this research aims to depict distinct courses of disability and to ascertain how the probabilities of experiencing these trajectories vary across Black, Hispanic, and White middle-aged and older Americans.

METHODS

Data came from the 1995-2006 Health and Retirement Study, which involved a national sample of 18,486 Americans older than 50 years of age. Group-based semiparametric mixture models (Proc Traj) were used for data analysis.

RESULTS

Five trajectories were identified: (a) excellent functional health (61%), (b) good functional health with small increasing disability (25%), (c) accelerated increase in disability (7%), (d) high but stable disability (4%), and (e) persistent severe impairment (3%). However, when time-varying covariates (e.g., martial status and health conditions) were controlled, only 3 trajectories emerged: (a) healthy functioning (53%), moderate functional decrement (40%), and (c) large functional decrement (8%). Black and Hispanic Americans had significantly higher probabilities than White Americans in experiencing poor functional health trajectories, with Blacks at greater risks than Hispanics.

CONCLUSIONS

Parallel to the concepts of successful aging, usual aging, and pathological aging, there exist distinct courses of changing functional health over time. The mechanisms underlying changes in disability may vary between Black and Hispanic Americans.

Symptomatic remission in a multiracial urban population of older adults with schizophrenia

OBJECTIVE

Symptomatic remission has been reported in younger patients with schizophrenia. This study aims to determine the prevalence of symptomatic remission in older adults with schizophrenia.

METHODS

The Schizophrenia Group consisted of 198 persons aged 55+ years living in the community who developed schizophrenia before age 45 years. Our definition of remission was adapted from the criteria of the Remission in Schizophrenia Working Group. To attain remission, persons had to have scores of <3 on eight domains of the Positive and Negative Symptom Scale and no hospitalizations within the previous year. Using George's Social Antecedent Model, we examined the association of remission with 18 predictor variables.

RESULTS

Forty-nine percent of the sample met the criteria for symptomatic remission. In logistic regression analysis, four variables--fewer total network contacts, greater proportion of intimates, fewer lifetime traumatic events, and higher Dementia Rating Scale scores--were significantly associated with remission.

CONCLUSIONS

Remission rates were consistent with those reported in younger samples. Our findings suggest that symptomatic remission is an attainable goal and that treatments focused on those variables associated with remission may augment outcomes in older persons with schizophrenia.

Educational differences in health risks and illness over the life course: a test of cumulative disadvantage theory

This study tests the cumulative disadvantage hypothesis by examining the age-varying relationships between education, health risks, and disease onset and survival duration. Results based on 20 years of longitudinal data suggest that education is related to both the individual and accumulated number of behavioral, social, and economic health-risks, which in turn, are related to increasing educational differences in rates of disease incidence and survival. For hypertension, behavioral risks fully account for education's negative effect on disease onset whereas educational differences in survival are best explained by the accumulation of social and economic risks. For heart attack, a combination of behavioral, social, and economic risks mediate the association between education and incidence, but neither the individual nor accumulated health-risks could account for education's positive effect on surviving after a heart attack. Similar findings for diabetes and stroke are also discussed.

Gender differences in functional status in middle and older age: are there any age variations?

OBJECTIVES

The present study examines gender differences in changes in functional status after age 50 and how such differences vary across different age groups.

METHODS

Data came from the Health and Retirement Study, involving up to six repeated observations of a national sample of Americans older than 50 years of age between 1995 and 2006. We employed hierarchical linear models with time-varying covariates in depicting temporal variations in functional status between men and women.

RESULTS

As a quadratic function, the worsening of functional status was more accelerated in terms of the intercept and rate of change among women and those in older age groups. In addition, gender differences in the level of functional impairment were more substantial in older persons than in younger individuals, although differences in the rate of change between men and women remained constant across age groups.

DISCUSSION

A life course perspective can lead to new insights regarding gender variations in health within the context of intrapersonal and interpersonal differences. Smaller gender differences in the level of functional impairment in the younger groups may reflect improvement of women's socioeconomic status, greater rate of increase in chronic diseases among men, and less debilitating effects of diseases.

Cumulative Disadvantage and Black-White Disparities in Life-Course Health Trajectories

In this study, the authors use longitudinal data from the Panel Study of Income Dynamics and growth curve models to examine the utility of the concept of cumulative disadvantage as an explanation for race differences in life-course health (self-rated) in the United States. The authors ask whether socioeconomic resources equally benefit the health of Blacks and Whites, or if Whites receive higher rates of return to resources across the life course. The authors find that the relationship differs depending on the indicator of socioeconomic status that is examined. Education does not offer the same advantages for the health of Blacks as it does for Whites, particularly at higher levels of education, and this is compounded with age. In contrast, returns to income and wealth are similar for Blacks and Whites, and these resources remain equally important to protecting the health of Blacks and Whites across the life course. Over time, Blacks are at an increasing health disadvantage relative to Whites, a result that is not attenuated by educational attainment.

Factors impacting human telomere homeostasis and age-related disease

Loss of telomere length homeostasis has been linked to age-related disease especially cancer. In this review, we discuss two major causes of telomere dysfunction that potentially lead to tumorigenesis: replicative aging and environmental assaults. Aging has long been recognized as a source for telomere dysfunction through increasing numbers of cell divisions in the absence of sufficient telomerase activity. However, environmental assaults that cause telomere dysfunction are only beginning to be identified and recognized. Environmental stressors that influence telomere length may be physical or induced by psychological situations like stress. Knowledge of all factors, including genetic and environmental forces, that moderate telomere length will be critical for understanding basic mechanisms of human telomere maintenance during development and aging as well as for disease prevention and treatment strategies.

The Health Trade-off of Rural Residence for Impaired Older Adults: Longer Life, More Impairment

CONTEXT

Years lived with and without physical impairment are central measures of public health.

PURPOSE

We sought to determine whether these measures differed between rural and urban residents who were impaired at the time of a baseline measurement. We examined 16 subgroups defined by rural/urban residence, gender, race, and education.

METHODS

This is a 20-year retrospective cohort study, following 2,939 Americans who were aged 65-69 in 1982 and physically impaired at the time of the baseline measurement, with data from the National Long-Term Care Survey. Interpolated Markov chain analysis and microsimulation estimated life expectancy at age 65 and expected number of years with physical impairment. Impairment was defined as requiring help in 1 or more activities of daily living.

FINDINGS

Among older individuals with physical impairments at baseline, rural residents lived notably longer than urban residents. In all but 1 group, rural residents lived more years with physical impairment, and they also had a notably larger proportion of remaining life impaired.

CONCLUSIONS

Results suggest a notable public health impact of rural residence for impaired individuals, a longer expected period of impairment. Needs for services for people with impairments may be greater in rural areas.

Lifestyle risk and delaying factors

Research findings suggest that dementia risk is lower in individuals with more extensive education, greater engagement in mentally stimulating leisure activities during adulthood, and higher occupational complexity. Other recent findings support the importance of early-life risk factors, such as socioeconomic conditions, early-life development, and exposure to infection, in explaining individual differences in dementia risk. Life-style variables have been conceptualized as delaying factors, postponing onset of dementia and thereby reducing total population burden of dementia. Using a sample of Swedish twins from the HARMONY study, we found that education significantly affects dementia onset, that is, occurrence and timing of dementia symptoms. In the HARMONY data, we also showed that differences in education are reflected in differences in leisure activities and occupation, suggesting that differences in cognitive engagement begin early and persist over the life course. Such findings point to the importance of taking a life-course perspective to designing interventions to delay or to prevent dementia.