Social inequalities in trajectories of contacts with the healthcare system in adolescence and young adulthood.

BACKGROUND: Understanding of healthcare utilization of different populations is useful for prevention and prioritization of healthcare resources. This study aims to identify populations following different trajectories of contacts with the healthcare system and to describe social inequalities between the groups. METHODS: Individuals born 1980-2000 in Denmark were linked to national registers. Contacts with somatic hospitals, psychiatric hospitals, general practitioners, and redeemed prescriptions were counted for each year between 16 and 37 years of age. Trajectories of contacts with the four dimensions of healthcare use were identified using group-based multi-trajectory modeling. RESULTS: Five trajectory groups were identified. One group had low healthcare utilization over time (12% in women; 27% in men). The largest group had low healthcare utilization but more contacts with especially GP (39% in women; 43% in men). A third group had more contacts with most dimensions of the healthcare system (33% in women; 21% in men). The fourth group had many contacts with especially somatic hospitals and GP (7% in women; 4% in men). The fifth group had many contacts especially to psychiatric hospitals (8% in women; 5% in men). Shorter parental education, parental unemployment, family income below the poverty line, and cohabitation with one or no parent was more frequent in the two high utilization groups compared to the lower utilization groups. CONCLUSION: The observed trajectories of health service use and the social inequalities between trajectory groups highlight that prevention and treatment targeting the entire population will benefit from a complementary focus on social inequalities in health.

Full body musculoskeletal model for simulations of gait in persons with transtibial amputation.

This paper describes the development, properties, and evaluation of a musculoskeletal model that reflects the anatomical and prosthetic properties of a transtibial amputee using OpenSim. Average passive prosthesis properties were used to develop CAD models of a socket, pylon, and foot to replace the lower leg. Additional degrees of freedom (DOF) were included in each joint of the prosthesis for potential use in a range of research areas, such as socket torque and socket pistoning. The ankle has three DOFs to provide further generality to the model. Seven transtibial amputee subjects were recruited for this study. 3 D motion capture, ground reaction force, and electromyographic (EMG) data were collected while participants wore their prescribed prosthesis, and then a passive prototype prosthesis instrumented with a 6-DOF load cell in series with the pylon. The model's estimates of the ankle, knee, and hip kinematics comparable to previous studies. The load cell provided an independent experimental measure of ankle joint torque, which was compared to inverse dynamics results from the model and showed a 7.7% mean absolute error. EMG data and muscle outputs from OpenSim's Static Optimization tool were qualitatively compared and showed reasonable agreement. Further improvements to the muscle characteristics or prosthesis-specific foot models may be necessary to better characterize individual amputee gait. The model is open-source and available at (https://simtk.org/projects/biartprosthesis) for other researchers to use to advance our understanding and amputee gait and assist with the development of new lower limb prostheses.

Evaluation of a quasi-passive biarticular prosthesis to replicate gastrocnemius function in transtibial amputee gait.

Lower limb amputees experience gait impairments, in part due to limitations of prosthetic limbs and the lack of a functioning biarticular gastrocnemius (GAS) muscle. Energy storing prosthetic feet restore the function of the soleus, but not GAS. We propose a transtibial prosthesis that implements a spring mechanism to replicate the GAS. A prototype Biarticular Prosthesis (BP) was tested on seven participants with unilateral transtibial amputation. Participants walked on an instrumented treadmill with motion capture, first using their prescribed prosthesis, then with the BP in four different spring stiffness conditions. A custom OpenSim musculoskeletal model, including the BP, was used to estimate kinematics, joint torques, and muscle forces. Kinematic symmetry was evaluated by comparing the amputated and intact angles of the ankle, knee, and hip. The BP knee and ankle torques were compared to the intact GAS. Finally, work done by the BP spring was calculated at the ankle and knee. There were no significant differences between conditions in kinematic symmetry, indicating that the BP performs similarly to prescribed prostheses. When comparing the BP torques to intact GAS, higher spring stiffness better approximated peak GAS torques, but those peaks occurred earlier in the gait cycle. The BP spring did positive work on the knee joint and negative work on the ankle joint, and this work increased as BP spring stiffness increased. The BP has the potential to improve amputee gait compensations associated with the lack of biarticular GAS function, which may reduce their walking effort and improve quality of life.

The lasting imprint of childhood disadvantage: cumulative histories of exposure to childhood adversity and trajectories of psychological distress in adulthood.

This study contributes to the literature on the long-term effects of childhood disadvantage on mental health by estimating the association between patterns of cumulative childhood adversity on trajectories of psychological distress in adulthood. There is little research that investigates how compositional variations in the accumulation of childhood adversity may initiate distinct processes of disadvantage and differentially shape trajectories of psychological distress across the adult life course. Using the Panel Study of Income Dynamics' Childhood Retrospective Circumstance Study and latent class analysis, we first identify distinct classes representing varied histories of exposure to childhood adversities using 25 indicators of adversity across multiple childhood domains. Next, the latent classes are included as predictors of trajectories of psychological distress in adulthood. The results demonstrate that patterns of experiences of childhood adversity are associated with higher levels of adult psychological distress that persists, and in some cases worsens, in adulthood, contributing to disparities in mental health across the life course.

Design and Development of a Quasi-Passive Transtibial Biarticular Prosthesis to Replicate Gastrocnemius Function in Walking.

Lower-limb amputees experience many gait impairments and limitations. Some of these impairments can be attributed to the lack of a functioning biarticular gastrocnemius (GAS) muscle. We propose a transtibial prosthesis that implements a quasi-passive spring mechanism to replicate GAS function. A prototype biarticular prosthesis (BP) was designed, built, and tested on one subject with a transtibial amputation. They walked on an instrumented treadmill with motion capture under three different biarticular spring stiffness conditions. A custom-developed OpenSim musculoskeletal model, which included the BP, was used to calculate the work performed and torque applied by the BP spring on the knee and ankle joints. The BP functioned as expected, generating forces with similar timing to GAS. Work transfer occurred from the ankle to the knee, with stiffer springs transferring more energy. Driven mostly by kinematics, the quasi-passive design of the BP consumed very low power (5.15 W average) and could lend itself well to future lightweight, low-power designs.

The childhood roots of adult psychological distress: Interdisciplinary perspectives toward a better understanding of exposure to cumulative childhood adversity.

BACKGROUND: Although most children experience at least one adversity, it is the experience of multiple adversities that produces a context of disadvantage that increases the risk of various negative outcomes in adulthood. Previous measures of cumulative childhood adversity consider a limited number of adversities, overlook potential differences across experiences of adversity, and fail to measure the effects of multiple co-occurring childhood adversities. These limitations have led to inconsistent and incomplete conclusions regarding the impact of multiple adverse childhood experiences on adult mental health. OBJECTIVE: This study assesses how the operationalization and modeling of exposure to cumulative childhood adversity (CCA) influences estimates of the association between CCA and adult psychological distress and develops an improved measure of CCA. METHODS: We use data from the Panel Study of Income Dynamics, a nationally representative sample of households in the United States, and its supplement, the Childhood Retrospective Circumstances Study (N = 4219). We compare four measures of CCA that consider various distinct aspects of adverse experiences (additive, severity, type, and patterns of experience using latent class analysis). RESULTS: All measures of CCA were associated with increases in adult psychological distress, but effects depend on the measurement of CCA. Results suggest the sum score overestimates the overall impact of CCA. Latent class analysis captures the co-occurrence of adversities across severity and type, providing an improved measure of CCA. CONCLUSIONS: The heterogeneity across adversities impacts estimates of adult psychological distress. Measuring CCA as patterns of co-occurring adverse experiences is a promising approach.

Trajectories of Work Disability and Economic Insecurity Approaching Retirement.

OBJECTIVES: In this article, we examine the connection between trajectories of work disability and economic precarity in late midlife. We conceptualize work disability as a possible mechanism linking early and later life economic disadvantage. METHODS: We model trajectories of work disability characterized by timing and stability for a cohort of Baby Boomers (22-32 in 1981) using 32 years of data from the Panel Study of Income Dynamics and latent class analysis. Measures of childhood disadvantage are included as predictors of work disability trajectories, which are subsequently included in logistic regression models predicting four economic outcomes (poverty, asset poverty, home ownership, and pension ownership) at ages 54-64. RESULTS: Childhood disadvantage selected individuals into five distinct classes of work disability that differed in timing and stability. All of the disability trajectories were associated with an increased risk of economic insecurity in late midlife compared to the never work disabled. DISCUSSION: This study contributes to the aging literature through its incorporation of the early life origins of pathways of disability and their links to economic outcomes approaching retirement. Findings suggest work disability is anchored in early life disadvantage and is associated with economic insecurity later in life.

A Longitudinal Analysis of the Intergenerational Transmission of Health Inequality.

Objectives: Empirical investigations of cumulative dis/advantage typically treat health inequality as an intraindividual process rooted in early-life conditions and operating within the span of the individual life course, while literature on processes of intergenerational transmission has historically focused on socioeconomic mobility, largely overlooking health. The current study examines the persistence of work disability across generations and multiple explanations for this relationship, including the role of early-life disadvantage, childhood health, educational attainment, and social mobility. Methods: We model latent classes of midlife work disability characterized by timing and stability using longitudinal data from the intergenerational component of the U.S. Panel Study of Income Dynamics (N = 3,328). Latent class analysis captures the initial risk of experiencing a work disability and how this risk changes across mid-life as a function of early-life conditions, childhood health, educational attainment, mobility, and parent's work disability. Results: Early disadvantage, childhood health, and educational attainment were associated with patterns of midlife work disability, and although upward mobility provided some protection, intergenerational continuity in health remained net of all of these factors. Discussion: Findings support the importance of looking beyond the individual life course to the transmission of health inequality across generations within families.

Life Course Pathways of Economic Hardship and Mobility and Midlife Trajectories of Health.

We utilize over 40 years of prospective data from the Panel Study of Income Dynamics (N = 1,229) and repeated-measures latent class analysis to examine how long-term patterns of stability and change in economic hardship from childhood to adulthood are related to subsequent trajectories of midlife health. We review conceptual and methodological approaches to examining health inequality across the life course and highlight the contribution of a person-centered, disaggregated approach to modeling health and its association with long-term pathways of economic resources, including changing resources associated with mobility. Findings suggest those who experienced early mobility out of economic hardship were less likely than those in persistent economic hardship to experience a high-risk health trajectory, while experiencing later mobility did not lessen this risk. We conclude with a call for further investigation into the role of social mobility and the timing, degree, and direction of change in investigations of health inequality.

Patterns of cumulative abuse among female survivors of intimate partner violence: links to women's health and socioeconomic status.

Drawing on the Women's Health Effects Study, a community sample of women (N = 309) who recently left an abusive partner, this study examines patterns of cumulative abuse experiences over the life course, their socioeconomic correlates, and associations with a range of health outcomes. Latent class analysis identified four groups of women with differing cumulative abuse profiles: Intimate Partner Violence (IPV) Dominant, Child Abuse and IPV, All Forms, and All Forms Extreme. We find a relationship pattern between cumulative abuse and socioeconomic circumstances, and significantly worse health outcomes among women with the All Forms Extreme profile. Implications for research and practice are discussed.

Economic hardship in childhood and adult health trajectories: An alternative approach to investigating life-course processes.

In this study, we advance existing research on health as a life course process by conceptualizing and measuring both childhood disadvantage and health as dynamic processes in order to investigate the relationship between trajectories of early life socioeconomic conditions and trajectories of health in midlife. We utilize a trajectory-based analysis that takes a disaggregated, person-centered approach to understand dynamic trajectories of health as latent variables that reflect the timing, duration and change in health conditions experienced by respondents over a period of 10 years in midlife as a function of stability and change in exposure to economic hardship in early life. Results from repeated-measures latent class analysis of longitudinal data from the Panel Study of Income Dynamics indicate that economic hardship in childhood has long-term, negative consequences for health both among individuals beginning life and remaining in poverty as well as those moving into poverty. In contrast, adults with more advantaged early life experiences, or who moved out of poverty during the period of observation, were at a lower risk of experiencing health trajectories characterized by the early onset or increasing risk of disease. We argue that a person-centered, disaggregated approach to the study of the relationship between socioeconomic status and health across the life course holds potential for the study of health inequality and that a greater focus on trajectory-based analysis is needed.