53 research outputs found
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The Developmental Impact of Two First Grade Preventive Interventions on Aggressive/Disruptive Behavior in Childhood and Adolescence: An Application of Latent Transition Growth Mixture Modeling
We examine the impact of two universal preventive interventions in first grade on the growth of aggressive/disruptive behavior in grades 1ā3 and 6ā12 through the application of a latent transition growth mixture model (LT-GMM). Both the classroom-centered and family-centered interventions were designed to reduce the risk for later conduct problems by enhancing the child behavior management practices of teachers and parents, respectively. We first modeled growth trajectories in each of the two time periods with separate GMMs. We then associated latent trajectory classes of aggressive/disruptive behavior across the two time periods using a transition model for the corresponding latent class variables. Subsequently, we tested whether the interventions had direct effects on trajectory class membership in grades 1ā3 and 6ā12. For males, both the classroom-centered and family-centered interventions had significant direct effects on trajectory class membership in grades 6ā12, whereas only the classroom-centered intervention had a significant effect on class membership in grades 1ā3. Significant direct effects for females were confined to grades 1ā3 for the classroom-centered intervention. Further analyses revealed that both the classroom-centered and family-centered intervention males were significantly more likely than control males to transition from the high trajectory class in grades 1ā3 to a low class in grades 6ā12. Effects for females in classroom-centered interventions went in the hypothesized direction but did not reach significance
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The impact of measurement differences on cross-country depression prevalence estimates: A latent transition analysis
Background
Depression is currently the second largest contributor to non-fatal disease burden globally. For that reason, economic evaluations are increasingly being conducted using data from depression prevalence estimates to analyze return on investments for services that target mental health. Psychiatric epidemiology studies have reported large cross-national differences in the prevalence of depression. These differences may impact the cost-effectiveness assessments of mental health interventions, thereby affecting decisions regarding government and multi-lateral investment in mental health services. Some portion of the differences in prevalence estimates across countries may be due to true discrepancies in depression prevalence, resulting from differential levels of risk in environmental and demographic factors. However, some portion of those differences may reflect non-invariance in the way standard tools measure depression across countries. This paper attempts to discern the extent to which measurement differences are responsible for reported differences in the prevalence of depression across countries.
Methods and findings
This analysis uses data from the World Mental Health Surveys, a coordinated series of psychiatric epidemiology studies in 27 countries using multistage household probability samples to assess prevalence and correlates of mental disorders. Data in the current study include responses to the depression module of the World Mental Health Composite International Diagnostic Interview (CIDI) in four countries: Two high-income, western countriesāthe United States (n = 20, 015) and New Zealand (n = 12,992)āan upper-middle income sub-Saharan African country, South Africa (n = 4,351), and a lower-middle income sub-Saharan African country, Nigeria (n = 6,752). Latent class analysis, a type of finite mixture modeling, was used to categorize respondents into underlying categories based on the variation in their responses to questions in each of three sequential parts of the CIDI depression module: 1) The initial screening items, 2) Additional duration and severity exclusion criteria, and 3) The core symptom questions. After each of these parts, exclusion criteria expel respondents from the remainder of the diagnostic interview, rendering a diagnosis of ānot depressedā. Latent class models were fit to each of the three parts in each of the four countries, and model fit was assessed using overall chi-square values and Pearson standardized residuals. Latent transition analysis was then applied in order to model participantsā progression through the CIDI depression module. Proportion of individuals falling into each latent class and probabilities of transitioning into subsequent classes were used to estimate the percentage in each country that ultimately fell into the more symptomatic class, i.e. classified as ādepressedā. This latent variable design allows for a non-zero probability that individuals were incorrectly excluded from or retained in the diagnostic interview at any of the three exclusion points and therefore incorrectly diagnosed. Prevalence estimates based on the latent transition model reversed the order of depression prevalence across countries. Based on the latent transition model in this analysis, Nigeria has the highest prevalence (21.6%), followed by New Zealand (17.4%), then South Africa (15.0%), and finally the US (12.5%). That is compared to the estimates in the World Mental Health Surveys that do not allow for measurement differences, in which Nigeria had by far the lowest prevalence (3.1%), followed by South Africa (9.8%), then the United States (13.5%) and finally New Zealand (17.8%). Individuals endorsing the screening questions in Nigeria and South Africa were more likely to endorse more severe depression symptomology later in the module (i.e. they had higher transition probabilities), suggesting that individuals in the two Western countries may be more likely to endorse screening questions even when they donāt have as severe symptoms. These differences narrow the range of depression prevalence between countries 14 percentage points in the original estimates to 6 percentage points in the estimate taking account of measurement differences.
Conclusions
These data suggest fewer differences in cross-national prevalence of depression than previous estimates. Given that prevalence data are used to support key decisions regarding resource-allocation for mental health services, more critical attention should be paid to differences in the functioning of measurement across contexts and the impact these differences have on prevalence estimates. Future research should include qualitative methods as well as external measures of disease severity, such as impairment, to assess how the latent classes predict these external variables, to better understand the way that standard tools estimate depression prevalence across contexts. Adjustments could then be made to prevalence estimates used in cost-effectiveness analyses
Psychosocial Stress and Changes in Estimated Glomerular Filtration Rate Among Adults with Diabetes Mellitus
Background: Psychosocial stress has been hypothesized to impact renal changes, but this hypothesis has not been adequately tested. The aim of this study was to examine the relationship between psychosocial stress and estimated glomerular ļ¬ltration rate (eGFR) and to examine other predictors of eGFR changes among persons with diabetes mellitus (DM). Methods: Data from a survey conducted in 2005 by a major health maintenance organization located in the southeastern part of the United States, linked to patientsā clinical and pharmacy records (n Ā¼ 575) from 2005 to 2008, was used. Study participants were working adults aged 25ā59 years, diagnosed with DM but without advanced microvascular or macrovascular complications. eGFR was estimated using the Modiļ¬cation of Diet in Renal Disease equation. A latent psychosocial stress variable was created from ļ¬ve psychosocial stress subscales. Using a growth factor model in a structural equation framework, we estimated the association between psychosocial stress and eGFR while controlling for important covariates. Results: The psychosocial stress variable was not directly associated with eGFR in the ļ¬nal model. Factors found to be associated with changes in eGFR were age, race, insulin use, and mean arterial pressure. Conclusion: Among fairly healthy DM patients, we did not ļ¬nd any evidence of a direct association between psychosocial stress and eGFR changes after controlling for important covariates. Predictors of eGFR change in our population included age, race, insulin use, and mean arterial pressure
Evaluating a Method to Estimate Mediation Effects With Discrete-Time Survival Outcomes
The utility of evaluating mediation effects spans across research domains. The model facilitates investigation of underlying mechanisms of event timing and, as such, has the potential to help strengthen etiological research and inform intervention work that incorporates the evaluation of mediating variables. In order for the analyses to be maximally useful however, it is critical to employ methodology appropriate for the data under investigation. The purpose of this paper is to evaluate a regression-based approach to estimating mediation effects with discrete-time survival outcomes. We empirically evaluate the performance of the discrete-time survival mediation model in a statistical simulation study, and demonstrate that results are functionally equivalent to estimates garnered from a potential-outcomes framework. Simulation results indicate that parameter estimates of mediation in the model were statistically accurate and precise across the range of examined conditions. Type 1 error rates were also tolerable in the conditions studied. Adequate power to detect effects in the model, with binary X and continuous M variables, required effect sizes of the mediation paths to be medium or large. Possible extensions of the model are also considered
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Child Care Assistance for Families Involved in the Child Welfare System: Predicting Child Care Subsidy Use and Stability
Early child care and education programs have the potential to play a supportive role in the lives of vulnerable children and families involved in the child welfare system. Child care subsidies can help low-income families to access these programs. The current study examines the use and stability of child care subsidies among children from families involved in the child welfare system. Administrative data were obtained from the Oregon Department of Human Services through two linked datasets: Child Welfare Services and Employment Related Day Care (Oregon's child care subsidy program). Results indicate that children placed out of their biological homes through child welfare services, and those with more instability in child welfare placements, are less likely to receive subsidized child care than those protected in their homes. Findings further suggest that children involved in child welfare services have even less stability in child care subsidy use than other children from low-income families, evidenced by shorter durations of subsidy use. These findings provide a platform for future research in this area, and have implications for the well-being of children and families involved in child welfare services, whose lives involve a host of challenges, risks, and instabilities.Keywords: Child welfare, Child care, Subsidy, Stability, Foster car
Katherine E. Masyn - Modeling measurement error and bias in the determination of event occurrence and event timing for discrete-time survival processes using a latent variable framework
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