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[Factor structure of the SOC scale 13-item version in Japanese university students].

The purpose of the present study was to examine the construct validity of Antonovsky's (1987) sense of coherence scale (SOC) 13-item version, with a sample of Japanese university students. Subjects were 1,110 university students who completed a self-administered questionnaire including items on individual characteristics (age, sex), the Zung self-rating depression scale (SDS) and the SOC scale. Exploratory factor analysis of the SOC scale yielded an interpretable two-factor solution with "comprehensibility-manageability" and "meaningfulness". Confirmatory factor analysis demonstrated an a priori defined SOC second-order factor model composed of comprehensibility-manageability and meaningfulness factor to have an acceptable fit (chi-square=327.065, df=64, GFI=0.957, CFI=0.872, RMSEA= 0.061). Moreover, structural equation modeling showed that there are theoretically consistent relationships among individual SOC factors and depression. In particular, the meaningfulness factor proved better predictor of depression than the comprehensibility-manageability factor. These findings support the construct validity of the SOC scale and suggest that two SOC sub scores may provide clinically applicable information, rather than the total score.

Adult↗

Determinants of perceived health in patients with left ventricular dysfunction: a structural modeling analysis.

OBJECTIVE: Few studies have evaluated the determinants of perceived health in patients with chronic illness. The present study was designed to evaluate the role of biomedical, demographic, and psychosocial influences on global subjective health by means of a structural equation modeling approach. METHOD: A conceptual model of perceived health was tested in a subsample of patients (N = 146) from the multicenter Studies of Left Ventricular Dysfunction (SOLVD) trial. Domain-specific quality of life constructs (emotional status, social support, and physical functioning), were assessed by means of multiple indicators. These latent (mediating) variables, along with six single-indicator biomedical and background variables, were modeled as predictors of a composite index of perceived health. RESULTS: A satisfactory fit was obtained for the proposed model, with practical fit indices ranging from .89 to .95. High levels of perceived health were associated with low levels of emotional distress and high levels of physical functioning. Social support was positively correlated with physical functioning and negatively associated with emotional distress. Among the background variables, no direct associations were observed between any of the single-indicator variables and perceived health. Several background variables (eg, age, income, walk-test scores) had indirect effects via associations with the latent variables of physical functioning and emotional distress. CONCLUSIONS: These findings support the use of a structural modeling approach in assessing determinants of perceived health in patients with congestive heart failure. Further research is needed to evaluate the utility of the model in other patient populations.

Activities of Daily Living↗

The social predictors of adolescent alcohol misuse: a test of the social development model.

OBJECTIVE: This study was conducted to investigate the ability of the social development model (SDM) to predict alcohol misuse at age 16 and to investigate the ability of the SDM to mediate the effects of alcohol use at age 14 on alcohol misuse at age 16. METHOD: The sample of 807 (411 males) is from the longitudinal panel of the Seattle Social Development Project which, in 1985, surveyed all consenting fifth-grade students from 18 elementary schools serving high-crime neighborhoods in Seattle, Washington. Alcohol use was measured at age 14, predictors of alcohol misuse were measured at age 15 and alcohol misuse was measured at age 16. Structural equation modeling was used to examine the fit of the model to the data. RESULTS: All factor loadings were highly significant and the measurement model achieved a good fit with the data (Comparative Fit Index [CFI] = 0.93). A second-order structural model fit the data well (CFI = 0.91) and also explained 45% of the variance in alcohol misuse at age 16. The SDM partially and significantly mediated the direct effect of age-14 alcohol use on age-16 alcohol misuse. CONCLUSIONS: The risk and protective processes specified by the SDM serve as potential targets for the prevention or reduction of adolescent alcohol misuse.

Adolescent↗

Effect of initial fMRI data modeling on the connectivity reported between brain areas.

Nearly all neuroimaging data analysis rests upon some form of variance partitioning. Conventional analyses, with a general linear model (GLM), partition the variance in the measured response variable into partitions described by a design matrix of explanatory variables. This approach can also be adopted in the initial modeling of the data in studies using data-led methods to summarize functional connectivity, such as principle component analysis, or studies of effective connectivity, using for example structural equation modeling. The point made in this technical note is that the partition of the original time series has to be precisely described to qualify the sources of variations that are taken into account. For conventional analyses using the GLM, the partition investigated corresponds to the subspaces of the design matrix that are tested. However, in the analyses of functional and effective connectivity, the particular subspaces considered are not always specified explicitly. Here we show that selecting different subspaces, or variance partitions, can have a profound effect, both qualitatively and quantitatively, on the sample covariances and the ensuing inferences about connectivity. We will illustrate this using simulated data that include condition and block-related effects and their interactions. We will use these three subspaces to show how the correlation between two voxels depends on which sub-partitions are examined. We will also show how the partition of the design matrix influences the resulting correlation matrix observed when studying correlations between error terms. We will finally demonstrate, quantitatively, the effect of the variance partitions considered on the correlations between two regions using a real fMRI study of biological motion.

Brain↗

Recall and recognition in mild hypoxia: using covariance structural modeling to test competing theories of explicit memory.

To test theories of explicit memory in amnesia, we examined the effect of hypoxia on memory performance in a group of 56 survivors of sudden cardiac arrest. Structural equation modeling revealed that a single-factor explanation of recall and recognition was insufficient to account for performance, thus contradicting single-process models of explicit memory. A dual-process model of recall in which two processes (e.g., declarative memory and controlled search) contribute to recall performance, whereas only one process (e.g., declarative memory) underlies recognition performance, also failed to explain the results adequately. In contrast, a dual-process model of recognition provided an acceptable account of the data. In this model, two processes--recollection and familiarity--underlie recognition memory, whereas only the recollection process contributes to free recall. The best-fitting model was one in which hypoxia and aging led to deficits in recollection, but left familiarity unaffected. Moreover, a controlled search process was correlated with recollection, but was not associated with familiarity or the severity of hypoxia. The results support models of explicit memory in which recollection depends on the hippocampus and frontal lobes, whereas familiarity-based recognition relies on other brain regions.

Aged↗

Primary caregivers of cancer patients in the palliative phase: a path analysis of variables influencing their burden.

Research has shown that several variables influence the burden of primary caregivers of cancer patients staying at home in the palliative phase, but the associations between these variables have hardly been explored. The aim of this study was to examine the associations of theory-driven variables with the caregivers' burden by means of path analysis. The sample consisted of 96 caregivers of cancer patients in the palliative phase staying at home recruited from a hospital trust in Norway. The dimensions of burden from the Caregiver Reaction Assessment, namely self esteem, lack of family support, impact on finances, and impact on daily schedule, were used as the dependent variable. The following independent variables were tested in the models: the patients' levels of pain, fatigue, and nausea; and the caregivers' physical quality of life, anxiety and depression, and social support. The Partial Least Squares approach to structural equation modelling was used for the path analysis. Model 1 shows the direct associations between the independent variables and the dependent variable, explaining 16% of the variance in caregiver burden. Model 1 supports the finding that only caregivers' depression has a direct significant association with caregiver burden, and shows further that the effects of the other independent variables on burden are mediated through depression. In Model 2, anxiety and depression are mediating factors between three other independent variables and caregiver burden, and 12% of the variance is explained. Model 2 supports none of the independent variables as antecedents of burden. Testing of the models suggested that caregivers' depression was the main factor associated with caregiver burden, but also an important mediator of indirect associations of indirect associations of caregivers' anxiety and physical health.

Aged↗

Direct and indirect latent-variable parenting outcomes of two universal family-focused preventive interventions: extending a public health-oriented research base.

Recent literature underscores the need for studies of family-based preventive interventions oriented toward public health objectives. This article illustrates a program evaluation approach for the study of family intervention outcomes in general populations. Thirty-three rural schools were randomly assigned to 1 of 3 conditions: the Preparing for the Drug-Free Years Program (PDFY), the Iowa Strengthening Families Program (ISFP), and a minimal-contact control group. Self-report and observational data collected from 523 families were used to develop measurement models of 3 latent parenting constructs that included measurement method effects. Analyses were conducted to ensure initial and attrition-related group equivalencies and to assess school effects. Structural equation models of the hypothesized sequence of direct and indirect effects for both PDFY and ISFP were then fit to the data. All hypothesized effects were significant for both interventions. The discussion addresses the potential public health benefits of evaluation research on universal preventive interventions.

Adolescent↗

Mood changes during pregnancy and the postpartum period: development of a biopsychosocial model.

OBJECTIVE: Women are vulnerable to mood changes during pregnancy and the postpartum period. We set out to empirically test the hypothesis that biological and psychosocial variables interact to result in this vulnerability. METHOD: Using structural equation modeling techniques, we developed an integrative model of perinatal mood changes from clinical, psychosocial, hormone and mood data collected from 150 women in late pregnancy and at 6-weeks postpartum. RESULTS: In the prenatal model, biological variables had no direct effect on depressive symptoms. However, they did act indirectly through their significant effects on psychosocial stressors and symptoms of anxiety. The same model did not fit the postpartum data, suggesting that different causal variables may be implicated in postpartum mood. CONCLUSION: This model demonstrates the importance of considering both biological and psychosocial variables in complex health conditions such as perinatal mood disorders.

Adult↗

Epidemiology of breastfeeding: advances and multidisciplinary applications.

Advancing understanding of the importance of breastfeeding (BF) has required advances in application of epidemiologic methods to BF research. This chapter considers, in the context of BF epidemiology, how different research designs complement each other to establish firmer causal inferences, the need for multidisciplinary collaborations, and the application of powerful analytical methods to strengthen epidemiologic studies. A recent global meta-analysis of 47 studies documenting the inverse association between lifetime BF duration and breast cancer risk illustrates the value of longitudinal (cohort) studies to establish the temporal sequence of events and to rule out differential recall biases that can threaten the internal validity of case-control studies. The discovery of the transmission of human immunodeficiency virus (HIV) via human milk has led epidemiologists to provide important hypotheses to be tested at the molecular and cellular level and in turn test hypotheses generated in laboratory studies. Application of powerful statistical methods to BF epidemiology has helped strengthen causal inferences. A retrospective analysis of the 1976--1977 Malaysian Family Life Survey found interactive multivariate statistical models to better understand how different socioeconomic and cultural contexts modify the influence of BF on child health. Further, a study conducted in Cebu City, Philippines, demonstrated how structural equation models can be used to test the pathways through which proximate (e.g., BF) and distal (e.g., socioeconomic status) determinants affect child health after adjusting for reverse causality (i.e., child health influencing maternal BF choice). For ethical reasons, BF randomized controlled trials (RCTs) have seldom been conducted. Recent RCTs examining the link between BF peer counseling and BF outcomes in diverse settings provides a unique opportunity to firmly establish the causal inferences regarding BF and the prevention of diarrheal diseases. The value of rapid assessment anthropologic methods to guide development of peer counseling interventions subsequently tested through RCTs is presented. This chapter also illustrates how Cox regression and logistic regression can be applied to BF research.

Breast Feeding↗

Multivariate multipoint linkage analysis of quantitative trait loci.

Resolution of the genetic components of complex disorders may require simultaneous analysis of the contribution of individual quantitative trait loci (QTLs) to multiple variables. A likelihood approach is used to illustrate how the complexities of multivariate data may be resolved with multipoint linkage analysis. Sibling pair data were simulated from a model in which two QTLs and trait-specific polygenic effects explained all the sibling resemblance within and between five variables. Multipoint linkage analysis was used to obtain individual pair probabilities of having zero, one, or two alleles identical by descent, and these probabilities were applied in a weighted maximum-likelihood fit function. The results were compared with those obtained using conventional linear structural equation modeling to estimate the contribution of latent genetic factors to the genetic covariance in the multiple measures. Both analyses were conducted using the Mx package. Relatively poor agreement was found between genetic factors defined in purely statistical terms by varimax rotation of the first two factors of the genetic covariance matrix and the structure obtained by fitting a model jointly to the phenotypic and the multipoint linkage data.

Animals↗

Validity of MMPI-2 profiles in chronic back pain patients: differences in path models of coping and somatization.

OBJECTIVE: To show clinical utility and empirical validity of Minnesota Multiphasic Personality Inventory-2 (MMPI-2) chronic pain patient subgroups by identification of differential multivariate relationships across groups. METHOD: This study used structural equation modeling to test cognitive coping strategies and somatization as mediator variables in path models with pain severity and depression used as exogenous (independent) variables and patient's activity level as the final endogenous (dependent) variable, across MMPI-2 profiles. RESULTS: Hierarchical cluster analysis, performed on a sample of 569 chronic low back patients, resulted in four cluster profiles identifiable as those found in previous work with the MMPI-2 (within normal limits, V-type, neurotic triad, and depressed-pathological). Somatization mediated the relationship between depression and activity level for the neurotic triad group but not the other three groups. A positive linear relationship was found between somatization and depression for the within normal limits, neurotic triad, and depressed-pathological groups, whereas their linear association was negative for the V-type group. Cognitive coping strategies mediated the relationship between depression and activity level for the within normal limits group. In addition, cognitive coping was predictive of activity level for the within normal limits, V-type, and neurotic triad groups but not for the depressed-pathological group. CONCLUSION: Consistent with previous cluster analytic studies, this study replicated four MMPI-2 cluster profile groups in chronic pain patients. These results have also shown that several multivariate relationships between variables are different across MMPI-2 groups, providing evidence for the validity for these MMPI-2 subgroups.

Adaptation, Psychological↗

Models of speech perception and phonological processing in reading.

Multiple measures of speech perception, phonological awareness, naming speed, verbal short-term memory, and word reading were concurrently administered to 136 third- and fourth-grade children. Structural equation modeling was used to contrast 5 models of the relations of speech perception and phonological processing skills to reading with IQ controlled. The best-fitting model, the Indirect Model, was one in which the effect of speech perception on reading was mediated by its relations with phonological processing abilities. Naming speed was particularly highly associated with speech perception, possible evidence for the Motor Theory. Phonological awareness was also substantially correlated with speech perception.

Child↗

A population-based twin study in women of smoking initiation and nicotine dependence.

BACKGROUND: The development of drug dependence requires prior initiation. What is the relationship between the risk factors for initiation and dependence? METHODS: Using smoking as a model addiction, we assessed smoking initiation (SI) and nicotine dependence (ND) by personal interview in 1898 female twins from the population-based Virginia Twin Registry. We developed a twin structural equation model that estimates the correlation between the liability to SI and the liability to ND, given SI. RESULTS: The liabilities to SI and ND were substantially correlated but not identical. Heritable factors played an important aetiological role in SI and in ND. While the majority of genetic risk factors for ND were shared with SI, a distinct set of familial factors, which were probably partly genetic, solely influenced the risk for ND. SI was associated with low levels of education and religiosity, high levels of neuroticism and extroversion and a history of a wide range of psychiatric disorders. ND was associated with low levels of education, extroversion, mastery, and self-esteem, high levels of neuroticism and dependency and a history of mood and alcohol use disorders. CONCLUSIONS: The aetiological factors that influence SI and ND, while overlapping, are not perfectly correlated. One set of genetic factors plays a significant aetiological role in both SI and ND, while another set of familial factors, probably in part genetic, solely influences ND. Some risk factors for SI and ND impact similarly on both stages, some act at only one stage and others impact differently and even in opposite directions at the two stages. The pathway to substance dependence is complex and involves multiple genetic and environmental risk factors.

Adult↗

Including measured genotypes in statistical models to study the interplay of multiple factors affecting complex traits.

The etiology of complex traits may perhaps best be conceptualized by an interplay of multiple factors that mediate the influence of the genes on the eventual outcome. The possibilities of studying aspects of this interplay using existing methods are generally limited. We therefore propose a model with observed and latent variables that does not impose restrictions on the number of variables or the direction of their causal relations and provides a general approach for fitting structural equation models to empirical data. The model is very flexible and (1) allows for genetic effects on the means, variances, and relations between variables, (2) can control for stratification effects on all these components, (3) can be fitted in nuclear families of any size, (4) is estimated using an interpretable parameterization, and (5) can incorporate di- and multi-allelic loci, marker haplotypes, multiple loci simultaneously, and parental genotypes. We indicate how the model can be estimated with the Mx software (Neale et al., 1999) and have written a program to enable geneticists who are not acquainted with Mx to fit their own submodels in a simple and efficient way. A simulation study showed that the model yielded correct Type I errors, unbiased parameter estimates, and satisfactory power to discriminate between alternative models. An example is also given that illustrates how the model could be applied to real data.

Gene Frequency↗

Behavioral-diagnostic analysis of compliance with universal precautions among nurses.

This study used the PRECEDE model (L.W. Green, M.W. Kreuter, S.G. Deeds, & K.B. Partridge, 1980) to examine individual, job-task, and environmental-organizational factors related to compliance with universal precautions (UP) among nurses. Structural equation modeling showed that the hypothesized model did a better job predicting general compliance (R2 = .41) than compliance with personal protective equipment (PPE; R2 = .18). All 3 categories of diagnostic factors (predisposing, enabling, and reinforcing) influenced general compliance, but predisposing factors were relatively unimportant for compliance with PPE. With a set of nested models, the greatest improvement in model fit occurred when the indirect effects of reinforcing factors were added. A positive safety climate may increase the likelihood that the work environment will contain features that enable workers to comply with safe work practices.

Acquired Immunodeficiency Syndrome↗

Development and test of a model linking safety-specific transformational leadership and occupational safety.

The authors developed, tested, and replicated a model in which safety-specific transformational leadership predicted occupational injuries in 2 separate studies. Data from 174 restaurant workers (M age = 26.75 years, range = 15-64) were analyzed using structural equation modeling (LISREL 8; K. G. Jöreskog & D. Sörbom, 1993) and provided strong support for a model whereby safety-specific transformational leadership predicted occupational injuries through the effects of perceived safety climate, safety consciousness, and safety-related events. Study 2 replicated and extended this model with data from 164 young workers from diverse jobs (M age = 19.54 years, range = 14-24). Safety-specific transformational leadership and role overload were related to occupational injuries through the effects of perceived safety climate, safety consciousness, and safety-related events.

Adult↗

Impact of liking for advertising and brand allegiance on drinking and alcohol-related aggression: a longitudinal study.

AIMS: To test a hypothesized model of the effect of televised alcohol advertising and allegiance to specific brands of beer on subsequent beer consumption and self-reports of aggressive behaviour linked with drinking. DESIGN: Structural equation modelling was used to assess the fit between data collected as part of a longitudinal study of young people's health and development and a hypothesized model based on theoretical perspectives and previous research. SETTING: A birth cohort has been assessed every few years, most of them in their home city of Dunedin, New Zealand. The questions about alcohol are asked as part of the day-long assessment. PARTICIPANTS: Members of a longitudinal survey cohort at ages 18 and 21 years. Data from 630 beer drinking participants were analysed in this study. MEASUREMENTS: Responses to questions about beer consumption, liking for advertising, favourite brand of beer and self-reports of alcohol-related aggressive behaviour. FINDINGS: Our hypothesized model assumed a positive impact of liking of alcohol advertising and brand allegiance at age 18 on the volume of beer consumed at age 21 and self-reports of alcohol-related aggressive behaviour. This was found to be a good fit to the data from the longitudinal study. CONCLUSION: This measurable impact of alcohol advertising occurred during a time of decline in aggregate alcohol in New Zealand. While this effect was not large enough to halt the decline in aggregate alcohol consumption it does indicate a measurable, specific impact of broadcast alcohol advertising on alcohol consumption and related behaviour which is of relevance for public health policy.

Adolescent↗

The influence of age and gender on drug use in the United Kingdom--a review.

The aim of this study is to review UK epidemiological research in light of studies on the influence of age and gender on drug use in young people. Literature for this review came from English language publications using a structured search strategy. Within the UK, drug use is commoner in young males than other population groups. When integrated social development models are employed, drug use is seen to be determined by the complex interaction of factors such as age, parental monitoring, and peer group associations. Suggested research directions include combining structural equation modeling with large-scale, UK-based longitudinal social development model studies to develop prevention and intervention efforts that are sensitive to the role of individual, social, and cultural factors.

Adolescent↗