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Results for “causality”

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PubMed1988

Home health care utilization: a causal model.

The present study develops and tests a causal model of home health care utilization by the Lucas County elderly. Path analysis was employed to evaluate the model on an area probability sample of 400 Ohio elderly. The findings indicate that the predictors of home health care are more diverse than was expected with the need factor (need for care, use of health appliances, limits to daily activities), enabling factor (knowledge of resources) and predisposing (age) factors all contributing to the use process.

Activities of Daily Living↗

PubMed1993

Alcohol and risk/sensation seeking: specifying a causal model on high-risk driving.

The authors examine the driving patterns of those at high-risk of drinking-driving. A specially designed questionnaire collected data from 878 respondents in alcohol treatment and criminal justice facilities. The LISREL program is used to analyze the causal structure underlying driving behaviors and various alcohol-and nonalcohol-related factors. Findings indicate that high-risk driving associates with risk/sensation seeking attitudes: A person who is risk/sensation seeking in general tends to drive at high risk in particular. Further, while chronological age is a significant predictor of high-risk driving, early experience with alcohol intensifies risky driving through its impact on risk/sensation seeking attitudes.

Adolescent↗

PubMedDate not supplied

Causal factors in onset of adolescents' cigarette smoking: a prospective study of urban black youth.

This research is based on a two-wave panel study of 536 urban black adolescents. Six to eight years intervened between measuring the predictors and measurement of subsequent smoking initiation. Separate prediction models were tested for males and females, based on a multivariate causal model which spanned five domains of prior conditions: personal background, school achievement, family-peer orientations, psychogenic orientations, health attitudes and behaviors. Variables from all five domains influenced subsequent smoking but different predictors were implicated for adolescent males vs. females. This lends support to one of the major hypotheses in this research--that the salient experiences which governed the decision to start smoking were different for black males and females. Applying the same prediction model to cigarette smoking and to illicit drug involvement showed no overlap in prediction for males and but two of the same influences to be significantly implicated in females' illicit drug use and cigarette smoking.

Achievement↗

PubMed1984

Causal attribution of drinking antecedents in American Indian and Caucasian social drinkers.

Sixty-five American Indian and 100 Caucasian college students were tested with Beckman's rating scale for antecedents of drinking. Subjects were social drinkers who had had no previous alcohol-related problems (arrests, accidents, etc.). They were matched on age, education, and drinking history. The scale addresses beliefs about drinking and its related causes--internal and external. Results indicate only one major difference between Indians and Caucasians (alcoholism as an illness was rated higher by Indians), while similarities in rating patterns were found in comparing our college sample to college students from the Los Angeles area tested by Beckman. American Indian college students were significantly different in their causal attribution of drinking problems from white college students in Los Angeles.

Adolescent↗

PubMed2004

Causal attributions in delusional thinking: an investigation using qualitative methods.

OBJECTIVES: To investigate the attributions offered spontaneously during interview by patients who have delusional beliefs. Specifically, to assess whether people with delusional beliefs reason in a way that is analysable. If so, to extend the findings from previous research to provide a detailed picture of the patients' accounts that could inform cognitive therapies for psychosis. METHOD: A group of 31 patients with delusional beliefs were interviewed using a semi-structured open-ended interview. Their causal attributions were identified and analysed in terms of standard definitions of attributional theory using the Leeds Attributional Coding System. RESULTS: Patients made an average of 96 attributions each. These showed a high degree of recognizable coherence in reasoning, including when directly discussing delusional beliefs. The patterns of attributing were partly consistent with previous research findings, with external attributions being offered for negative events. Several other aspects emerged, indicating a pervasive negativity, with non-delusional aspects of the illness being a major concern. When delusions were described as a cause of events, the dominant pattern of attributing was stable, internal, personal and uncontrollable, with negative outcomes. When delusions were reported as an outcome, the patient was more in control. CONCLUSIONS: The reasoning processes of patients with delusional beliefs are in many aspects normal and include patterns not identified by the ASQ. Attributing in relation to delusions differs from talk about other subjects. The qualitative attributional approach provided a detailed and rich picture of the world of these patients. Interpretable tendencies are described that should provide information useful to those practising and evaluating cognitive therapies.

Adult↗

PubMed2003

The effects of the psychiatric label 'borderline personality disorder' on nursing staff's perceptions and causal attributions for challenging behaviours.

OBJECTIVES: The aim of the study was to investigate how the psychiatric label 'borderline personality disorder' (BPD) affected staff's perceptions and causal attributions about patients' behaviour. METHODS AND DESIGN: The study utilized a within-participants questionnaire methodology and participants comprised qualified mental health nursing staff. The questionnaire contained descriptions of challenging behaviour in which the patient was described with a diagnosis of depression, schizophrenia or BPD. Participants were asked to identify a likely cause of the behaviour and then on a Likert-type scale rate attributions of internality, stability, globality and controllability. In addition they recorded their level of sympathy with the patient and their optimism for change. RESULTS: Patients with a label of BPD attracted more negative responses from staff than those with a label of schizophrenia or depression. Causes of their negative behaviour were rated as more stable and they were thought to be more in control of the causes of the behaviour and the behaviour itself. Staff reported less sympathy and optimism towards patients with a diagnosis of BPD and rated their personal experiences as more negative than their experiences of working with patients with a diagnosis of depression or schizophrenia. CONCLUSIONS: Staff regard patients with a BPD label to be more in control of negative behaviour than patients with a label of schizophrenia or depression. In accord with Weiner's (1985) model, attributions of control were inversely related to staff sympathy. Addressing attributions of control may provide a means to modify staff sympathy towards patients with a diagnosis of BPD and counteract their negative experiences.

Attitude of Health Personnel↗

PubMed2004

Delusional discourse: an investigation comparing the spontaneous causal attributions of paranoid and non-paranoid individuals.

Research into the nature of attributional reasoning in paranoia has for the most part been restricted to questionnaire-based approaches. This fails to address the issue of whether a distinctive attributional style underpins the everyday talk of paranoid individuals. This study aimed to investigate whether attributional models of paranoid delusions applied to spontaneous attributions generated in the discourse of 12 paranoid and 12 non-paranoid speakers. Causal attributions for negative and positive life experiences were extracted from interview transcripts and rated using the Content Analysis of Verbatim Explanations (CAVE) technique. It was found that, as a proportion, paranoids made more attributions for negative events that were of an external-personal, stable and global nature (as attributional models would predict). They also made significantly more external-personal attributions for negative events and, in one of two datasets, showed a more external mean CAVE rating for negative events than the non-paranoid controls. This paper highlights important issues underlying the extraction of attributions from paranoid talk, and discusses the implications for attributional models of paranoia and future discourse-based research in this area.

Adult↗

PubMed1998

A new perspective on the causal influence of soft tissue composition on DXA-measured in vivo bone mineral density.

An extensive series of quantitative simulation studies replicating ideal dual-energy X-ray absorptiometric (DXA) bone mineral density (BMD) measurements of typical and realistic in vivo lumbar vertebral and proximal femoral sites has been carried out to quantitatively assess the extent of inherent systematic inaccuracies in such measurements. The results for these bone sites indicate that BMD inaccuracies as high as 20% or more can be anticipated clinically, particularly in cases of osteopenic, osteoporotic, and elderly patients. It is found that the most important soft-tissue anthropometric determinants of the extent of bone site-specific systematic in vivo BMD inaccuracies reflected in DXA measurements are the ratio of the areal density of extraosseous fat to that of lean muscle tissue immediately surrounding the interrogated bone site and the specific yellow/red marrow mix within the scanned bone. As such, the present findings focus directly on the question of whether or not the strong, positive correlations and associations between soft tissue compositional parameters and DXA-measured in vivo BMD determined in a large number of previous clinical investigations are, in toto or in part, biologically causal. The present results are seen to be quantitatively and qualitatively in conformity with the many clinical studies that have found marked general decreases (increases) in measured BMD as body weight and/or body fat mass decreases (increases). It is concluded that the clinically observed correlations between DXA-measured BMD and these anthropometric parameters are artefacts of the systematic errors (inaccuracies) inherent in planar DXA methodology and are unlikely to be of biological genesis.

Absorptiometry, Photon↗

PubMed2001

Role of the instantaneous spectrum on pulse propagation in causal linear dielectrics.

A model-independent theorem demonstrates how a causal linear dielectric medium responds to the instantaneous spectrum, that is, the spectrum of the electric field pulse that is truncated at each new instant (as a given locale in the medium experiences the pulse). This process leads the medium to exchange energy with the front of a pulse differently than with the back as the instantaneous spectrum laps onto or off of nearby resonances. So-called superluminal pulse propagation in either absorbing or amplifying media as well as highly subluminal pulse propagation are understood qualitatively and quantitatively within this context.

Journal Article↗

PubMed1989

Temporal impulse responses from flicker sensitivities: causality, linearity, and amplitude data do not determine phase.

A recent paper [J. Opt. Soc. Am. A 4, 1130 (1987)] advances a method for the determination of an impulse response from amplitudes of a measured amplitude spectrum. The crucial step in this derivation is the assumption that if a transfer function is analytic and causal, then so is its logarithm. This assumption is tantamount to that of minimum phase and is not justified, both in principle and in practice. In the absence of additional information or assumptions, every amplitude spectrum is consistent with a multiplicity of phase spectra.

Algorithms↗

PubMed2005

Apparent causality paradox in frustrated Gires-Tournois interferometers.

Negative group delay times upon total reflection from frustrated Gires-Tournois interferometers seem to violate causality. Contrary to what has been recently argued in the literature, I show with the example of total light reflection upon an ideal nonabsorbing plasma that adding the time associated with the Goos-Hänchen shift does not solve the paradox, which remains open.

Journal Article↗

PubMed2006

On modeling HIV and T cells in vivo: assessing causal estimators in vaccine trials.

The first efficacy trials--named STEP--of a T cell vaccine against HIV/AIDS began in 2004. The unprecedented structure of these trials raised new modeling and statistical challenges. Is it plausible that memory T cells, as opposed to antibodies, can actually prevent infection? If they fail at prevention, to what extent can they ameliorate disease? And how do we estimate efficacy in a vaccine trial with two primary endpoints, one traditional, one entirely novel (viral load after infection), and where the latter may be influenced by selection bias due to the former? In preparation for the STEP trials, biostatisticians developed novel techniques for estimating a causal effect of a vaccine on viral load, while accounting for post-randomization selection bias. But these techniques have not been tested in biologically plausible scenarios. We introduce new stochastic models of T cell and HIV kinetics, making use of new estimates of the rate that cytotoxic T lymphocytes--CTLs; the so-called killer T cells--can kill HIV-infected cells. Based on these models, we make the surprising discovery that it is not entirely implausible that HIV-specific CTLs might prevent infection--as the designers explicitly acknowledged when they chose the endpoints of the STEP trials. By simulating thousands of trials, we demonstrate that the new statistical methods can correctly identify an efficacious vaccine, while protecting against a false conclusion that the vaccine exacerbates disease. In addition to uncovering a surprising immunological scenario, our results illustrate the utility of mechanistic modeling in biostatistics.

AIDS Vaccines↗

PubMed2024

Causal association of menstrual reproductive factors on the risk of osteoarthritis: A univariate and multivariate Mendelian randomization study.

OBJECTIVE: Several observational studies have revealed a potential relationship between menstrual reproductive factors (MRF) and osteoarthritis (OA). However, the precise causal relationship remains elusive. This study performed Mendelian randomization (MR) to provide deeper insights into this relationship. METHODS: Utilizing summary statistics of genome-wide association studies (GWAS), we conducted univariate MR to estimate 2 menstrual factors (Age at menarche, AAM; Age at menopause, AMP) and 5 reproductive factors (Age at first live birth, AFB; Age at last live birth, ALB; Number of live births, NLB; Age first had sexual intercourse, AFSI; Age started oral contraceptive pill, ASOC) on OA (overall OA, OOA; knee OA, KOA and hip OA, HOA). The sample size of MRF ranged from 123846 to 406457, and the OA sample size range from 393873 to 484598. Inverse variance weighted (IVW) method was used as the primary MR analysis methods, and MR Egger, weighted median was performed as supplements. Sensitivity analysis was employed to test for heterogeneity and horizontal pleiotropy. Finally, multivariable MR was utilized to adjust for the influence of BMI on OA. RESULTS: After conducting multiple tests (P<0.0023) and adjusting for BMI, MR analysis indicated that a lower AFB will increase the risk of OOA (odds ratio [OR] = 0.97, 95% confidence interval [CI]: 0.95-0.99, P = 3.39×10-4) and KOA (OR = 0.60, 95% CI: 0.47-0.78, P = 1.07×10-4). ALB (OR = 0.61, 95% CI: 0.45-0.84, P = 2.06×10-3) and Age AFSI (OR = 0.66, 95% CI: 0.53-0.82, P = 2.42×10-4) were negatively associated with KOA. In addition, our results showed that earlier AMP adversely affected HOA (OR = 1.12, 95% CI: 1.01-1.23, P = 0.033), and earlier ASOC promote the development of OOA (OR = 0.97, 95% CI: 0.95-1.00, P = 0.032) and KOA (OR = 0.58, 95% CI: 0.40-0.84, P = 4.49×10-3). ALB (OR = 0.98, 95% CI: 0.96-1.00, P = 0.030) and AFSI (OR = 0.98, 95% CI: 0.97-0.99, P = 2.66×10-3) also showed a negative association with OOA but they all did not pass multiple tests. The effects of AAM and NLB on OA were insignificant after BMI correction. CONCLUSION: This research Certificates that Early AFB promotes the development of OOA, meanwhile early AFB, ALB, and AFSI are also risk factors of KOA. Reproductive factors, especially those related to birth, may have the greatest impact on KOA. It provides guidance for promoting women's appropriate age fertility and strengthening perinatal care.

Humans↗

PubMed2004

Causal models of reading disability: a twin study.

The genetic and environmental relationships among measures of phoneme awareness, naming speed, Intelligence Quotient (IQ), and reading performance were investigated in 623 identical and fraternal twin pairs tested in the Colorado Learning Disabilities Research Center. A Cholesky decomposition analysis of these measures provided evidence supporting the double deficit hypothesis that difficulties in phonological processing and naming speed both contribute to reading disability. Additionally, the model revealed marginally significant genetic and significant non-shared environmental relationships between IQ and reading independent of naming speed and phoneme awareness. Thus a more complete causal model of reading disability should include IQ as well as measures of phonological processing and naming speed.

Dyslexia↗

PubMed1985

Alcohol and property crime: exploring the causal nexus.

The literature on the relationship between alcohol use and property crime is reviewed. Four sources of data (detailed criminal and drinking histories of 32 men prison inmates, interviews with 67 men imprisoned for robbery, biographies of 10 criminals, and case materials found in scholarly works on "causal" and "professional" property crime) reveal three models of the alcohol-crime link: Drinking at the time of the offense and alcoholism are deterrents to professional property crime because they lead to the perception of unreliability by crime partners and thus serve as barriers to admission to crime partnerships. Certain aspects of the professional criminal lifestyle are conducive to heavy drinking--being unmarried, being geographically unstable, having alternating periods of intense activity and leisure, and having large amounts of money to spend. Heavy drinking provides easy companionship and relaxation to criminals who lack the normal family and work restraints. There is a complex relationship between alcohol use and casual property crime committed in groups. Social isolation leads some individuals to drink to form a "primary group atmosphere." Group participation in crime serves to maintain the cohesiveness of the group. Intoxication facilitates participation in unplanned, low-profit, high-risk crime since it causes group members to focus on the immediate reward of group cohesion and not on the longer-term negative consequences.

Adolescent↗

PubMed2005

Causal factors of acute gastroenteritis in infants and young children.

Respiratory, gastrointestinal and skin diseases represent the most common diseases in infants and young children. Causal factors of these diseases are important infectious agents and causes of pathological conditions in children, but they are also very important for their parents, as well as for people in their close environment. Greater incidence of infections in infants and young children can be explained in different ways. A cause can be insufficient maturity of their immune system, but also their exposure to infections within collective accommodations (cribs, nurseries, pre-school institutions), where they are, at the same time, exposed to a number of unknown agents. Today, a great emphasis is devoted to the ways and kinds of children's nutrition. The problem of relation between infected young organism and infectious agent itself, is also reflected in a long resistance and excretion of microorganisms in their exterior environment. It is well-known that microorganisms resist and excrete much longer in younger organisms, compared to adults, where their resistance and excretion is much shorter or very rare. Actually, adults have already formed protective immunity against particular infectious agents. It doesn't prevent infections in adults, colonization of pathogens, nor eventual development of disease. Established immunity can shorten the time necessary for excretion of microorganisms in their exterior environment and, if disease gets developed, it is of shorter duration and slower progress.

Acute Disease↗

PubMedDate not supplied

The causal pathway model and cerebral palsy.

This article reviews possible prenatal, perinatal, and postnatal causes of cerebral palsy. The interactive effects of various causes are evaluated. Groups of intervention strategies are then presented based on the causal pathway model.

Asphyxia Neonatorum↗

PubMed1997

Posttraumatic stress disorder among female Vietnam veterans: a causal model of etiology.

OBJECTIVES: The Vietnam and Persian Gulf wars have awakened people to the realization that military service can be traumatizing for women as well as men. This study investigated the etiological roles of both war and sexual trauma in the development of chronic posttraumatic stress disorder among female Vietnam veterans. METHODS: Data from the National Vietnam Veterans Readjustment Study for 396 Vietnam theater women and 250 Vietnam era women were analyzed with structural equation modeling. RESULTS: An etiological model with highly satisfactory fit and parsimony was developed. Exposure to war trauma contributed to the probability of posttraumatic stress disorder in theater women, as did sexual trauma in both theater and era women. Lack of social support at the time of homecoming acted as a powerful mediator of trauma for both groups of women. CONCLUSIONS: Within the constraints and assumptions of causal modeling, there is evidence that both war trauma and sexual trauma are powerful contributors to the development of posttraumatic stress disorder among female Vietnam veterans.

Adult↗