SEARCH · PubMed Health

Results for “causality”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 667 records · Page 37Linked to original sources

PubMed2000

[Smoking and mortality. Evaluation of statistical analyses of causality].

Present quantification of "death by smoking" is based on unreliable, biased generalizations of retrospectively collected data. Big samples cannot heal the bias. Not even causality can be derived. Even less possible is an adequate estimate of the degree of the risk of death caused by "smoking" by means of epidemiological methods. The first aim of the paper is a discussion of the difficulties to prove causality with statistical procedures. Defining four variants of excess mortality it is proved that these different definitions are mixed in the current problem discussion. Besides it is difficult, if not impossible, to find appropriate estimates of the degree of dependency considering the necessary complexity of the model.

Animals↗

PubMedDate not supplied

Is there a causal link between maltreatment and adolescent pregnancy? A literature review.

CONTEXT: Despite a sizable amount of research addressing the relationship between violence and women's reproductive health, it has not been shown whether there is sufficient evidence of a causal link between childhood maltreatment and subsequent adolescent pregnancy. METHODS: Three databases (Medline, PsychiNFO and SocioFile) were searched for studies published between 1980 and 2000 relating maltreatment and adolescent pregnancy. The review was limited to empirical studies; theoretical articles and those with no women who were aged 21 or younger during the research period or when they experienced maltreatment were excluded. RESULTS: Fifteen articles on the topic were found All were published after 1989; all but one were cross-sectional, were retrospective and relied on recall. All of the studies dealt with sexual maltreatment, either alone or in combination with other types of maltreatment; few covered emotional abuse or neglect. The studies lacked consistent definitions of the various types of maltreatment. Only one examined adolescent mothers' relationships with men, and none examined relationships with perpetrators. Few dealt with racial and ethnic differences related to violence. All lacked a specific theoretical approach. Ten of the studies supported a link between maltreatment and adolescent pregnancy, and five eitherdid not support a link or qualified the relationship. Substance abuse, poor mental health and promiscuity were among the mediating variables examined. CONCLUSIONS: Because recent studies have reached conflicting findings, had methodological weaknesses and lacked theoretical grounding, whether a causal link exists between maltreatment and adolescent pregnancy remains an unanswered question.

Adolescent↗

PubMed2002

A longitudinal causal relationship among cardiovascular risk factors in the employees of the government savings bank.

A longitudinal structural causal model was generated to examine the causal relationship among determinants which were composed of four personal factors, stress, four health behaviors, and BMI on five physiological risks for cardiovascular disease: SBP, DBP, FBS, TC and HDL-C in 1,019 bank employees, within a five-year interval. A fourteen-item food frequency questionnaire for assessing eating habits and the Health Opinion Survey for the stress test were included in the self-administered questionnaires. Weight, height and blood pressure were measured and blood samples were collected for blood chemical analysis. Data analysis by LISREL showed that the determinants in the proposed model explained as much as 96 per cent variation in physiological risks for CVD (R2 = 0.96, relative chi-square = 1.92, RMSEA = 0.03, GFI = 0.96 and AGFI = 0.95). The findings also indicated that current physiological status was affected by their status of age, education, health behaviors, BMI and physiological status 5 years ago.

Adult↗

PubMed2002

Recursive retrospective revaluation of causal judgments.

Recursive causal evaluation is an iterative process in which the evaluation of a target cause, T, is based on the outcome of the evaluation of another cause, C, the evaluation of which itself depends on the evaluation of a 3rd cause, D. Retrospective revaluation consists of backward processing of information as indicated by the fact that the evaluation of T is influenced by subsequent information that is not concerned with T directly. Two experiments demonstrate recursive retrospective revaluation with contingency information presented in list format as well as with trial-by-trial acquisition. Existing associative models are unable to predict the results. The model of recursive causal disambiguation that conceptualizes the revaluation as a recursive process of disambiguation predicts the pattern of results correctly.

Adult↗

PubMed2004

Influenza and cardiovascular disease: is there a causal relationship?

There is mounting evidence in support of a significant role for influenza infection in the development of atherosclerosis and the triggering of its complications. Here we review the biologic basis of this relationship, with special emphasis on the pro-inflammatory and pro-thrombotic effects of influenza infection. We also discuss the related epidemiologic findings and discuss in detail the possible causal relationship between influenza and cardiovascular disease. We appraise the relationship between influenza and coronary heart disease, on the basis of Bradford Hill's criteria of causality. We show that our proposed relationship meets the following criteria: strength of association, consistency, temporal sequence, coherence, biologic plausibility, experimental evidence, and analogy. Further studies are needed to assess whether it meets the criterion of biologic gradient. Specificity is not met, but meeting that criterion is of least importance in the study of multifactorial chronic diseases such as coronary heart disease. These criteria do not yield indisputable evidence for or against cause-and-effect, but they can help researchers appraise available evidence and determine the areas that need further research. The case for expanding the research on the effect of influenza on cardiovascular disease is a strong one, for most of Hill's criteria are met.

Blood Coagulation↗

PubMed2005

Counterfactual overdetermination vs. the causal exclusion problem.

This paper aims to show that a counterfactual approach to causation is not sufficient to provide a solution to the causal exclusion problem in the form of systematic overdetermination. Taking into account the truthmakers of causal counterfactuals provides a strong argument in favour of the identity of causes in situations of translevel, causation.

Biological Science Disciplines↗

PubMed1991

Sticks and stones may break my bones ... reasoning about illness causality and body functioning in children who have a chronic illness.

Children's concepts about illness causality and bodily functioning change in a predictable way with advancing age. Differences in the understanding of these concepts in healthy children vs children with a chronic illness have not been clearly delineated. This study included 49 children with a seizure disorder, 47 children with an orthopaedic condition, and 96 healthy children, all with normal intelligence and ranging in age from 5 to 16 years. It demonstrates systematic differences in children's general reasoning skills and in their understanding of concepts about illness causality and bodily functioning, as a function of their age and experience of illness. At all ages, children who had a condition with orthopaedic involvement reported less sophisticated general reasoning and concepts about illness than did healthy children; children with a seizure disorder reported similar general reasoning skills to those of healthy children, but considerably less sophisticated concepts about illness. Children's concepts about body functioning did not differ as a function of the presence of a chronic illness. When their different levels of general cognitive reasoning were statistically controlled, children with a chronic illness had somewhat more sophisticated concepts about bodily functioning than did healthy children. Differences in conceptual development among children with different types of illnesses lead to interesting speculations with regard to the effects of particular illness characteristics on children's cognitive development.

Adolescent↗

PubMed1995

On the nature, magnitude, and causality of suicidal behaviors: an international perspective.

The central questions addressed in this paper are whether present generations of adolescents and adults worldwide are at greater risk of developing suicidal reactions than previous generations were and what the possible causal mechanisms involved are. On the basis of data from international and national data banks as well as an extensive review of the literature, it is concluded that a true increase in suicide mortality and morbidity has occurred over the larger part of this century among the White urban adolescent and young adult populations of North America and Europe, particularly among (young) males over the last three decades. Among the possible causal mechanisms identified are (1) the corresponding increase in the prevalence of depressive disorders; (2) the corresponding increase in the prevalence of substance (ab)use and substance abuse disorders, and a lowering of age of onset of (ab)use; (3) psychobiological changes, in particular the dramatic lowering of the age of puberty; (4) an increase in the number of social stressors with extensive consequences for youth; (5) changes in attitudes towards suicidal behaviors and the related increased availability of suicidal models.

Adolescent↗

PubMed1997

[Alcohol, breast cancer and causal inference in epidemiology].

In order to demonstrate how possible causal relationships are critically evaluated in epidemiologic research, literature on the association between alcohol and breast cancer is reviewed and discussed. A cause can be defined as a factor which, in combination with other factors, known and unknown, is sufficient to produce an effect. Since the hypothesis-generating study was published in 1977, a total of 34 positive and 16 negative studies have been published. Methodological problems, such as chance, bias and confounding, cannot be considered as plausible explanations for the above majority of positive findings. The question of causality was then evaluated using the guidelines developed by Bradford Hill in 1965. Among these, the strength of the association, consistency, temporality, biological gradient and biological plausibility, are the most important. In spite of the relatively weak association and somewhat inconsistent results, it is concluded that alcohol consumption should be considered as a cause of breast cancer. It is estimated that in Norway, between 24 and 180 cases of breast cancer may be attributed to alcohol consumption. Future research should focus on the question of effect-modification and on the possible implications of different patterns of alcohol consumption.

Alcohol Drinking↗

PubMed1998

[Tobacco and ectopic pregnancy. Arguments in favor of a causal relation].

BACKGROUND: The risk associated with smoking has been studied for a long time in fertility epidemiology. This paper reviews the association between smoking and ectopic pregnancy (EP) using results collected in our previous studies. It provides arguments for a causal interpretation of this association. METHODS: Data came from three case-control studies performed between 1988 and 1996 and from the register of ectopic pregnancies in Auvergne (France) from 1992 to 1995. The methods are those classically used in the analysis of case-control studies. RESULTS: The risk of EP increased significantly with smoking (p < 0.01): the adjusted OR are 1.5 for 1-9 cigarettes a day, 2.0 for 10-19 cigarettes a day, and 2.5 for more than 20 cigarettes a day. The attributable risk of smoking ranged between 17% and 32% according to the study. Similarly, the risk of EP recurrence increased significantly with smoking (p < 0.02): after adjustment, OR = 1.3 for 1-9 cigarettes a day, OR = 1.5 for 10-19 cigarettes a day, and OR = 1.7 for more than 20 cigarettes a day. Finally, smoking was associated with the site of EP. CONCLUSIONS: Thus there is a large body of arguments towards a causal relationship between smoking and EP. This provides additional arguments to persuade women to stop or to reduce smoking, especially hypofertile women.

Case-Control Studies↗

PubMed1998

Estimating the causal effect of compliance on binary outcome in randomized controlled trials.

We examine likelihood based methods aimed at analysing the causal effect of actual exposure to drug treatment on a (repeated) binary outcome in two randomized trials with partial compliance. Starting with the univariate compliance summary 'total treatment dose history', we apply a method for ordinal compliance and monotone dose response, proposed by Goetghebeur and Molenberghs. In a short duration trial of blood pressure reduction, this summary leads to meaningful effect estimators. However, in the analysis of a vitamin A trial, this method reaches a boundary solution; the estimated possible benefit from vitamin A for children who did not receive any pills on the treatment arm is zero. In our formulation the number of pills that were taken captures part of the outcome, and the corresponding effect parameters suffer from this confounding. To gain additional insight, we account explicitly for the temporal structure of compliance. We extend the likelihood based methodology for univariate ordered compliance to more dimensional compliance with only a partial order structure on exposure. The randomization assumptions in the causal formulation of Rubin are translated to this setting. We motivate a set of parametric assumptions on the joint distribution of potential outcomes and observed compliance levels and reanalyse the vitamin A trial. Our findings suggest that one capsule of vitamin A had a large impact on mortality during the first 4 months. The greatest reduction in risk was estimated amongst children who received two doses. This supports findings from a vitamin A trial in Ghana and in Nepal. Finally, we discuss extensions of this method, covering uncensored and censored grouped survival data.

Adult↗

PubMed1997

A causal functional explanation of maintaining a dependent elder in the community.

A causal functional structure demonstrates how a perpetual process, like caregiving, maintains itself. The caregiver functional learning model was used to identify factors influencing caregivers when maintaining dependent elders in the community. These factors include seriousness of illness, power, burden, care quality, self-assurance, an understanding of the elder's needs, and time spent in caregiving. This five-stage theoretical model was tested using a sample of 70 caregivers. Findings supported two of the theoretical relationships: seriousness of illness (beta = .60) with burden (R2 = 0.35), and self-assurance (beta = .36) with time (R2 = 0.18). Three new relationships were added with the empirical model: power (beta = .48) with burden (R2 = 0.52), seriousness of illness (beta = .36) with self-assurance (R2 = 0.11), and burden (beta = .33) with time (R2 = 0.24). A causal functional structure can be used to explain how the phenomenon of caregiving maintains itself.

Activities of Daily Living↗

PubMed1988

Oculoauriculovertebral anomaly: variability and causal heterogeneity.

The oculoauriculovertebral anomaly is a complex developmental field defect. There is lack of agreement on the minimal diagnostic criteria and the phenotypic spectrum. Causal heterogeneity has been described. This report reviews aspects of phenotypic variability and causal heterogeneity and discusses current understanding of the defect.

Female↗

PubMed1990

Neural tube defects: are neurulation and canalization forms causally distinct?

Neural tube defects (NTD) may be separated according to the overall location and probable embryological origin into 2 groups: upper or neurulation defects, and lower or canalization defects. Evidence as to whether these 2 forms are causally related or distinct was sought from 2 sources. Families with more than one NTD individual were studied to examine whether there was concordance within sibships for these 2 types of lesion. Seven of the 38 sibships were discordant (18%). Eight of the 10 cases of NTD that had arisen despite maternal periconceptional vitamin supplementation were neurulation defects and 2 were canalization defects. Both observations suggest that upper and lower types of NTD are causally related, and offer no support for the suggestion that they are distinct.

Humans↗

PubMed2002

Hippocampal LTP and memory in mouse strains: is there evidence for a causal relationship?

The mechanisms underlying memory are under intense investigation. One of the most promising candidates at the cellular level is long-term potentiation (LTP). Numerous pharmacological and molecular genetic manipulations have led to alteration in both LTP and memory. However, the causal relationship between these phenotypical changes is debated. The problem of causality can be addressed in numerous ways. One suggestion is to investigate natural variation in both LTP and memory performance in mouse strains. If variation in synaptic and behavioral phenomena is found, correlation between these traits may be investigated. The advantages and disadvantages of this approach are discussed. An empirical example using four mouse strains is also presented to highlight some general problems. The following arguments are made. First, multiple electrophysiological and behavioral paradigms with idiosyncratic condition characteristics should be conducted to avoid false-positive findings due to alterations unrelated to memory and its mechanisms. Multiple stimulation and memory protocols may also allow one to study the complexity and multiplicity of processes. Second, analysis of a large number of mouse strains may be needed to avoid false interpretation of results due to spurious gene associations and/or linkage disequilibrium. Third, quantitative genetic analysis using, for example, diallele crosses, may be employed to properly investigate biologically meaningful, i.e., genetic, effects. It is concluded that with the use of additional methods (e.g., QTL analysis, gene expression arrays, and biochemical analysis) providing converging evidence, analysis of mouse strains will be instrumental in addressing the question regarding the role LTP may play in memory.

Animals↗

PubMed2026

Subtype-Specific Causal Effects of C16 and C24 Ceramides on Heart Failure: Evidence From Univariable and Multivariable Mendelian Randomization Analyses.

Ceramides (Cer) are bioactive lipids implicated in cardiovascular disease (CVD), yet their subtype-specific causal effects remain unclear. We performed a two-sample Mendelian randomization (MR) analysis using publicly available GWAS summary statistics to investigate the effects of C16:0-ceramide homologs (Cer16:0) and C24:1-ceramide homologs (Cer24:1) on six CVD outcomes. Instrumental variables were rigorously selected, and multiple MR methods were applied to ensure robust inference. Univariable MR identified a significant inverse association between Cer(d18:1/24:1) and heart failure (HF), which remained significant after false discovery rate correction. In contrast, the association for Cer(d17:1/16:0) did not remain significant after correction. No causal associations were observed for other CVD outcomes. When aggregating subtypes, genetically predicted higher total Cer16:0 levels were associated with increased HF risk, while no significant association was found for total Cer24:1. Multivariable MR further demonstrated that the protective effect of Cer(d18:1/24:1) on HF was robust, while estimates for C16 subtypes were attenuated and sensitive to model specification. In conclusion, our findings support a stable protective role of Cer(d18:1/24:1) in HF and highlight the complexity of subtype-specific effects among structurally related ceramides. These results underscore the importance of considering ceramide heterogeneity in cardiovascular research. Further studies are warranted to validate these findings and explore their clinical implications.

Ceramides↗

PubMed2005

The Netherlands XTC Toxicity (NeXT) study: objectives and methods of a study investigating causality, course, and clinical relevance.

This paper describes the objectives and methods of The Netherlands XTC Toxicity (NeXT) study focussing on the causality, course, and clinical relevance of ecstasy neurotoxicity. Previous studies suggest that ecstasy (3,4 methylene-dioxymethamphetamine, MDMA, XTC) is toxic toward brain serotonin axons, but most of these studies have serious methodological limitations. The current study is a combination of different approaches with three substudies: (1) a crosssectional substudy among heavy ecstasy users and controls with variation in drug use, which will provide information about potential neurotoxic consequences of ecstasy in relation to other drugs; (2) a prospective cohort substudy in ecstasy-naive subjects with high risk for future ecstasy use, which will provide information on the causality and short-term course of ecstasy use and potential neurotoxicity, and (3) a retrospective cohort substudy in lifetime ecstasy users and matched controls of an existing epidemiological sample that will provide information on long-term course and outcome of ecstasy use in the general population. Neurotoxicity is studied using (a) different imaging techniques (beta-CIT SPECT, 1H-MR spectroscopy, diffusion tensor imaging, perfusion weighted imaging and functional magnetic resonance imaging), and (b) neuropsychological and psychiatric assessments of memory, depression, and personality. The combined results will lead to conclusions that can be used in prevention messages, clinical decision making, and the development of an (inter)national ecstasy policy.

Adolescent↗

PubMed2002

Model misspecification sensitivity analysis in estimating causal effects of interventions with non-compliance.

Randomized trials often face complications in assessing the effect of treatment because of study participants' non-compliance. If compliance type is observed in both the treatment and control conditions, the causal effect of treatment can be estimated for a targeted subpopulation of interest based on compliance type. However, in practice, compliance type is not observed completely. Given this missing compliance information, the complier average causal effect (CACE) estimation approach provides a way to estimate differential effects of treatments by imposing the exclusion restriction for non-compliers. Under the exclusion restriction, the CACE approach estimates the effect of treatment assignment for compliers, but disallows the effect of treatment assignment for non-compliers. The exclusion restriction plays a key role in separating outcome distributions based on compliance type. However, the CACE estimate can be substantially biased if the assumption is violated. This study examines the bias mechanism in the estimation of CACE when the assumption of the exclusion restriction is violated. How covariate information affects the sensitivity of the CACE estimate to violation of the exclusion restriction assumption is also examined.

Algorithms↗