There is little or no doubt that stressful situations can cause significant rise in blood pressure. It is no news that a more chronic form of blood pressure is termed “hypertension”. There is a need to discover whether the presence of stress really leads to the development over time.
A systematic review of literature on stress and hypertension
Studies reporting an association between stress and hypertension
A systematic review was carried out to identify, evaluate and summarize the literature related to establishing a causal relationship between stress and hypertension with the use of Bradford-Hills criteria of causality. A search was carried out using CINAHL, MEDLINE, and Pub Med databases and their reference list of included study and other internet sources
Keywords like stress, hypertension, plausibility, dose-response relationship, temporality, coherence, analogy, and epidemiology was used as the search criteria.
The search yielded 10 studies with about 2,000 citations. 4 studies provided moderate evidence for the causation criterion and 6 studies provided strong evidence for the causal criterion. None of the studies agreed with specificity of causes as a criterion for determining that stress causes hypertensions and no study was found that suggests analogy between stress and hypertension.
There is enough significant evidence to fulfill the basic criteria of causation as proposed by Austin Bradford Hill.
Table of Contents
1. Abstract
2. Introduction
3. Methods
4. Results
5. Discussions
5.1 Strength of association
5.2 Experimental Evidence
5.3 Dose Response Relationship
5.4 Specificity in Causes
5.5 Coherence
5.6 Temporality
5.7 Theoretical Plausibility
5.8 Consistency
5.9 Analogy
6. Limitations to utilizing Hill's Criteria
7. Conclusion
Research Objectives and Key Themes
This systematic review aims to evaluate the evidence regarding the potential causal link between stress and hypertension by applying the nine criteria of causation proposed by Sir Austin Bradford Hill. The study investigates whether stressful situations function as a causative agent for the development of chronic high blood pressure.
- Application of the Bradford-Hill criteria to stress-hypertension research.
- Evaluation of the strength, consistency, and dose-response relationship of the association.
- Analysis of biological plausibility and temporal sequence in stress-related hypertension.
- Critical review of experimental animal models and epidemiological evidence.
- Limitations of using traditional causal criteria in modern clinical research.
Excerpt from the Book
Experimental Evidence
Experimental evidence is defined as the condition can be altered (prevented or ameliorated) by an appropriate experimental regimen (Last, 2001). Rothman (2002) argued that, as a criterion, experimental evidence cannot be applied to all settings. However, the one area in which the experimental evidence criterion can be applied to is in the animal model.
In relation to this study, Animal studies support the point of view that stressful situations can lead to high blood pressure which will eventually lead to hypertension. For example, mice develop high blood pressure when crowded in small cages. (Green, Kreuter, 1999). Similar trends are described in dogs and non human primates (Jenicek, 2004) and it is very familiar that the physiologic make up of these animals are very similar to man. The study of overcrowding in mice suggests that people living in dense urban environments should endeavor to visit recreational parks and centers. These study provided experimental evidence in the causal link between stress and hypertension.
Summary of Chapters
Abstract: Provides a high-level overview of the study design, which utilizes a systematic literature review to examine the association between stress and hypertension using Bradford-Hill criteria.
Introduction: Outlines the historical context of causality in medical research, introducing John Stuart Mill and Sir Austin Bradford Hill, and defines the nine specific criteria for assessing cause-effect relationships.
Methods: Describes the search strategy across databases like CINAHL, MEDLINE, and PubMed, detailing the keywords and criteria used to select and evaluate relevant literature.
Results: Presents the findings from the selected studies, noting that while most criteria for causality are met, specificity and analogy remain inconsistent across the literature.
Discussions: Provides a deep dive into each of the nine criteria, exploring how they specifically apply to the relationship between stress and high blood pressure, including evidence from both human and animal studies.
Limitations to utilizing Hill's Criteria: Critically evaluates the applicability of the Bradford-Hill framework, discussing its limitations and the need to balance statistical significance with clinical validity.
Conclusion: Summarizes the final assessment that there is significant evidence to suggest stress acts as a causative agent in the development of hypertension.
Keywords
Stress, Hypertension, Causal link, Bradford-Hill criteria, Epidemiology, Biological plausibility, Dose-response relationship, Temporality, Consistency, Strength of association, Experimental evidence, Coherence, Analogy, Public health, Chronic blood pressure
Frequently Asked Questions
What is the fundamental purpose of this research?
The study aims to determine if there is a scientifically robust causal link between stress and the development of hypertension by applying the Bradford-Hill criteria of causation.
Which criteria are used to evaluate the causal relationship?
The study uses the nine classic criteria proposed by Sir Austin Bradford Hill: consistency, dose-response relationship, specificity, temporality, strength of association, theoretical plausibility, experimental evidence, coherence, and analogy.
What is the primary conclusion regarding the link between stress and hypertension?
The authors conclude that there is sufficient significant evidence in the literature to support the classification of stress as a causative agent for hypertension.
How was the research conducted?
The research was conducted as a systematic review of existing literature, searching databases like CINAHL, MEDLINE, and PubMed for studies reporting associations between stress and blood pressure.
Does stress directly cause hypertension according to the study?
The findings suggest that while stress may not be the sole direct cause, it contributes significantly to the development of hypertension, particularly when mediated by other factors like lifestyle and physiological responses.
What are the primary thematic areas covered?
The themes include clinical epidemiology, cardiovascular health, the methodology of establishing causation, and the intersection of psychological factors with physical disease processes.
Why are animal models significant in this review?
Animal models, such as studies on overcrowding in mice, provide critical experimental evidence that links stressful environmental conditions to physiological increases in blood pressure.
Are there limitations to the Bradford-Hill criteria mentioned?
Yes, the study notes that the criteria should not be viewed as hard rules; it discusses criticisms by scholars like Rothman and Henneken regarding the vagueness of certain criteria, particularly analogy.
How does temporality play a role in this research?
Temporality is identified as the most essential criterion, requiring evidence that the stressful exposure occurs before the onset of hypertension.
- Citation du texte
- Kingsley Adimabua (Auteur), A. M. Odiegwu (Auteur), G. A. Awemu (Auteur), 2013, A Systematic Review of the Causal Link between Stress and Hypertension with the Use of Hills Criteria of Causation, Munich, GRIN Verlag, https://www.grin.com/document/207814
