Models of disease causation in epidemiology pdf

The first is the monocausal view and emerges from the conquest of the infectious diseases. However, since most epidemiological studies are by nature observational rather than experimental, a number of possible explanations for an observed association need to be considered before we can infer a causeeffect relationship exists. Pdf causation and models of disease in epidemiology alex. We begin from rothmans pie model of necessary and sufficient causes, and then discuss newer approaches, which provide additional insights into multifactorial causal processes. Causation and models of disease in epidemiology alex broadbent department of history and philosophy of science, university of cambridge this is a. A backgrounder for journalists written for the american council on science and health by kathleen meister, m. Full text full text is available as a scanned copy of the original print version.

Causation is an essential concept in epidemiology, yet there is no single, clearly articulated definition for the discipline. Pdf causation and models of disease in epidemiology. Theories of disease causation development of understanding in pathogenesis dr. An introduction to traditional and modern epidemiology, second edition, by. Models of causation in epidemiology the relationship. The paper criticises the monocausal model of disease, so successful in the nineteenth century. States that disease results from the complex interaction of many risk factors so disease can be prevented by modifying these risk factors. Learn vocabulary, terms, and more with flashcards, games, and other study tools.

Centre for animal disease research and diagnosis indian veterinary research institute, izatnagar243122. What are the four theories of disease causation answers. Epidemiology has been defined as the study of disease occurrence in human populations. Mathematical models can project how infectious diseases progress to show the likely outcome of an epidemic and help inform public health interventions. First, how should it handle certain diseases, which appear to be etiologically more complex than the infections and deficiencies by which epidemiology made its name. The epidemiological triad world health organization. Consider an infant whose fi rst experiences are a jumble of sensations that include hunger, thirst, color, light, heat, cold, and many other stimuli. Identifying and understanding causes of disease is arguably the central aim of the discipline of epidemiology. This paper is an effort to resolve the resulting tension. The focus of attention in this paper will be on chronic disease epidemiology. Causation in epidemiology american journal of ophthalmology. Models use basic assumptions or collected statistics along with mathematics to find parameters for various infectious diseases and use those parameters to calculate the effects of different interventions, like mass vaccination programmes. Bhoj r singh, principal scientist vm ic epidemiology.

An epidemiological model is usually defined as a mathematical andor logical representation of the epidemiology of disease transmission and its associated processes. Among the simplest of these is the epidemiologic triad or triangle, the traditional model for. Models of causation health determinants april, 2012 core body of knowledge for the generalist ohs professional models of causation. It is in this area that the concept of causation has proved most elusive and has provoked the most confusion and debate. Mathematical modelling of infectious disease wikipedia. Theories of disease causationppt linkedin slideshare. Now lets turn to the topic of association in epidemiology. Introductiondisease is a dynamic process and it is just opposite tothe health. Theories of causation 81 cognitive behavioral therapy sociological theories anomie theory strain theory delinquency and drift techniques of neutralization illegitimate opportunity structure ecologicalsocial disorganization approach concentriczone theory theory of differential association theory of differential anticipation labeling theory. In epidemiology, on the other hand, we are dealing with the occurrence of a disease d in the population. Some social groups have higher mortality and morbidity rates from all causes and this probably results from the complex interaction of the environment, behaviors and. Two conceptual questions currently face epidemiology, both relating to causation.

Complex systems dynamic models may provide one approach for epidemiologists to account for the complexity of disease causation in populations. New models of causation, such as the black box 161, the web of causation 162, the chinese box 163, and contrastive 159 approaches perhaps need further exploration by those studying the. Building on holistic models of health developed between world. Head of epidemiology division, indian veterinary research.

Causation and models of disease in epidemiology sciencedirect. Aug 23, 2017 5 in epidemiology, there are several models of disease causation that help understand disease process. The focus will also be on the ontological nature of causation rather than on causal inference, a more epistemological con. The wheel of causation, an alternative model, according to harkness and demarco 2012, deemphasizes the agent as the sole cause of disease, whereas it emphasizes the interplay of physical, biological, and social environments p. It has been predicted that these diseases will increase rapidly in india and this country will be host to more than half the cases of heart disease in the world within the next 15 years. And the sufficient cause and component causes models rothmans component causes model general models of causation 6. Causal inference was the first step in a variety of notable epidemiologic accomplishments, such as decreasing coronary heart disease, mainly by decreasing smoking, high blood pressure, and cholesterol levels in the population. In addition, the criteria also had some limitations even with respect to infectious disease. In developed countries chronic diseases such as cancer and heart disease have received. The standard model of infectious disease causation under the epidemiological triad theory states that an external agent can cause diseases on a susceptible host when there is a conducive environment within the epidemiological triad the agent is known as a necessary factor.

Strengths and weaknesses of these categories are examined in terms of proposed characteristics. Causation of diseases national health portal of india. Coronary heart disease and stroke have increased in both urban and rural areas. Links between medical science and social science and health inequalities are critical in our understanding of the whole system health. However, while the discipline has matured over the past sixty years, developing a battery of quantitative tools and methods for data analysis, the discipline of epidemiology lacks an explicit, shared theoretical account of causation. Many definitions have been proposed, but the following definition captures the underlying principles and the.

A number of models of disease causation have been proposed. Perhaps the most important of these principles is selfevident from the model. A given disease can be caused by more than one causal mechanism, and every causal mechanism involves the joint action of a multitude of component causes. This article discusses current models for causation, as applied to experimental and observational data. According to its creators disease never depends upon single isolated cause rather it develops from a chain of causation in which each link itself is a result of complex interaction of preceding events these chain of causation which may be the fraction of the whole complex is known as web of causation. Basic epidemiology always deals with the cause of the disease, the targeted population, potential health hazards and a directed approach to study the relationship between the exposure and the effect. Cardiovascular diseases are major causes of mortality and disease in the indian subcontinent, causing more than 25% of deaths. Th e acquired wisdom that certain conditions or events bring about other conditions or events is an important survival trait.

Many definitions have been proposed, but the following definition captures the underlying principles and the public health spirit of epidemiology. Request pdf causation and models of disease in epidemiology nineteenth century medical advances were entwined with a conceptual. Causal thinking and complex system approaches in epidemiology. On the other hand, correlation is simply a relationship. There are several challenges facing the discipline in incorporating these methods into noninfectious disease epidemiology. However, a clear definition of the term does not seem to exist in the veterinary field. Kochs postulates established standard criteria for drawing conclusions about the cause of infectious disease, but the criteria obviously dont apply to noninfectious diseases. At this time the pathogen is present in host but can not transmit disease to other susceptible. To shed light on the accident phenomenon, over the years authors have developed a plethora of conceptual models. And, if youre feeling erudite, you can followup with, epidemiology comes from the greek epi. A set of minimal conditions and events that inevitably produce disease. Page 2 principles of epidemiology introduction the word epidemiology comes from the greek words epi, meaning on or upon, demos, meaning people, and logos, meaning the study of. Chapter 5 causation in epidemiology key messages the concept of cause sufficient or necessary sufficient and necessary a causal pathway single and multiple causes factors in causation interaction a hierarchy of causes establishing the cause of a disease considering causation temporal relationship plausibility consistency strength dose. A principal aim of epidemiology is to assess the cause of disease.

The presentation explains basic models of disease causation. It should be understood that these models of disease. Causation and causal inference in epidemiology ajph vol. The second era in the history of causation in medicine arises out of the study of chronic diseases like cancer or cardiovascular disease. Disease is a change from the state of good health resulting from a microbial population living in the tissues. Among the simplest of these is the epidemiologic triad or triangle, the traditional model for infectious disease. The definition of epidemiological models is very important for this technical item. In particular, chronic noncommunicable diseases cncds account for a larger proportion of deaths, at least in the industrialised. The focus of modern epidemiology, however, is on chronic noncommunicable diseases, which frequently do not seem to be attributable to any single causal factor. Epidemiology and causation of coronary heart disease and. Bradford hills ideas about causal inference were formulated in the heady early years of the rise of noncommunicable disease epidemiology, which was essentially a postsecond world war phenomenon. While causation and correlation can exist at the same time, correlation does not imply causation. A cause of a disease is an event, condition, or characteristics that plays an essential role in producing an occurrence of the disease.

If you continue browsing the site, you agree to the use of cookies on this website. Epidemiology is the study and analysis of the distribution who, when, and where, patterns and determinants of health and disease conditions in defined populations it is a cornerstone of public health, and shapes policy decisions and evidencebased practice by identifying risk factors for disease and targets for preventive healthcare. The paper criticises the monocausal model of disease, so successful in the. Transmission of disease starts with a low number of pathogen bacterial cells etc. The sufficientcomponent cause model in 1976 ken rothman, who is a member of the epidemiology faculty at busph, proposed a conceptual model of causation known as the sufficient component cause model in an attempt to provide a practical view of causation which also had a sound theoretical basis. The triad consists of an external agent, a susceptible host, and an environment that brings the host and agent together.

Even though vaccines are available for many infectious diseases, these diseases still cause suffering and mortality in the world, especially in developing countries. Rothman points out that the cause of any effect must consist of a constellation of components that act in concert. Health determinants abstract health is a state with both negative and positive dimensions. Models of disease and injury facilitate our understanding of their etiology or causes.

Many of the currently debated definitions and models have their roots in the purely deterministic model of disease causation described by henle and koch in the. Among the simplest of these is the epidemiologic triad or. Safety april, 2012 core body of knowledge for the generalist ohs professional models of causation. As noted earlier, one important use of epidemiology is to identify the factors that place some members at greater risk than others. Definition of causality causality can be defined as cause effect relationship in epidemiology cause is the exposure and effect is disease or death causal relation is a complex phenomenon the concept of cause itself continues to be debated as a philosophical matter in the scientific literature. Epidemiologists help with study design, collection, and. Finally environment includes climate, human population distribution, socioeconomic factors, and working conditions. Get a printable copy pdf file of the complete article 709k, or click on a page image below to browse page by page. The epidemiological triad triangle, the wheel, and the web. Causation and models of disease in epidemiology request pdf. This model comprises a susceptible host the person at risk for the.

Peeyush chandra some mathematical models in epidemiology. Nineteenth century medical advances were entwined with a conceptual innovation. The purpose of epidemiological studies is often not merely to describe, but also to explain, the occurrence of d. According to hippocrates the theories of disease causation are the 4 humors, blood, phlegm, yellow and black bile. For example, not all infectious diseases have good animal models. The epidemiological triad the best known, but most dated model of communicable disease is the epidemiologic triad figure 1. Web of causation and its implications for epidemiological. In this specific page you will find information on infectious and noncommunicable diseases and their relationship with causation theories. Health denotes perfect harmony and normalfunctioning of all the body system or state of completewellness whereas disease denotes disharmony anddeviation from normal functioning of. Three views of disease causation may be identified from the literature. Causation and models of disease in epidemiology article in studies in history and philosophy of science part c studies in history and philosophy of biological and biomedical sciences 404. Causation explicitly applies to cases where action a causation explicitly applies to cases where action a causes outcome b.

Epidemiology is the study of health and disease in populations. An epidemiologic study never predicts the exact cause of a disease in each and every individual. Jacob m najman, theories of disease causation and the concept of a general susceptibility. The model of causation implied by figure 1 illuminates several important principles regarding causes. Nov 26, 2012 theories of disease causation presented by. This includes all diseaserelated phenomena from before initiation of the disease the stage of susceptibility until resolution of the disease the stage of recovery, disability, or death. Nursing 1st year slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. Theories for social epidemiology in the 21st century. The intentiontotreat principle and the effect of treatment on the treated will also be discussed. We therefore explore different models of causality in the epidemiology of disease arising out of genes, environments, and the interplay between environments and genes.