Causation and Disease. A Chronological Journey

Transcription

1 Causation and Disease A Chronological Journey

2 Causation and Disease A Chronological Journey Alfred S. Evans Yale University New Haven, Connecticut Springer Science+ Business Media, LLC

3 Llbrary of Congress Cataloglng-ln-Publlcatl0n Data Evans, Alfred S., Causatlon and dlsease a chronologlcal Journey f Alfred S. Evans. p. cm. Includes blbll0graphlcal references and lndex. ISBN ISBN (ebook) DOI / seases--Causes and theorles of causatlon--hlstory. 1. Tltle. [ONLM 1. Dlsease--etlology. 2. Ep'dem,ology--h,story. E92c RB151.E ' 1--dc20 DNLM/DLC for Llbrary of Congress WA CIP ISBN Springer Science+Business Media New York Originally published by Plenum Publishing Corporation in 1993 Plenum Medical Book Company is an imprint of Plenum Publishing Corporation AII rights reserved No part of this book may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, microfilming, recording, or otherwise without written permis sion from the Publisher.

4 With love to my children, John, Barbara, and Christopher, and to their families

5 Foreword In the front material of this book both a foreword and a preface appear. What the content of a preface should be is well understood. It is the author's retrospective account of intent, of the labors to accomplish that intent, and of the content of the book that resulted. What a foreword should be is less obvious. Most properly, it is perhaps the brief testimony of one who knows the accomplishments of the author and the scope of the field and who may direct readers to the book. On some basis, the writer is assumed to have earned the right to undertake such a task. To undertake the writing of a foreword for so considerable a researcher, teacher, and scholar as Alfred Evans can be seen not only as an honor but also as a daunting one. My first thought, in truth, is that this wine needs no blush and that no foreword is needed. As John Rodman Paul Professor of Epidemiology at Yale, Alfred Evans has an established reputation in the field of causality. We have learned from his insights about the evolution of causal thinking as epidemiology passed from the era of the germ theory into that of the search for causes of chronic noncontagious diseases. It was he who drew attention to the effect of specific context in that evolution. He recognized the influence of the microbiology laboratory on that early set of criteria for causality, the Henle-Koch postulates, as against the influence of human population studies on later criteria. He applied this thinking to his quest to discover causes both of infectious diseases (for example, the role of the Epstein-Barr virus in infectious mononucleosis) and of chronic diseases (for example, the role of the same virus in lymphomas). In short, Alfred Evans is well traveled in both the history and the practice of the subject of this book. The territory is broad. The history is treated both generally, as criteria evolved, and specifically, as these criteria apply to a large array of diseases. I found much that was new to me in the accounts of the state of knowledge about the causes of many of these diseases and, equally, of the ways in which that knowledge was won. I recommend this book to students and researchers-which is to say all of us-in epidemiology, in clinical medicine, in microbiology and vii

6 viii Foreword related fields. All should find the book instructive, always interesting, and frequently illuminating. Mervyn Susser, M.D. Gertrude H. Sergievsky Professor Emeritus and Special Lecturer Columbia University New York, New York

7 Preface This monograph is a chronological account of the development of our concepts, postulates, and guidelines concerning disease causation, beginning with the postulates of Jacob Henle (1840) and of Robert Koch (1882, 1890). These Henle Koch postulates have become the "golden rules" that have guided many investigators in establishing a relationship between a disease and a new etiological agent or risk factor. Some persons believe that if the postulates are fully met, then that risk factor is the cause of that disease, and if they are not met, it is not the cause. This historical review will emphasize that the postulates were directed only at bacterial diseases, that Koch himself felt they could not be fulfilled by many common bacterial diseases, and that fulfillment of only the first two postulates might be enough to establish causation. Many other limitations to the postulates have appeared in the more than 100 years since their publication (Evans, 1977, 1980). The discovery of viruses has necessitated repeated modifications of these postulates, as have their applicability to immunological, chronic, and malignant diseases, and their use in law courts in cases of alleged occupational exposure. Changing technology and new concepts of pathogenesis, multiple causation, and the web of interacting factors have all required the introduction of new concepts of causation. Even the word "cause" has been replaced in chronic disease studies by "risk factors," and most infectious diseases require cofactors in their production. This book will review these chronological developments and show how various guidelines apply to various types of illness. This book is not a methods book that outlines the laboratory and epidemiological studies that help establish causation. A recent book of which the present writer is co-author deals with methods in observational epidemioi9gy, including both infectious and noninfectious diseases (Kelsey, Thompson, and Evans, 1986). Other recent texts on methodology that deal mainly with chronic disease, such as Hennekens and Buring (1986) and Rothman (1986), should also be consulted. Susser's excellent earlier book, Causal Thinking in the Health Sciences (1973), is recommended for a conceptual approach, and a recent book ix

8 x Preface by Rothman (1986) reviews ways of establishing causal inferences from epidemiological data. The questions of concept and theoretical methods to establish causation (if that is indeed possible) are not the subject of this book. This is a historical review, and the guidelines and postulates discussed are meant to be neither absolute nor unchanging but, rather, merely road maps to approaching practical levels of proof to guide prevention, intervention, and public policy. The reader will also find repetition in some of the chapters, such as those dealing with the clinical illness promotion factor (Chapter 11) and subclinical epidemiology (Chapter 12). This is done to make each chapter a coherent entity, so that a reader interested in a particular group of diseases or concepts can find a relatively complete discussion in a single chapter without the need to read the whole book. The material presented here is, in part, derived from material already published in various articles by the author, but many new themes have been added. Finally, the author makes no claim for originality in these concepts. They are based on the work of others. My only hope is that the reader has some plea'sure on this chronological journey and perhaps even gains a perspective on the everchanging need for new concepts of causation and of risk factors in the pathogenesis of disease. The criteria of causation presented are meant to be practical guidelines to seeking evidence that differentiates causation and association. The reader interested in the basic rationale and philosophy of causal inferences should read the books and articles written or edited by Greenland and Morgenstern (1988), Rothman (1976, 1986), and Susser (1973, 1991). The recent article by Susser is an excellent brief summary of various viewpoints and provides a useful definition of terms (Susser, 1991). References Evans AS: Limitations to Koch's postulates. Lancet 2: , Evans AS: Discussion, in Lilienfeld AM (ed): Time. Places and Persons: Aspects of the History of Epidemiology. Baltimore, Johns Hopkins University Press, 1980, pp Greenland S, Morgenstern H: Classification schemes for epidemiologic research designs. J Clin Epidemiol 41: , Henle J: On Miasmata and Contagie. Rosen G (trans). Baltimore, Johns Hopkins University Press, Hennekens CA, Buring J: Epidemiology in Medicine. Boston, Little Brown & Co, Kelsey J, Thompson WD, Evans AS: Observational Epidemiology. London, Oxford University Press, Koch R: Die Aetiologie der Tuberku10se. Berl Klin Wochenschr 15: , Koch R: Ueber bacterio10gische Forschung, in Verh X 1m Med Congr Berlin. 1890, 1892, P 35. Rothman K1: Causes. Am J Epidemioll04: , 1976.

9 Preface xi Rothman KJ Modern EpidemIOlogy Boston, LIttle Brown & Co, 1986 Susser M Causal Thinking In the Health SCiences Concepts and Strategies London, Oxford UmvefSlty Press, 1973 Susser M What IS a cause and how do we know one? A grammar of pragmatic epidemiology Am J EpldemlOl 133: , 1991

10 Contents Chapter 1. Concepts and Background of Causation.... Causality in the Natural Sciences.... Concepts of Contagion... 2 Epidemiology and Causation... 3 Causation of Epidemics in the Prebacteriology Era... 4 Scurvy Lead Colic Cholera Puerperal Sepsis... 7 The Age of Bacteriological Discovery... 8 References Chapter 2. Causation and Bacterial Diseases Jacob Henle EdwinKlebs Robert Koch New Diseases Legionnaire's Disease Lyme Disease References Chapter 3. Causation and Acute Viral Diseases The Epidemiological Concept Agents in Search of Disease New Diseases Acquired Immunodeficiency Syndrome (AIDS) References xiii

11 xiv Contents Chapter 4. Slow and Persistent Viral Infections Introduction Unconventional or True Slow Viral Infections Chronic CNS Diseases Due to Conventional Viruses Subacute Sclerosing Pan Encephalitis (SSPE) Progressive Multifocal Leukoencephalopathy (PML) New Challenges Summary References Chapter 5. Viruses and Cancer Burkitt's Lymphoma Nasopharyngeal Carcinoma Hodgkin's Disease Non-Hodgkin's Lymphoma Lymphomas and Other Malignancies in AIDS Patients Hepatitis B Virus (HBV) and Hepatocellular Carcinoma (HCC) Genital Herpes, Papillomaviruses, and Cervical Cancer Human T-cell Leukemia Virus, Type I (HTLV-I) and T-cell Leukemia Summary References Chapter 6. Causation of Epidemics and Immunological Diseases Epidemic Diseases Immunological Diseases Immunological Nature of a Disease Relation of Pathological Changes to Autoimmunization Criteria for Immune-Mediated Disease References Chapter 7. Limitations of the Henle-Koch Postulates: Effect of New Concepts and of Technology Factors Directly Limiting the Henle-Koch Postulates as Originally Stated

12 Contents xv Role of New Developments in Technology on Causation Introduction Bacteriology Virology Immunology References Chapter 8. Challenges to the Epidemiology of Infectious Diseases in the Next Decade Retroviruses Other Infectious Agents Immunization Programs Emergence of New Viruses and New Viral Infections Early Diagnosis and Detection Other Challenges in Infectious Disease Epidemiology Summary References Chapter 9. Causation and Chronic Diseases Toward a Unified Concept References Chapter 10. Causation and Occupational Diseases Introduction Epidemiological Issues Legal Issues Causation and the Law Elements of Causal Proof in the Law Guidelines for Causation in Occupational Diseases Limitations and Applications Current Examples of Toxic Tort Litigation Agent Orange Swine Flu Vaccine and the Guillain-Barre Syndrome Possible Modifications of the System Summary References

13 xvi Contents Chapter 11. The Clinical Illness Promotion Factor: A Third Ingredient Acute Infectious Diseases Viruses and Cancer Viruses and Chronic Disease Discussion References Chapter 12. Subclinical Epidemiology References Epilogue Index