Epidemiology for public health practice 5th edition ebook

pidemiology for Public Health Practice Robert H. Friis, PhD Professor, Emeritus, and Chair Emeritus Health Science Department California State University Long Beach, California

Thomas A. Sellers, PhD, MPH Director Moffitt Cancer Center & Research Institute Tampa, Florida

FIFTH EDITION

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Library of Congress Cataloging-in-Publication Data Friis, Robert H. Epidemiology for public health practice / Robert H. Friis and Thomas Sellers.—5th ed. p. ; cm. Includes bibliographical references and index. ISBN 978-1-4496-5158-9 (pbk.) I. Sellers, Thomas A. II. Title. [DNLM: 1. Epidemiology. 2. Epidemiologic Methods. 3. Public Health. WA 105] 614.4—dc23

2012039130

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New to This Edition ................................................... ix

Introduction ............................................................... xiii

Preface ........................................................................ xvii

Acknowledgments ...................................................... xix

About the Authors ............................................................ xxiii

Chapter 1 History and Scope of Epidemiology ........................... 1 Introduction ................................................................... 2 Epidemiology Defined .................................................... 8 Foundations of Epidemiology ......................................... 15 Historical Antecedents of Epidemiology ......................... 23 Recent Applications of Epidemiology ............................. 41 Conclusion ..................................................................... 48 Study Questions and Exercises ........................................ 49 References ....................................................................... 51

Chapter 2 Practical Applications of Epidemiology ..................... 55 Introduction ................................................................... 56 Applications for the Assessment of the Health Status of Populations and Delivery of Health Services .............. 59 Applications Relevant to Disease Etiology ....................... 83 Conclusion ..................................................................... 101 Study Questions and Exercises ........................................ 101 References ....................................................................... 104

Contents

iii

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Chapter 3 Measures of Morbidity and Mortality Used in Epidemiology ......................................................... 107

Introduction ................................................................... 108 Definitions of Count, Ratio, Proportion, and Rate ......... 108 Risk Versus Rate; Cumulative Incidence ......................... 121 Interrelationship Between Prevalence and Incidence ....... 124 Applications of Incidence Data ....................................... 126 Crude Rates .................................................................... 126 Specific Rates and Proportional Mortality Ratio ............. 138 Adjusted Rates ................................................................ 144 Conclusion ..................................................................... 151 Study Questions and Exercises ........................................ 152 References ....................................................................... 155

Chapter 4 Descriptive Epidemiology: Person, Place, Time ......... 157 Introduction ................................................................... 158 Characteristics of Persons ................................................ 163 Characteristics of Place ................................................... 203 Characteristics of Time ................................................... 217 Conclusion ..................................................................... 223 Study Questions and Exercises ........................................ 223 References ....................................................................... 225 Appendix 4—Project: Descriptive Epidemiology of a Selected Health Problem ......................................... 233

Chapter 5 Sources of Data for Use in Epidemiology ................... 235 Introduction ................................................................... 236 Criteria for the Quality and Utility of Epidemiologic Data ................................................... 239 Online Sources of Epidemiologic Data ........................... 241 Confidentiality, Sharing of Data, and Record Linkage .... 244 Statistics Derived from the Vital Registration System ..... 247 Reportable Disease Statistics ........................................... 254 Screening Surveys ........................................................... 259 Disease Registries ............................................................ 260 Morbidity Surveys of the General Population ................. 262 Insurance Data................................................................ 267 Clinical Data Sources ...................................................... 267 Absenteeism Data ........................................................... 271 School Health Programs ................................................. 272

iv C o n t e n t s

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Morbidity in the Armed Forces: Data on Active Personnel and Veterans .............................................. 272 Other Sources: Census Data ........................................... 273 Conclusion ..................................................................... 274 Study Questions and Exercises ........................................ 274 References ....................................................................... 276

Chapter 6 Study Designs: Ecologic, Cross-Sectional, Case-Control .......................................................... 279

Introduction ................................................................... 280 Observational Versus Experimental Approaches in Epidemiology ............................................................. 281 Overview of Study Designs Used in Epidemiology ......... 282 Ecologic Studies .............................................................. 287 Cross-Sectional Studies ................................................... 294 Case-Control Studies ...................................................... 303 Conclusion ..................................................................... 317 Study Questions and Exercises ........................................ 317 References ....................................................................... 319

Chapter 7 Study Designs: Cohort Studies ................................... 323 Introduction ................................................................... 324 Cohort Studies Defined .................................................. 325 Sampling and Cohort Formation Options ...................... 335 Temporal Differences in Cohort Designs ........................ 341 Practical Considerations .................................................. 344 Measures of Effect: Their Interpretation and Examples ... 347 Summary of Cohort Studies ............................................ 358 Conclusion ..................................................................... 359 Study Questions and Exercises ........................................ 362 References ....................................................................... 363

Chapter 8 Experimental Study Designs ...................................... 367 Introduction ................................................................... 368 Hierarchy of Study Designs ............................................ 371 Intervention Studies ........................................................ 373 Clinical Trials ................................................................. 374 Community Trials .......................................................... 392 Conclusion ..................................................................... 404 Study Questions and Exercises ........................................ 405 References ....................................................................... 406

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Chapter 9 Measures of Effect ...................................................... 409 Introduction ................................................................... 410 Absolute Effects .............................................................. 410 Relative Effects ............................................................... 414 Statistical Measures of Effect ........................................... 420 Evaluating Epidemiologic Associations ........................... 423 Models of Causal Relationships ...................................... 425 Conclusion ..................................................................... 430 Study Questions and Exercises ........................................ 431 References ....................................................................... 432 Appendix 9—Cohort Study Data for Coffee Use and Anxiety ................................................................ 433

Chapter 10 Data Interpretation Issues .......................................... 435 Introduction ................................................................... 436 Validity of Study Designs ............................................... 437 Sources of Error in Epidemiologic Research .................... 440 Techniques to Reduce Bias ............................................. 449 Methods to Control Confounding .................................. 450 Bias in Analysis and Publication ...................................... 454 Conclusion ..................................................................... 456 Study Questions and Exercises ........................................ 456 References ....................................................................... 458

Chapter 11 Screening for Disease in the Community ................... 461 Introduction ................................................................... 462 Screening for Disease ...................................................... 464 Appropriate Situations for Screening Tests and Programs .................................................................... 468 Characteristics of a Good Screening Test ........................ 471 Evaluation of Screening Tests ......................................... 471 Sources of Unreliability and Invalidity ............................ 476 Measures of the Validity of Screening Tests .................... 476 Effects of Prevalence of Disease on Screening Test Results........................................................................ 479 Relationship Between Sensitivity and Specificity ............. 482 Evaluation of Screening Programs ................................... 483 Issues in the Classification of Morbidity and Mortality ... 485 Conclusion ..................................................................... 486 Study Questions and Exercises ........................................ 487 References ....................................................................... 488 Appendix 11—Data for Problem 6 ................................. 490

vi C o n t e n t s

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Chapter 12 Epidemiology of Infectious Diseases .......................... 491 Introduction ................................................................... 492 Agents of Infectious Disease ............................................ 493 Characteristics of Infectious Disease Agents .................... 496 Host ............................................................................... 497 The Environment ........................................................... 499 Means of Transmission: Directly or Indirectly from Reservoir .................................................................... 500 Measures of Disease Outbreaks ....................................... 506 Procedures Used in the Investigation of Infectious Disease Outbreaks ...................................................... 511 Epidemiologically Significant Infectious Diseases in the Community ............................................................... 513 Conclusion ..................................................................... 539 Study Questions and Exercises ........................................ 539 References ....................................................................... 542 Appendix 12—Data from a Foodborne Illness Outbreak in a College Cafeteria ................................. 545

Chapter 13 Epidemiologic Aspects of Work in the Environment .......................................................... 547

Introduction ................................................................... 548 Health Effects Associated with Environmental Hazards .. 550 Study Designs Used in Environmental Epidemiology ..... 550 Toxicologic Concepts Related to Environmental Epidemiology ............................................................. 555 Types of Agents .............................................................. 557 Environmental Hazards Found in the Work Setting ....... 571 Noteworthy Community Environmental Health Hazards ...................................................................... 575 Conclusion ..................................................................... 588 Study Questions and Exercises ........................................ 591 References ....................................................................... 592

Chapter 14 Molecular and Genetic Epidemiology ........................ 599 Introduction ................................................................... 600 Definitions and Distinctions: Molecular Versus Genetic Epidemiology ............................................................. 605 Epidemiologic Evidence for Genetic Factors ................... 609 Causes of Familial Aggregation ....................................... 610 Shared Family Environment and Familial Aggregation ... 612 Gene Mapping: Segregation and Linkage Analysis .......... 616

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Genome-Wide Association Studies (GWAS) .................. 626 Linkage Disequilibrium Revisited: Haplotypes ............... 628 Application of Genes in Epidemiologic Designs .............. 631 Genetics and Public Health ............................................ 638 Conclusion ..................................................................... 642 Study Questions and Exercises ........................................ 642 References ....................................................................... 643

Chapter 15 Social, Behavioral, and Psychosocial Epidemiology ... 649 Introduction ................................................................... 650 Research Designs Used in Psychosocial, Behavioral, and Social Epidemiology ................................................... 655 The Social Context of Health ......................................... 657 Independent Variables .................................................... 660 Moderating Variables ...................................................... 669 Dependent (Outcome) Variables: Physical and Mental Health ........................................................................ 684 Conclusion ..................................................................... 691 Study Questions and Exercises ........................................ 692 References ....................................................................... 694

Chapter 16 Epidemiology as a Profession ..................................... 701 Introduction ................................................................... 702 Specializations within Epidemiology ............................... 703 Career Roles for Epidemiologists .................................... 705 Epidemiology Associations and Journals ......................... 708 Competencies Required of Epidemiologists .................... 711 Resources for Education and Employment ..................... 712 Professional Ethics in Epidemiology ............................... 714 Conclusion ..................................................................... 719 Study Questions and Exercises ........................................ 720 References ....................................................................... 72