BU Incidence Rate Discussion

BU Incidence Rate Discussion
Sample Answer for BU Incidence Rate Discussio

BU Incidence Rate Discussion
SELF-STUDY Course SS1000 Principles of Epidemiology in Public Health Practice Third Edition An Introduction to Applied Epidemiology and Biostatistics U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES Centers for Disease Control and Prevention (CDC) Office of Workforce and Career Development Atlanta, GA 30333 CONTENTS Acknowledgments………………………………………………………………………………………………….v Introduction………………………………………………………………………………………………………. viii Lesson One: Introduction to Epidemiology Lesson Introduction …………………………………………………………………………………………… 1-1 Lesson Objectives ……………………………………………………………………………………………… 1-1 Major Sections Definition of Epidemiology …………………………………………………………………………… 1-2 Historical Evolution of Epidemiology …………………………………………………………….. 1-7 Uses………………………………………………………………………………………………………….. 1-12 Core Epidemiologic Functions …………………………………………………………………….. 1-15 The Epidemiologic Approach ………………………………………………………………………. 1-21 Descriptive Epidemiology …………………………………………………………………………… 1-31 Analytic Epidemiology ……………………………………………………………………………….. 1-46 Concepts of Disease Occurrence ………………………………………………………………….. 1-52 Natural History and Spectrum of Disease………………………………………………………. 1-59 Chain of Infection ………………………………………………………………………………………. 1-62 Epidemic Disease Occurrence ……………………………………………………………………… 1-72 Summary …………………………………………………………………………………………………… 1-80 Exercise Answers…………………………………………………………………………………………….. 1-81 Self-Assessment Quiz ………………………………………………………………………………………. 1-85 Answers to Self-Assessment Quiz ……………………………………………………………………… 1-90 References………………………………………………………………………………………………………. 1-93 Lesson Two: Summarizing Data Lesson Introduction …………………………………………………………………………………………… 2-1 Lesson Objectives ……………………………………………………………………………………………… 2-1 Major Sections Organizing Data …………………………………………………………………………………………… 2-2 Types of Variables ……………………………………………………………………………………….. 2-3 Frequency Distributions………………………………………………………………………………… 2-6 Properties of Frequency Distributions …………………………………………………………… 2-10 Methods for Summarizing Data……………………………………………………………………. 2-14 Measures of Central Location………………………………………………………………………. 2-15 Measures of Spread…………………………………………………………………………………….. 2-35 Choosing the Right Measure of Central Location and Spread ………………………….. 2-52 Summary …………………………………………………………………………………………………… 2-58 Exercise Answers…………………………………………………………………………………………….. 2-59 Self-Assessment Quiz ………………………………………………………………………………………. 2-65 Answers to Self-Assessment Quiz ……………………………………………………………………… 2-70 References………………………………………………………………………………………………………. 2-72 Introduction Page ii Lesson Three: Measures of Risk Lesson Introduction …………………………………………………………………………………………… 3-1 Lesson Objectives ……………………………………………………………………………………………… 3-1 Major Sections Frequency Measures …………………………………………………………………………………….. 3-2 Morbidity Frequency Measures ……………………………………………………………………. 3-10 Mortality Frequency Measures …………………………………………………………………….. 3-20 Natality (Birth) Measures ……………………………………………………………………………. 3-38 Measures of Association ……………………………………………………………………………… 3-38 Measures of Public Health Impact………………………………………………………………… 3-47 Summary …………………………………………………………………………………………………… 3-50 Exercise Answers…………………………………………………………………………………………….. 3-51 Self-Assessment Quiz ………………………………………………………………………………………. 3-55 Answers to Self-Assessment Quiz ……………………………………………………………………… 3-61 References………………………………………………………………………………………………………. 3-64 Lesson Four: Displaying Public Health Data Lesson Introduction …………………………………………………………………………………………… 4-1 Lesson Objectives ……………………………………………………………………………………………… 4-1 Major Sections Introduction to Tables and Graphs………………………………………………………………….. 4-2 Tables…………………………………………………………………………………………………………. 4-3 Graphs ………………………………………………………………………………………………………. 4-22 Other Data Displays……………………………………………………………………………………. 4-42 Using Computer Technology……………………………………………………………………….. 4-63 Summary …………………………………………………………………………………………………… 4-66 Exercise Answers…………………………………………………………………………………………….. 4-72 Self-Assessment Quiz ………………………………………………………………………………………. 4-80 Answers to Self-Assessment Quiz ……………………………………………………………………… 4-85 References………………………………………………………………………………………………………. 4-88 Lesson Five: Public Health Surveillance Lesson Introduction …………………………………………………………………………………………… 5-1 Lesson Objectives ……………………………………………………………………………………………… 5-1 Major Sections Introduction…………………………………………………………………………………………………. 5-2 Purpose and Characteristics of Public Health Surveillance………………………………… 5-3 Identifying Health Problems for Surveillance ………………………………………………….. 5-4 Identifying or Collecting Data for Surveillance………………………………………………. 5-11 Analyzing and Interpreting Data…………………………………………………………………… 5-21 Disseminating Data and Interpretation ………………………………………………………….. 5-32 Evaluating and Improving Surveillance…………………………………………………………. 5-36 Summary …………………………………………………………………………………………………… 5-40 Appendix A. Characteristics of Well-Conducted Surveillance ……………………….. 5-41 Introduction Page iii Appendix B. Appendix C. Appendix D. Appendix E. CDC Fact Sheet on Chlamydia ……………………………………………….. 5-43 Examples of Surveillance ………………………………………………………. 5-46 Major Health Data Systems in the United States……………………….. 5-50 Limitations of Notifiable Disease Surveillance and Recommendations for Improvement………………………………………… 5-51 Exercise Answers…………………………………………………………………………………………….. 5-55 Self-Assessment Quiz ………………………………………………………………………………………. 5-61 Answers to Self-Assessment Quiz ……………………………………………………………………… 5-66 References………………………………………………………………………………………………………. 5-71 Lesson Six: Investigating an Outbreak Lesson Introduction …………………………………………………………………………………………… 6-1 Lesson Objectives ……………………………………………………………………………………………… 6-1 Major Sections: Introduction to Investigating an Outbreak ……………………………………………………….. 6-2 Steps of an Outbreak Investigation …………………………………………………………………. 6-8 Summary …………………………………………………………………………………………………… 6-57 Exercise Answers…………………………………………………………………………………………….. 6-59 Self-Assessment Quiz ………………………………………………………………………………………. 6-65 Answers to Self-Assessment Quiz ……………………………………………………………………… 6-72 References………………………………………………………………………………………………………. 6-76 Glossary Introduction Page iv ACKNOWLEDGMENTS Developed by U.S. Department of Health and Human Services Centers for Disease Control and Prevention (CDC) Office of Workforce and Career Development (OWCD) Career Development Division (CDD) Atlanta, Georgia 30333 Technical Content Richard Dicker, MD, MSc., Lead Author, CDC/OWCD/CDD (retired) Fátima Coronado, MD, MPH, CDC/OWCD/CDD Denise Koo, MD, MPH, CDC/OWCD/CDD Roy Gibson Parrish, II, MD (contractor) Development Team Sonya Arundar, MS, CDC (contractor) Cassie Edwards, CDC (contractor) Nancy Hunt, MPH, CDC (contractor) Ron Teske, MS, CDC (contractor) Susan Baker Toal, MPH, Public Health Consultant (contractor) Susan D. Welch, M.Ed., Georgia Poison Center Planning Committee Chris Allen, RPh, MPH, CDC Walter Daley, DVM, MPH, CDC Pat Drehobl, RN, MPH, CDC Sharon Hall, RN, PhD, CDC Dennis Jarvis, MPH, CHES, CDC Denise Koo, MD, MPH, CDC Graphics/Illustrations Sonya Arundar, MS, CDC (contractor) Lee Oakley, CDC (retired) Jim Walters, CDC (contractor) Technical Reviewers Tomas Aragon, MD, DrPH, UC Berkeley Center for Infectious Disease Preparedness Diane Bennett, MD, MPH, CDC Danae Bixler, MD, MPH, West Virginia Bureau for Public Health R. Elliot Churchill, MS, MA, CDC (retired) Roxanne Ereth, Arizona Department of Health Services Stephen Everett, MPH, Yavapai County Community Health Services, Arizona Introduction Page v Michael Fraser, PhD., National Association of County and City Health Officials Nancy Gathany, M. Ed., CDC Marjorie A.Getz, MPHIL, Bradley University, Illinois John Mosely Hayes, DrPH, MBA, MSPH, Tribal Epidemiology Center United South and Eastern Tribes, Inc., Tennessee Richard Hopkins, MD, MSPH, Florida Department of Health John M. Horan, MD, MPH, Georgia Division of Public Health Christy Bruton Kwon, MSPH, SAIC Edmond F. Maes, PhD, CDC Sharon McDonnell, MD, MPH, Darmouth Medical School William S. Paul, MD, MPH, Chicago Department of Public Health James Ransom, MPH, National Association of County and City Health Officials Lynn Steele, MS, CDC Donna Stroup, PhD., MSc., American Cancer Society Douglas A. Thoroughman, PhD, CDC Kirsten Weiser, MD, Darmouth Hitchcock Medical School Celia Woodfill, PhD, California Department of Health Services Field Test Participants Sean Altekruse, DVM, MPH, PhD, United States Department of Agriculture Gwen Barnett, MPH, CHES, CDC Jason Bell, MD, MPH Lisa Benaise, MD, CDC Amy Binggeli, DrPH, RD, CHES, CLE, Imperial County Public Health Department, California Kim M. Blindauer, DVM, MPH, ATSDR Randy Bong, RN, Federal Bureau of Prisons Johnna Burton, BS, CHES, Tennessee Department of Health Catherine C.Chow, MD, MPH, CDC Janet Cliatt, MT., CLS (NCA), National Institutes of Health Catherine Dentinger, FNP, MS, NYC Department of Health and Mental Hygiene Veronica Gordon, RN, BSN, MS, Indian Health Service, New Mexico Sue Gorman, Pharm. D., CDC Deborah Gould, PhD., CDC Juliana Grant, MD, CDC Lori Evans Hall, Pharm. D., CDC Nazmul Hassan, MS, Food and Drug Administration Daniel L. Holcomb, ATSDR Asim A. Jani, MD, MPH FACP, CDC Jean Jones, RN, CDC Charletta Lewis, BSN, Wellpinit Indian Health Service, Washington Sheila F. Mahoney, CNM., MPH, National Institutes of Health Cassandra Martin, MPH, CHES, Georgia Department of Human Resources Joan Marie McFarland, RN, PHN, Winslow Indian Health Care Center, Arizona Rosemarie McIntyre, RN, MS, CHES, CDC Introduction Page vi Gayle L. Miller, DVM, PhD(c), Jefferson County Department of Health and Environment, Missouri Long S. Nguyen, MPH, CHES, CDC (contractor) Paras M. Patel, R.Ph., Food and Drug Administration Rossanne M. Philen, MD, MS, CDC Alyson Richmond, MPH, CHES, CDC (contractor) Glenna A. Schindler, MPH, RN, CHES, Missouri Sandra Schumacher, MD, MPH, CDC Julie R.Sinclair, DVM, MPH, CDC Nita Sood, R.Ph., Pharm.D., Health Resources and Services Administration P. Lynne Stockton, VMD, MS, CDC Jill B. Surrency, MPH, CHES, CDC (contractor) Joyce K. Witt, RN, CDC Introduction Page vii INTRODUCTION This course was developed by the Centers for Disease Control and Prevention (CDC) as a self-study course. Continuing education credits are offered for certified public health educators, nurses, physicians, pharmacists, veterinarians, and public health professionals. CE credit is available only through the CDC/ATSDR Training and Continuing Education Online system at www.cdc.gov/phtnonline. To receive CE credit, you must register for the course (SS1000) and complete the evaluation and examination online. You must achieve a score of 70% or higher to pass the examination. If you do not pass the first time, you can take the exam a second time. For more information about continuing education, call 1-800-41TRAIN (1-800-4187246) or by e-mail at ce@cdc.gov. Course Design This course covers basic epidemiology principles, concepts, and procedures useful in the surveillance and investigation of health-related states or events. It is designed for federal, state, and local government health professionals and private sector health professionals who are responsible for disease surveillance or investigation. A basic understanding of the practices of public health and biostatistics is recommended. Course Materials The course materials consist of six lessons. Each lesson presents instructional text interspersed with relevant exercises that apply and test knowledge and skills gained. Lesson One: Introduction to Epidemiology Key features and applications of descriptive and analytic epidemiology Lesson Two: Summarizing Data Calculation and interpretation of mean, median, mode, ranges, variance, standard deviation, and confidence interval Lesson Three: Measures of Risk Calculation and interpretation of ratios, proportions, incidence rates, mortality rates, prevalence, and years of potential life lost Lesson Four: Displaying Public Health Data Preparation and application of tables, graphs, and charts such as arithmetic-scale line, histograms, pie chart, and box plot Lesson Five: Public Health Surveillance Processes, uses, and evaluation of public health surveillance in the United States Introduction Page viii Lesson Six: Investigating an Outbreak Steps of an outbreak investigation A Glossary that defines the major terms used in the course is also provided at the end of Lesson Six. Supplementary Materials In addition to the course materials, students may want to use the following: • A calculator with square root and logarithmic functions for some of the exercises. • A copy of Heymann, DL, ed. Control of Communicable Diseases Manual, 18th edition, 2004, for reference. Available from the American Public Health Association (202) 777-2742. Objectives Students who successfully complete this course should be able to correctly: • Describe key features and applications of descriptive and analytic epidemiology. • Calculate and interpret ratios, proportions, incidence rates, mortality rates, prevalence, and years of potential life lost. • Calculate and interpret mean, median, mode, ranges, variance, standard deviation, and confidence interval. • Prepare and apply tables, graphs, and charts such as arithmetic-scale line, scatter diagram, pie chart, and box plot. • Describe the processes, uses, and evaluation of public health surveillance. • Describe the steps of an outbreak investigation. General Instructions Self-study courses are “self-paced.” We recommend that a lesson be completed within two weeks. To get the most out of this course, establish a regular time and method of study. Research has shown that these factors greatly influence learning ability. Each lesson in the course consists of reading, exercises, and a self-assessment quiz. Reading Assignments Complete the assigned reading before attempting to answer the self-assessment questions. Read thoroughly and re-read for understanding as necessary. A casual reading may result in missing useful information which supports main themes. Assignments are designed to cover one or two major subject areas. However, as you progress, it is often necessary to combine previous learning to accomplish new skills. A review of previous lessons may be necessary. Frequent visits to the Glossary may also be useful. Exercises Exercises are included within each lesson to help you apply the lesson content. Some exercises may be more applicable to your workplace and background than others. You should review the answers to all exercises since the answers are very detailed. Answers to Introduction Page ix the exercises can be found at the end of each lesson. Your answers to these exercises are valuable study guides for the final examination. Self-Assessment Quizzes After completing the reading assignment, answer the self-assessment quizzes before continuing to the next lesson. Answers to the quizzes can be found at the end of the lesson. After passing all six lesson quizzes, you should be prepared for the final examination. • Self-assessment quizzes are open book • Unless otherwise noted, choose ALL CORRECT answers. • Do not guess at the answer • You should score at least 70% correct before continuing to the next lesson. Tips for Answering Questions • • Carefully read the question. Note that it may ask, “Which is CORRECT?” as well as “Which is NOT CORRECT?” or “Which is the EXCEPTION?” Read all the choices given. One choice may be a correct statement, but another choice may be more nearly correct or complete for the question that is asked. Final Examination and Course Evaluation The final examination and course evaluation are available only on-line. The final requirement for the course is an open-book examination. We recommend that you thoroughly review the questions included with each lesson before completing the exam. It is our sincere hope that you will find this undertaking to be a profitable and satisfying experience. We solicit your constructive criticism at all times and ask that you let us know whenever you have problems or need assistance. Introduction Page x Continuing Education Credit To receive continuing education credit for completing the self-study course, go to the CDC/ATSDR Training and Continuing Education Online at http://www.cdc.gov/phtnonline and register as a participant. (For individuals interested in obtaining RACE credit please contact the CDC Continuing Education office for details, 1-800-41TRAIN or ce@cdc.gov.) You will need to register for the course (SS1000) and complete the course evaluation and exam online. You will have to answer at least 70% of the exam questions correctly to receive credit and to be awarded CDC’s certificate of successful completion. For more information about continuing education credits, please call 1-800-41TRAIN (1-800-418-7246). Continuing Education Accreditation Statements The Centers for Disease Control and Prevention is accredited by the Accreditation Council for Continuing Medical Education (ACCME) to provide continuing medical education for physicians. The Centers for Disease Control and Prevention designates this educational activity for a maximum of 17 category 1 credits toward the AMA Physician’s Recognition Award. Each physician should claim only those credits that he/she actually spent in the activity. • • • This activity for 17 contact hours is provided by the Centers for Disease Control and Prevention, which is accredited as a provider of continuing education in nursing by the American Nurses Credentialing Center’s Commission on Accreditations. • • • The Centers for Disease Control and Prevention is a designated provider of continuing education contact hours (CECH) in health education by the National Commission for Health Education Credentialing, Inc. This program is a designated event for the CHES to receive 17 Category I contact hours in health education, CDC provider number GA0082. • • • CDC is accredited by the Accreditation Council for Pharmacy Education as a provider of continuing pharmacy education. This program is a designated event for pharmacists to receive 17 Contact Hours (1.7 CEUs) in pharmacy education. The Universal Program Number is 387-000-06-035-H04. Introduction Page xi The Centers for Disease Control and Prevention has been approved as an Authorized Provider of continuing education and training programs by the International Association for Continuing Education and Training and awards 1.7 Continuing Education Units (CEUs). • • • This program was reviewed and approved by the AAVSB RACE program for continuing education. Please contact the AAVSB RACE program at race@aavsb.org should you have any comments/concerns regarding this program’s validity or relevancy to the veterinary profession. Course Evaluation Even if you are not interested in continuing education credits, we still encourage you to complete the course evaluation. To do this, go to http://www.cdc.gov/phtonline and register as a participant. You will then need to register for the course (SS1000) and complete the course evaluation online. Your comments are valuable to us and will help to revise the self-study course in the future. Ordering Information A hard-copy of the text can be obtained from the Public Health Foundation. Specify Item No. SS-1000 when ordering. • Online at: http://bookstore.phf.org • By phone: toll free within the US: 877-252-1200 international: 301-645-7773. • By fax at 301-843-0159 or 202-218-4409 to the attention of Publication Sales. • By mail: PHF Publication Sales PO Box 753 Waldorf, MD 20604 Introduction Page xii 1 INTRODUCTION TO EPIDEMIOLOGY Recently, a news story described an inner-city neighborhood’s concern about the rise in the number of children with asthma. Another story reported the revised recommendations for who should receive influenza vaccine this year. A third story discussed the extensive disease-monitoring strategies being implemented in a city recently affected by a massive hurricane. A fourth story described a finding published in a leading medical journal of an association in workers exposed to a particular chemical and an increased risk of cancer. Each of these news stories included interviews with public health officials or researchers who called themselves epidemiologists. Well, who are these epidemiologists, and what do they do? What is epidemiology? This lesson is intended to answer those questions by describing what epidemiology is, how it has evolved and how it is used today, and what some of the key methods and concepts are. The focus is on epidemiology in public health practice, that is, the kind of epidemiology that is done at health departments. Objectives After studying this lesson and answering the questions in the exercises, you will be able to: • Define epidemiology • Summarize the historical evolution of epidemiology • Name some of the key uses of epidemiology • Identify the core epidemiology functions • Describe primary applications of epidemiology in public health practice • Specify the elements of a case definition and state the effect of changing the value of any of the elements • List the key features and uses of descriptive epidemiology • List the key features and uses of analytic epidemiology • List the three components of the epidemiologic triad • Describe the different modes of transmission of communicable disease in a population Major Sections Definition of Epidemiology …………………………………………………………………………………………… 1-2 Historical Evolution of Epidemiology …………………………………………………………………………….. 1-7 Uses………………………………………………………………………………………………………………………….. 1-12 Core Epidemiologic Functions …………………………………………………………………………………….. 1-15 The Epidemiologic Approach ………………………………………………………………………………………. 1-21 Descriptive Epidemiology …………………………………………………………………………………………… 1-31 Analytic Epidemiology ……………………………………………………………………………………………….. 1-46 Concepts of Disease Occurrence ………………………………………………………………………………….. 1-52 Natural History and Spectrum of Disease………………………………………………………………………. 1-59 Chain of Infection ………………………………………………………………………………………………………. 1-62 Epidemic Disease Occurrence ……………………………………………………………………………………… 1-72 Summary …………………………………………………………………………………………………………………… 1-80
A Sample Answer For the Assignment: BU Incidence Rate Discussion
Title: BU Incidence Rate Discussion
Introduction to Epidemiology Page 1-1 Definition of Epidemiology Students of journalism are taught that a good news story, whether it be about a bank robbery, dramatic rescue, or presidential candidate’s speech, must include the 5 W’s: what, who, where, when and why (sometimes cited as why/how). The 5 W’s are the essential components of a news story because if any of the five are missing, the story is incomplete. The same is true in characterizing epidemiologic events, whether it be an outbreak of norovirus among cruise ship passengers or the use of mammograms to detect early breast cancer. The difference is that epidemiologists tend to use synonyms for the 5 W’s: diagnosis or health event (what), person (who), place (where), time (when), and causes, risk factors, and modes of transmission (why/how). The word epidemiology comes from the Greek words epi, meaning on or upon, demos, meaning people, and logos, meaning the study of. In other words, the word epidemiology has its roots in the study of what befalls a population. Many definitions have been proposed, but the following definition captures the underlying principles and public health spirit of epidemiology: Epidemiology is the study of the distribution and determinants of health-related states or events in specified populations, and the application of this study to the control of health problems.1 Key terms in this definition reflect some of the important principles of epidemiology. Study Epidemiology is a scientific discipline with sound methods of scientific inquiry at its foundation. Epidemiology is data-driven and relies on a systematic and unbiased approach to the collection, analysis, and interpretation of data. Basic epidemiologic methods tend to rely on careful observation and use of valid comparison groups to assess whether what was observed, such as the number of cases of disease in a particular area during a particular time period or the frequency of an exposure among persons with disease, differs from what might be expected. However, epidemiology also draws on methods from other scientific fields, including biostatistics and informatics, with biologic, economic, social, and behavioral sciences. In fact, epidemiology is often described as the basic science of public health, and for good reason. First, epidemiology is a quantitative discipline that relies on a working knowledge of probability, statistics, and sound research methods. Second, epidemiology is a method of causal reasoning based on developing and testing hypotheses grounded in such scientific fields as biology, behavioral sciences, physics, and ergonomics to explain health-related behaviors, states, and events. However, epidemiology is not just a research activity but an integral component of public health, providing the foundation for directing practical and appropriate public health action based on this science and causal reasoning.2 Introduction to Epidemiology Page 1-2 Distribution Epidemiology is concerned with the frequency and pattern of health events in a population: Frequency refers not only to the number of health events such as the number of cases of meningitis or diabetes in a population, but also to the relationship of that number to the size of the population. The resulting rate allows epidemiologists to compare disease occurrence across different populations. Pattern refers to the occurrence of health-related events by time, place, and person. Time patterns may be annual, seasonal, weekly, daily, hourly, weekday versus weekend, or any other breakdown of time that may influence disease or injury occurrence. Place patterns include geographic variation, urban/rural differences, and location of work sites or schools. Personal characteristics include demographic factors which may be related to risk of illness, injury, or disability such as age, sex, marital status, and socioeconomic status, as well as behaviors and environmental exposures. Characterizing health events by time, place, and person are activities of descriptive epidemiology, discussed in more detail later in this lesson. Determinant: an