Developed through the APTR Initiative to Enhance Prevention and Population Health Education in collaboration with the Brody School of Medicine at East Carolina University with funding from the Centers for Disease Control and Prevention Measuring Health and Disease

APTR wishes to acknowledge the following individuals that developed this module:  Kristina Simeonsson, MD, MSPH Department of Public Health Brody School of Medicine at East Carolina University  Jeffrey Bethel, PhD Department of Public Health Brody School of Medicine at East Carolina University This education module is made possible through the Centers for Disease Control and Prevention (CDC) and the Association for Prevention Teaching and Research (APTR) Cooperative Agreement, No. 5U50CD The module represents the opinions of the author(s) and does not necessarily represent the views of the Centers for Disease Control and Prevention or the Association for Prevention Teaching and Research.

 Define epidemiology and recognize some of its uses  Interpret distribution of disease according to person, place, and time  Calculate measures of disease occurrence and severity

 Study of health and disease among populations  Basic science of public health  What causes disease?  How does disease spread?  What prevents disease?  How to control disease?

 Identify etiology and risk factors  Determine the extent of disease in a population  Study natural history and prognosis  Evaluate existing and new preventive and therapeutic measures/modes of healthcare delivery  Provide foundation for developing public policy and regulatory decisions

 The study of the distribution and determinants of diseases or other health-related outcomes in populations and the application of this study to control health problems

 Analysis of disease patterns  Person  Place  Time

Source: National Notifiable Diseases Surveillance System, 2006.

Source: National Notifiable Diseases Surveillance System, Incidence of acute hepatitis B, by county—United States, 2007

 Counts  Proportions  Prevalence  Rates  Incidence  Attack rate  Mortality rate  Case fatality rate  Infant mortality rate

 Measure of disease frequency  Number of cases or other health outcome being studied

CDC, MMWR Summary of Notifiable Diseases, US 2008

 Answers the question: How common is it?  Burden of disease in a population  A slice through the population at a point in time at which it is determined who has the disease and who does not  Often stated as a percentage (i.e. per 100)

# of cases of a disease present in the population at a specified time # of persons in the population at that specified time

 Don’t know when disease developed or the duration  Numerator is a mix of people with different durations of disease  Do not have a measure of risk  Prevalence is appropriate measure of the burden of a relatively stable chronic condition  Diabetes  Hypertension  Useful for allocating health resources

No Data <10% 10%–14% 15%–19% 20%–24% 25%–29% ≥30% CDC, BRFSS, 1990, 1999, 2009

CDC’s Division of Diabetes Translation. National Diabetes Surveillance System

 Measures change from non-disease to disease  Can provide a measure of risk  Also known as incidence rate  Often stated per 100,000 population per year

# of new cases of a disease during a specified period of time Total number of people at risk during that period of time

Department of Health and Human Services, Centers for Disease Control and Prevention, and National Cancer Institute, 2010

 Monitor changes over time  Comparisons between groups  Age-specific rates  Sex-specific rates  Goal setting  Healthy People 2020 Objectives

 Similar to incidence (rate)  Used when nature of the disease is such that population is observed for a short time period, often as a result of specific exposure  Foodborne outbreaks  Compares the risk of disease in groups with different exposures

# of people who ate potato salad who developed gastroenteritis Total # of people who ate potato salad

 Prevalence = incidence x duration of disease  An increased prevalence may reflect  Increased risk of disease in the population ▪ Increased incidence  Increased duration of illness ▪ Fewer deaths from the disease (increased survival) ▪ Fewer responses to treatment

 An increased prevalence may reflect  Increased risk of disease in the population ▪ Increased incidence  An increased prevalence may also reflect  Increased duration of illness ▪ Fewer deaths from the disease (increased survival) ▪ Fewer responses to treatment

 Mortality Rate  Case Fatality Rate  Infant Mortality Rate

# of all deaths in one year # persons in the population at midyear

# of persons dying during a specified period after disease onset or diagnosis Total # of people with the specified disease

309 deaths from H5N1 522 cases of H5N1 CFR 59% WHO website, accessed 2/25/2011

Mausner & Kramer, 1985

National Cancer Institute; A Snapshot of Pancreatic Cancer

# of deaths under one year of age during a specified time interval # of live births reported during the same time period Expressed per 1,000

 Epidemiology is the basic science of public health  Count, describe, divide, compare  Must use rates to compare groups and assess risk  Primary measures of disease occurrence  Incidence  Prevalence  Primary measure of disease severity  Case fatality rate

 Center for Public Health Continuing Education University at Albany School of Public Health  Department of Community & Family Medicine Duke University School of Medicine

Mike Barry, CAE Lorrie Basnight, MD Nancy Bennett, MD, MS Ruth Gaare Bernheim, JD, MPH Amber Berrian, MPH James Cawley, MPH, PA-C Jack Dillenberg, DDS, MPH Kristine Gebbie, RN, DrPH Asim Jani, MD, MPH, FACP Denise Koo, MD, MPH Suzanne Lazorick, MD, MPH Rika Maeshiro, MD, MPH Dan Mareck, MD Steve McCurdy, MD, MPH Susan M. Meyer, PhD Sallie Rixey, MD, MEd Nawraz Shawir, MBBS

 Sharon Hull, MD, MPH President  Allison L. Lewis Executive Director  O. Kent Nordvig, MEd Project Representative