Centers for Disease Control and Prevention Global Health Odyssey Museum Tom Harkin Global Communications Center June 6-10, 2011 Teach Epidemiology Professional Development Workshop Day 2

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Teachers Team-Teaching Teachers (TTTT) Existing Lesson Team leads other workshop participants in a portion of a selected existing epidemiological lesson.

11 They can then use that ability to think about their own thinking … to grasp how other people might learn. They know what has to come first, and they can distinguish between foundational concepts and elaborations or illustrations of those ideas. They realize where people are likely to face difficulties developing their own comprehension, and they can use that understanding to simplify and clarify complex topics for others, tell the right story, or raise a powerfully provocative question. Ken Bain, What the Best College Teachers Do Metacognition Teach Epidemiology Epi – Grades 6-12

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Teachers Team-Teaching Teachers (TTT) Teach Existing Epidemiological Lessons (EL) (4 Groups) Team leads other workshop participants in a portion of a selected existing epidemiological lesson.

17 They can then use that ability to think about their own thinking … to grasp how other people might learn. They know what has to come first, and they can distinguish between foundational concepts and elaborations or illustrations of those ideas. They realize where people are likely to face difficulties developing their own comprehension, and they can use that understanding to simplify and clarify complex topics for others, tell the right story, or raise a powerfully provocative question. Ken Bain, What the Best College Teachers Do Metacognition Teach Epidemiology Epi – Grades 6-12

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Teachers Team-Teaching Teachers (TTT) Teach Existing Epidemiological Lessons (EL) (4 Groups) Team leads other workshop participants in a portion of a selected existing epidemiological lesson. TTTT 3 EL

26 They can then use that ability to think about their own thinking … to grasp how other people might learn. They know what has to come first, and they can distinguish between foundational concepts and elaborations or illustrations of those ideas. They realize where people are likely to face difficulties developing their own comprehension, and they can use that understanding to simplify and clarify complex topics for others, tell the right story, or raise a powerfully provocative question. Ken Bain, What the Best College Teachers Do Metacognition Teach Epidemiology Epi – Grades 6-12

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View a News Item from an Epidemiological Perspective Team leads other workshop participants in the analysis of a news item from an epidemiological perspective. Teach Epidemiology Teachers Team-Teaching Teachers (TTT)

35 They can then use that ability to think about their own thinking … to grasp how other people might learn. They know what has to come first, and they can distinguish between foundational concepts and elaborations or illustrations of those ideas. They realize where people are likely to face difficulties developing their own comprehension, and they can use that understanding to simplify and clarify complex topics for others, tell the right story, or raise a powerfully provocative question. Ken Bain, What the Best College Teachers Do Metacognition Teach Epidemiology Epi – Grades 6-12

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44 They can then use that ability to think about their own thinking … to grasp how other people might learn. They know what has to come first, and they can distinguish between foundational concepts and elaborations or illustrations of those ideas. They realize where people are likely to face difficulties developing their own comprehension, and they can use that understanding to simplify and clarify complex topics for others, tell the right story, or raise a powerfully provocative question. Ken Bain, What the Best College Teachers Do Metacognition Teach Epidemiology Epi – Grades 6-12

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Marian R Passannante, PhD Associate Professor University of Medicine and Dentistry of New Jersey New Jersey Medical School School of Public Health Teach Epidemiology EPI-501

51 Teach Epidemiology Enduring Epidemiological Understandings Epidemiology Descriptive –concentrates on examining the distribution of diseases in the population in terms of person, (who gets the disease), place (where they get the disease) and time (when they get the disease) –Generates hypotheses

52 Teach Epidemiology Enduring Epidemiological Understandings Descriptive Epidemiology Person Source: Reported Tuberculosis in the United States, urv2009/slides/surv9.htm

53 Teach Epidemiology Enduring Epidemiological Understandings Descriptive Epidemiology Place Reference Hootman JM, Pan L, Helmick CG, Hannan C. State-specific trends in obesity prevalence among adults with arthritis, Behavioral Risk Factor Surveillance System, 2003–2009.MMWR 2011;60(16):

54 Teach Epidemiology Enduring Epidemiological Understandings Descriptive Epidemiology Time source:

55 Teach Epidemiology Enduring Epidemiological Understandings Epidemiology Descriptive Analytic

56 Teach Epidemiology Enduring Epidemiological Understandings Epidemiologic Study Designs What is the relationship between physical activity and health status among high school students? Define outcome and how it will be measured. Define the exposure and how it will be measured.

57 Teach Epidemiology Enduring Epidemiological Understandings Epidemiologic Study Designs What is the relationship between physical activity and health status among high school students? Define outcome and how it will be measured. Health status: absenteeism Define the exposure and how it will be measured. Physical Activity: participation in varsity sports

58 Teach Epidemiology Enduring Epidemiological Understandings Epidemiologic Study Designs Ecological Studies Information is collected on groups, not individuals Often called correlation studies Easy to perform- data often already available

59 Teach Epidemiology Enduring Epidemiological Understandings Epidemiologic Study Designs Ecological Study High school Absenteeism Rate Number of lost school days due to absence /(Number of students) x (Number of schooldays) x 100 % of high school students on varsity sports teams

60 Teach Epidemiology Enduring Epidemiological Understandings Epidemiologic Study Designs Ecological Studies Advantages Information is collected on groups, not individuals Easy to perform- data often already available Disadvantages Doesn’t control for other factors (confounders) Individual associations may not be the same as group associations

61 Teach Epidemiology Enduring Epidemiological Understandings Epidemiology Analytic –concerned with studying the relationship between an exposure and an outcome –test hypotheses –Includes a comparison group

62 Teach Epidemiology Enduring Epidemiological Understandings Analytic Epidemiology Outcomes –Health or Disease outcomes –Dependent variable –Y variable Exposures –Risk or Protective Factor –Independent or Predictor variable –X variable

Analytic Epidemiology Outcome 63 Exposure+- + AB -CD

64 Teach Epidemiology Enduring Epidemiological Understandings Epidemiology Analytic –Observational Cross-Sectional Case-Control Cohort –Experimental Behavioral Trials Clinical Trials

65 Teach Epidemiology Enduring Epidemiological Understandings Epidemiologic Study Designs Cross-Sectional Studies Data on possible risk factors and disease outcomes are collected at the same time. These studies are sometimes called prevalence studies since the information collected can be used to provide prevalence (the proportion in a population with a particular outcome).

66 Teach Epidemiology Enduring Epidemiological Understandings Epidemiologic Study Designs How would you measure the exposure and outcome? Physical ActivityHealth Status

67 Teach Epidemiology Enduring Epidemiological Understandings Epidemiologic Study Designs How would you measure the exposure and outcome? Physical ActivityHealth Status 1. Participation in organized sports1. Days Absent 2. Amount of daily/weekly exercise2. Body Mass Index 3. Amount of vigorous exercise 3. Blood Pressure

68 Teach Epidemiology Enduring Epidemiological Understandings Epidemiologic Study Designs How would you design a cross sectional study of Physical ActivityHealth Status among high school students? Health Status (BMI) Physical Activity + Obese - Non-Obese + HighAB - LowCD

69 Teach Epidemiology Enduring Epidemiological Understandings Epidemiologic Study Designs How would you design a cross sectional study of Physical ActivityHealth Status among high school students? Obesity Conduct a Survey asking questions about current Physical activity, height and Body weight. Physical Activity +- + AB -CD

70 Teach Epidemiology Enduring Epidemiological Understandings Epidemiologic Study Designs How would you design a cross sectional study of Physical ActivityHealth Status among high school students? Obesity Conduct a Survey –Calculate Prevalence of Health Outcome In both Physical Activity Groups A/A+B and C/C+D –Calculate a Prevalence Ratio to compare groups (A/A+B)/(C/C+D) Physic al Activity +- + AB -CD

71 Teach Epidemiology Enduring Epidemiological Understandings Epidemiologic Study Designs How would you design a cross sectional study of Physical ActivityHealth Status among high school students? Advantages Good for generating prevalence Obese Can be done over a short period of time Disadvantages Survey data difficult to verify Can not provide information on causal associations Unclear whether exposure or disease came first (e.g. Are students obese because they are less physically active or are they less physically active because they are obese?) Physica l Activity +- + AB -CD

72 Teach Epidemiology Enduring Epidemiological Understandings Epidemiologic Study Designs How would you design a case-control study of Physical ActivityHealth Status among high school students? Obesity 1) Identify cases and controls 2) Interview cases and control to ask about physical activity during the past 4 years 3) Fill in the 2 x 2 table and calculate The Odds Ratio Physical Activity + case - control + AB -CD

73 What is an odds ratio? ►A measure of association used to quantify the relationship between an exposure and an outcome. It is also called the cross-products ratio. –Outcome: obesity –Exposure: physical activity ►The ratio of the odds that cases (obese) were exposed to a particular risk factor (physical activity) as compared with the odds that the controls (non-obese) were exposed to that same risk factor (physical activity). –In a case-control study the odds ratio= Odds that a case was exposed / Odds that a control was exposed

74 What is an odds ratio? Can be calculated using a simple 2-by-2 contingency table. Odds of that a case was exposed: a/c Odds of that a control was exposed: b/d Ratio of the odds or Odds Ratio: (a/c)/(b/d) = ad/bc (cross-products ratio) Outcome ExposureCase Control yesab nocd

75 Teach Epidemiology Enduring Epidemiological Understandings Epidemiologic Study Designs How would you design a case-control study of Physical ActivityHealth Status among high school students? 1)Identify those with high and low health status (# of cases and # controls may or may not be the same) 1)Ask them questions about prior physical activity level 2)Calculate a measure of risk: Odds Ratio A x D = 12 x 178 = 2136 =.507 B x C 183 x Odds that obese students were physically active were about 50% lower than the odds that non-obese students were physically activity. Physic al Activity Case Obes e Controls Non- obese +A 12 B 23 -C 183 D 178

76 Interpretation of the Odds Ratio source: modified from Jekel et al. Epidemiology, Biostatistics and Preventive Medicine, pg 93. | |- 4.0 (4/1) | |- 2.0 (2/1) | | (1/1)= equal odds in two groups | |- 0.5 (1/2) | | (1/4)

77 Interpretation of the Odds Ratio source: modified from Jekel et al. Epidemiology, Biostatistics and Preventive Medicine, pg 93. | |- 4.0 (4/1) Odds that cases were exposed are 4 times higher than | the odds that controls were exposed |- 2.0 (2/1) (the exposure is positively related to the disease) | | (1/1)= equal odds in two groups | (the exposure is not related to the disease ) |- 0.5 (1/2) | | (1/4) Odds that cases were exposed are | 25% as high or 75% lower l than the odds that controls were exposed | (the exposure is negatively related to the disease)

78 Teach Epidemiology Enduring Epidemiological Understandings Epidemiologic Study Designs How would you design a case-control study of Physical ActivityHealth Status among high school students? Obesity Advantages –Good for studying rare outcomes –Do not need very large sample Disadvantages –Can not calculate incidence rates –Must estimate relative risk using the odds ratio –Estimates may be affected by recall bias Physical Activity +- + AB -CD

79 Teach Epidemiology Enduring Epidemiological Understandings Epidemiologic Study Designs How would you design a cohort study of Physical ActivityHealth Status among high school students? Obesity Physical Activity +- + AB -CD

80 Teach Epidemiology Enduring Epidemiological Understandings Epidemiologic Study Designs How would you design a cohort study of Physical ActivityObesity among high school students? Obesity 1) Identify students with high and low activity level who are not obese at the start of high school 2) Follow them over time and calculate BMI 3) Calculate Incidence of obesity in both exposure groups 4) Calculate Relative Risk (incidence in exposed group divided by incidence in unexposed group) (A/ A+B) / (C/C+D) = 10/500 =.50 20/500 The risk of obesity is 50% lower in those who had high levels of physical activity compare d to those who did not. Physical Activity +- +A 10 B C 20 D 48 0

81 Interpretation of the Relative Risk source: modified from Jekel et al. Epidemiology, Biostatistics and Preventive Medicine, pg 93. | |- 4.0 (4/1) Risk of outcome is 4 times higher among those with the | factor as compared to those without the factor |- 2.0 (2/1) | | (1/1)= equal risk in two groups | |- 0.5 (1/2) | | (1/4) Risk of outcome is 25% as high or 75% lower among | those with the factor as compared to those without the factor

82 Teach Epidemiology Enduring Epidemiological Understandings Epidemiologic Study Designs How would you design a cohort study of Physical ActivityHealth Status among high school students? Advantages Health Status –Allow for the direct calculation of incidence rates –Good for studying rare exposures –Allows investigators to assess the progression from exposure to disease Disadvantages –Need a large sample –Can take a long time to complete the study –More costly and labor intensive than other studies –Those who are lost to follow-up can bias the outcome Physical Activity +- + AB -CD

83 Teach Epidemiology Enduring Epidemiological Understandings Epidemiologic Study Designs Experimental How would you design a behavioral trial of Physical ActivityHealth Status among high school students? Health Status Physical Activity +- + AB -CD

84 Teach Epidemiology Enduring Epidemiological Understandings Epidemiologic Study Designs Experimental How would you design a behavioral trial of Physical ActivityHealth Status among high school students? Obesity 1)Random assignment of normal weight students to different activity level 2) Follow groups over time to calculate incidence of health status outcome (blind evaluation) 3)Calculate Relative Risk (incidence in exposed group divided by incidence in unexposed group) Would this be ethical? Physical Activity +- + AB -CD

85 Teach Epidemiology Enduring Epidemiological Understandings Epidemiologic Study Designs Experimental How would you design a clinical trial of Vitamin CHealth Status among high school students? Health Status 1)Random assignment of healthy to Vitamin C 2)Follow groups over time to calculate incidence of health status outcome (blind evaluation) 3)Calculate Relative Risk (incidence in exposed group divided by incidence in unexposed group) Would this be ethical? Vitamin C +- + AB -CD

86 Teach Epidemiology Enduring Epidemiological Understandings Epidemiologic Study Designs Ethical Issues Minimizing Risks and Maximizing Benefits Informed Consent Confidentiality of information Respect for Human Rights Scientific Integrity

87 Teach Epidemiology Enduring Epidemiological Understandings Epidemiologic Study Designs Ethical Issues Minimizing Risks and Maximizing Benefits Physical Emotional Especially in vulnerable populations

88 Teach Epidemiology Enduring Epidemiological Understandings Epidemiologic Study Designs Ethical Issues Informed Consent –Investigators must provide clear and complete information regarding a research project so that potential participants area able to decide whether or not to be part of the study.. Source: Coughlin S, Ethical issues in epidemiologic research and public health practice. Emerging Themes in Epidemiology 2006, 3:16 open access

89 Teach Epidemiology Enduring Epidemiological Understandings Epidemiologic Study Designs Ethical Issues Confidentiality of Information –Limiting access to study data –Study records locked away –Limit/delete identifying information on data collection forms and in computer files –Encrypting of computer databases –Limit geographic detail Source: Coughlin S, Ethical issues in epidemiologic research and public health practice. Emerging Themes in Epidemiology 2006, 3:16 open access

90 Teach Epidemiology Enduring Epidemiological Understandings Epidemiologic Study Designs Ethical Issues Confidentiality of Information –Certificate of Confidentiality Certificates protect against compulsory legal demands, such as court orders and subpoenas, for identifying information or identifying characteristics of a research participant. Source:

91 Teach Epidemiology Enduring Epidemiological Understandings Epidemiologic Study Designs Ethical Issues Respect for Human Rights –Individual rites –Right of the Population

92 Teach Epidemiology Enduring Epidemiological Understandings Epidemiologic Study Designs Ethical Issues Scientific Integrity –Research sponsorship Appearance of conflict of interest Possible conflict of interest –Conducting and reporting research honestly

93 Teach Epidemiology Enduring Epidemiological Understandings Epidemiologic Study Designs Ethical Issues The institutional review board system (IRB) United States, federal regulations to protect human research subjects (45 CFR 46) have resulted in a complex IRB system. Similar safeguards exist in many other countries. We recommend that students doing epidemiologic research Login to the NIH Protecting Human Research Participants training modules ( Complete three of the seven training modules; History, Codes and Regulations, and Respect for Persons. Source: Coughlin S, Ethical issues in epidemiologic research and public health practice. Emerging Themes in Epidemiology 2006, 3:16 open access

94 Teach Epidemiology Enduring Epidemiological Understandings Epidemiologic Study Designs Break

95 Teach Epidemiology Enduring Epidemiological Understandings Analytic Observational Study Type Main FeatureOutcome Measure Cross-sectionalExposure and outcome assessed at the same time Prevalence Prevalence Ratio Case-ControlAssemble Cases and Controls Ask about prior exposure Odds Ratio CohortAssemble cohort based on exposure All free of outcome at beginning Follow over time to assess outcome Incidence Rate Relative Risk

Epidemiologic Measures of Morbidity Incidence refers to the occurrence of new cases of disease or injury in a population over a specified period of time. Prevalence refers to the proportion of persons in a population who have a particular disease or attribute at a specified point in time or over a specified period of time. 96 Identifying Patterns of Health and Disease and Formulating Hypotheses Teach Epidemiology Source of Definitions: Principles of Epidemiology in Public Health Practice Third Edition, U.S. DHHS, CDC

Cross-Sectional Studies Data on exposure and outcome are collected at the same time. Prevalence Ratio –Prevalence of Outcome among those who have the exposure A/A+B –Prevalence of the Outcome among those who did not have the exposure C/C+D –Calculate a Prevalence Ratio to compare groups (A/A+B)/(C/C+D) Outcome +Outcome - Exposure +AB Exposure -CD 97

Outcome measures Case-Control Study Odds Ratio = A x D B x C aka: Cross-Products Ratio ExposureCaseControl YesAB NoCD Cohort study Relative Risk= Incidence in Exposed = (A/A+B) Incidence in Unexposed (C/C+D) 98 Exposur e DiseaseNo Disease YesAB NoCD

99 Teach Epidemiology Enduring Epidemiological Understandings Analytic Epidemiology

100 Teach Epidemiology Enduring Epidemiological Understandings Analytic Epidemiology Self Check

101 Teach Epidemiology Enduring Epidemiological Understandings Analytic Epidemiology Source: Principles of Epidemiology in Public Health Practice Third Edition, U.S. DHHS, CDC

102 Teach Epidemiology Enduring Epidemiological Understandings Analytic Epidemiology Answer: A and E Experimental Clinical Trial

103 Teach Epidemiology Enduring Epidemiological Understandings Analytic Epidemiology Source: Principles of Epidemiology in Public Health Practice Third Edition, U.S. DHHS, CDC

104 Teach Epidemiology Enduring Epidemiological Understandings Analytic Epidemiology Answer: A and E Experimental Clinical Trial

105 Teach Epidemiology Enduring Epidemiological Understandings Analytic Epidemiology Source: Principles of Epidemiology in Public Health Practice Third Edition, U.S. DHHS, CDC

106 Teach Epidemiology Enduring Epidemiological Understandings Analytic Epidemiology Answer: B and C Observational Cohort Study

107 Teach Epidemiology Enduring Epidemiological Understandings Analytic Epidemiology Source: Principles of Epidemiology in Public Health Practice Third Edition, U.S. DHHS, CDC

108 Teach Epidemiology Enduring Epidemiological Understandings Analytic Epidemiology

109 Teach Epidemiology Enduring Epidemiological Understandings Analytic Epidemiology

110 Teach Epidemiology Enduring Epidemiological Understandings Analytic Epidemiology OR = (32x60) = 12 (8 x 20) Source: Principles of Epidemiology in Public Health Practice Third Edition, U.S. DHHS, CDC StorageCaseControl + inside outside860

111 Teach Epidemiology Enduring Epidemiological Understandings Analytic Epidemiology What is the appropriate measure of risk? Calculate this measure. Source: Principles of Epidemiology in Public Health Practice Third Edition, U.S. DHHS, CDC

112 Teach Epidemiology Enduring Epidemiological Understandings Analytic Epidemiology Relative Risk Incidence of illness in exposed group (those who ate cake) = 50/53 =.943 = 6.1 Incidence of illness in non-exposed group (did not eat cake) 4/ Source: Principles of Epidemiology in Public Health Practice Third Edition, U.S. DHHS, CDC

Analytic Epidemiology A cross-sectional study was conducted among 1000 high school students. Students were asked to provide information on their gender and whether they had smoked more than 1 cigarette during the past week. The study data are provided in the table below. What is the prevalence of smoking Among males? Among Females? Calculate a Prevalence Ratio. 113 GenderSmokedDidn’t smoke Male40380 Female30570 Enduring Epidemiological Understandings Teach Epidemiology

Analytic Epidemiology A cross-sectional study was conducted among 1000 randomly selected high school students. Students were asked to provide information on their gender and whether they had smoked more than 1 cigarette during the past week. The study data are provided in the table. What is the prevalence of smoking Among males? 40/400 = 10% Among Females? 30/600 = 5% Prevalence Ratio 10/5 = GenderSmokedDidn’t smoke Male40360 Female30570 Enduring Epidemiological Understandings Teach Epidemiology

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123 Emergency Operation Center Teach Epidemiology Tours

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