This document provides an overview of a training session on descriptive and analytic epidemiology. Descriptive epidemiology involves describing disease frequency, distribution, and determinants in populations using measures like prevalence and incidence. Analytic epidemiology aims to understand why diseases occur using study designs like cohort studies and case-control studies to test hypotheses. Key terms discussed include measures of association like relative risk and odds ratio, and statistical tests like confidence intervals and p-values.

1. Public Health Information Network (PHIN) Series I is for Epi Epidemiology basics for non-epidemiologists

4. Series I Sessions May 5 “ Epidemiology Specialties Applied” April 7 “ Surveillance” March 3 “ Descriptive and Analytic Epidemiology” February 3 “ An Epidemiologist’s Tool Kit” January 12 “ Epidemiology in the Context of Public Health” Date Title

8. Series I Session III “ Descriptive and Analytic Epidemiology”

12. Descriptive Epidemiology Prevalence and Incidence

26. Prevalence and Incidence Prevalence = prevalent cases

27. Prevalence and Incidence Old (baseline) prevalence = prevalent cases = incident cases New prevalence Incidence No cases die or recover

28. Prevalence and Incidence = prevalent cases = incident cases = deaths or recoveries

29. Time for you to try it!!!

30. Descriptive Epidemiology Person, Place, Time

33. Data Characterized by Person http://www.vahealth.org/civp/Injury%20in%20Virginia_Report_2004.pdf

34. Data Characterized by Person http://www.vdh.virginia.gov/std/AnnualReport2003.pdf

35. Data Characterized by Person http://www.vdh.virginia.gov/epi/cancer/Report99.pdf

36. Data Characterized by Person http://www.vahealth.org/chronic/Data_Report_Part_3.pdf

38. Data Characterized by Time http://www.dhhs.state.nc.us/docs/ecoli.htm

39. Data Characterized by Time http://www.vdh.virginia.gov/std/HIVSTDTrends.pdf

40. Data Characterized by Time http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5153a1.htm

41. Data Characterized by Time http://www.health.qld.gov.au/phs/Documents/cdu/12776.pdf

43. Data Characterized by Place http://www.vdh.virginia.gov/epi/Data/region03t.pdf

44. Data Characterized by Place http://www.vdh.virginia.gov/epi/Data/Maps2002.pdf

45. Data Characterized by Place http://www.vahealth.org/civp/preventsuicideva/epiplan%202004.pdf

46. Data Characterized by Place http://www.vahealth.org/civp/preventsuicideva/epiplan%202004.pdf

47. Data Characterized by Place Source: Olsen, S.J. et al. N Engl J Med. 2003 Dec 18; 349(25):2381-2.

48. 5 Minute Break

49. Analytic Epidemiology Hypotheses and Study Designs

52. Borgman, J (1997). The Cincinnati Enquirer. King Features Syndicate.

64. Cohort Studies Disease No Disease Study Population Exposed Non-exposed No Disease Disease Exposure is self selected Follow through time

67. Case-Control Studies Had Exposure No Exposure Study Population Cases Controls No Exposure Had Exposure

69. Cohort versus Case-Control Study

70. Classification of Study Designs Source: Grimes DA, Schulz KF. Lancet 2002; 359: 58

71. Time for you to try it!!!

72. 5 Minute Break

73. Analytic Epidemiology Measures of Association and Statistical Tests

78. Relative Risk Example a / ( a + c ) 23 / 33 RR = = = 6.67 c / ( c+ d ) 7 / 67 100 70 30 Total 67 60 7 No 33 10 23 Yes Total No Yes Pink hamburger Escherichia coli ?

80. Odds Ratio Example a x d 130 x 135 OR = = = 1.27 b x c 115 x 120 500 250 250 Total 255 135 120 No 245 115 130 Yes Total No Yes MMR Vaccine? Autism

85. 95% CI Example Grodstein F, Goldman MB, Cramer DW. Relation of tubal infertility to history of sexually transmitted diseases . Am J Epidemiol. 1993 Mar 1;137(5):577-84 0.2 – 1.0 0.4 Genital warts 0.5 – 1.8 0.9 Herpes 1.0 – 2.7 1.7 Other vaginitis 1.0 – 1.7 1.3 Yeast 1.3 – 2.8 1.9 Trichomonas 1.3 – 4.4 2.4 Gonorrhea 95% CI Odds Ratio Disease

88. p-value Example Grodstein F, Goldman MB, Cramer DW. Relation of tubal infertility to history of sexually transmitted diseases . Am J Epidemiol. 1993 Mar 1;137(5):577-84 0.05 0.2 – 1.0 0.4 Genital warts 0.80 0.5 – 1.8 0.9 Herpes 0.04 1.0 – 2.7 1.7 Other vaginitis 0.04 1.0 – 1.7 1.3 Yeast 0.001 1.3 – 2.8 1.9 Trichomonas 0.004 1.3 – 4.4 2.4 Gonorrhea p-value 95% CI Odds Ratio Disease

89. Time for you to try it!!!

90. Questions???