The document discusses the process of disease prevention, which includes four main steps: hazard identification, dose-response assessment, exposure assessment, and risk characterization. It provides examples of each step. Hazard identification involves determining possible causes of health symptoms in a neighborhood. Dose-response assessment uses toxicology studies to establish if substances can damage health and determine safe exposure levels. Exposure assessment measures real-world contaminant levels. Risk characterization integrates all the data to evaluate health risks and recommend preventive actions.

1. PREVENTING THE CAUSES OF DISEASEDavid Kim, PhDVestergaardFrandsen West Africa18 March 2011

2. DEATHBIRTHHEALTHDISEASE

4. The Workplace

5. Mine

6. Busy Street

7. Farm

8. The Environment

9. Indoor Cooking

10. Swimming Pools

11. Vehicular Emissions

12. PreventionThe act of hinderingMerriam-Webter’s dictionary

14. Prevention of Disease Requires…Hazard identificationDose-response assessmentExposure assessmentRisk characterization

15. Hazard IdentificationGroup Exercise:You are part of a public health team that has been sent to a neighbourhood of a city where parents have been complaining of their children experiencing coughing, runny noses, and fevers that won’t go away. The number of children with these symptoms is growing every year; the numbers are 4 times larger than expected. With your team, discuss the possible causes of these symptoms.

16. Childhood Leukaemia in WoburnA 1981 Department of Public Health study confirmed a childhood leukaemia cluster in Woburn, MA. The number of cases was 4 times higher than the national average.Woburn has a 130-year industrial history that resulted in significant local deposition of chemical manufacturing waste.

17. EpidemiologyEpidemiology is the basic science of public health.Purpose is to study (1) the distribution of disease in a population, and (2) the determinants of that disease.Concerned with person, place, and time.

18. Person

19. PlaceFamilyVillageCityCountryContinentGlobal

20. TimeHourDayWeekMonthYearDecadeCentury

21. Unit of Measure𝐼𝑛𝑐𝑖𝑑𝑒𝑛𝑐𝑒 𝑅𝑎𝑡𝑒= 𝑃𝑒𝑟𝑠𝑜𝑛𝑃𝑙𝑎𝑐𝑒×𝑇𝑖𝑚𝑒 1000 people living in Accra contracted the flu last year. What is the incidence rate?

22. Relative Risk𝑅𝑒𝑙𝑎𝑡𝑖𝑣𝑒 𝑅𝑖𝑠𝑘 (𝑅𝑅)= 𝐼𝑛𝑐𝑖𝑑𝑒𝑛𝑐𝑒 𝑅𝑎𝑡𝑒 1𝐼𝑛𝑐𝑖𝑑𝑒𝑛𝑐𝑒 𝑅𝑎𝑡𝑒 2 The IR of swine flu when flying with Delta is 2 cases per 1000 people each week. The IR of swine flu on all airlines is 1 case per 1000 each week. What is the RR of getting swine flu when flying with Delta?

23. Woburn MA: personChild diagnosed with leukaemia before 19th birthday.Diagnosed between 1969 and 1989.A resident of Woburn MA at the time of diagnosis.

24. Woburn MA: place

25. Woburn MA: time

26. Woburn MA: Relative RiskRR = 9 For those living near contaminated well water relative to all residents of Woburn. Is there a reason for concern?

27. Summary of Epidemiology StudiesAdvantagesStudy human populations.Can examine adverse effects associated with exposures to risk factors in real time.Convincing data if studies are conducted correctly.DisadvantagesLong time to executeCostlyDifficult to establish causality

28. Dose-Response AssessmentDetermine whether the causative agent can damage human cells/tissues/organs.Studies are typically conducted in laboratories.Fundamental science is toxicology

29. ToxicologyParacelsus, the father of toxicology“The dose makes the poison”

30. ToxicokineticsWhat the body does to the chemical.Defined by absorption, distribution, metabolism, and excretion (ADME).Establishes the DOSE in dose-response.

31. ToxicodynamicsWhat the chemical does to the body.Defined by cellular damage, DNA modifications, protein concentration changes, etc.Establishes the RESPONSE in dose-response.Decreased dopamine levels in Parkinson’s disease patients

32. In Vivo Experiments

33. In Vitro Experiments

34. In Silico Experiments

35. Dose-Response CurvesNOAEL: No Observed Adverse Effect LevelLOAEL: Lowest Observed Adverse Effect Level

36. Dose-Response Curve for Cr(VI)

37. Summary of Toxicology StudiesAdvantagesHighly controlled.Fast results.Can better establish causal relationship between dose and effect.DisadvantagesLaboratory conditionsExtensive use of animalsQuestionable relevance to humans

38. Exposure AssessmentStudy of contaminant levels in:AirWaterSoilBiological SamplesFood

39. Objectives of Exposure AssessmentMeasure the amount of contaminant in the environment.Record how often humans come into contact with the contaminant.Identify who comes into contact with the contaminant.

40. Air Monitoring

41. Water Monitoring

42. Spoil Monitoring

43. Biological Monitoring

45. Summary of Exposure StudiesAdvantagesQuantitativeReal-world valuesDisadvantagesHigh cost of conducting studies (i.e., analytical chemistry)Small number of samples due to intensive nature of studies

46. Risk CharacterizationFinal phase of a risk assessment.Integrates information collected from EPIDEMIOLOGY, TOXICOLOGY, and EXPOSURE ASSESSMENT studies.Qualitative and quantitative conclusions.Synthesizes all the information and recommends actions to prevent diseases from spreading.

47. Risk Characterization for Cr(VI)Clearly there is an association between leukaemia and living where Cr(VI) levels are high.Toxicological studies demonstrate a positive dose-response, suggesting a causal relationship.Exposure studies have measured presence of Cr(VI) levels in drinking water that exceed health standards.All evidence seems to point to the need to reduce Cr(VI) levels in order to prevent childhood leukaemia from occurring.

48. Final Group ExerciseSmall-scale mining in Ghana.

49. Mercury is used to clean gold nuggets.

50. Mercury is associated with skin cancer and other deadly ailments later in life.

51. Environmental contamination has made water undrinkable.

52. Biological monitoring shows that people are exposed to dangerous levels of mercury.What evidence do you need to evaluate whether or not preventive action should be taken?