CHAPTER OUTLINE Basic Concepts in Public Health

1 35 CHAPTER2 Basic Concepts in Public Health Marion Willard Evans Jr., DC, PhD, CHESDEFINITIONS IN Public HEALTHP ublic Health , as defined by C. E. A. Winslow, a leading figure in the history of Public Health , is the science and art of preventing disease, prolonging life,and promoting Health and efficiency through organizedcommunity efforts for the sanitation of the environ-ment, the control of community infections, the educa-tion of the individual in personal Health , the organizationof medical and nursing services for the early diagnosisand preventive treatment of disease.

2 And the develop-ment of the social machinery which will ensure toevery individual in the community a standard of livingadequate for the maintenance or improvement was not a bad definition for 1920. Today theAmerican Public Health Association (APHA) states thatpublic Health is the practice of preventing disease andCHAPTER OUTLINED efinitions in Public HealthTerms Used in Public HealthReportingCausation and Sir Austin BradfordHill s Criteria Assessment of Risk and Occurrenceof DiseaseRates Reported in Public HealthMeasuring for Causation and Risk AssessmentRisk DifferenceRisk RatioPreventionThe Mission of Healthy People in the Prevention of DiseaseScreening Counseling Patients on BehaviorChangeStages of Change Health Belief Modelpromoting good Health within groups of people.

3 Fromsmall communities to entire furtherstates it includes Health professionals from many fieldsworking together with the common purpose of protect-ing the Health of a population. The goal of any community, or Health care providerfor that matter, should be to prolong the number ofyears of healthy life of the population it represents orcares for. With that goal in mind, people, social infra-structure, government aid to those most in need, andinvestigation of disease outbreaks may all play a role inthe Public s Health .

4 Public Health uses the trends and oc-currences of disease in our populations and populationsubsets to infer the riskof disease for individuals. Tosome degree, the basis of risk or a risk factor(makingone more susceptible to a disease) takes its originloosely from the work of Koch. Koch s postulates lookedEcological Model of HealthPromotionWorking with Patients TowardBehavior ChangeLearning More About the BehaviorChange 10/12/09 5:51 PM Page 35 Jones and Bartlett Publishers, LLC. NOT FOR SALE OR DISTRIBUTION some diseases. Race, socioeconomic grouping, nationality,ethnicity, and where one lives in proximity to the equatormay be a risk factor for certain diseases.

5 Hypertension ismore prevalent in Blacks than Whites; that is, there areproportionally more existing casesof the disease amongBlacks than Whites, which is the definition of the termprevalence. Living in an area of the country where sun ex-posure is greater more days of the year may increaserisks of skin cancer, and living where there are fewerdays of sun could reduce the amount of vitamin D onehas circulating in the blood, which is now thought to in-crease risks for a host of , it is felt thatthere is a web of causation for most chronic diseasessuch that few instances exist where a single risk factorcauses a disease to occur.

6 Epidemics occur when there are a large number of casesof a disease that are out of proportion with what is nor-mally expected to be seen for that time, place, or actual number may vary depending on the type of dis-ease or the population that has been exposed. For in-stance, in a country where there is a high prevalence ofmalaria, a disease caused by a parasite in the blood carriedby mosquitoes, a few extra cases may be meaningless, butin Panama City Beach, Florida, during Spring Break, even ahalf-dozen cases would sound an alarm.

7 That is becauseeven in Florida, malaria is not seen as an endemicdisease;that is, a disease that is constantly present in the commu-nity or population. Unfortunately, diseases like human im-munodeficiency virus or acquired immune deficiencysyndrome (HIV/AIDS), influenza, hepatitis, and others areconsidered endemic in the United States. Among those diseases endemic in a society, occasionallythere are dramatic spikes in the numbers that are higherthan those expected to be seen in the community or is known as an outbreak. Any occurrence of an en-demic disease that is out of proportion to what is ex-pected may be seen as an outbreak.

8 Certainly, an increasein a disease occurrence that is rarely seen or thought to beeradicated would also constitute an outbreak, and evenone case of the latter may signal serious Public healthconcerns. The Centers for Disease Control andPrevention (CDC) tracks thousands of outbreaks each yearin the United States and more informationon outbreak investigations, go to Terms Used in Public Health ReportingNumerous terms are used to describe Public healthevents, risk levels, and causes of disease. Among the morecommon are morbidity, mortality, prevalence,and inci-dence.

9 Morbidity is the number of people suffering from aat diseases caused by living organisms and stated that ba-sically the following four relationships must occur re-garding causes of disease: 1. One must observe the [causative] organism inevery case of the It must be able to be grown in a pure The pure culture must, when inoculated into asusceptible host animal, reproduce the The microorganism must be observed in, and recov-ered from, the experimentally diseased s Concepts would be great if they could be ap-plied to every disease state, but how can one apply theseto chronic diseases that take years to develop and per-haps are due to multiple causes or risks?

10 Unfortunately,they can t. This brings up the concept of risk factors are those exposures or causal agents thatmake one more likely to suffer a disease or Health prob-lem. Although a risk factor may cause a disease if present,it may not actually be the true cause. The presence ofother factors may be necessary to cause the disease tooccur. One can use tobacco as an example of how one riskfactor can predispose a person to several diseases at onetime. Friis and Sellers point out that risk factors havethree The frequency of the disease varies by categoryor value of the factor.