Nies and

Nies and McEwen: Chapter 4: ATI: Chapter 3Epidemiology

Objectives --EpidemiologyObjective 1. Define and discuss the following terms; compare and contrast the following methods and concepts of epidemiology related to community health 1. descriptive epidemiology 2. analytic epidemiology Objective 2. Define the following epidemiological concepts, including their identifying factors and interconnection in epidemiology and the disease process: 1. epidemiological triangle a. agent b. host c. environmentObjective 3. Define and differentiate, and be able to calculate, as well as discuss the implication of the following epidemiological rates: 1. attack rate 2. incidence rate 3. prevalence rate 4. age-adjusted rate 5. proportionate mortality rateObjective 4. Define and discuss the concepts of risk and risk factors as the two terms relate to the epidemiological process

Objective 5. Define, discuss, and differentiate the concepts of screening and surveillance as they relate to the epidemiological process

Objective 6. Define, discuss, and differentiate between the concepts of cross-sectional studies and retrospective studies.

Objective 1. Define and discuss the following terms; compare and contrast the following methods and concepts of epidemiology related to community health descriptive epidemiology uses person, place, and time variables to describe disease patterns.analytic epidemiology analyzes complex relationships among determinants of diseases. The focus is on disease etiology.

Objective 2: Define the following epidemiological concepts, including their identifying factors and interconnection in epidemiology and the disease process: 1. the epidemiological triangle a. agent b. host c. environment

Objective 2

Agent FactorsNutritive elementsChemical agentsPhysical agentsInfectious agents

Objective 2

Host FactorsGeneticsAgeSexEthnic groupPhysiological statePrior immunological experienceInter-current or preexisting diseaseHuman behavior

Influence, exposure, susceptibility, or response to agentObjective 2

Environmental FactorsPhysical environmentBiological environmentSocioeconomic environment

Influence Existence of the Agent, Exposure, or Susceptibility to AgentObjective 2

The Epidemiological TriangleObjective 2

Objective 3. Define and differentiate, and be able to calculate, as well as discuss the implication of the following epidemiological rates: 1. attack rate 2. incidence rate 3. prevalence rate 4. age-adjusted rate 5. proportionate mortality rate

Incidence ofRocky Mountain Spotted FeverIn The United States

Epidemiological RatesRates are arithmetic expressions that help practitioners consider a count of an event relative to the size of the population from which it is extracted

Rate: Numerator/Denominator =Number of health events in a specified period/Population in same area in same specified period k

Objective 3

Attack RateAn attack rate is a special incidence rate that documents the number of new cases of a disease in those exposed to a disease.

Objective 3

Incidence RateIncidence ratesNew cases

Number of New Cases in a Given Time PeriodPopulation at Risk During Same Time Period

Example: In a total population of 4000, where 250 individuals already have the disease, 75 new cases are reported. 75 75 4000 250 3750

X 1000==0.02 x 1000 = 20 per 1000 per time periodObjective 3

Prevalence RatePrevalence ratesAll cases

Number of Existing Cases Total Population

Example: In a population of 4000 , 250 individuals have a particular disease. 250 4000

X 1000= 0.0625 X 1000 = 62.5 per 1000Objective 3

Age-Adjusted RateAge-adjustment or standardized rates reduce bias due to unequivalent age distribution of the populations being compared.Objective 3

Proportionate Mortality rateThe proportionate mortality rate (PMR) represents the percentage of deaths resulting from a specific cause relative to deaths from all causes.

Objective 3

Comparing RatesThe occupational health nurse notes that during the past year 4 of 628 factory employees have developed asbestososis. He checks with MMWR, and notes that the incidence rate of asbestososis in the general population is 5 per 1000.Is the rate for the factory higher or lower than for the general population?5 / 1000 = 0.005 4 / 628 = 0.0064

0.005 X 1000 = 5 per 1000 0.0064 X 1000 = 6.4 per 1000 Incidence in General PopulationIncidence in FactoryObjective 3

Objective 4. Define and discuss the concepts of risk and risk factors as the two terms relate to the epidemiological process

Objective 4

RISK FACTORSa. Identification of risk factors is closely associated with chronic disease reduction.b. Risk factors are variables that have been shown to increase the rate of disease in persons who have them or have been exposed to them.c. Identification of risk factors is critical to development of prevention interventions.d. Risk is the likelihood that healthy persons exposed to a factor will acquire a specific disease.e. Risk factor refers to the specific exposure factor. Risk factors may be fixed characteristics non-modifiable-- (i.e., age, sex, genetics), or modifiable--lifestyle factors (dietary habits, exercise regimens), or external to the individual (i.e., cigarette smoking, stress, noise).

Objective 4

Objective 5. Define, discuss, and differentiate the concepts of screening and surveillance as they relate to the epidemiological process

ScreeningThe purpose of screening programs is to identify risk factors and diseases in their earliest stages. Screening is usually classified as a secondary prevention activity because disease is discovered after a pathological change has occurred. Guidelines for screening programs include:1.Adequate and appropriate follow-up should be planned for those who test positive.2.Early diagnosis of the disease should be beneficial.3.Acceptable and medically sound treatment should be available.4.Procedures for ensuring confidentiality should be in place.5.Tests must be cost effective and acceptable to the client.6.Costs of program, follow-up, and resulting medical care should have a bearing on the decision to screen.7.Screening tests should ideally have high sensitivity (the ability of a test to detect those with the disease) and specificity (the extent to which a test can identify those without the disease)

Objective 5

SurveillanceSurveillance allows ongoing collection of information by monitoring changes in disease frequency and trends in occurrence of risk factors. The nurse evaluates trends in morbidity by identifying new cases and calculating incidence rates.

Objective 5

Objective 6. Define, discuss, and differentiate between the concepts of cross-sectional studies and retrospective studies.

Cross-Sectional StudiesCross-sectional studies (also known as prevalence or correlational studies) examine relationships between potential causal factors and disease at a point in time.

Objective 6

Retrospective StudiesRetrospective (case control) studies compare a group of individuals known to have a disease with a similar group of individuals who do not have the disease to determine whether the diseased group differs from the non-diseased group in its exposure to a specific factor or characteristic. Data collection extends back in time to determine previous exposure or risk factors.

Objective 6

Objectives ~ EpidemiologyObjective 1. Define and discuss the following terms; compare and contrast the following methods and concepts of epidemiology related to community health 1. descriptive epidemiology 2. analytic epidemiology Objective 2. Define the following epidemiological concepts, including their identifying factors and interconnection in epidemiology and the disease process: 1. epidemiological triangle a. agent b. host c. environmentObjective 3. Define and differentiate, and be able to calculate, as well as discuss the implication of the following epidemiological rates: 1. attack rate 2. incidence rate 3. prevalence rate 4. age-adjusted rate 5. proportionate mortality rateObjective 4. Define and discuss the concepts of risk and risk factors as the two terms relate to the epidemiological process

Objective 5. Define, discuss, and differentiate the concepts of screening and surveillance as they relate to the epidemiological process

Objective 6. Define, discuss, and differentiate between the concepts of cross-sectional studies and retrospective studies.

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