The Impact of Epidemiology The Impact of Epidemiology in Public Healthin Public Health

Robert HirokawaRobert HirokawaEpidemiologist, Science and Research GroupEpidemiologist, Science and Research Group

HHI / TSP, Hawaii Department of HealthHHI / TSP, Hawaii Department of Health

3 Core Functions of Public Health3 Core Functions of Public Health

The Institutes  of Medicine (IOM) defines the The Institutes  of Medicine (IOM) defines the three core functions of governmental public three core functions of governmental public health as:health as:

AssessmentAssessment

Policy developmentPolicy development

Assurance Assurance

10 Essential Public Health Services10 Essential Public Health Services

Monitor health status to identify community problems.Monitor health status to identify community problems.Diagnose and investigate health problems and health hazards in the Diagnose and investigate health problems and health hazards in the community.community.Inform, educate, and empower people about health issues.Inform, educate, and empower people about health issues.Mobilize community partnerships and action to identify and solve health Mobilize community partnerships and action to identify and solve health problems.problems.Develop policies and plans that support individual and community health Develop policies and plans that support individual and community health efforts.efforts.Enforce laws and regulations that protect health and ensure safety.Enforce laws and regulations that protect health and ensure safety.Link people to needed personal health services and assure the provision Link people to needed personal health services and assure the provision of  health care when otherwise unavailable.of  health care when otherwise unavailable.Assure a competent public health and personal health care workforce.Assure a competent public health and personal health care workforce.Evaluate effectiveness, accessibility, and quality of personal and Evaluate effectiveness, accessibility, and quality of personal and population- based health services.population- based health services.Research for new insights and innovative solutions to health Research for new insights and innovative solutions to health problems.problems.

Epidemiology DefinedEpidemiology Defined

The study of The study of distributiondistribution and and determinantsdeterminants of of health and disease in human populationshealth and disease in human populations

3 Essential Components of Epidemiology3 Essential Components of Epidemiology

Disease distributionDisease distribution

Disease determinantsDisease determinants

Disease frequencyDisease frequency Expected levelsExpected levels EndemicEndemic SporadicSporadic EpidemicEpidemic PandemicPandemic

Types of Epidemiologic StudiesTypes of Epidemiologic Studies

DescriptiveDescriptive

AnalyticAnalytic

Descriptive StudiesDescriptive Studies

Frequency of occurrence of a particular Frequency of occurrence of a particular conditioncondition

Patterns of occurrencePatterns of occurrence PersonPerson PlacePlace TimeTime

Hawaii Obesity and Diabetes TrendsHawaii Obesity and Diabetes Trends

0%

10%

20%

30%

40%

50%

% Obesity 9.1% 10.7% 9.7% 10.3% 10.6% 10.8% 12.9% 13.6% 15.5% 15.7% 15.7% 17.9% 17.1% 16.4% 20.9% 19.7% 20.6%

% Diabetes 3.2% 4.6% 5.0% 5.6% 5.2% 5.2% 6.2% 5.8% 7.6% 6.8% 7.3% 8.2%

1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006

1. Percentage of Hawaii adults that are obese, BRFSS 1990 - 20061. Percentage of Hawaii adults that are obese, BRFSS 1990 - 2006 2. Percentage of Hawaii adults who have been diagnosed with diabetes, BRFSS 1995 - 20062. Percentage of Hawaii adults who have been diagnosed with diabetes, BRFSS 1995 - 2006

Hawaii crude adult obesity (BMI Hawaii crude adult obesity (BMI >> 30) prevalence (%), 30) prevalence (%), BRFSS, 2005BRFSS, 2005

0%

10%

20%

30%

40%

50%

% obese 19.7% 17.8% 30.9% 24.4%

Haw aii Colorado Mississippi US

Hawaii crude adult obesity (BMI Hawaii crude adult obesity (BMI >> 30) prevalence (%) by 30) prevalence (%) by race/ethnicity, BRFSS, 2005race/ethnicity, BRFSS, 2005

0%

10%

20%

30%

40%

50%

% Obese 18.2% 43.1% 13.1% 10.4% 24.4% 19.7%

White Haw aiian Filipino Japanese Others Haw aii

Hawaii crude adult diabetes prevalence (%), Hawaii crude adult diabetes prevalence (%), BRFSS, 2005BRFSS, 2005

0%

5%

10%

15%

20%

25%

Percent Diabetes 7.3% 4.4% 12.5% 7.3%

Haw aii Alaska Puerto Rico US

Hawaii crude adult diabetes prevalence (%) by race/ethnicity,Hawaii crude adult diabetes prevalence (%) by race/ethnicity,BRFSS, 2005BRFSS, 2005

0%

5%

10%

15%

20%

25%

Percent Diabetes 5.3% 12.2% 8.1% 6.9% 7.6% 7.3%

White Haw aiian Filipino Japanese Others Haw aii

Analytic StudiesAnalytic Studies

Observational Studies Observational Studies (exposure not controlled)(exposure not controlled)

Case-controlCase-control CohortCohort

Experimental Experimental (exposure controlled)(exposure controlled)

Case-Control Study (Observational Study)Case-Control Study (Observational Study)

Exposure

Disease

Group 1 has disease (Cases)???

Group 2 disease free (Controls)???

Cohort Study (Observational Study)Cohort Study (Observational Study)

Exposure

Disease

Group 1 has exposure ???

Group 2 not exposed ???

Experimental StudyExperimental Study

Intervention StudiesIntervention Studies

Clinical TrialClinical Trial

Basic Presentation of ResultsBasic Presentation of Results

YesYes NoNo TotalsTotals

YesYes 4040 6060 100100

NoNo 1010 9090 100100

TotalsTotals 5050 150150 200200

Lung Cancer?

Smoke?

Relative Risk = Probability of disease among those exposed divided by the probability of disease among those not exposed

Basic Presentation of ResultsBasic Presentation of Results

YesYes NoNo TotalsTotals

YesYes 4040 6060 100100

NoNo 1010 9090 100100

TotalsTotals 5050 150150 200200

Lung Cancer?

Smoke?

RR = 40/100 divided by 10/100 = .4/.1 = 4

Measurement ErrorsMeasurement Errors

BiasBias InformationInformation SelectionSelection

ConfoundingConfounding

Statistical ErrorsStatistical Errors

Cause – Effect RelationshipCause – Effect Relationship

Strength of associationStrength of association

ConsistencyConsistency

TemporalityTemporality

Biological plausibilityBiological plausibility

Gradient (dose – response)Gradient (dose – response)

Measures of Disease FrequencyMeasures of Disease Frequency

Prevalence Rate = # of existing cases / Prevalence Rate = # of existing cases / total populationtotal population

Incidence Rate = # of new cases / total Incidence Rate = # of new cases / total population at riskpopulation at risk

Commonly Used Rates Commonly Used Rates

CrudeCrude

Category-specificCategory-specific

Age-adjustedAge-adjusted

Impact of Epidemiology in Public Impact of Epidemiology in Public HealthHealth

Improved understanding of the distribution and Improved understanding of the distribution and determinants of health and disease in human determinants of health and disease in human populationspopulations

Used to drive program planning, resource Used to drive program planning, resource allocation, interventions, and evaluationallocation, interventions, and evaluation

Thank you!Thank you!