Applied Epidemiology

PU 520-6

Unit 9

Overview Epidemiologic specializations Research design Global Burden of Disease Study Disability-adjusted life year Test Your Knowledge Breslow’s study Overview of Exam 3

Psychologic What might psychological epidemiology

be? What are psychological processes and how

do they influence health?

Behavioral Studies the role of behavioral factors in

health

Examples tobacco use

physical activity risky sexual behavior

consumption of unhealthy foods

Social The influence of a person’s position in the

social structure upon the development of disease

Research Designs Used Case Control

Cohort Cross sectional

Experimental

Global Burden of Disease Study Measures burden of disease Combines years of life lost Due to premature mortality Years of life lost Comprehensive regional and global

assessment

Disability-Adjusted Life Year Metric that assess the burden of disease Measures the gap between current health and

ideal health Sum of the Years of Life Lost What are the 10 leading specific causes of

global DALYs?

Test Your Knowledge What is the person-environment fit model? What is stress? What is the stress press model? Name a stressful life event. What are ways

you deal with stress? What is the Social Readjustment Rating

Scale?

Healthy People 2010

What is healthy people 2010? What are the overarching goals? Give me two focus areas!

Breslow's study Moderate food intake Eating regularly Eating breakfast Not Smoking Cigarettes Moderate or no use of alcohol Moderate exercise 7 to 8 hours of sleep daily

Exam 3 Review Sensitivity Specificity Reliability Validity Direct Transmission Indirect Transmission Case Fatality Rate

Mortality Rate Major resurgence of

measles TB rates in recent years Passive Immunity Selective Screening Mass Screening Ad hoc Screening Multiphasic Screening

What am I? Epidemiology Monitor Lyme Disease is consider what type of

vector? How many specialties are in the field of

epidemiology? What is virulent virus? Foods that transmit salmonella

Other Terms to Know High subclinical/clinical ratio Portal of exit Portal of entry Asbestos Exposure Electronic & Mechanic Fields Exposure Threshold Latency Synergism

Difference Between Studies Experimental Retrospective Cohort Prospective Cohort Case -Control Cross-Sectional

Test Your Knowledge What is person-environment fit model ? What is the most important methodological

problems in the measurement of life events? According to The Association of Schools of

Public Health, What competencies in epidemiology is need to be achieved by Master of Public Health degree candidates?

What is sensitivity? The sensitivity of a test is the probability

that the test is positive when given to a group of patients with the disease. Sensitivity is sometimes abbreviated Sn.

The formula for sensitivity is

Sn = True Positive Test____

All Patients With DiseaseAll Patients With Disease

Sensitivity Formula In a study of 5,113 subjects checked for

gastric cancer by endoscopy There were 13 patients with gastric cancer confirmed by endoscopy. 11 of these patients were positive on the test.

The sensitivity is 11/13 = 85%.

Predictive Value of a Positive Test Proportion of persons with positive test who

have condition.

PPV= True Positive___

True + False Positive (All Positive)

Predictive Value Formula 1000 patients in a clinic, being tested for syphilis 100 have

the characteristics and 900 don’t. Among the 100 patients with syphilis, 95 of them tested

positive, and 5 tested negative. Among the 900 patients without syphilis, 90 tested positive, and 810 tested negative. In this case, TP=95, FN=5, FP=90, and TN=810.

In the case above, that would be 95/(95+90)= 51.4%. The positive predictive value tells us how likely someone is to have the characteristic if the test is positive. Among all people that test positive, what proportion truly has the characteristic? 51.4% PPV means that if you test positive, you have a 51.4% chance of actually having the disease.

Last Thoughts