Epi Midterm

Transmission of disease

100

Define epidemiology

Study of the distribution and determinants of health and disease in human populations to enable health services to be planned rationally, disease surveillance to be carried out, and preventive and control programs to be implemented and evaluated.

200

State the five objectives of epidemiology

1. Identify cause of disease and relevant risk factors

2. Determine extent of disease in community 

3. Study natural history and progression of disease 

4. Evaluate new and existing preventive and therapeutic measures and modes of healthcare delivery 

5. Provide foundation for developing public policy relating to environmental problems, genetic issues, and other considerations regarding disease

300

What are the stages of the natural progression of disease (for individuals and populations)?

Individuals

1. Healthy

2. Unaware of point in time when disease begins 

3. Symptoms develop, patient seeks medical care 

4. Diagnosis is made, treatment begins 

5. Cure, control of disease, disability, death 

Population

1. Total population 

2. Sick 

3. Seeks care

4. Hospitalized

400

What are primary, secondary, and tertiary prevention and give an example of each

Primary prevention: action taken to prevent the development of a disease in a person who is well and does not yet have the disease in question

Secondary prevention: Identifying people in whom disease process has already begun but who have not yet developed clinical signs and symptoms of illness

Tertiary prevention: Preventing complications in those who have already developed signs and symptoms of an illness and have been diagnosed (people who are in the clinical phase)

500

What are the steps of the epidemiologic approach?

1. Determine whether an association exists between exposure to a factor and the development of a disease 

2. Derive appropriate inferences about a possible causal relationship from the patterns of associations

Measures of disease frequency

100

What is incidence a measure of?

Risk

200

What is prevalence a measure of?

Disease burden

300

What is the difference between point and period prevalence?

• Point prevalence: Prevalence of the disease at a certain point in time
• Period prevalence: How many people have had the disease at any point during a certain time period

400

Is proportionate mortality a measure of risk?

no

500

What factors impact prevalence?

Only incidence can increase prevalence, only death and cure can decrease prevalence

Rate adjustment

100

When are crude rates not enough?

For comparing rates across populations

200

What is the single most important predictor of mortality?

Age

300

What are two important uses of mortality data?

1. Compare two or more populations 

2. Compare population in different time periods

400

When do you use direct vs indirect adjustment?

Use direct adjustment only when you have strata-specific rates for the target population

500

List the steps for direct adjustment and the process for indirect adjustment

Direct

1. Calculate the observed rate by strata 

2. Standardize the population

3. Calculate expected number of the event of interest

4. Calculate sum of expected events

5. Use the sum divided by the total standardized pop to find the adjusted rate 

Indirect

Standard mortality ratio: Total observed deaths in a pop / total expected deaths in a pop

Indirect adjusted rate = SMR x crude rate

Number of expected deaths found by applying the age-specific rates of the standard population to the population of interest 

Surveillance

100

Name the vital events

Births and fetal deaths, marriage, divorce, death

200

Name the four types of surveillance (and give an example)

Mass screening

Selective screening

Multiphasic screening

Case finding

300

What type of surveillance (active vs passive) is more effective generally and why?

Active is more effective due to resource allocation