Epi 320

epidemiology

The study of the distribution and determinants or disease or other related health outcomes in human populations and the application of that study to controlling health problems.

What are the five most important aspects of epidemiology?

1) Distribution

2) Determinants

3) Disease

4) Human population

5) Controlling Health Populatoins

What does distribution include in epidemiology?

person (individual characteristics like sex and age), place, time

What do determinants include in epidemiology?

cause of disease or outcome, factors that are capable of bringing about a change in health

etiology

all determinants of a disease

What does disease include in epidemiology?

used to mean any health related condition or outcome

What do human populations include in epidemiology?

epi examines disease occurrence among human population groups not individuals. epi is often referred to as population medicine.

Measure of morbidity: Count or frequency of prevelance

number telling us how many people have an outcome

What is count or frequency of prevalence useful for and not useful for?

useful for rare conditions or during short time spans, less useful for making comparisons (denominators are so different)

How should you word prevalence proportion?

_____ out of ______ possible people with a health outcome. Percentage (Ex. 20 people out of 100 possible people will have the disease)

How do you calculate the prevalence proportion?

#of cases present in the population at a specified time / # of people at that time.

• expressed as some unit of people (per 100, per 1000)

What are the types of prevalence proportions?

period prevalence and point prevalence

period prevalence

proportion of people with disease over a length of specified time

point prevalence

proportion of people with a disease at one specific time

Measures of morbidity - Count of incidence

The new cases of disease that have developed

How would we word count of incidence?

_____ new cases of disease per _______ people at risk

incidence proportion

#new cases observed during some time period / # people at risk at the start of the time period

What would we exclude in the incidence proportion?

people who already have the disease, and anyone not capable of getting the disease

Compare prevalence count to incidence count

prevalence count is a number representing all cases, and incidence count is a number representing just new cases

Measure of morbidity - Incidence rate

looks at each person in the population and determines how long they were at ris

How do you measure incidence rate?

new cases of disease in a time period / total person-time of population at risk

person-time

sum of individual units of time that a person is at risk for developing disease have been followed

What is the relationship between incidence and prevalence?

a continual addition of new cases (incidence) increases the prevalence while death and/or cure decreases the prevalence

How do you calculate prevalence?

prevalence = incidence x duration