Exam II Lecture 6 Flashcards
What is epidemiology?
The pattern of disease in a population.
Primary goal is to identify the cause of disease.
Descriptive epidemiology
The first stage of investigation.
Focuses on describing disease distribution by characteristics relating to TIME, PLACE, AND PERSON.
Analytic Epidemiology
Second stage in the epidemiologic study in which the HYPOTHESIS generated in the descriptive phase are tested.
What is the key feature of an analytic epidemiology?
The comparison group!
Determines why and the how of the disease (causes)
Epidemiology case control study
A group of people with disease and a group of people without the disease.
this is an observational study.
Epidemiology Cohort study
Observational study.
Records whether each study participant is exposed or not and then tracks them to see if they develop the disease.
Cross sectional study
Observational study
Samples persons from a population and then measures exposures and health outcomes similtaneously.
Can assess the prevalence of the health outcome at that point of time without regard to duration.
Objective epidemiology
Evaluation of trends in health and disease and comparisons among countries and subgroups within countries.
Prevalence
number of existing cases in a population at some designated time.
Incidence rate
The rate of development of a disease in a group over a certain time period.
New cases/ Population at risk.
What does the incidence of a disease help you determine?
Helps to determine the risk of developing the disease and the effects of exposure to a hypothesized factor of incedence
What is morbidity?
Another term for illness, it is not death!
Prevalence often measures morbidity in a population.
What is mortality?
another term for death.
The number of deaths due to a disease devided by the entire population is the mortality rate.
What is the crude rate of something?
The actual number of cases/events in a population over a given time period.
**They do not permit comparison of populations that vary in composition.
Adjusted rate
A rate after controlling for differences in the distribution of a factor in a population.
ex- Age adjusted rate.
Odd ratio that is less than 1
Protective factor
Odds ratio that is greater than 1
Suggests a risk factor.
Relative risk
Incidence rate in the exposed population/ incidence rate in the non exposed population,
Describe how to interpret relative risk
RR = 1 no association
RR > 1 exposure is a risk factor
RR<1 exposure is a protective factor.
Whats the difference between the odds ratio and the relative risk?
Odds ratio concerns the statement if people have the disease now how likely were they exposed to the risk factor in the past? (looks backward)
Relative risk is more if people are exposed how likely will they develop the disease (looks forward)
Population atributable risk
Measures excess disease rate in the population.
Ex those who die from lung cancer that smoke vs those that dont.
Sensitiivty
Proportion of persons with a condition who test positive on the screening test.
Specificity
Proportions of persons without the condition who test negative on screening.
Positive predictev value
The proportion of persons with a positive test who have the condition (true positives)
Negative predictive value
Proportion of persons with negative tests who do not have the condition.
