Midterm 2 (Simplified) Flashcards
Definition of epidemiology
The study of the distribution and determinants of health-related states in specified populations, and the applications of this study to control health problems
Applications of epidemiology
- Identifying the cause of a new syndrome
- Assessing the risks of exposure
- Determining whether treatment X is effective
- Identifying health services use needs and trends
- Identifying practical prevention strategies
Definition of endemic
Cases are continually occurring in the population; regularly found among particular people or in a certain area.
Definition of epidemic
Outbreak of a disease in a localized group of people; spread by 1. vectors 2. carriers 3. sudden intro of new pathogen
Definition of pandemic
Epidemics that have spread beyond their local region and are affecting people in various/all parts of the world
Total people living with HIV in 2021
38.4 million
Total people newly infected with HIV in 2021
1.5 million
Total deaths from AIDS in 2021
650,000
Total people infected with TB in 2016
10.4 million
Total deaths from TB in 2016
1.8 million
Total deaths from HIV + TB in 2016
400,000
Prevalence
Proportion of individuals in a population with the disease at a given point in time
Prevalence formula
Number of cases/total population
Cumulative incidence
Proportion of individuals who become diseased during a specific time period
Cumulative incidence formula
Number of new cases of disease in a specific time period/number of people in the population at risk of developing the disease AT THE BEGINNING of the period
Incidence rate
Measure of the rate of development of a disease in a population
Incidence rate formula
Number of new cases of disease during given time period/number of person time [years/months/days] when people were at risk of developing the disease during observation
Sensitivity test
The ability of a test to correctly identify patients with a disease
Specificity test
The ability of a test to correctly identify people without the disease
Point prevalence
Individuals in a population with disease at a given point in time
Point prevalence formula
Number of diseased person on date /population of date
Period prevalence
Individuals in a population with disease at any time
Period prevalence formula
Cases/population of date
Case fatality rate formula
Number of deaths in a given point/total deaths
Sensitivity formula
Number of individuals with disease who test positive/number of individuals with disease x 100
Specificity formula
Number of individuals without disease who test negatively/number of individuals without disease x100
Why is false negatives important (2):
- Could contribute to spread a disease
- Treatment delay
Why is false positive important (3):
- Patient anxiety
- Stigma
- Waste of health care resources
Standarized rate
Statistical measure of any rates in a population. It is adjusted to take into account the vital differences between populations that may affect their birthrates or death rates
Why do we use standard rates
It removes the confounding effect of variables that we know or think differ in populations we wish to compare and it allows us to be able to compare these rates across different countries, locations, or regions
John Snow
- English physician widely known for his contributions to cholera
- Considered the father of contemporary epidemiology
- Developed 2 theories: Miasma & Germ
Main aspects of health promotion action (5):
- Build a health public policy
- Create supportive environments
- Strengthen community action
- Develop personal skills
- Reorient health services
HIV
Human immunodeficiency virus type 1. It causes CD4 T-cell depletion that results in AIDS
The epidemiologic approach (3):
- Counting cases and describing them in terms of time, place, and person
- Dividing the number of cases by an appropriate denominator to calculate rates (morbidity/mortality)
- Comparing the rates over time
Crude mortality rate
Overall incidence of death in a population
Establishing causation (5):
- Temporality: Exposure must come first Essential
- Strength of association: Strong effect?
- Biological plausibility: What is the likely biological mechanism?
- Consistency: Found across a range of studies?
- Dose response: Level and duration of exposure?
Prevention Paradox
Seemingly contradictory situation that states that large numbers of people must participate in a preventive strategy for direct benefit to relatively few
