Epidemiology I Flashcards
What are the objectives of epidemiology?
- Identify causes of disease
- Surveillance (extent in community)
- Disease investigation (natural history and prognosis)
- Evaluate impact of therapies and health care delivery
- Public policy
What are some important epidemiologic milestones?
- Water fluoridation to prevent cavities
- Streptomycin to prevent TB
- Cigarettes increased lung cancer
- Tampons increased TSS
- Aspirin increased Reye’s syndrome
- Folate to prevent spina bifida
- Sleeping on back to prevent SIDS
What are the 3 most important factors in an epidemiological study?
- Person (age, gender, etc.)
- Place (geographic origin, common exposure, etc.)
- Time (exposure time, progression of disease, etc.)
This information can then be used to determine the cause and transmission of disease.
How do we measure the incidence of disease, and what are some important considerations?
(# new cases of disease) / (# ppl vulnerable to disease)
- Over a given time frame (usu. 1 year)
- Usu. expressed per 1,000 but can express as appropriate (e.g. per 100,000 for rare diseases)
- Need to be able to define onset of disease
- Use of appropriate denominator (i.e., including only males in prostate cancer incidence calculations, or including only women of child-bearing age when looking at birth rates)
How do we measure disease prevalence?
(# existing cases, old and new) / (# ppl vulnerable to disease)
- For a given time (point prevalence vs. period prevalence)
- Depends on incidence and duration; could change if either factor changes
- High incidence, short duration → low prevalence
- Low incidence, long duration → high prevalence
What is the attack rate, and when would it be used?
(# ill patients) / (# patients at risk)
Attack rate is used during outbreaks.
Define endemic, epidemic, and pandemic.
Endemic: Baseline rate of disease (in incidence or prevalence)
Epidemic: An increase in the number of cases compared to baseline for a given population, time, and place
Pandemic: Worldwide epidemic
What are the objectives of an epidemiologic investigation?
- Confirm the threat or existence of an epidemic
- Identify causative agent of disease (source and mode of transmission)
- Determine the geographic distribution
- Determine the public health impact, identifying those persons who are at highest risk for disease
- Assess local response capacity
- Identify the most effective control measures
Why should epidemiologic studies be conducted?
- Apparent number of persons affected
- Presence of unusual or severe clinical symptoms
- Lack of an obvious explanation for disease occurrence
- Perceived need to implement control measures
- Level of public concern
- Potential for contributing to medical knowledge
