T7: Epidemiology Flashcards
epidemiology
Epidemiology is the study of how diseases affect the health and illness of populations. It focuses on the distribution (who, when, and where) and determinants (why and how) of health-related states or events, including diseases.
- Objective: The primary goal is to understand the causes and patterns of health and disease in populations, which can then inform public health strategies and policies to prevent and control diseases.
descriptive epidemiology
Descriptive epidemiology is a branch of epidemiology that focuses on describing the distribution of diseases and health outcomes according to person, place, and time.
Objective: Its primary aim is to identify patterns and trends in health events by categorizing them based on demographic factors (e.g., age, gender), geographic locations, and time periods.
descriptive epidemiology focuses on the…
WHO, WHEN, WHERE, WHAT, PERSON, PLACE, TIME
analytic epidemiology
looks at the etiology (origins or causes) of the disease and deals with determinants of health and disease.
analytic epidemiology focuses on the…
CAUSES AND EFFECTS, HOW AND WHY
determinants of health events
are those factors exposures, characteristics, behaviors, and contexts that determine (or influence) the patterns.
john snows study
- Mapping Cases: Snow demonstrated the use of geographic mapping to identify disease patterns and clusters.
- Identifying the Source: He linked cholera outbreaks to contaminated water sources, particularly the Broad Street pump.
- Comparative Analysis: He compared cholera rates among households served by different water companies, highlighting the impact of water quality on disease spread.
- Scientific Reasoning: Snow’s methodical approach and evidence-based reasoning challenged prevailing theories and laid the groundwork for modern epidemiology and public health practices.
what is the only cholera vaccine approved by the FDA
Vaxchora
Sources of data in epidemiology
o Routinely collected data (census data, vital record, and surveillance data)
o Data collected for other purposes (medical records)
o Epidemiological data
age-adjusted rate
a rate used to make comparisons across groups and over time when groups differ in age structure
Direct Adjusted Rate
used if age-specific death rates in a population to be standardized are known and a suitable standard population is available
Indirect Adjusted Rate
If age-specific death rates of the population for standardization are unknown or unstable, for example, because the rates to be standardized are based on a small population.
Use SMR (Standard Mortality ratio)
comparison groups
to decide if the rate of disease is the result of a suspected risk factor, compare the exposed group with a group of comparable unexposed persons. Provides a picture of how things are or have been.
rate
a statistic used for describing an event, characteristic, or happening. TIME important or a proportion.
crude rate
rate expressed for a TOTAL POPULATION
specific rate
rate for a particular POPULATION SUBGROUP
rate formula
(Number of events/population at risk) X 100,000
morbidity rate
the extent that illness to disease symptoms are present and affecting a population
mortality rate
the number of deaths as a result of a disease or health event
incidence rate
number of NEW cases of a specific disease or injury within a specific time frame/population at risk x 100,000
prevalence rate
number of ALL cases of a specific disease or injury at a given point in time/population at risk x 100,000
endemic
approximately the same as incidence and recovery, constant presence of disease within a geographical area or population
epidemic
affecting a larger number of people at the same time (Maurer & Smith)/Unusual rise in incident rate and prevalence rate, rate of disease, injury, or other condition is clearly more than the usual (endemic) level of that condition
pandemic
affecting an extremely high number of people, usually in many countries (M&S)/ an epidemic occurring worldwide and affecting large populations
professional nursing roles of surveillance in epidemiology
-case finding
-reporting
-surveillance
-followup/evaluation
purpose of surveillance
Helps public health departments:
o Identify trends and unusual disease patterns.
o Set priorities for using scarce resources.
o Develop and evaluate programs for commonly occurring and universally occurring diseases or events.
National Notifiable Disease Surveillance System (NNDSS)
The CDC and the Council of State and Territorial Epidemiologists have a policy that requires state health
Types of Surveillance Systems
passive, active, sentinel, special
Types of Surveillance Systems: passive system
case reports are sent to local health departments by health care providers (i.e., physicians, nurses), or laboratory reports of disease occurrence are sent to the local health department.
Types of Surveillance Systems: active system
nurse, as an employee of the health department, may begin a search for cases through contacts with local health providers and healthcare agencies
Types of Surveillance Systems: sentinel system
monitors key health events when information is unavailable or in vulnerable populations to calculate or estimate disease morbidity.
Types of Surveillance Systems: special systems
developed for collecting particular types of data and may be a combination of active, passive, and/or sentinel systems.
syndromic surveillance systems
as a result of bioterrorism, these newer systems are being developed to monitor illness syndromes or events
epidemiological triangle
Agent, Host, and Environment
web of causation
Epidemiologic model that strongly emphasizes the concept of multiple causation while de-emphasizing the role of agents in explaining illness.
vectors
the presence of a vector, or non-human organism (often insects), mechanically or biologically play a role in transmission of disease from source to host.
screening
-A key component of many secondary prevention interventions
-Involves the testing of groups of individuals who are at risk for a specific condition but do not have symptoms.
what is the goal of screening
The goal is to determine the likelihood that these individuals will develop the disease.
reliability
o Precision of the measurement
o Consistency or repeatability of the measurement
validity
Is the measurement really measuring what we think it is, and how exactly?
sensitivity
quantifies how accurately the test identifies those with the condition or trait; true positives.
specificity
indicates how accurately the test identifies those without the condition or trait; true negatives.
Positive predictive value
the proportion of persons with a positive test who actually have the disease.
negative predictive value
the proportion of persons with a negative test who are actually disease-free.
health care acquired infections
infections acquired during hospitalization or developed within the hospital setting.
Universal Precautions
procedures to prevent exposure to blood-borne diseases.
how can morbidity be expressed?
illness rates
what is the term used to describe a disease that is constantly present in an area at a constant rate?
endemic
what does incidence mean
the number of new cases of a disease
