2 (Epidemiology) PRELIM PUBLIC HEALTH

What is the meaning epidemiology?

study of the distribution and determinants of health related states or events in specified populations, and the application of this study to the control of health problems

method of causal reasoning based on developing and testing hypotheses grounded in such scientific fields as biology, behavioral sciences, physics, and ergonomics to explain health-related behaviors, states, and events

Enumerate the Epidemiologic functions

what is the purpose of public health surveillance

the ongoing, systematic collection, analysis, interpretation, and dissemination of health data to help guide public health decision making and action

require the coordinated efforts of dozens of people to characterize the extent of an epidemic and to identify its cause

Field investigation is also known as

Often the methods are used in combination — with surveillance and field investigations providing clues or hypotheses about causes and modes of transmission, and analytic studies evaluating the credibility of those hypotheses.

s determining the appropriate research strategy and study design, writing justifications and protocols, calculating sample sizes, deciding on criteria for subject selection

nvolves securing appropriate clearances and approvals

describing the characteristics of the subjects.

the process of determining, as systematically and objectively as possible, the relevance, effectiveness, efficiency, and impact of activities with respect to established goal

to the ability of a program to produce the intended or expected results in the field

o the ability of the program to produce the intended results with a minimum expenditure of time and resources.

an investigation an epidemiologist usually participates as either a member or the leader of a multidisciplinary team

characterizes the amount and distribution of disease within and across populations.

common variables involve in Descriptive epidemiology

5 W’s of descriptive epidemiology

refers to the study of the determinants of health- related outcomes

Anticipated direction of effect is specified

No direction is specified

Frequently used to evaluate research hypothesis

3 characteristics of Measures of effect

Compares the incidence rate (IR)among the exposed the with the incidence rate among the non-exposed (IRE/IRNE)

Compares the incidence (I) proportion (risk) among exposed (E) with the incidence proportion (risk) among the non-exposed (NE) by the means of a ratio (IE/INE)

Compares the odds of exposure among those with the health outcome of interest to the odds of exposure among those without the health outcome

3 characteristics of evaluating associations

Refers to likelihood of observing an apparent exposure/health outcome relationship, when in fact, one does not truly exist

Refers to systematic error in the conduct of study

state the Errors due to bias that can occur

7 part of BIAS

Occurs when dissimilar procedures are used to select study subjects, and such procedures relate to the exposure or health outcome under study

Occurs when subjects are differentially referred into a study based on knowledge of their exposure status

Refers to different types of errors to the manner in which information is collected

outcome misclassification differs among persons exposed or not exposed, or similarly, exposure misclassification differs among case subjects and control subjects

magnitude is unrelated to exposure or outcome status

Occurs when subjects in the study groups formed recall of their exposure or outcome history differently

Occurs when individuals involved in the collection of exposure or outcome data probe for or record information in a differential manner

Refers to selective suppression or revealing of information, including sensitive information and information related to attitudes, beliefs, and perceptions

Can occur when subjects over-report exposure information in an attempt to show that a specific health condition experienced is not their fault

Refers to incorrect classification of the presence of an exposure that occurs after the onset of the health outcome under study, rather than before it

Frequently occurs in nonrandomized (observational) studies

Nuisance effect that distorts the study results

2 categories of epidemiological studies:

r determines through a controlled process the exposure for each individual (clinical trial) or community (community trial), and then tracks the individuals or communities over time to detect the effects of the exposure.

the epidemiologist simply observes the exposure and disease status of each study participant

• the investigator observes rather than determines the participants’ exposure status.

investigators start by enrolling a group of people with disease (at CDC such persons are called case-patients rather than cases, because case refers to occurrence of disease, not a person)

• a sample of persons from a population is enrolled and their exposures and health outcomes are measured simultaneously.

originally referred to an infectious microorganism or pathogen: a virus, bacterium, parasite, or other microbe.

refers to the human who can get the disease.

refers to extrinsic factors that affect the agent and the opportunity for exposure.

was proposed by Rothman in 1976, and has come to be known as what

what are the chains of infection

the habitat in which the agent normally lives, grows, and multiplies.

is the path by which a pathogen leaves its host. The portal of exit usually corresponds to the site where the pathogen is localized

what are the different modes of transmission

occurs through skin-to-skin contact, kissing, and sexual intercourse.

refers to spray with relatively large, short-range aerosols produced by sneezing, coughing, or even talking.

refers to the transfer of an infectious agent from a reservoir to a host by suspended air particles, inanimate objects (vehicles), or animate intermediaries (vectors)

an indirect transmission that occurs when infectious agents are carried by dust or droplet nuclei suspended in air

a type of indirect transmission that indirectly transmit an infectious agent include food, water, biologic products (blood), and fomites (inanimate objects such as handkerchiefs, bedding, or surgical scalpels)

a type of indirect transmission that indirectly transmits an infectious agent includes food, water, biologic products (blood), and fomites (inanimate objects such as handkerchiefs, bedding, or surgical scalpels)

such as mosquitoes, fleas, and ticks may carry an infectious agent through purely mechanical means or may support growth or changes in the agent.

• refers to the manner in which a pathogen enters a susceptible host.

Susceptibility of a host depends on genetic or constitutional factors, specific immunity, and nonspecific factors that affect an individual’s ability to resist infection or to limit pathogenicity.