GPH: Chapter 9

Associations

The relationships between two or more events or variables. Events are said to be associated when they occur more frequently together than one would expect by chance. Association does not necessarily imply a causal relationship.

Case-control studies

The relationships between two or more events or variables. Events are said to be associated when they occur more frequently together than one would expect by chance. Association does not necessarily imply a causal relationship.

Cases

In a case-control study, people who have the disease being studied.

Chronic diseases

Diseases that are marked by long duration or frequent recurrence, usually incurable but not immediately fatal. Common diseases that are considered chronic include cardiovascular disease, cancer, diabetes, Alzheimer's disease, and acquired immunodeficiency syndrome (AIDS).Cohort study:

Control group

A group of individuals used by an experimenter as a standard for comparison—to see the effect of changing one or more variables in an experimental (or treatment) group.

Controls

In a case-control study, healthy individuals who do not have the disease being studied.

Descriptive epidemiology

Analyzing and organizing disease and health data in order to understand how disease varies over time and in different geographic locations among people and their personal characteristics.

Determinants

Any of a group of variables, such as specific disease agents and environmental factors, that directly or indirectly influence the frequency or distribution of a disease.

Disease frequency

A public health measure that shows how a common disease or other health condition behaves in a given population over a specific time period.

Distribution of disease

A description of a pattern of an illness and how it relates to a person, place, and time.

Double-blind

Both the patient and the doctor are blind as to whether the patient is receiving a drug or a placebo in a clinical trial.

Endemic rate

The usual prevalence of a disease within a given geographic area.

Epidemic

The occurrence in a community or geographic area of a disease at a rate that clearly exceeds the normally expected rate.

Epidemic curves

A plot of time trends in the occurrence of a disease or other health related event for a defined population and time period.

Epidemiologic surveillance

The ongoing and systematic collection, analysis, and interpretation of health data essential to the planning, implementation, and evaluation of public health practice, closely integrated with the timely dissemination of these data to those who need to know. The final link in the surveillance chain is the application of these data to prevention and control.

Epidemiologic investigation

A set of procedures used to identify the cause, i.e. the infectious agent, responsible for a disease.

Epidemiology

The study of populations to seek the causes of health and disease; the study of the distribution and determinants of disease frequency in human populations.

Framingham Heart Study

A long-term, ongoing cardiovascular cohort study of residents of the city of Framingham, Massachusetts.

Health outcomes

Results of healthcare interventions.

Incidence

A measure of the number of new cases occurring in a population within a given amount of time, usually a year.

Incubation period

The time between infection of an individual by a pathogen and the manifestation of the disease it causes.

Intervention study

An epidemiologic study in which the impact of some intervention on one group of subjects is compared with the effect of a placebo or conventional therapy on a control group; for example, a clinical trial.

Mortality rates

The incidence of deaths per unit of time, most often per year, in a population.

Notifiable diseases

Diseases that the law requires to be reported to public health authorities as part of the public health surveillance system.

Odds ratios

A measure of the strength of an association between an exposure and a disease. The numerator of the odds ratio is the ratio of exposed subjects to nonexposed subjects in the case group; the denominator is the ratio of exposed subjects to nonexposed subjects in the control group.

Placebo

A supposedly ineffective pill or agent used in a control group to gauge the effect of an actual treatment in another group. Experimenters often must allow for a placebo effect, a response caused by suggestion.

Prevalence

Proportion of persons in a population who have a particular disease or attribute at a specified point in time or during a specified time period.

Randomized

A procedure or experiment performed using random selection or sampling.

Rate

The proportion of some disease or condition in a group usually per unit of time, with a numerator and denominator (stated or implied) indicating "so many per so many per year or other unit of time."

Relative risk

A comparison of two rates (e.g., a comparison of morbidity rates) using a calculation of the ratio of one to the other.

Risk factors

Characteristics that have been demonstrated statistically to increase a person's chance of developing a disease or being injured.

"Shoeleather" epidemiology

Epidemiologic investigation.

Treatment group

The treated group in a study, in contrast to an untreated or more conventionally treated control group.

Vital statistics

Systematically collected statistics on births, deaths, marriages, divorces, and other life events. More broadly, the statistics of life, health, disease, and death—the statistics that measure progress, or lack of it, against disease.