Definitions for "Cohort study"
Related Terms:
Prospective study, Cross-sectional study, Epidemiological study, Epidemiological studies, Selection bias, Case-control study, Epidemiology, Longitudinal study, Retrospective study, Observational study, Demography, Biostatistics, Biometry, Cohort analysis, Statistician, Comparison group, Case control study, Meta-analysis, Target population, Epidemiological, Controls, Generalizability, Demographic, Sample survey, Case studies, External validity, Sampling, Randomisation, Sample, Absolute risk, Quantitative research, Convenience sample, Universe, Population dynamics, Randomization, Longitudinal studies, Demographic data, Cohort, Random sample, Retrospective, Matching, Inferential statistics, Random assignment, Stratified sampling, Random sampling, Controlled experiment, Prevalence, Statistical inference, Descriptive study, Stratified random sample
in analytical epidemiology, a study where a population which is exposed to a presumed cause of disease is followed over a set period of time to monitor the appearance of the disease. A control group is also monitored to identify the cause and effect of infection. It is also known as a prospective study.
A study involving a group of people who either have or do not have a certain factor, such as exposure to a disease-causing agent. Such studies are usually used to compare disease rates.
A prospective investigation of the factors that might cause a disorder. A cohort (group) of persons who do not have the outcome of interest but who are exposed to the putative cause are compared to a cohort who are also free of the outcome but have not been exposed to the putative cause. Both cohorts are followed to compare the incidence of the outcome of interest. These studies are sometimes called prospective studies since the logic of the study design begins with exposure to the risk factor and the patients are followed for the development of the outcome. For example, a cohort of patients without evidence of liver disease but who have received a blood transfusion are compared to a cohort of patients without liver disease but have not been exposed to a blood transfusion. The two cohorts are followed over time and the incidence of hepatitis C is determined for each cohort.
A study in which exposed and non-exposed groups are followed up so that they can be compared with respect to subsequent disease incidence.
involves identifying two groups (cohorts) of subjects, one that did receive the exposure of interest and another that did not, and following these cohorts forward for the outcome of interest.
Study in which subjects are listed based on their presence (exposed) or absence (not exposed) in the presence of risk factors. Subjects are followed for a period of time for the development of the disease in question.
An epidemiology study that observes a large group of people over a period of time. Within the cohort, morbidity or mortality rates can be calculated for group members with different exposures.
involves identification of two groups (cohorts) of patients, one which did receive the exposure of interest, and one which did not, and following these cohorts forward for the outcome of interest.
Also called a "prospective observational study", this design follows a group of patients, called a "cohort", over time to determine general outcome as well as the outcomes of different subgroups.
A study design that looks forward in time from baseline data. Health status and related characteristics are assessed and later reassessed to determine which characteristics preceded or caused newly developed health outcomes. This design best allows for estimates of the probability or risk of developing the outcome.
a longitudinal study that divides a defined population into those who are exposed and those who are not exposed to a particular risk factor
an analytical study in which individuals with differing exposures to a suspected factor are identified and then observed for the occurrence of certain health effects over some period, commonly years rather than weeks or months
a study in which researchers compare two groups over a period of time
A study in which a group of people (or cohort) are identified then followed over time to see what happens to them (e.g. to see which people become ill and which do not).
See prospective study.
One type of epidemiological study. A group of people (the cohort) are examined over time to see which of them develop the disease under study.
A study design in which a population cohort is prospectively defined and divided according to the presence or absence of an exposure variable of interest and then followed over time for the occurrence of prespecified outcomes.
Follow-up of exposed and non-exposed defined groups, with a comparison of disease rates during the time covered. ( Harm, Prognosis)
an observational study in which outcomes in a group of patients that received an intervention are compared with outcomes in a similar group i.e., the cohort, either contemporary or historical, of patients that did not receive the intervention. In an adjusted- (or matched-) cohort study, investigators identify (or make statistical adjustments to provide) a cohort group that has characteristics (e.g., age, gender, disease severity) that are as similar as possible to the group that experienced the intervention.
A type of observational analytic study. Enrollment into the study is based on exposure characteristics or membership in a group. Disease, death, or other health-related outcomes are then ascertained and compared.
A type of study that involves the identification of two groups (cohorts) of patients, one of which received the exposure of interest, and one of which did not. Both groups are followed forward over time and studied for the outcome of interest.
A study in which a group is observed over a period of time.
A study in which a group of people with a past exposure to chemicals or other risk factors are followed over time and their disease experience compared to that of a group of people without the exposure.
An observational study that takes a group (cohort) of patients and follows their progress over time in order to measure outcomes and make comparisons according to the treatments or interventions that patients received.
An epidemiological study where scientists select the study population according to their exposure, regardless of whether the group has the disease or health outcome being studied. The researchers then determine the outcomes and compare the results on the basis of the individuals' exposure(s). Cohort studies are often referred to as prospective studies because they follow the study population forward in time.
A study in which a clearly identified group is characterized by exposure and is followed for the outcome.
A study in which individuals are identified who have or have not been exposed to something of interest (asbestos in the workplace, hypertension) and are then followed over time to see if they develop a particular outcome (pleural mesothelioma, stroke).
(Syn: follow-up, longitudinal, or incidence study) A type of observational analytical study. Enrolment in the study is based on membership in a "cohort" and on exposure characteristics. Disease, death, or other outcome rates are ascertained over the follow-up period and are compared between different exposure subsets of the cohort.
Statistics: A cohort study is a non-experimental study that looks for differences between members of an existing group. For example, a study that compared the previous-year trading results of traders using different trading software would be a cohort study. Cohort studies are not generally considered to be as reliable as randomized controlled trials, because results often are misleading. For example, in the software cohort study described above, different trading results between groups using different software might be due to the fact that experienced traders tend to use different software, rather than to the software itself. There might be other reasons for trading performance differences between the groups. See: Randomized Controlled Trials
The method of epidemiological study in which subsets of a defined population can be identified who are, have been or in the future may be exposed or not exposed or exposed in different degrees, to a factor or factors hypothesised to influence the probability of occurrence of a given disease or other outcome. Whilst cohort studies are sometimes referred to as "prospective studies" in relation to gastrointestinal outbreaks cohort studies are undertaken after the event has occurred. However a cohort study is only appropriate when the number of exposed persons can be identified (eg an outbreak at a wedding etc).
a group of people with a common characteristic or set of characteristics are followed up for a specified period of time to determine the incidence of some outcome; there is no comparison group.
A specific kind of trend study involving the study of a cohort over time.
A research study that compares a particular outcome, such as lung cancer, in groups of individuals who are alike in many ways but differ by a certain characteristic - for example, female nurses who smoke compared with those who do not smoke.
(see Appendix N) An observational study in which two or more sub-sets of defined populations are identified by the presence of a common factor or factors (eg non-randomly assigned to therapy involving the proposed drug or to therapy involving the main comparator(s)) and then followed in time to investigate the influence of the factors on the probability of occurrence of an outcome or outcomes.
a study that follows a large group of people over a long period of time, often 10 years or more. In cohort studies, dietary information is gathered before disease occurs, rather than relying on recall after disease develops.
An observational study that begins with a set of subjects who have a risk factor (or have been exposed to an agent) and a second set of subjects who do not have the risk factor or exposure. Both sets are followed prospectively through time to learn how many in each set develop the outcome or consequences of interest.
follow-up study of a (usually large) group of people, initially disease-free. Differences in disease incidence within the cohort are calculated in relation to different levels of exposure to specific factors, e.g., smoking, alcohol consumption, diet and exercise, that were measured at the start of the study and, sometimes, at later times during the study.
A 'cohort' is a group of people clearly identified: a cohort study follows that group over time, and reports on what happens to them. A cohort study is an observational study, and it can be prospective (following people forward over time) or retrospective (looking at what happened in the past). For example, a cohort study of 4th graders could follow them forward as they age, or look back at their previous health and school histories.
An epidemiologic study comparing those with an exposure of interest to those without the exposure. These two cohorts are then followed over time to determine the differences in the rates of disease between the exposure subjects.
A cohort study is a form of longitudinal study used in medicine and social science. It is one type of study design.