What are confounders in epidemiology?

What are confounders in epidemiology?

Confounding is one type of systematic error that can occur in epidemiologic studies. Confounding is the distortion of the association between an exposure and health outcome by an extraneous, third variable called a confounder.

What do confounders do?

A Confounder is an extraneous variable whose presence affects the variables being studied so that the results do not reflect the actual relationship between the variables under study. The aim of major epidemiological studies is to search for the causes of diseases, based on associations with various risk factors.

What is confounding association?

Confounding is a distortion of the association between an exposure and an outcome that occurs when the study groups differ with respect to other factors that influence the outcome.

Which method is associated with confounding variables?

There are several methods you can use to decrease the impact of confounding variables on your research: restriction, matching, statistical control and randomization. In restriction, you restrict your sample by only including certain subjects that have the same values of potential confounding variables.

What do confounders mean?

confounding factor
A confounder (or ‘confounding factor’) is something, other than the thing being studied, that could be causing the results seen in a study. If researchers do not consider confounders, the results of their research might not be valid. …

Are confounders associated with the outcome?

The confounding factor must be associated with both the risk factor of interest and the outcome. The confounding factor must be distributed unequally among the groups being compared. A confounder cannot be an intermediary step in the causal pathway from the exposure of interest to the outcome of interest.

What are the potential confounders in your study?

Confounding variables are those that may compete with the exposure of interest (eg, treatment) in explaining the outcome of a study. The amount of association “above and beyond” that which can be explained by confounding factors provides a more appropriate estimate of the true association which is due to the exposure.

What is stratification in epidemiology?

Stratification Stratification allows the association between exposure and outcome to be examined within different strata of the confounding variable. For example by age, sex or alcohol consumption. This gives us an overall summary measure of effect [1].

What is an example of confounding by indication?

Patients prescribed medications are more likely to have more severe disease than those not prescribed medication, which is a source of confounding. For example, aspirin is an indication for cardiovascular disease. …

What are confounding variables in a study?

A confounding variable (confounder) is a factor other than the one being studied that is associated both with the disease (dependent variable) and with the factor being studied (independent variable). A confounding variable may distort or mask the effects of another variable on the disease in question.

How is confounding controlled in epidemiology?

Strategies to reduce confounding are:

  1. randomization (aim is random distribution of confounders between study groups)
  2. restriction (restrict entry to study of individuals with confounding factors – risks bias in itself)
  3. matching (of individuals or groups, aim for equal distribution of confounders)

What are confounds in research?

What is confounding? Confounding is often referred to as a “mixing of effects”1,2 wherein the effects of the exposure under study on a given outcome are mixed in with the effects of an additional factor (or set of factors) resulting in a distortion of the true relationship.