{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

Limitations cohort studies are more costly and there

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Limitations: Cohort studies are more costly and there is a greater chance of losing subjects to follow-up based on the long time period over which the cohort is followed. Appropriate measure of association: The measure of association between exposure and disease in cohort studies is the relative risk. The relative risk is the ratio of the incidence rate of index subjects to that of control subjects. A relative risk of 1.0 signifies that the incidence rate is the same among exposed and non-exposed subjects and indicates a lack of association between exposure and disease. A relative risk of less than 1.0 provides evidence for a protective effect of exposure (the incidence rate of disease among exposed is lower than non-exposed) whereas a relative risk
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
above 1.0 suggests that exposed people are at higher risk of disease than non-exposed persons. 3. Experimental Studies: An experimental study, also known as a trial, investigates the role of some agent in the prevention or treatment of a disease. In this type of study, the investigator assigns individuals to two or more groups that either receive or do not receive the preventive or therapeutic agent. The group that is allocated the agent under study is generally called the treatment group, and the group that is not allocated the agent under study is called the comparison group. Depending on the purpose of the trial, the comparison group may receive no treatment at all, an inactive treatment such as a placebo, or another active treatment. [Morabia A] Characteristics: Studies preventions and treatments for diseases; investigator actively manipulates which groups receive the agent under study. Limitations: Experimental studies are expensive and often infeasible and unethical Appropriate measure of association: Correlation coefficient or chi-square test for association can be used as a measure of association experimental study. References: Morabia A. A History of Epidemiologic Methods and Concepts. Basel : Birkha¨user, 2004, p. 175 Jan P Vandenbroucke, and Neil Pearce, Incidence rates in dynamic populations , International Journal of Epidemiology 2012;41:1472–1479
Background image of page 2
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

Page1 / 2

Limitations Cohort studies are more costly and there is a...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon bookmark
Ask a homework question - tutors are online