Case control studies ppt

Thus, potential stroke cases were selected as all patients in whom a CT scan of the brain was performed within 10 days after surgery. Data Collection Preoperative patient data were collected from preoperative evaluation clinic electronic patient records.

Overview Design of Case-Control Studies The investigator selects cases with the disease, and appropriate controls without the disease and obtains data regarding past exposure to possible etiologic factors in both groups.

Case control studies are also known as "retrospective studies" and "case-referent studies. Childhood Asthma and Passive Smoking: Use to investigate factors other than cigarette smoking Symptom syndromes: These consisted of both biometric data such as age, gender, weight, and preoperative blood pressure and medical history.

Case-control and cohort studies offer specific advantages by measuring disease occurrence and its association with an exposure by offering a temporal dimension i.

Case-control approaches are the most efficient for rare diseases, e. Issues in Selection of Controls: This is the case with some cohort studies.

It then looks back to see if an exposure to something in particular e. You can choose whether to allow people to download your original PowerPoint presentations and photo slideshows for a fee or free or not at all. Depending on the type and complexity of surgery, an ischemic stroke occurs in 0.

Observational Studies: Cohort and Case-Control Studies

Childhood Asthma and Passive Smoking How would you design a study to evaluate whether passive smoking is a risk factor for childhood asthma. Well-designed observational studies have been shown to provide results similar to randomized controlled trials, challenging the belief that observational studies are second-rate.

This could be either a matched or unmatched study, but efforts would need to be made to ensure that the former lifeguards are of the same average age, and lifeguarded for a similar number of seasons and amount of time per season.

Whether your application is business, how-to, education, medicine, school, church, sales, marketing, online training or just for fun, PowerShow. You're not following anyone, it's simply a "At this point, do you have or not have a disease" - along with covariates of course.

Because patients were not subjected to investigational actions and all patients were treated with care as usual, no written informed consent was necessary. Or use it to find and download high-quality how-to PowerPoint ppt presentations with illustrated or animated slides that will teach you how to do something new, also for free.

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Using previously collected data and obtaining additional measurements of exposures from available biospecimens, the investigator compares the exposure frequencies in cases and controls as in a non-nested case-control study.

Introduction to study designs - case-control studies

The conduct of a case-control study may be facilitated by the availability of a case-ascertainment system. Case-control designs may also be appropriate for more common diseases, such as COPD.

HP infection status was determined using serum obtained in the beginning of the follow-up. Results from observational studies are often criticized for being vulnerable to influences by unpredictable confounding factors.

Increased potential for information bias because subcohort may have been established after t0 exposure information collected at different times e.

Cross-sectional studies, also known as prevalence studies, examine the data on disease and exposure at one particular time point Figure 2. Childhood Asthma and Passive Smoking 3. Matching The process of selecting controls so that they are similar to the cases in regard to certain characteristics such as age, sex and race.

The nested case-control study is thus considered a strong observational study, comparable to its parent cohort study in the likelihood of an unbiased association between an exposure and an outcome.

Explanation A nested-case control study depends on the pre-existence of a cohort that has been followed over time. How would you evaluate exposure.

Evaluating Information on Exposure a Problems of recall in case-control studies i Limitations in human ability to recall ii Recall bias cases may remember their exposure with a higher or lower accuracy than controls do 2. A ratio of approximately 1:.


Case-control study power and sample size calculations using Stata

Learning objectives:You will learn about basic introduction to case-control studies, its analysis and interpretation of studies are one of the frequently used study designs due to the relative ease of its application in comparison with other study designs.

Study Goal: Assess the association between alcohol consumption and heart disease (case-control study) Matching Variable: sleep apnea (want to control for conditions that may influence oxygenation) If sleep apnea is a condition that occurs as a result of alcohol consumption and is a risk factor for heart disease, then matching.

The PowerPoint PPT presentation: "CASE CONTROL STUDIES" is the property of its rightful owner. Do you have PowerPoint slides to share? If so, share your PPT presentation slides online with Case-Control Studies E R I C N O T E B O O K S E R I E S Case-control studies are used to determine if there is an association denominators obtained in a case-control study do not represent the total number of exposed and non-exposed persons in the source population.

Case Control Study Definition A study that compares patients who have a disease or outcome of interest (cases) with patients who do not have the disease or outcome (controls), and looks back retrospectively to compare how frequently the exposure to a risk factor is present in each group to determine the relationship between the risk.

A Case-Control Study of Alcoholism and Pneumonia Cases and controls selected from hospitalized patients Alcoholics with pneumonia are more likely to be admitted.

Case control studies ppt
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Case control study | Institute for Work & Health