A. You finally receive funding to study the potential risk factors for an extrem

Question

A. You finally receive funding to study the potential risk factors for an extremely rere blood disorder. 1. what study design would be most appropriate for this research? 2. Justify the choice of the design. 3. What are the strength and limitation of the design. B. Describe your hypothetical study of the blood disorder from problem A. 1) What are the characteristics of the subject you would select for the study? 2). What exposures, outcome, and potential confounders would you measure? 3). What would be the focus of your analysis?

Explanation / Answer

Ans 1: We can choose Case Control study

Ans 2: This is because it entails comparisons made between an index case group and a refernce group of people free of the disorder at times of cases' diagonesis. Typically efforts are made to enrol all possible cases who meet study inclusion criteria, and controls are then selected as a sample of the source population that generated the cases.

Ans 3: It has been recognised that the case control design has decided advantages in terms of efficiency, relative to full cohort studies. For studies of "rare diseases" case control studies offer a cost and time efficient means of accruing relatively large number of cases, thus avoiding prolonged follow up of large cohorts. Also the reduced study size of a case control study compared to a full cohort study can permit efficient resource allocation to refining exposure assessment and obtaining data on potential confounding factors which may not be practical in a cohort study.

Control selection for nested case control studies is a relatively straightforward matter in most instances whereas the choice of controls in community based studies is often more complicated and are subject to uncertainity. In community based studies controls should be a random sample of the source population but this may not always be well defined or enumerated. Ideally controls should be selected from population registers but when these are not available controls may be selected from other sources such as patients in the same hospital but admitted for a different illness, neighbours or family members. There can be several alternative choices for controls for a given study each with characteristic advantages and limitaions in terms of validity, efficiency for addressing study questions of interest and feasibilty.

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.