Question

A study was carried out to examine the hypothesis that rugby playing increases the risk of developing arthritis. Using a general practice database, all people with arthritis in one or both knees were identified. A comparison group was randomly selected from among the patients who did not have arthritis in either knee. Those agreeing to participate in the study were interviewed to determine whether or not they had played rugby before being diagnosed with arthritis. a) Classify this study accordingly:

(i) descriptive analytic
(ii) cross-sectional longitudinal
(iii) observational experimental
(iv) cohort study randomised controlled trial descriptive survey case-control study

Answer 1

The study described is an observational case-control study, designed to compare a group with arthritis to a control group without the disease to find a link to prior rugby playing.

Step-by-step explanation:

A study was carried out to examine the hypothesis that rugby playing increases the risk of developing arthritis. This type of study design could be classified as an observational study because researchers are not manipulating the conditions but are observing naturally occurring phenomena to identify associations. Specifically, since researchers are comparing a group with arthritis to one without to determine a prior exposure (rugby playing), this constitutes a case-control study. A case-control study is a type of analytical observational study where two groups differing in outcome are identified and compared to find a causal factor. The group with the disease or outcome of interest (in this case, arthritis) are the cases. Those without the disease – the control group – are randomly selected from the same population but without the outcome of interest. Researchers then look back retroactively to assess whether there was a difference in exposure to a potential risk factor between the two groups.