Question

A case-control and a prospective cohort study were conducted to assess the association between exposure X and disease Y. The results of the case-control study suggested that the odds of exposure X were 2.05 times higher among those who had disease Y compared to those who did not (Odds Ratio = 2.05, 95% confidence interval 1.50, 3.13). However, the results of

A case-control and a prospective cohort study were conducted to assess the association between exposure X and disease Y. The results of the case-control study suggested that the odds of exposure X were 2.05 times higher among those who had disease Y compared to those who did not (Odds Ratio = 2.05, 95% confidence interval 1.50, 3.13).However, the results of the prospective cohort study suggested that the risk of outcome Y was only 3% higher and not statistically significant among those who were exposed to X compared to those who were not (Risk Ratio = 1.03, 95% confidence interval 0.97, 1.86). Assuming the results from the prospective cohort study are reflective of the true association, which of the following responses would most likely explain the differing results?

A.Recall bias within the case-control study

B.Recall bias within the prospective cohort study

C.Berkson's bias (i.e. Diagnostic Bias) within the case-control study

D.Placebo effect within the case-control study

Answer 1

The discrepancy between the case-control study Odds Ratio of 2.05 and the prospective cohort study Risk Ratio of 1.03 is most likely due to recall bias in the case-control study, which is retrospective. Recall bias may cause participants to misremember past exposures, leading to an overestimated association between exposure X and disease Y.

Step-by-step explanation:

An analysis of the case-control and prospective cohort studies reveals a discrepancy in measuring the association between exposure X and disease Y. The case-control study, which is retrospective in nature, had an Odds Ratio (OR) of 2.05, indicating a higher likelihood of exposure amongst those with the disease. Conversely, the prospective cohort study, typically more accurate due to its forward-looking approach and direct data collection, showed a not statistically significant Risk Ratio (RR) of 1.03.

The differing results between the two studies can be explained by recall bias within the case-control study. Recall bias occurs when participants do not accurately remember past exposures or events. In contrast, data collected prospectively in a cohort study tends to be more reliable as the information is recorded over time as events unfold, reducing the likelihood of misremembering or altering past exposures.

Given that recall bias affects retrospective studies like the case-control study, option A (Recall bias within the case-control study) is the most plausible explanation for the disparity in results. This bias might result in an overestimation of the strength of the association between exposure X and disease Y.