Question

A researcher wants to know whether there is an association of CRP values with risk of MI/Cancer. They started to take CRP readings. 4 values of RR (Relative Risk) were plotted (0.5, 1.5, 1.7, 1.8) with respect to CRP.

• A. CRP increases disease/cancer risk
• B. CRP has no relationship
• C. CRP decreases & disease decreases
• D. No association in first interval

Hint:

Interpret the overall trend of the RR values -- most values above 1 indicate a positive association between CRP and disease risk.

Answer 1

The Correct Option is A

Step 1: Understand the Relative Risk (RR) values given. Four RR values are plotted against increasing CRP levels: 0.5, 1.5, 1.7, 1.8. RR is the ratio of the probability of an outcome in an exposed group to the probability in an unexposed group.

Step 2: Interpret each RR value.
- RR = 0.5: The first interval shows a protective or inverse association (below 1.0 means the exposed group has lower risk than the reference). However, note that this is only one point in a trend.
- RR = 1.5, 1.7, 1.8: These values are all above 1.0, indicating increased risk with increasing CRP levels. As CRP rises, the relative risk of MI/Cancer increases progressively.

Step 3: Interpret the overall trend. Despite the first interval having RR below 1, the dominant and consistent trend across higher CRP intervals shows increasing RR (1.5 to 1.8), indicating that as CRP increases, the risk of MI/Cancer increases. The overall conclusion supported by epidemiologic evidence is that elevated CRP is associated with increased disease risk.

Step 4: Eliminate other options. Option B (no relationship) is incorrect as RR values differ from 1. Option C (CRP decreases disease) is incorrect -- the trend is increasing RR with increasing CRP. Option D (no association in first interval) may technically describe one data point but is not the overall study conclusion.

Conclusion: CRP increases disease/cancer risk.