Question
Based on the following data, what is the relative risk (RR) of developing pulmonary embolism among oral contraceptive (OC) users compared with non-users?
| Pulmonary Embolism | OC Users | OC Non-Users | Total |
|---|---|---|---|
| Yes | 120 | 10 | 130 |
| No | 80 | 70 | 150 |
| Total | 200 | 80 | 280 |
| A. |
0.48 |
| B. |
4.80 |
| C. |
2.40 |
| D. | 0.24 |
Show Answer
|
Correct Answer » B Explanation |
 |
The Relative Risk (RR) compares the risk of developing a disease (pulmonary embolism) between an exposed group (OC users) and an unexposed group (non-users).
Formula for Relative Risk:
RR=Risk in Exposed Group/ Risk in Unexposed Group
Step-by-Step Calculation:
Step 1: Calculate Risk in Exposed Group (OC Users)
Risk in OC Users=Number of cases in OC users/ Total number of OC users
=120/200 =0.60
Step 2: Calculate Risk in Unexposed Group (Non-Users)
Risk in Non-Users=Number of cases in non-users/ Total number of non-users
=80/10 =0.125
Step 3: Calculate Relative Risk (RR)
RR=0.60 / 0.125
RR=4.80