What is the relative risk of developing pulmonary embolism in users of oral contraceptives as per the information given below?
Women using OCs Pulmonary embolism Total Yes No Yes 120 80 200 No 10 70 80 Total 130 150 280
Data Summary from 2x2 Table
The provided table shows the distribution of pulmonary embolism (PE) cases among oral contraceptive (OC) users and non-users.
| Women using OCs | Pulmonary embolism Yes | Pulmonary embolism No | Total |
|---|---|---|---|
| Yes | 120 | 80 | 200 |
| No | 10 | 70 | 80 |
| Total | 130 | 150 | 280 |
Calculating Relative Risk (RR)
Relative risk compares the likelihood of an event (PE) occurring in an exposed group (OC users) versus an unexposed group (non-OC users).
The formula for Relative Risk (RR) is:
$ RR = \frac{\text{Risk of PE in OC users}}{\text{Risk of PE in non-OC users}} $First, calculate the risk of PE in each group:
- Risk in OC users = (Number of OC users with PE) / (Total OC users) $ \text{Risk}_{\text{OC users}} = \frac{120}{200} = 0.6 $
- Risk in non-OC users = (Number of non-OC users with PE) / (Total non-OC users) $ \text{Risk}_{\text{non-OC users}} = \frac{10}{80} = 0.125 $
Now, calculate the relative risk:
$ RR = \frac{0.6}{0.125} $ $ RR = 4.8 $Therefore, the relative risk of developing pulmonary embolism in users of oral contraceptives is 4.8.
Important Questions from Biostatistics
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In a case-control study, 300 women aged 20-45 years suffering from breast cancer were compared with age-matched 300 women without breast cancer. It was observed that 120 women among cases and 60 women among controls were obese. The odds ratio of developing breast cancer among obese women is:
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What is the Standardized Mortality Ratio (SMR) for the hazardous industry workers (as compared to national popu-lation) ?
