Therefore, the RR of CVD among participants with low physical activity compared to those with high physical activity is 2.94. A case-control study was conducted to investigate the relationship between smoking and lung cancer. The study included 500 cases with lung cancer and 500 controls without lung cancer. The results are shown in the table below: Smoking Status Number of Cases Number of Controls Smoker 400 200 Non-smoker 100 300 What is the odds ratio (OR) of lung cancer among smokers compared to non-smokers? Answer To calculate the OR, we need to calculate the odds of smoking in each group:
Here are five practice problems to test your epidemiology study analysis skills: A cohort study was conducted to investigate the relationship between physical activity and the risk of cardiovascular disease (CVD). The study included 10,000 participants who were followed for 5 years. The results are shown in the table below: Physical Activity Level Number of Participants Number of CVD Cases Low 3,000 150 Medium 4,000 100 High 3,000 50 What is the relative risk (RR) of CVD among participants with low physical activity compared to those with high physical activity? Answer To calculate the RR, we need to calculate the risk of CVD in each group: 5.1.1 epidemiology study analysis practice problems answers
Total number of participants with diabetes = 10 + 40 + 60 = 110 Prevalence of diabetes = ⁄ 1000 = 0.11 Therefore, the RR of CVD among participants with
Odds of smoking in cases = ⁄ 100 = 4 Odds of smoking in controls = ⁄ 300 = 0.67 The results are shown in the table below:
OR = Odds of smoking in cases / Odds of smoking in controls = 4 / 0.67 = 6.0