A large cohort study is conducted to assess the association between smoking and squamous cell carcinoma of the esophagus among middle-aged Chinese men. During 10 years of follow-up, smokers have 5 times the risk of esophageal carcinoma compared to non smokers (relative risk = 5.0, 95% confidence interval = 2.9-7.1). According to the study results, what percentage of squamous cell carcinoma of the esophagus in smokers can be attributed to smoking?
- AR= [(RR - 1)/ RR]
- AR= [(5-1)/ 5]
- AR= 0.8
- AR= 80%
- Therefore 80% of esophagus squamous cell carcinoma cases in smokers were attributable to smoking.