In a study of 200 smokers and 300 non- smokers were followed up over a period of 10 yrs to find out incidence of hypertension. Out of 200 smokers,60 developed hypertension, as compared to 600 non- smokers of which 30 developed hypertension . The risk ratio of the study:

Relative Risk (RISK RATIO) is used to estimate risk of disease (calculated as incidence of that disease) with exposure to a factor Relative Risk (RR) - Incidence among exposed/ Incidence among non-exposed In the given question, 200 smokers & 300 non-smokers were followed up over a period of 10 yrs to find out incidence of hypertension, Out of 200 smokers, 60 developed hypertension, thus Iexp = 60/ 200 × 1000 = 300 And, out of 600 non-smokers, 30 developed hypertension, thus Inon-exp a 30/ 600 ×1000 = 50 = 300/50 =6