Cohort Studies, Relative Risk Calculation

A longitudinal study followed 5,000 factory workers exposed to silica dust and 5,000 unexposed workers for 10 years to determine the incidence of silicosis. At the end of follow-up, 450 cases of silicosis were identified in the exposed group and 15 cases in the unexposed group. What is the relative risk of silicosis in exposed workers compared to unexposed workers?

A public health researcher follows 1200 adults without diabetes for 5 years. At baseline, 600 participants consume a high-salt diet and 600 consume a low-salt diet. After 5 years, 120 participants in the high-salt group develop diabetes, while 40 in the low-salt group develop diabetes. What is the relative risk of diabetes in the high-salt group compared to the low-salt group?

A researcher enrolls 500 disease-free factory workers exposed to asbestos dust and 500 disease-free workers from an office setting with no asbestos exposure. Both groups are followed for 10 years to determine the incidence of lung cancer. At the end of the study, 50 cases of lung cancer developed in the exposed group and 5 cases in the unexposed group. What is the relative risk of lung cancer in asbestos-exposed workers?

A prospective cohort study in rural India enrolled 800 farmers without hypertension at baseline. After 3 years of follow-up, 120 farmers who were exposed to high occupational heat stress developed hypertension, compared to 40 farmers in the low heat-stress group (n=400 each). What is the relative risk of developing hypertension in the high heat-stress group?

A prospective cohort study is conducted to evaluate the association between oral contraceptive use and venous thromboembolism (VTE) in Indian women. 2000 women using oral contraceptives and 2000 women not using oral contraceptives are followed for 5 years. At the end of the study, 40 cases of VTE are identified in the exposed group and 8 cases in the unexposed group. What is the relative risk of VTE in women using oral contraceptives?