Answer:
Cohort study
Step-by-step explanation:
There are 3 main classes of epidemiologic studies: 1-Cross-sectional studies; 2- Case-control studies; and 3- Cohort studies. Cross-sectional studies (also known as prevalence studies) involve looking at data possible factors of risk and disease outcomes from a given population at one specific point in time. Moreover, a case–control study is an observational study where two groups are identified and subsequently compared to identify possible factors associated with a medical condition. Finally, a cohort study initially classifies the subjects of study into two different groups depending on their exposure status and then the occurrence of the outcome of interest is assessed. In consequence, the example above described refers to a cohort study because this study examines a cohort (i.e., workers) that were classified by their exposure to asbestos, and then analyzes the incidence rate of cancer as the outcome.