The researchers identify the type of study in the method section. The study design was a retrospective register study. This type of study mean group participants based on their exposure status and compare their incidence of condition. However, in this case both exposure status and outcome are ascertained retrospectively (“Cohort studies,” n.d.). Also Retrospective register studies “looks backwards and examines medical files and record to find patterns” (LACN 2035, 2016). This type can be effective the aim because it is particularly important for unusual exposures or occupational exposures. In our opinion, Researchers had been successful in choosing the type of the study because this type has helped them to bring out the very obvious
