Problem
In a study to determine the incidence of disease A (chronic disease), 150 people were examined at the end of the follow-up period. Twelves cases were found to have the disease, giving a cumulative incidence rate of 8% (check if my calculation is correct). Fifty other members of the initial cohort that enrolled to the study could not be examined regarding the presence or absence of the disease, 20 of them because they died before the study completed.
Answer the following questions.
1) What source of bias should be of concern in this example
2) What will be the incidence rate if all people who were lost to be followed had the disease and what will be the incidence rate if all people who were lost to be followed did not have the disease.