Diabetes is a risk factor for atrial fibrillation. In one longitudinal study, researchers investigated the association between diabetes and atrial fibrillation, stratified by sex. These data are given in the table below.”

Table: Incidence of Atrial Fibrillation (AF) by diabetes status, stratified by sex

	Cases of AF	Person years of follow-up per 1,000
Males
Diabetes	37	2,336
No diabetes	355	26,454
Females
Diabetes	65	3,896
No diabetes	334	37,120
Total
Diabetes	102	6,232
No diabetes	689	63,574

“Use the data in the table to assess the association between diabetes and atrial fibrillation, and then stratified by sex. (meaning the association in males and the association in females” [ 4 marks]

“After using the statistical software, the authors found that the sex-adjusted relative risk (rate-ratio in this case) they found adjusted RR of 1.51.

Is sex best characterized as a confounder or an effect modifier of the relationship between diabetes and atrial fibrillation? Explain.” [ 4 marks]

c) “What is the Attributable risk fraction of diabetes among Males and how would you interpret the finding [4 marks]

d) “What is the population-attributable fraction of diabetes on the occurrence of atrial fibrillation that is potentially preventable, assuming a causal association between diabetes and Atrial Fibrillation.” [4 marks] explain in words your findings

Question 3

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 was completed.

What source of bias should be of concern in this example (4 points)

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? (Show your denominator and numerator in the calculation.