What is the incidence rate (absolute risk) of endometrial cancer among who didn’t use oral contraceptives?
a) 630 / (50 + 630)
b) 75 / (245 + 75)
c) 50 / (50 + 630)
d) 245 / (245 + 75)
e) Insufficient data
Key: True: c 50/ (50 + 630)
In a prospective study of the relationship between oral contraceptive use and the subsequent
risk of developing endometrial cancer, a cohort of 1000 women were followed for 5 years. The
results were as follows:
Present Absent
A 245
B 75
C 50
D 630
A + C = 295 B + D = 705 n = 1000