Question
Read the abstract for the paper by Cohn et al. entitled “DDT and Breast Cancer in Young Women: New Data on the Significance of Age at Exposure” and answer the following questions:
A. What type of study design did the authors use?
B. Is this a concurrent or non-concurrent study? Was exposure information collected prospectively or retrospectively? (refer to the Methods Section: Serum assays if necessary)
C. How did the authors choose the controls?
D. For what reason might the authors have chosen to use this method of control selection?
E. What does the calculated OR estimate?
F. What must be true for the OR to estimate this measure?
Source: 250B problem set
