In a large case-control study of patients with pancreatic cancer, 17% of the patients were found to be diabetic at the time of diagnosis, compared to 4% of a well-matched control group (matched by age, sex, ethnic group, and several other characteristics) that was examined for diabetes at the same time as the cases were diagnosed. It was concluded that the diabetes played a causal role in the pancreatic cancer. What does this conclusion suggest?
a We cannot say diabetes caused pancreatic cancer because it is too difficult to identify all patients with diabetes
b Diabetes definitely caused pancreatic cancer in this study
c It is not accurate to assume diabetes played a causal role since we cannot establish the timing of disease in the disease pattern
d None of the above.