Question

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 with 4% o f 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. This conclusion:

a. Is correct
b. May be incorrect because there is no control or comparison group
c. May be incorrect because of failure to establish the time sequence between onset of the diabetes and diagnosis of pancreatic cancer
d. May be incorrect because of less complete ascertainment of diabetes in the pancreatic cancer cases
e. May be incorrect because of more complete ascertainment of pancreatic cancer in nondiabetic persons

Answer 1

The conclusion that diabetes plays a causal role in pancreatic cancer may be incorrect due to the failure to establish the time sequence between diabetes onset and cancer diagnosis. Both pancreatic tumors, which may increase glucagon, and Type I diabetes, which results from a lack of insulin, can lead to hyperglycemia. The Correct Answer is Option. C.

Step-by-step explanation:

In a large case-control study where 17% of patients with pancreatic cancer were found to be diabetic at diagnosis compared to 4% in a well-matched control group, it was concluded that diabetes played a causal role in the pancreatic cancer. However, this conclusion may be incorrect because of the failure to establish the time sequence between the onset of diabetes and the diagnosis of pancreatic cancer. It's crucial to determine whether diabetes preceded cancer or developed as a result of the cancer itself to establish a causal relationship.

Pancreatic tumors may cause excess secretion of glucagon, while Type I diabetes is characterized by a failure to produce insulin. Considering these hormonal roles, the correct statement about these two conditions is that both a pancreatic tumor and Type I diabetes can cause hyperglycemia, as a pancreatic tumor leading to excess glucagon promotes glucose release into the blood, and lack of insulin in Type I diabetes prevents glucose uptake by cells, also leading to high blood sugar levels.