###Rationale: Cigarette smoking is associated with a fivefold increased risk for adenocarcinoma of the pancreas. Cholelithiasis (choice B) and alcohol abuse (choice A) are associated with pancreatitis, not pancreatic adenocarcinoma.Diagnosis: Pancreatic adenocarcinoma

###Answer: OPTION C IS CORRECT.
###Question: A 65-year-old woman presents with a 5-week history of yellow skin and sclera, anorexia, and epigastric pain. Her past medical history is significant for insulin-dependent diabetes mellitus. She smoked one pack of cigarettes a day for the past 20 years. Physical examination reveals jaundice and a palpable gallbladder. Laboratory studies show a serum bilirubin level of 10 mg/dL, mostly in the conjugated form, and an elevated alkaline phosphatase (260 U/L). A CT scan of the abdomen discloses a mass in the head of the pancreas and multiple nodules in the liver measuring up to 3 cm. Which of the following is the most important risk factor for the neoplasm arising in the patient?
###Options:
A. Alcohol abuse
B. Cholelithiasis
C. Cigarette smoking
D. Diabetes mellitus type 1
