Exocrine pancreatic cancer clinical factors were related to timing of blood extraction and influenced serum concentrations of lipids

Objective: Disease-induced changes in blood concentrations of lipids may bias etiologic studies. We analyzed the influence of clinical factors and timing of blood extraction on serum concentrations of cholesterol and triglycerides in exocrine pancreatic cancer (EPC). Study Design and Setting: Subjects were 144 incident cases of EPC prospectively recruited in five teaching hospitals in eastern Spain. Results: Higher concentrations of cholesterol, triglycerides, and total lipids were observed among patients with a shorter interval from first symptom of cancer to blood extraction (IES); but concentrations were lower in patients with longer IES. The relationship between cholesterol and tumor stage was n-shaped. Jaundice and other components of the cholestatic syndrome increased cholesterol and triglycerides. Invasive diagnostic tests were associated with lower cholesterol. All these factors were related to changes > 50 mg/dl in cholesterol (P < 0.05), even when adjusting by stage. Statistical models including IES, number of invasive diagnostic tests, jaundice, weight loss, and stage explained over 28% of the variation in lipid concentrations. Conclusion: Restriction and adjustment by stage maybe insufficient to prevent biases related to disease progression. Multivariate analyses may allow to control to some extent the influence of clinical symptoms, procedures, and timing of blood extraction in studies on the etiological significance of lipids and lipophilic compounds, either risk factors or protective agents. (c) 2008 Elsevier Inc. All rights reserved.