ABO blood group and chronic pancreatitis risk in the NAPS2 cohort

A risk association has been observed between non-O blood groups and pancreatic adenocarcinoma. Chronic pancreatitis also increases risk for pancreatic cancer, raising questions as to whether non-O blood groups are a risk for chronic pancreatitis and whether the pathophysiologic pathways are linked. Our goal was to determine whether ABO blood group may affect the risk of chronic pancreatitis.

The study cohort included chronic pancreatitis patients (n = 499) and healthy controls (n = 631) from the North American Pancreatitis Study 2 study. Genotyping was performed using Sequenom assay of rs8176746 A/C and rs505922 C/T to classify participants into ABO blood groups.

O blood group was nonsignificantly more common among cases (44.7% vs 42.0%; P = 0.36), particularly among cases with alcohol-related chronic pancreatitis (49.3% vs 42%; P = 0.060). Alcoholic patients without coexisting high-risk PRSS1, CFTR, or SPINK1 variants had a significant overrepresentation of O blood type when compared with controls (odds ratio, 1.54; 95% confidence interval, 1.09-2.17; P = 0.01).

A, B, and AB blood groups were not associated with a greater likelihood of having chronic pancreatitis and may decrease the risk of chronic pancreatitis in individuals who are very heavy drinkers. These results suggest that the mechanism linking non-O blood type with pancreatic pathology is specific to carcinogenesis.