Allergies are associated with reduced pancreas cancer risk: A population-based case-control study in Ontario, Canada

Pancreatic adenocarcinoma is one of the deadliest cancers with mortality rates almost equaling incidence rates. Each year, approximately 3,500 Canadians are diagnosed with this disease. Although somewhat inconsistent, epidemiological studies have found that allergies are associated with a reduced pancreas cancer risk while there appears to be no association with asthma. These associations were evaluated in a population-based case-control study conducted in Ontario. Incident cases of pancreatic adenocarcinoma, identified through the Ontario Cancer Registry (OCR), and diagnosed April 1, 2003 to June 1, 2006, were recruited by the Ontario Pancreas Cancer Study (OPCS). Controls were recruited from the Ontario Familial Colorectal Cancer Registry (OFCCR). Data on 276 cases and 378 controls were available for the current study. Multivariable logistic regression analysis was used to obtain age-adjusted odds ratio (AOR) estimates. Ever having allergies or hayfever was associated with reduced pancreas cancer risk (OR = 0.43, 95% confidence interval (CI): 0.29-0.63). There was no association observed between a history of asthma and pancreas cancer risk. Findings are of great importance to understanding the biological mechanisms involved in pancreas cancer development.