Objective Studies indicate an inverse association between ductal adenocarcinoma of the pancreas (PDAC) and nasal allergies. However, controversial findings are reported for the association with asthma. Understanding PDAC risk factors will help us to implement appropriate strategies to prevent, treat and diagnose this cancer. This study assessed and characterised the association between PDAC and asthma and corroborated existing reports regarding the association between allergies and PDAC risk.
Design Information about asthma and allergies was collated from 1297 PDAC cases and 1024 controls included in the PanGenEU case–control study. Associations between PDAC and atopic diseases were studied using multilevel logistic regression analysis. Meta-analyses of association studies on these diseases and PDAC risk were performed applying random-effects model.
Results Asthma was associated with lower risk of PDAC (OR 0.64, 95% CI 0.47 to 0.88), particularly long-standing asthma (>=17 years, OR 0.39, 95% CI 0.24 to 0.65). Meta-analysis of 10 case–control studies sustained our results (metaOR 0.73, 95% CI 0.59 to 0.89). Nasal allergies and related symptoms were associated with lower risk of PDAC (OR 0.66, 95% CI 0.52 to 0.83 and OR 0.59, 95% CI 0.46 to 0.77, respectively). These results were supported by a meta-analysis of nasal allergy studies (metaOR 0.6, 95% CI 0.5 to 0.72). Skin allergies were not associated with PDAC risk.
Conclusions This study shows a consistent inverse association between PDAC and asthma and nasal allergies, supporting the notion that atopic diseases are associated with reduced cancer risk. These results point to the involvement of immune and/or inflammatory factors that may either foster or restrain pancreas carcinogenesis warranting further research to understand the molecular mechanisms driving this association.
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Acknowledgements The authors acknowledge the coordinators, field and administrative workers, technicians and study participants of the European Study into Digestive Illnesses and Genetics (PanGenEU) study.
Contributors NM; PG-R, J-PZ, FXR, MR: design of the study; analysis and interpretation of the data; preparation of the manuscript; and review and approval of the manuscript. MM: design, organisation and coordination of the study; management of the data and databases. LS, MH, AC, LI, CM, XM, AF, JP, WG, MOR, AT, TG, VB, TC-J, ED-M, LM-B, CA-U, JB, LB, EC, CG-P, JK, BK, RL, ML, JM, LM, DOD, PP, IP, AS: design of the study; recruitment of subjects; collection of biological samples; and review and approval of the manuscript.
Funding The work was partially supported by Fondo de Investigaciones Sanitarias (FIS), Instituto de Salud Carlos III, Spain (#PI11/01542, #PI0902102, #PI12/01635, #PI12/00815); Red Temática de Investigación Cooperativa en Cáncer, Spain (#RD12/0036/0034, #RD12/0036/0050, #RD12/0036/0073); European Cooperation in Science and Technology - COST Action #BM1204: EUPancreas. Acción Especial de Genómica, Spain (#GEN2001-4748-c05-03); EU-6FP Integrated Project (#018771-MOLDIAG-PACA), EU-FP7-HEALTH (#259737-CANCERALIA, #256974-EPC-TM-Net), Cancer Focus Northern Ireland and Department for Employment and Learning; and ALF (#SLL20130022), Sweden. The funders had no role in study design, data collection and analysis, decision to publish or preparation of the manuscript.
Competing interests None declared.
Patient consent Obtained.
Ethics approval The study was approved by the local ethics committee of the participating centres.
Provenance and peer review Not commissioned; externally peer reviewed.
Data sharing statement The data of the PanGenEU study are only available upon request and evaluation by the Study Steering Committee. Requests should be addressed to NM