Previous studies suggested an association between atopic conditions and specific cancers. The results on the association with urothelial bladder cancer (UBC) are scarce and inconsistent. To evaluate the association between asthma and risk of UBC, we considered 936 cases and 1022 controls from the Spanish Bladder Cancer/EPICURO Study (86% males, mean age 65. 4 years), a multicenter and hospital based case-control study conducted during 1998-2001. Participants were asked whether they had asthma and detailed information about occupational exposures, smoking habits, dietary factors, medical conditions, and history of medication was collected through face-to-face questionnaires performed by trained interviewers. Since asthma and UBC might share risk factors, association between patients' characteristics and asthma was studied in UBC controls. Association between UBC and asthma was assessed using logistic regression unadjusted and adjusted for potential confounders. The complex interrelationships, direct, and mediating effect of asthma on UBC, were appraised using counterfactual mediation models. Asthma was associated with a reduced risk of UBC (odds ratio (OR)=0.54, 95% confidence interval (CI) 0.37, 0.79) after adjusting for a wide range of confounders. No mediating effect was identified. The reduced risk associated with asthma was restricted to patients with high-risk non-muscle invasive (OR=0.25, 95%CI 0.10, 0.62) and muscle invasive UBC (OR=0.32, 95%CI 0.15, 0.69). Our results support that asthma is associated with a decreased risk of UBC, especially among aggressive tumors. Further work on the relationship between asthma and other atopic conditions and cancer risk should shed light on the relationship between immune response mechanisms and bladder carcinogenesis. This article is protected by copyright. All rights reserved.
International journal of cancer. 2017 Sep 22 [Epub ahead of print]
Marta Rava, Maciej J Czachorowski, Debra Silverman, Mirari Márquez, Sirish Kishore, Adonina Tardón, Consol Serra, Montse García-Closas, Reina Garcia-Closas, Alfredo Carrato, Nathaniel Rothman, Francisco X Real, Manolis Kogevinas, Núria Malats
Genetic and Molecular Epidemiology Group, Spanish National Cancer Research Centre (CNIO), Madrid, and CIBERONC, Spain., Division of Cancer Epidemiology and Genetics, National Cancer Institute, Department of Health and Human Services, Bethesda, Maryland, USA., Department of Preventive Medicine, Universidad de Oviedo, and CIBERESP, Spain., Center for Research in Occupational Health (CiSAL), Universitat Pompeu Fabra, IMIM-Hospital del Mar Medical Research Institut, Barcelona, and CIBERESP, Spain., Hospital Universitario de Canarias, La Laguna, Spain., Servicio de Oncología, Hospital Universitario Ramon y Cajal, Madrid, Servicio de Oncología, Hospital Universitario de Elche, and CIBERONC, Spain., Epithelial Carcinogenesis Group, Spanish National Cancer Research Centre (CNIO), Madrid, Departament de Ciències Experimentals i de la Salut, Universitat Pompeu Fabra, Barcelona, and CIBERONC, Spain., Centre for Research in Environmental Epidemiology (CREAL), Parc de Salut Mar, Barcelona, and CIBERESP, Madrid, Spain.