title: History of allergy and reduced incidence of colorectal cancer, Iowa Women's Health Study.
abstract: Previous epidemiologic studies have reported that a history of allergy is associated with reduced risk of colorectal cancer and other malignancies. We studied the association between allergy history and incident colorectal cancer (n=410) prospectively in 21,292 Iowa women followed for 8 years. Allergy was defined from four self-reported questions about physician-diagnosed asthma (a), hay fever (b), eczema or allergy of the skin (c), and other allergic conditions (d). A history of any allergy was inversely associated with incident colorectal cancer: after multivariate adjustment, the hazard ratio (HR) was 0.74 [95% confidence interval (95% CI), 0.59-0.94]. Compared with women with no allergy, women reporting only one of the four types of allergy and women reporting two or more types had HRs of 0.75 (95% CI, 0.56-1.01) and 0.58 (95% CI, 0.37-0.90), respectively (P trend=0.02). The inverse association persisted in analyses restricted to any type of nonasthmatic allergy (HR, 0.73; 95% CI, 0.56-0.95). HRs were similar for rectal and colon cancers as well as for colon subsites: proximal and distal (HRs for any allergy ranged from 0.63 to 0.78 across these end points). Allergy history, which may reflect enhanced immunosurveillance, is associated with a reduced risk of colorectal cancer.
authors.affiliation: Division of Epidemiology and Community Health, School of Public Health, University of Minnesota, Minneapolis, MN 55455, USA.
authors.forename: Anna E
authors.initials: AE
authors.lastname: Prizment
authors.forename: Aaron R
authors.initials: AR
authors.lastname: Folsom
authors.forename: James R
authors.initials: JR
authors.lastname: Cerhan
authors.forename: Andrew
authors.initials: A
authors.lastname: Flood
authors.forename: Julie A
authors.initials: JA
authors.lastname: Ross
authors.forename: Kristin E
authors.initials: KE
authors.lastname: Anderson
mesh_terms: D000368:Aged; D001249:Asthma / Q000453:epidemiology / Q000276:immunology; D015331:Cohort Studies; D015179:Colorectal Neoplasms / Q000453:epidemiology* / Q000276:immunology*; D005260:Female; D006801:Humans; D006967:Hypersensitivity / Q000453:epidemiology* / Q000276:immunology*; D015994:Incidence; D007484:Iowa / Q000453:epidemiology; D011446:Prospective Studies