Associations between Atopic Dermatitis and Risk of Gastric Cancer: A Nationwide Population-based Study.

Background/Aims: Epidemiologic and clinical data indicate that allergies may be associated with reduced risks for several cancers; however, to date, only a few studies have examined the associations between allergies and gastric cancer. This study aimed to examine the associations between allergies and gastric cancer using a large population-based dataset. Methods: This cross-sectional study obtained data from the Korea National Health and Nutrition Examination Survey between 2010 and 2014, involving a total of 24,089 participants. The associations between allergies and gastric cancer were analyzed using univariable and multivariable logistic regression analyses with complex sampling, while adjusting for confounding factors that included age, sex, body mass index, smoking status, alcohol intake, and level of education. Results: Multivariable logistic regression analyses that were adjusted for the potential confounders determined that a history of allergic diseases tended to be associated with reduced risk of gastric cancer; however, this relationship was not statistically significant (any allergy: odds ratio [OR], 0.62; 95% confidence interval [CI], 0.34-1.12; atopic dermatitis: OR, 0.34; 95% CI, 0.50-1.72; allergic rhinitis: OR, 0.71; 95% CI, 0.34-1.46; asthma: OR, 0.44; 95% CI, 0.15-1.29). Multivariable analysis showed that a history of atopic dermatitis was associated with reduced risk of gastric cancer in men (OR, 0.16; 95% CI, 0.03-0.75). Conclusions: This findings of this study suggest that individuals with allergies tend to have a reduced risk of gastric cancer, without a statistically significant association. Furthermore, atopic dermatitis was associated with reduced risk of gastric cancer, particularly in men.