Bi-directional association between allergic rhinitis and diabetes mellitus from the national representative data of South Korea.

Allergic rhinitis (AR) and diabetes mellitus (DM) share a common cause in inflammation; however, potential relationships between them are not clear. Therefore, we aimed to explore the associations between AR and DM. In this cross-sectional study, data were extracted from the Korean National Health and Nutrition Examination Survey 2007-2018 and weighted based on sociodemographic characters. AR and DM were defined by diagnoses thereof. Since self-reporting was not perfect, in order to complement the validity, we additionally performed sensitivity analysis by defining DM according to HbA1c and medication history. After excluding invalid data, the number of final participants was 29,246 (mean age, 54.95 ± 14.27 years). We calculated the odds ratio (OR) of newly self-reported DM among AR patients without DM history by multivariable logistic regression adjusted for potential confounders. A reverse association was also assessed. Patients with AR showed lower ORs for DM than those without AR (OR, 95% CI: men, 0.28, 0.19-0.42; women, 0.33, 0.24-0.46). Similarly, DM patients showed lower ORs for AR than patients without DM (men, 0.41, 0.31-0.56; women, 0.34, 0.25-0.46). The same results were obtained in sensitivity analysis defining DM according to HbA1c levels or DM treatment and in stratification analysis for age, residency, comorbidity, BMI, and menopause. In conclusion, we discovered that AR and DM show mutual inverse associations, regardless of sex, in individuals aged 30 years and older.