Association of alzheimer's disease with prior allergic rhinitis.

Alzheimer's disease (AD) is a growing public health concern, with neuroinflammation implicated in its pathogenesis. Allergic rhinitis (AR), a prevalent chronic inflammatory disorder, may contribute to systemic inflammation and potentially influence AD risk. This study sought to critically assess the association between a history of AR and subsequent AD development in a large, representative Taiwanese cohort. Leveraging Taiwan's National Health Insurance Research Database (LHID2010), this nationwide case-control study identified 4,681 individuals aged ≥ 65 years with a first-time AD diagnosis (cases) and 14,043 propensity-score-matched controls. A rigorous definition of prior AR required at least two clinical diagnoses, including one by an otolaryngology specialist. Multivariable logistic regression was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs), adjusting for potential confounders. The prevalence of prior AR was significantly higher in AD patients than in controls (25.29% vs. 21.01%, p < 0.001). Following meticulous adjustment for demographic variables, socioeconomic status, geographic factors, and medical comorbidities (including hyperlipidemia, diabetes, coronary heart disease, hearing loss, and hypertension), prior AR was robustly associated with elevated odds of AD (adjusted OR = 1.279, 95% CI = 1.182 ~ 1.384). This association remained significant for both males (adjusted OR = 1.196, 95% CI = 1.053 ~ 1.358) and females (adjusted OR = 1.339, 95% CI = 1.210 ~ 1.482). This study suggests a significant association between prior AR and an increased odds of developing AD in an elderly Taiwanese population. These findings highlight chronic peripheral inflammation as a factor potentially associated with neurodegeneration.