Associations of Head and Neck Cancer with Prior Allergic Rhinitis

<b>Background/Objectives</b>: Chronic inflammation has been implicated in cancer development, but the association between allergic rhinitis (AR) and head and neck cancer (HNC) remains unclear. This study aims to investigate this potential relationship using a population-based dataset. <b>Methods</b>: Utilizing the Taiwan Longitudinal Health Insurance Database 2010, we conducted a case-control study encompassing 14,913 HNC patients and 59,652 propensity-score matched controls. Multivariate logistic regression analyses were performed to quantitatively evaluate the association between HNC and prior AR, adjusting for demographic factors and medical comorbidities such as hyperlipidemia, diabetes, hypertension, tobacco use disorder, HPV infection, and alcohol-related disorders. <b>Results</b>: This study identified that 20.19% of the entire cohort had a prior diagnosis of AR, with a significantly higher prevalence in HNC patients relative to controls (26.2% vs. 18.70%). The adjusted odds ratio (OR) for previous AR in HNC patients was 1.559 (95% CI = 1.494-1.627). Furthermore, site-specific analysis revealed increased odds ratios for AR among patients with cancers of the larynx (OR = 1.537, 95% CI = 1.307-1.807), hypopharynx (OR = 1.220, 95% CI = 1.035-1.437), nasopharynx (OR = 2.933, 95% CI = 2.722-3.160), sinonasal (OR = 3.100, 95% CI = 2.424-3.964), salivary glands (OR = 1.470, 95% CI = 1.158-1.865), and thyroid (OR = 1.566, 95% CI = 1.447-1.693). <b>Conclusions</b>: The findings robustly support a significant link between AR and an elevated risk of developing HNC, notably affecting the nasopharynx, sinonasal cavities, larynx, salivary glands, and thyroid.