Importance: Chronic rhinosinusitis (CRS), allergic rhinitis (AR), and nasal septal deviation (NSD) are frequent rhinologic diseases that consume considerable health care resources.

Objective: To determine the prevalence and risk factors of CRS, AR, and NSD in Korea.

Design, setting, and participants: This study analyzed 5-year cross-sectional data from the Korean National Health and Nutrition Examination Survey (KNHANES) 2008-2012. A total of 35 511 participants, who underwent an interview regarding nasal symptoms and a nasal examination, were enrolled and subsequently divided into 3 groups: children (aged 7-12 years), adolescents (aged 13-19 years), and adults (aged ≥20 years).

Main outcomes and measures: Adult CRS was classified into CRS with nasal polyps (CRSwNP) and CRS without nasal polyps (CRSsNP). Diagnosis of AR was based on symptoms and serum levels of specific IgE for 3 allergens, including Dermatophagoides farinae. The precise prevalence of AR was reestimated by multiplying the reciprocal of D farinae frequency based on a conventional skin prick test. Nasal septal deviation was diagnosed via nasal endoscopy after nasal decongestion. This study estimated the association of the 3 diseases with demographic data, including sex, age, obesity, level of education, socioeconomic status, residence, smoking, and alcohol.

Results: The prevalence of CRSwNP and CRSsNP in 28 912 adults was 2.6% and 5.8%, respectively. An association was found between CRSwNP and age (odds ratio [OR], 1.03; 95% CI, 1.02-1.04; P < .001), lower level of education (OR, 1.40; 95% CI, 1.02-1.92; P = .04), and obesity (OR, 1.46; 95% CI, 1.16-1.84; P = .001). Symptom-based and allergy test result-based AR had a prevalence of 27.5% (n = 35 511) and 16.1% (n = 2298), respectively. The reestimated prevalence of AR was 18.5% for all ages. Urban residence increased the risk of AR (OR, 1.21; 95% CI, 1.06-1.38; P = .005), but age was associated with a decreased risk (OR, 0.99; 95% CI, 0.98-0.99; P < .001). The prevalence of NSD was 48.0% and increased with age. In addition, NSD was a risk factor for CRSsNP (adjusted OR, 1.16; 95% CI, 1.02-1.32; P = .03) but not for CRSwNP.

Conclusions and relevance: In KNHANES 2008-2012, older age was associated with increased risk for CRSwNP and NSD but associated with a decreased risk for AR. Obesity was another risk factor for CRSwNP.