Prevalence of nasal polyps and its risk factors: Korean National Health and Nutrition Examination Survey 2009-2011

Background: Although nasal polyps (NPs) are thought to be a common otorhinolaryngologic disease, there have been few population-based epidemiologic studies on the prevalence of NPs. The aim of this study is to evaluate the prevalence of NPs and the risk factors in the general Korean population. Methods: The data were obtained from the Korea National Health and Nutrition Examination Survey (KNHANES) (2009-2011), which was a cross-sectional survey of noninstitutionalized populations all around the country (n = 28,009). Among them, 19,152 participants (age more than or equal to 20 years) completed medical interviews, physical examinations and endoscopic examination. Analyses were performed using a complex sample design to identify the prevalence and its risk factors. Results: The weighted prevalence of NPs was 2.5%. The increased prevalence was associated with increasing age. In the multivariate analyses, male sex [adjusted odds ratio (OR) = 1.68, 95% confidence interval (CI) = 1.25-2.26], low education level (adjusted OR = 1.57, CI = 1.16-2.13), obesity (adjusted OR = 1.49, CI = 1.19-1.87), asthma (adjusted OR = 1.80, CI = 1.24-2.62), and thyroid cancer (adjusted OR = 2.98, CI = 1.26-7.09) were associated with NPs. Among those with NPs, the proportion of symptomatic NPs was 34.4% and asthma was the only significant associated risk factor. Conclusion: The prevalence of NPs in the Korean general population was not low despite advances in medical and surgical treatment and two thirds of the subjects with NPs were asymptomatic. Further investigation is needed to exhibit the causal relationship between the associated risk factors identified and NPs.