Epidemiology of Nasal Polyposis

Abstract

Nasal polyps (NP) are benign, edematous masses growing into nasal cavity that could have multiple etiological factors. Basic etiological factor for polyp formation is chronic inflammatory change and thus stromal nasal and paranasal mucosa edema. All theories about NP formation try to explain the edema formation. Edema and mucosal inflammation may originate from trauma, bacterial, viral, or fungal infections, environmental irritants, or allergens. The prevalence of NP in the general population is unclear. It varies from 0.2% to 5.6%. Different diagnostic measurements and criteria may be responsible for this wide range. Additionally, age, gender, and such demographical factors affect the variability. Ethnic and genetic factors should also be taken into consideration. The prevalence of NP shows a wide range according to etiology. The most important data on the epidemiology of NP are obtained from NP etiology studies. For these reasons, in this chapter, epidemiological data are presented parallel to the etiological reasons and hypotheses of NP. There may be hereditary factors for NP but there is limited knowledge in this area. However, we have some evidence for genetic inheritance. Studies reported that up to 14% of patients with NP have a family history. A link has been indicated that NP and asthma have an association with HLA-A1B8 and HLA-A74 genes. The main hypotheses that lead to the development of NP will be discussed below with the current incidence and prevalence rates.