Relative frequencies of symptoms and risk factors among patients with chronic rhinosinusitis with nasal polyps using a case-control study.

The aim of this study was to investigate the relative frequency of important symptoms of chronic rhinosinusitis with nasal polyps (CRSwNP), the link between CRSwNP and the lower airways and the importance of smoking in CRSwNP.Three hundred and sixty-eight patients with CRSwNP and 1349 controls were recruited to the study and underwent a structured interview about symptoms from the upper and lower airways, and about smoking habits. Furthermore, all participants were clinically examined using nasal endoscopy.Due to interactions between the outcome variables, a multiple logistic regression model was fitted to the data. Nasal secretions, nasal blockage and impaired sense of smell were symptoms associated with CRSwNP. Furthermore, male gender, increasing age and asthma were also associated with the disease. Current smoking was less frequent among patients with CRSwNP.By comparing symptoms and risk factors of patients with CRSwNP with those of a large population-based control group and testing them in a multiple logistic regression model, we have been able to generate data that address key research interests in CRSwNP.