Introduction

BACKGROUND:
Chronic rhinosinusitis (CRS) is a common condition of the upper respiratory tract(1) with poor quality of life and known associations with the lower respiratory tract(2). It is known that socioeconomic deprivation can be associated with a higher prevalence of asthma and poorer lung function (3, 4). The Chronic Rhinosinusitis Epidemiology Study (CRES) was designed to distinguish differences in socio-economic status, geography, medical/psychiatric co-morbidity, lifestyle and overall quality of life between patients with CRS and healthy controls. Our previous analysis of the CRES dataset did not show evidence of any socioeconomic disparity between CRS cases and controls(5) and this was corroborated by a recent systematic review that found smoking was the only key association (6). However, given the differing rates of asthma in the two main phenotypes of CRS (2), it is possible that disparities between these two phenotypes exist. Smoking does not appear to differ between phenotypes both in our recent analysis and a larger dataset7,8. Other studies have considered socioeconomic variables but have not usually compared the two main phenotypes (9, 10). The latter review by Geramas et al10 showed an association in some studies between CRS and low socioeconomic status but not all studies relied on clinicians confirming the diagnosis of CRS, as is the case in the CRES11.
Previous analyses of the CRES dataset have considered quality of life, mood disturbances, rates of surgery and revision surgery, use of medication, rates of allergy, asthma, aspirin sensitivity and Eustachian tube dysfunction and the role of dietary salicylates and smoking, as well as qualitative analyses (2, 7, 12-21). The aim of the analysis of the CRES database presented here was to specifically compare these variables between the two phenotypes of CRS, as this was not a feature of our original analysis(5), and for any variables not examined in any of the subsequent analyses that appeared worthy of closer examination.