Background: Vitamin D deficiency is reported to be associated with increased incidence of allergic airway diseases and is correlated with the severity of asthma. This study was designed to determine if serum Vitamin D level is lower in chronic rhinosinusitis with nasal polyposis (CRSwNP) patients and if low serum Vitamin D level is correlated with the severity of CRSwNP.
Methods: New CRSwNP patients undergoing elective endoscopic sinus surgery were recruited. Patients with malignancies or asthma were excluded. Twenty chronic rhinosinusitis without nasal polyposis (CRSsNP) patients were used as control. Demographic characteristic information was collected. The severity of CRSwNP was assessed with the Lund-Mackay (LM) score and polyp grading system. Vitamin D status was assessed by measuring circulating 25-hydroxyvitamin D (25OHD) by using commercial chemiluminescence immunoassay. Data were stratified by factors known to affect serum 25OHD, including sex, race, and body mass index.
Results: Serum 25OHD levels (ng/mL ± SD) were significantly lower in patients with CRSwNP (21.4 ± 5.7) than in those with CRSsNP (28.8 ± 6.2; p < 0.001). The incidences of vitamin D deficiency (<20 ng/mL) in CRSwNP and CRSsNP patients were 45.5 and 6.3%; however, the incidences of vitamin D insufficiency (20-30 ng/mL) in these patients were 50.0 and 62.5%, respectively. A significantly negative relationship was found between serum 25OHD level and polyp grade (r = -0.63; p = 0.001), indicating lower serum 25OHD was associated with higher polyp grade. Serum 25OHD was inversely related to both LM score and total IgE level as well; however, statistical significance was not found.
Conclusion: A significantly lower vitamin D level was found in a group of Taiwanese CRSwNP patients, which revealed an association with greater nasal polyp size. Serum vitamin D levels could be added to the routine workup of patients suffering from CRS and these data could be used to potentially help determine the disease severity.