The Correlation Between Vitamin D Deficiency and Chronic Rhinosinusitis: A Systematic Review.

Chronic rhinosinusitis (CRS) is marked by inflammation of the paranasal sinuses and mucosal lining of the nose. CRS can be classified as CRS with nasal polyps or CRS without polyps. In recent years, there has been increased attention on the immunological role of vitamin D in treating CRS, coupled with the observation of vitamin D deficiency among CRS patients. Vitamin D is acknowledged for its immunomodulatory properties, especially in allergic conditions. Recent studies suggest that individuals with CRS, especially those with CRS with nasal polyps, frequently demonstrate lower than normal levels of vitamin D. We conducted searches across various databases, including PubMed, Web of Science, ScienceDirect, and the Cochrane Library, both electronically and manually, to identify pertinent studies. Studies from 2003 to 2023 were included. Deficiency of vitamin D was considered with levels of vitamin D less than 30 ng/mL, and only original studies were included. Studies including patients taking vitamin D supplementation previously and patients with chronic kidney and liver diseases were excluded. We included nine studies that recruited 1,042 patients in total. More than half of the studies reported the presence of nasal polyps in CRS, and participants from four studies had CRS without nasal polyps. All of the included studies reported a negative correlation between levels of vitamin D and CRS. The majority of the studies depicted quite low levels of vitamin D among CRS patients. The degree of CRS severity as measured by endoscopic and radiological scores is moderately inversely correlated with vitamin D intake. Therefore, it is recommended that the relationship between various serum vitamin D concentrations and the severity of CRS be investigated in detail, along with an understanding of the cellular effects of vitamin D levels on the nasal mucosa.