A new study reported that vitamin D3 deficiency is associated with increased sinus tissue proliferation in chronic rhinosinusitis with nasal polyps.
Chronic rhinosinusitis (CRS) is a common condition in which the sinuses become inflamed and swollen for at least twelve weeks. The condition causes mucus to buildup, interfering with drainage. This often results in tenderness and swelling around the face, difficulty breathing, ear pain and headaches.
CRS may be caused by an infection, a deviated nasal septum or abnormal growths in the sinuses, known as nasal polyps. Oral steroids are currently the most effective treatment for CRS caused by nasal polyps. However, the compliance for oral steroids is reduced due to their substantial side effects.
Vitamin D possesses anti-inflammatory and anti-proliferative properties, leading researchers to believe that vitamin D may be able to reduce inflammation and inhibit the abnormal sinus tissue growth that occurs in CRS with nasal polyps (CRSwNP). Studies have shown that patients with CRSwNP have significantly reduced vitamin D levels. Furthermore, vitamin D deficiency has been linked to a more severe disease state among patients with CRSwNP.
A research team recently conducted a study to further understand the mechanism of vitamin D within CRSwNP. They wanted to know whether vitamin D deficiency led to increased sinus tissue proliferation, which would potentially explain the link between low vitamin D levels and a more severe form of CRSwNP.
The researchers analyzed blood and sinus tissue collected from 15 patients with CRSwNP and 12 control subjects. They also measured the vitamin D levels of all study participants.
Here is what the researchers found:
- As the researchers expected, the patients with CRSwNP had significantly higher sinus tissue proliferation than the control participants (p < 0.01).
- Vitamin D deficiency was associated with increased sinus tissue proliferation among patients with CRSwNP (p = 0.0135). However, this relationship was not seen for control participants (p = 0.3869).
The researchers continued their analysis by investigating whether the sinus tissue was capable of metabolizing 25(OH)D3 to its active form, 1,25(OH)2D3, also known as calcitriol. They administered 25(OH)D3 to the sinus tissue for 24 hours. Then, they assessed the tissue for the presence of calcitriol. The researchers discovered that neither tissue samples from the control group or the CRSwNP patients were able to convert the 25(OH)D3 to its active form.
Next, the researchers wanted to determine how the sinus tissue would respond to physiological doses of calcitriol. They found that there was a significant decrease in sinus cell proliferation among patients with CRSwNP (p < 0.01), but not control participants (p > 0.05). In addition, the calcitriol reduced the sinus tissue proliferation to a level similar to that observed in the control group.
The researchers concluded,
“We demonstrate an inverse relationship between [sinus cell] proliferation and VD3 levels in CRSwNP… Proliferation was significantly decreased upon stimulating [sinus cells] with 1,25 VD3.”
The researchers also acknowledge the study’s weaknesses, “There are a number of limitations to the current study, including small sample size, study design/level of evidence, and lack of confirmatory method.”
Further investigation into how vitamin D supplementation may impact the severity of CRSwNP is warranted.
Tovey, A. & Cannell, JJ. The role of vitamin D in chronic rhinosinusitis. The Vitamin D Council Blog/Newsletter, February 2016.
William, C. et al. Vitamin D deficiency is associated with increased human sinonasal fibroblast proliferation in chronic rhinosinusitis with nasal polyps. International Forum of Allergy & Rhinology, 2016.