In the news: Vitamin D Improves Allergic Rhinitis; Vitamin D Linked to Uveitis Activity

Vitamin D Supplements in Allergic Rhinitis

Allergic rhinitis, commonly called hay fever, refers to a group of symptoms that occur in sensitized individuals such as sneezing and nasal itchiness, discharge, and congestion, and often accompanied by allergic ocular symptoms as well.

Studies suggest that vitamin D may play an important role in the prevention of various autoimmune as well as allergic diseases. Vitamin D affects both innate as well as adaptive immunity and almost all types of immunologic cells, including T, B, dendritic cells, monocytes and macrophages. In addition to its effects on immune cells by modulating a variety of cytokines, vitamin D may have a key role in the pathogenesis of many allergic disorders, including allergic rhinitis.

Against this backdrop, university endocrinology researchers aimed to determine whether short-term vitamin D supplementation could improve symptoms in allergic rhinitis (AR) patients with low vitamin D levels.

This randomized double-blind placebo-controlled clinical trial (1) was performed on 80 AR patients with vitamin D deficiency. AR was diagnosed by the Allergic Rhinitis and its Impact on Asthma (ARIA) guidelines and confirmed by skin prick testing. Half the group received vitamin D (50,000 IU weekly) plus routine antihistamine medication (cetirizine); the other half received cetirizine plus placebo. The clinical symptoms questionnaire was completed at baseline and after 4 and 8 weeks of treatment

Comparison of the mean scores of symptoms severity showed no significant difference between the groups at study initiation and 4 weeks, whereas a significant difference was seen between baseline and 8 weeks of treatment (p = 0.007). Many of the individual symptom scores improved in the vitamin D group vs. placebo, including rhinorrhea, nasal pruritus, and sneezing (all p = 0.001); eyelid edema reached borderline significance (p = 0.06). Vitamin D levels increased significantly in the supplemented group.

The authors conclude that supplemental vitamin D along with antihistamines can result in symptom improvement in AR patients with vitamin D deficiency.

Effects of Vitamin D Levels on Uveitis

Numerous studies have associated low serum levels of vitamin D with increased risk of ocular inflammation such as non-infectious uveitis and scleritis.

In the current prospective case-control study, Australian researchers compared vitamin D levels and patterns of UV and dietary exposure between patients with active and non-active non-infectious uveitis, and population controls2.

Vitamin-D levels were compared between patients with active (n = 74) and inactive uveitis (n = 77) and population-based estimates, stratified by geographic region and season. Vitamin D intakes and exposures based on questionnaire results, including vitamin D sup-plementation and sunlight exposures on weekdays and weekends, were compared between active and inactive uveitis groups.

The median serum vitamin D level in those with active uveitis was found to be significantly lower than the inactive control group (p<0.001). The active uveitis group also had lower median serum vitamin D levels than the local population median.

Vitamin D supplementation was also significantly associated with uveitis inactivity (Kendall’s tau test, p = 0.026). In a sub-analysis of vitamin D deficient participants, UV exposure was significantly associated with uveitis inactivity (p=0.014 for weekday and weekend analyses).

Additional prospective studies are warranted to evaluate whether low vitamin D increases uveitis risk, and the role of vitamin D supplementation in the prevention and treatment of uveitis.

References

1. Bakhshaee M, et al. Therapeutic effect of vitamin D supplementation on allergic rhinitis. Eur Arch Otorhinolaryngol. Epub July 22, 2019.
2. Chiu ZK, et al. Patterns of vitamin D levels and exposures in active and inactive non-infectious uveitis patients. Ophthalmol. Epub July 11, 2019.