title: Vitamin D levels in allergic rhinitis: a systematic review and meta-analysis.
abstract: We aimed to systematically review observational studies investigating the relationship between vitamin D levels and allergic rhinitis (AR).
  
  
  
  Studies were selected if they evaluated the relationship between vitamin D levels and AR, and included studies that evaluated other allergic conditions if those studies also contained data on AR. We assessed the incidence and prevalence of AR according to vitamin D levels and compared vitamin D levels in patients with AR to levels in controls.
  
  
  
  Nineteen studies were selected. Of these, only seven focused solely on AR; 10 studies evaluated the other allergic diseases as well as AR; and two studies evaluated asthma primarily, but also included data on patients with AR. The pooled odds ratios (ORs) for the incidence of AR according to vitamin D levels were not statistically significant for either children or adults. Lower vitamin D levels were associated with a higher AR prevalence only in children (pooled OR [95% confidence interval (CI)], 0.75 [0.58, 0.98]). The pooled mean vitamin D level in patients with AR was lower than that of controls only in children (pooled means difference [95% CI], -7.63 [-13.08, -2.18]).
  
  
  
  Prior vitamin D levels were not related to developing AR, but lower vitamin D levels were associated with a higher AR prevalence only in children. There is insufficient evidence to support vitamin D supplementation for AR prevention. However, physicians should consider evaluating patients for vitamin D deficiency during AR management, especially in children.
authors.affiliation: Department of Pediatrics, Institute of Allergy, Brain Korea 21 PLUS Project for Medical Science, Severance Hospital, Yonsei University College of Medicine, Seoul, South Korea.
authors.forename: Yoon Hee
authors.initials: YH
authors.lastname: Kim
authors.affiliation: Department of Pediatrics, Institute of Allergy, Brain Korea 21 PLUS Project for Medical Science, Severance Hospital, Yonsei University College of Medicine, Seoul, South Korea.
authors.forename: Kyung Won
authors.initials: KW
authors.lastname: Kim
authors.affiliation: Department of Pediatrics, Institute of Allergy, Brain Korea 21 PLUS Project for Medical Science, Severance Hospital, Yonsei University College of Medicine, Seoul, South Korea.
authors.forename: Min Jung
authors.initials: MJ
authors.lastname: Kim
authors.affiliation: Department of Pediatrics, Institute of Allergy, Brain Korea 21 PLUS Project for Medical Science, Severance Hospital, Yonsei University College of Medicine, Seoul, South Korea.
authors.forename: In Suk
authors.initials: IS
authors.lastname: Sol
authors.affiliation: Department of Pediatrics, Institute of Allergy, Brain Korea 21 PLUS Project for Medical Science, Severance Hospital, Yonsei University College of Medicine, Seoul, South Korea.
authors.forename: Seo Hee
authors.initials: SH
authors.lastname: Yoon
authors.affiliation: Department of Preventive Medicine, College of Medicine, Korea University, Seoul, South Korea.
authors.forename: Hyeong Sik
authors.initials: HS
authors.lastname: Ahn
authors.affiliation: Department of Preventive Medicine, College of Medicine, Korea University, Seoul, South Korea.
authors.forename: Hyun Jung
authors.initials: HJ
authors.lastname: Kim
authors.affiliation: Department of Pediatrics, Institute of Allergy, Brain Korea 21 PLUS Project for Medical Science, Severance Hospital, Yonsei University College of Medicine, Seoul, South Korea.
authors.forename: Myung Hyun
authors.initials: MH
authors.lastname: Sohn
authors.affiliation: Department of Pediatrics, Institute of Allergy, Brain Korea 21 PLUS Project for Medical Science, Severance Hospital, Yonsei University College of Medicine, Seoul, South Korea.
authors.forename: Kyu-Earn
authors.initials: KE
authors.lastname: Kim
mesh_terms: D000328:Adult; D000818:Animals; D001249:Asthma / Q000453:epidemiology*; D002648:Child; D006801:Humans; D015994:Incidence; D015995:Prevalence; D065631:Rhinitis, Allergic / Q000453:epidemiology*; D014807:Vitamin D / Q000378:metabolism*; D014808:Vitamin D Deficiency / Q000453:epidemiology*
chemical_list: D014807:Vitamin D
keywords: allergic rhinitis; children; incidence; prevalence; vitamin D