title: The relationship between serum levels of vitamin D with asthma and its symptom severity: A case-control study.
abstract: BACKGROUND
  Asthma is a heterogeneous disease characterised by chronic inflammatory airways, and is affected by several immunological factors. One of the most discussed and researched hypotheses is the relationship between vitamin D serum levels with asthma. This study aimed to investigate the relationship between vitamin D serum levels with asthma and pulmonary functions in children in Kurdistan province, Iran.
  
  
  METHODS
  In this case-control study, 120 children ranging from 6 to 18 years were referred in summer for investigation. Participants were divided into two groups: asthma group, N=60; and control group, N=60. After serum separation, samples were analysed using vitamin D ELISA kit. Additionally, pulmonary function test and serum IgE levels were measured in both groups. Data were analysed using Chi-square test and multiple regression analysis in SPSS15.
  
  
  RESULTS
  No difference was shown between the groups in terms of gender composition (male: 57.5; female: 42.5) (P>0.05). Average Vitamin D serum level in the case group (17.98±8.68) was less than in control group (22.35±6.26) (P<0.01). In addition, the difference of vitamin D deficiency in level of suboptimal between the asthma (17.77±6.41) and the control group (24.9±3.18) was statistically significant (P<0.0001). Positive correlation existed between vitamin D levels with FEV1, FVC, and FEV1/FVC. Multiple regression analysis showed a reverse relationship between vitamin D levels with IgE serum levels; this remained after adjustment for potential confounders (e.g. age, sex, BMI, FEV1, and FVC).
  
  
  CONCLUSIONS
  The results showed that serum levels of vitamin D in asthma patients were less than in healthy people, and also reduced lung function in these patients. So, the serum levels of vitamin D in asthma patients must be checked continuously.
authors.affiliation: Cellular & Molecular Research Center, Kurdistan University of Medical Sciences, Sanandaj, Iran.
authors.forename: Rasoul
authors.initials: R
authors.lastname: Nasiri Kalmarzi
authors.affiliation: Student Research Committee, Kurdistan University of Medical Sciences, Sanandaj, Iran.
authors.forename: A
authors.initials: A
authors.lastname: Zamani
authors.affiliation: Kurdistan University of Medical Sciences, Sanandaj, Iran.
authors.forename: A
authors.initials: A
authors.lastname: Fathallahpour
authors.affiliation: Social Determinants of Health Research Center, Kurdistan University of Medical Sciences, Sanandaj, Iran.
authors.forename: E
authors.initials: E
authors.lastname: Ghaderi
authors.affiliation: Kurdistan University of Medical Sciences, Sanandaj, Iran.
authors.forename: Ramesh
authors.initials: R
authors.lastname: Rahehagh
authors.affiliation: Student Research Committee, Kurdistan University of Medical Sciences, Sanandaj, Iran. Electronic address: wesamkooti@gmail.com.
authors.forename: W
authors.initials: W
authors.lastname: Kooti
mesh_terms: D000293:Adolescent; D001249:Asthma / Q000175:diagnosis*; D016022:Case-Control Studies; D002648:Child; D018450:Disease Progression; D005260:Female; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood; D007492:Iran; D008168:Lung / Q000502:physiology*; D008297:Male; D012044:Regression Analysis; D013147:Spirometry; D014807:Vitamin D / Q000097:blood*
chemical_list: D014807:Vitamin D; D007073:Immunoglobulin E
keywords: Asthma; Kurdistan; Vitamin D