title: Vitamin D binding protein genotype variants and risk of chronic obstructive pulmonary disease: a meta-analysis.
abstract: OBJECTIVE
  Genetic susceptibility for development of chronic obstructive pulmonary disease (COPD) is under intensive investigation. Among the three alleles of vitamin D binding protein, or group-specific (GC) components, some have suggested that having GC-1F and GC-2 alleles was associated with a risk of COPD. Although previous studies have shown considerable variance, no meta-analysis has been conducted.
  
  
  METHODS
  Through four databases, two independent investigators searched for case-control studies providing sufficient data to calculate odds ratios by the vitamin D binding protein allele variant and genotype variant for a case of COPD. Studies whose control did not satisfy the Hardy-Weinberg equilibrium (Chi-square P ≥ 0.05) were excluded. We used a fixed-model to estimate the pooled odds ratio at both allele and genotype level.
  
  
  RESULTS
  Of 141 candidate studies, six were included. We analysed 1712 subjects, consisting of 466 Asians, 1246 Caucasians, 531 COPD cases and 1181 non-COPD controls. The prevalence of each allele among the 1181 controls was as follows: GC-1F 14.0%, GC-1S 53.8% and GC-2 31.9%. When compared to GC-1S, the GC-1F allele and GC-2 allele were associated with COPD risk with pooled odds ratios of 1.44 (95% CI 1.14-1.83, P = 0.002) and 0.83 (95% CI 0.69-0.996, P = 0.045), respectively. When compared to the 1S-1S genotype, the 1F-1F genotype was a risk factor of COPD with pooled odds ratio of 2.64 (95% CI 1.29-5.39, P = 0.008).
  
  
  CONCLUSIONS
  The GC-1F allele of the vitamin D binding protein was a risk for COPD in recessive mode.
authors.affiliation: Department of Respiratory Medicine, Saiseikai Yokohamashi Nanbu Hospital, Yokohama, Japan.
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Horita
authors.forename: Naoki
authors.initials: N
authors.lastname: Miyazawa
authors.forename: Koji
authors.initials: K
authors.lastname: Tomaru
authors.forename: Miyo
authors.initials: M
authors.lastname: Inoue
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Ishigatsubo
authors.forename: Takeshi
authors.initials: T
authors.lastname: Kaneko
mesh_terms: D000483:Alleles; D044466:Asian People / Q000235:genetics; D016022:Case-Control Studies; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006801:Humans; D016017:Odds Ratio; D029424:Pulmonary Disease, Chronic Obstructive / Q000235:genetics* / Q000503:physiopathology; D012307:Risk Factors; D014809:Vitamin D-Binding Protein / Q000235:genetics*; D044465:White People / Q000235:genetics
chemical_list: D014809:Vitamin D-Binding Protein
keywords: Mendelian model; allele; group-specific component; inheritance; single nucleotide polymorphism