title: Vitamin D deficiency is associated with impaired disease control in asthma-COPD overlap syndrome patients.
abstract: BACKGROUND
  The association between vitamin D and clinical parameters in obstructive lung diseases (OLDs), including COPD and bronchial asthma, was previously investigated. As asthma-COPD overlap syndrome (ACOS) is a new clinical entity, the prevalence of vitamin D levels in ACOS is unknown.
  
  
  OBJECTIVE
  Our aim was to assess the levels of circulating vitamin D (25-hydroxyvitamin D [25(OH)D]) in different OLDs, including ACOS patients, and its correlation with clinical parameters.
  
  
  METHODS
  A total of 106 men and women (control, n=21; asthma, n=44; COPD, n=21; and ACOS, n=20) were involved in the study. All patients underwent detailed clinical examinations; disease control and severity was assessed by disease-specific questionnaires (COPD assessment test, asthma control test, and modified Medical Research Council); furthermore, 25(OH)D levels were measured in all patients.
  
  
  RESULTS
  The 25(OH)D level was significantly lower in ACOS and COPD groups compared to asthma group (16.86±1.79 ng/mL and 14.27±1.88 ng/mL vs 25.66±1.91 ng/mL). A positive correlation was found between 25(OH)D level and forced expiratory volume in 1 second (r=0.4433; P<0.0001), forced vital capacity (FVC) (r=0.3741; P=0.0004), forced expiratory flow between 25% and 75% of FVC (r=0.4179; P<0.0001), and peak expiratory flow (r=0.4846; P<0.0001) in OLD patient groups. Asthma control test total scores and the 25(OH)D level showed a positive correlation in the ACOS (r=0.4761; P=0.0339) but not in the asthma group. Higher COPD assessment test total scores correlated with decreased 25(OH)D in ACOS (r=-0.4446; P=0.0495); however, this was not observed in the COPD group.
  
  
  CONCLUSIONS
  Vitamin D deficiency is present in ACOS patients and circulating 25(OH)D level may affect disease control and severity.
authors.affiliation: Department of Pulmonology, Semmelweis University, Budapest, Hungary.
authors.forename: Balázs
authors.initials: B
authors.lastname: Odler
authors.affiliation: Department of Pulmonology, Semmelweis University, Budapest, Hungary.
authors.forename: István
authors.initials: I
authors.lastname: Ivancsó
authors.affiliation: Department of Pulmonology, Semmelweis University, Budapest, Hungary.
authors.forename: Vivien
authors.initials: V
authors.lastname: Somogyi
authors.affiliation: Heart and Vascular Centre, Semmelweis University, Budapest, Hungary.
authors.forename: Kálmán
authors.initials: K
authors.lastname: Benke
authors.affiliation: Department of Pulmonology, Semmelweis University, Budapest, Hungary.
authors.forename: Lilla
authors.initials: L
authors.lastname: Tamási
authors.affiliation: Department of Pulmonology, Semmelweis University, Budapest, Hungary.
authors.forename: Gabriella
authors.initials: G
authors.lastname: Gálffy
authors.affiliation: Department of Laboratory Medicine, Semmelweis University, Budapest, Hungary.
authors.forename: Balázs
authors.initials: B
authors.lastname: Szalay
authors.affiliation: Department of Pulmonology, Semmelweis University, Budapest, Hungary.
authors.forename: Veronika
authors.initials: V
authors.lastname: Müller
mesh_terms: D000328:Adult; D000368:Aged; D001249:Asthma / Q000503:physiopathology*; D016022:Case-Control Studies; D005260:Female; D005541:Forced Expiratory Volume / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D029424:Pulmonary Disease, Chronic Obstructive / Q000503:physiopathology*; D011788:Quality of Life; D012307:Risk Factors; D011795:Surveys and Questionnaires; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D014808:Vitamin D Deficiency / Q000453:epidemiology*
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D
keywords: ACOS; CAT; obstructive lung disease