title: Vitamin D deficiency and airflow limitation in the Baltimore Longitudinal Study of Ageing.
abstract: BACKGROUND
  Vitamin D deficiency is common in patients with chronic obstructive pulmonary disease (COPD) and has also been linked to comorbidities often present in COPD.
  
  
  OBJECTIVE
  The aim of this study was to investigate whether vitamin D deficiency was related specifically to airflow limitation or whether vitamin D deficiency was determined by conditions that frequently coexist with COPD: insulin resistance, hypertension, anaemia, obesity and hypercholesterolaemia.
  
  
  METHODS
  For this cross-sectional analysis, we included 897 subjects from the Baltimore Longitudinal Study of Aging. Subjects taking vitamin D supplements were excluded. Airflow limitation was defined as FEV1 /FVC < lower limit of normal. Logistic regression was used to assess the association between vitamin D deficiency (25-hydroxy vitamin D < 20 ng/mL) and possible determinants.
  
  
  RESULTS
  Vitamin D deficiency was not specific for subjects with airflow limitation. Body mass index (BMI) (OR: 1.05, P < 0.03) and obesity (BMI > 30 kg/m(2)) (OR: 1.9, P < 0.002) were significantly associated with vitamin D deficiency in the adjusted multivariate regression analysis. Physical activity was associated with a decreased risk of vitamin D deficiency.
  
  
  CONCLUSIONS
  Airflow limitation was not an independent determinant of vitamin D deficiency. The effect of weight loss and increased physical activity on vitamin D levels should be investigated further in intervention studies.
authors.affiliation: Section of Respiratory Medicine, Hvidovre University Hospital, Hvidovre, Denmark.
authors.forename: Mia
authors.identifier: http://orcid.org/0000-0002-0960-4260
authors.initials: M
authors.lastname: Moberg
authors.affiliation: Longitudinal Studies Section, Translational Gerontology Branch, National Institute on Aging, Baltimore, MD, USA.
authors.forename: Palchamy
authors.initials: P
authors.lastname: Elango
authors.affiliation: Longitudinal Studies Section, Translational Gerontology Branch, National Institute on Aging, Baltimore, MD, USA.
authors.forename: Luigi
authors.initials: L
authors.lastname: Ferrucci
authors.affiliation: Department of Research & Education, CIRO+, Centre of Expertise for Chronic Organ Failure, Horn, The Netherlands.|Faculty of Medicine and Life Sciences, REVAL - Rehabilitation Research Center, BIOMED - Biomedical Research Institute, Hasselt University, Diepenbeek, Belgium.
authors.forename: Martijn A
authors.initials: MA
authors.lastname: Spruit
authors.affiliation: Department of Research & Education, CIRO+, Centre of Expertise for Chronic Organ Failure, Horn, The Netherlands.
authors.forename: Emiel F
authors.initials: EF
authors.lastname: Wouters
authors.affiliation: Department of Research & Education, CIRO+, Centre of Expertise for Chronic Organ Failure, Horn, The Netherlands.
authors.forename: Erica P A
authors.initials: EP
authors.lastname: Rutten
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000740:Anemia / Q000453:epidemiology*; D015142:Baltimore / Q000453:epidemiology; D015331:Cohort Studies; D015897:Comorbidity; D003430:Cross-Sectional Studies; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D006937:Hypercholesterolemia / Q000453:epidemiology*; D006973:Hypertension / Q000453:epidemiology*; D007333:Insulin Resistance; D016015:Logistic Models; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000453:epidemiology*; D011446:Prospective Studies; D029424:Pulmonary Disease, Chronic Obstructive / Q000453:epidemiology* / Q000503:physiopathology; D012307:Risk Factors; D014797:Vital Capacity; D014807:Vitamin D / Q000031:analogs & derivatives / Q000097:blood; D014808:Vitamin D Deficiency / Q000097:blood / Q000453:epidemiology*
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D
keywords: Airflow limitation; airway obstruction; cardiovascular disease; comorbidities; physical activity; vitamin D