title: Self-reported exercise and longitudinal outcomes in cystic fibrosis: a retrospective cohort study.
abstract: BACKGROUND
  Cystic fibrosis (CF) is characterized by recurrent respiratory infections and progressive lung disease. Whereas exercise may contribute to preserving lung function, its benefit is difficult to ascertain given the selection bias of healthier patients being more predisposed to exercise. Our objective was to examine the role of self-reported exercise with longitudinal lung function and body mass index (BMI) measures in CF.
  
  
  METHODS
  A total of 1038 subjects with CF were recruited through the U.S. CF Twin-Sibling Study. Questionnaires were used to determine exercise habits. Questionnaires, chart review, and U.S. CF Foundation Patient Registry data were used to track outcomes.
  
  
  RESULTS
  Within the study sample 75% of subjects self-reported regular exercise. Exercise was associated with an older age of diagnosis (p = 0.002), older age at the time of ascertainment (p < 0.001), and higher baseline FEV1 (p = 0.001), but not CFTR genotype (p = 0.64) or exocrine pancreatic function (p = 0.19). In adjusted mixed models, exercise was associated with both a reduced decline in FEV1 (p < 0.001) and BMI Z-score (p = 0.001) for adults, but not children aged 10-17 years old.
  
  
  CONCLUSIONS
  In our retrospective study, self-reported exercise was associated with improved longitudinal nutritional and pulmonary outcomes in cystic fibrosis for adults. Although prospective studies are needed to confirm these associations, programs to promote regular exercise among individuals with cystic fibrosis would be beneficial.
authors.affiliation: Eudowood Division of Pediatric Respiratory Sciences, Johns Hopkins Medical Institutions, David M, Rubenstein Building, 200 North Wolfe Street, 21287 Baltimore, MD, USA. mcollac1@jhmi.edu.
authors.forename: Joseph M
authors.initials: JM
authors.lastname: Collaco
authors.forename: Scott M
authors.initials: SM
authors.lastname: Blackman
authors.forename: Karen S
authors.initials: KS
authors.lastname: Raraigh
authors.forename: Christopher B
authors.initials: CB
authors.lastname: Morrow
authors.forename: Garry R
authors.initials: GR
authors.lastname: Cutting
authors.forename: Shruti M
authors.initials: SM
authors.lastname: Paranjape
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D015992:Body Mass Index; D002648:Child; D002675:Child, Preschool; D003550:Cystic Fibrosis / Q000175:diagnosis / Q000503:physiopathology* / Q000534:rehabilitation*; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000235:genetics; D018450:Disease Progression; D015444:Exercise / Q000502:physiology*; D005260:Female; D005541:Forced Expiratory Volume; D005838:Genotype; D006801:Humans; D007223:Infant; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D046790:Pancreas, Exocrine / Q000503:physiopathology; D012189:Retrospective Studies; D057566:Self Report; D055815:Young Adult
chemical_list: C505032:CFTR protein, human; D019005:Cystic Fibrosis Transmembrane Conductance Regulator