title: The role of daily physical activity and nutritional status on bone turnover in cystic fibrosis: a cross-sectional study.
abstract: BACKGROUND
  Nutritional status and daily physical activity (PA) may be an excellent tool for the maintenance of bone health in patients with cystic fibrosis (CF).
  
  
  OBJECTIVE
  To evaluate the relationship between nutritional status, daily physical activity and bone turnover in cystic fibrosis patients.
  
  
  METHODS
  A cross-sectional study of adolescent and adult patients diagnosed with clinically stable cystic fibrosis was conducted. Total body, femoral neck, and lumbar spine bone mineral density (BMD) were determined by dual energy X-ray absorptiometry and bone metabolism markers ALP, P1NP, PICP, and ß-CrossLaps. PA monitoring was assessed for 5 consecutive days using a portable device. Exercise capacity was also determined. Serum 25-hydroxyvitamin D and vitamin K were also determined in all participants.
  
  
  RESULTS
  Fifty patients (median age: 24.4 years; range: 16-46) were included. BMI had positive correlation with all BMD parameters, with Spearman's coefficients ranging from 0.31 to 0.47. Total hip bone mineral density and femoral neck BMD had positive correlation with the daily time spent on moderate PA (>4.8 metabolic equivalent-minutes/day; r=0.74, p<0.001 and r=0.72 p<0.001 respectively), daily time spent on vigorous PA (>7.2 metabolic equivalent-minutes/day; r=0.45 p<0.001), body mass index (r=0.44, p=0.001), and muscle mass in limbs (r=0.41, p=0.004). Levels of carboxy-terminal propeptide of type 1 collagen were positively associated with the daily time spent on moderate (r=0.33 p=0.023) and vigorous PA (r=0.53, p<0.001).
  
  
  CONCLUSIONS
  BMI and the daily time spent on moderate PA were found to be correlated with femoral neck BMD in CF patients. The association between daily PA and biochemical markers of bone formation suggests that the level of daily PA may be linked to bone health in this patient group. Further research is needed to confirm these findings.
authors.affiliation: Departement of Phisical Therapy, Universidad de Sevilla (US), Sevilla, Spain.|Department of Trauma and Orthopedic Surgery, HU Virgen del Rocío, Sevilla, Spain.
authors.forename: Sergio
authors.initials: S
authors.lastname: Tejero
authors.affiliation: Department of Trauma and Orthopedic Surgery, HU Virgen del Rocío, Sevilla, Spain.
authors.forename: Pilar
authors.initials: P
authors.lastname: Cejudo
authors.affiliation: Department of Trauma and Orthopedic Surgery, HU Virgen del Rocío, Sevilla, Spain.
authors.forename: E
authors.initials: E
authors.lastname: Quintana-Gallego
authors.affiliation: Departement of Phisical Therapy, Universidad de Sevilla (US), Sevilla, Spain.
authors.forename: Borja
authors.initials: B
authors.lastname: Sañudo
authors.affiliation: Departement of Phisical Therapy, Universidad de Sevilla (US), Sevilla, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Oliva-Pascual-Vaca
mesh_terms: D015502:Absorptiometry, Photon; D000328:Adult; D015415:Biomarkers / Q000097:blood*; D015519:Bone Density / Q000502:physiology*; D016723:Bone Remodeling / Q000502:physiology*; D003430:Cross-Sectional Studies; D003550:Cystic Fibrosis / Q000503:physiopathology*; D015444:Exercise; D006801:Humans; D009752:Nutritional Status; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism / Q000502:physiology; D014812:Vitamin K / Q000737:chemistry / Q000378:metabolism / Q000502:physiology*
chemical_list: D015415:Biomarkers; D014812:Vitamin K; D014807:Vitamin D; C104450:25-hydroxyvitamin D