BackgroundNutritional status and daily physical activity (PA) may be an excellent tool for
the maintenance of bone health in patients with cystic fibrosis (CF).ObjectiveTo evaluate the relationship between nutritional status, daily physical activity
and bone turnover in cystic fibrosis patients.MethodA 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.ResultsFifty 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).ConclusionsBMI 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.