Peripheral quantitative computed tomography detects differences at the radius in prepubertal children with cystic fibrosis compared to healthy controls

Abstract

IntroductionIn 2015, 11.9% of people with cystic fibrosis (CF) in the United States had osteopenia, 5.1% osteoporosis, and 0.3% experienced a fracture. Screening for CF-related bone disease starts in childhood, and dual energy x-ray absorptiometry (DXA) is the recommended method. It is unknown whether peripheral quantitative computed tomography (pQCT) can detect deficits earlier than DXA. This study compared pQCT and DXA scans in a group of pre-pubertal children with CF and healthy controls.MethodsThis was a cross-sectional study of children at Tanner stage 1. A pQCT scan of the radius at proximal and distal sites was performed plus a total body DXA scan. Serum C-reactive protein, interleukin-6 and tumor necrosis factor-alpha were also measured.ResultsA total of 34 subjects completed the study; 14 with CF and 20 controls. At the distal radius, pQCT showed a lower total bone mineral density (BMD) Z-score for the CF group (P = 0.01 and P = 0.03 for 2 different reference databases) compared to controls. At the proximal site, the polar strength-strain index was lower in the CF group (P = 0.017). Finally, the total body BMD Z-score by DXA was lower in the CF group, although it did not meet the definition of reduced bone density (P = 0.004). Biomarkers of inflammation were not different.ConclusionsIn this group of pre-pubertal children with CF, measures of bone strength and density by both pQCT and DXA were reduced compared to healthy controls.

Bone accrual and structural changes over one year in youth with cystic fibrosis

“…Our findings of pQCT deficits are consistent O’Brien et al and Kelly et al However, in contrast to the present study, O’Brien et al examined the radius, which is a skeletal site exposed to limited weight-bearing loads, and the current study of tibia pQCT utilized more robust reference data [24] , [25] . A cross sectional study using HR-pQCT in adults with CF demonstrated inferior bone microarchitecture that was worse than expected for the lower BMI [9] .…”

Understanding the interplay between factors that influence bone mineral density in CF

“…In 2015, 11.9% of CF patients in the United States had osteopenia, 5.1% osteoporosis, and 0.3% experienced a fracture 2,3 . Osteoporosis‐related fractures, especially rib or vertebral fractures, may result in kyphosis, pain while breathing, reduced airway clearance, and impaired physical activity levels, which may further reduce bone acquisition 1,4 …”

“…1 In 2015, 11.9% of CF patients in the United States had osteopenia, 5.1% osteoporosis, and 0.3% experienced a fracture. 2,3 Osteoporosis-related fractures, especially rib or vertebral fractures, may result in kyphosis, pain while breathing, reduced airway clearance, and impaired physical activity levels, which may further reduce bone acquisition. 1,4 The European Cystic Fibrosis Bone Mineralization Guidelines recommend dual energy X-ray absorptiometry (DEXA) to assess BMD in all patients from the age of 8 years; measurement should be repeated every one to 5 years, depending on the age of the patient, value of the previous scan, and presence of risk factors (such as physical inactivity and steroid therapy).…”

Studying bone mineral density in young people: The complexity of choosing a pQCT reference database

“…Other parameters measured are bone mineral content, bone area and other derived geometric measurements (cross-sectional area, periosteal and endosteal circumferences, cross-sectional moment of inertia) [10]. pQCT has been J o u r n a l P r e -p r o o f used to study the effects of chronic illness on bone density and dimensions in children with a variety of underlying diseases, such as chronic kidney disease [11,12], cystic fibrosis [13], inflammatory bowel disease [14,15], arthritides [16], acute lymphoblastic leukaemia survivors [17], diabetes [18], nephrotic syndrome [19,20], anorexia nervosa [21,22] and Duchenne muscular dystrophy [23].…”