A prospective case–control pilot study to evaluate bone microarchitecture in children and teenagers on long-term parenteral nutrition using HR-pQCT

Abstract

Long-term parenteral nutrition (PN) may induce bone complications. Tridimensional bone imaging techniques such as high-resolution peripheral quantitative computed tomography (HR-pQCT) allow the assessment of both compartmental volumetric densities and microarchitecture. Our aim was to evaluate these parameters in children and teenagers receiving long-term PN. This cross-sectional, case–control study included children older than 9 years undergoing PN for at least 2 years. They were age-, gender- and puberty-matched with healthy controls (1:2). Evaluation included biological assessment of bone metabolism (serum calcium, phosphate, and albumin; urinary calcium and creatinine; 25-OH vitamin D, osteocalcin and PTH), dual X-ray absorptiometry (DXA) and HR-pQCT at the ultradistal tibia and radius. Results are presented as median [range]. Eleven patients (3 girls) with a median age of 16 [9–19] years were included. Bone parameters assessed by HR-pQCT at the ultradistal radius and tibia were similar in patients and controls. Parathyroid hormone (PTH) levels were higher (14 [7–115] vs 16 [12–27]) and osteocalcin levels were lower (44 [15–65] vs 65 [38–142]) in patients than in controls, although within the normal range. Conclusions: there were no differences for compartmental bone densities and microarchitecture in patients undergoing chronic PN. Further longitudinal studies are required to confirm these quite reassuring preliminary results.

Metabolic Bone Disease in Children with Intestinal Failure and Long-Term Parenteral Nutrition: A Systematic Review

“…Techniques of bone disease assessment were variable, and older studies were based on inaccurate and subjective methods (i.e., X-ray), while DXA is currently considered the gold standard for osteoporosis evaluation both in children and adults. Limiting the data to the studies based on DXA and in accordance with the current international pediatric definition [ 36 ], a “low bone mineral mass or density” (defined as BMC, BMD, or BMAD less than or equal to −2 z-score) was found in up to 45% of IF children [ 30 ]. As expected, reported prevalence increases when a less stringent cut-off (z-score ≤ −1) was adopted.…”

“…The only two studies documenting this correlation did not introduce any correction of DXA measures for anthropometric parameters or for bone age, while several other studies corrected the DXA findings for measures of poor growth, retrieving more accurate figures of bone mass or density [ 22 , 23 , 24 , 29 , 30 ]. Some degree of overestimation of MBD in children with faltering growth cannot be excluded; therefore, current guidelines [ 36 ] recommend in cases of short stature or poor growth an adjustment for the height z-score or the calculation of the BMAD as a parameter that considers the bone size. Interestingly, in the two controlled studies [ 18 , 24 ], differences in BMC or BMD between cases and controls were no longer significant after correction for weight and height.…”

Age‐related trajectory of bone density in children with intestinal failure: A longitudinal retrospective cohort study

“…5 In adults receiving long-term parenteral nutrition, metabolic bone disease manifests as decreased bone mineral density (BMD), as measured by dual-energy x-ray absorptiometry (DXA), and histologic features of incomplete osteoid mineralization on bone biopsies. 6 Bone health in pediatric patients with intestinal failure is less clear; some studies found a deficit in BMD among patients with intestinal failure compared with reference populations [7][8][9][10][11][12] whereas others did not. 10,13,14 The etiology of intestinal failure may confer different risks for metabolic bone disease.…”

“…6 Bone health in pediatric patients with intestinal failure is less clear; some studies found a deficit in BMD among patients with intestinal failure compared with reference populations [7][8][9][10][11][12] whereas others did not. 10,13,14 The etiology of intestinal failure may confer different risks for metabolic bone disease. Patients with congenital motility or enteropathy disorders have been found to have lower BMD z scores than patients with short bowel syndrome 7 in some but not all studies.…”

“… 15 A large multicenter study of pediatric intestinal patients receiving parenteral nutrition found that about a third had short stature, defined as a height-for-age z score (HAZ) < −2. 17 Some, 7 , 11 , 13 , 18 , 19 but not all 8 – 10 , 20 , 21 studies accounted for short stature when interpreting BMD measures in children with intestinal failure.…”