Bone health of children with intestinal failure measured by dual energy X-ray absorptiometry and digital X-ray radiogrammetry.

BACKGROUND & AIMS: Children with intestinal failure (IF) receiving long-term parenteral nutrition (PN) are at risk of developing low bone mineral density (BMD). Next to the dual energy X-ray absorptiometry (DXA) method, digital X-ray radiogrammetry (DXR) using the BoneXpert software has become available to obtain the Bone Health Index (BHI) in hand radiographs. In this study we 1) evaluated the prevalence of low BMD in children with IF using DXA and DXR, 2) compared DXA and DXR results, and 3) aimed to identify factors associated with low BMD. METHODS: A retrospective study was performed including all children with IF between 2000 and 2015 who underwent a DXA measurement and/or a hand radiograph. Z-scores of BMD total body (BMD TB) and lumbar spine (BMD LS), bone mineral apparent density (BMAD) and bone health index (BHI) were collected. A low BMD and low BHI were defined as a Z-score ≤ -2. DXA and DXR results were compared for cases in which a DXA and hand radiograph were performed within a 6 months' interval. RESULTS: Forty-six children were included. Overall, 24.3% of the children had a low BMD at the first DXA at a median age of 6 years; correction for growth failure (n = 6) reduced this to 16.2%. Fifty percent had a low BHI at the first hand radiograph. Median DXA and BHI Z-scores were significantly lower than reference scores. Age, duration of PN and surgical IF were related to lower Z-scores at the first DXA. Paired DXA and DXR results (n = 18) were compared, resulting in a Cohen's kappa of 0.746 ('substantial') for BMD TB. Spearman's correlation coefficient for BHI and BMD TB Z-scores was 0.856 (p < 0.001). Hand radiography had a sensitivity of 90% and specificity of 86% (BMD TB). CONCLUSIONS: Up to 50% of the children had a low BMD. Children with IF have a significantly poorer bone health than the reference population, also after weaning off PN. Bone health assessment by DXA and DXR showed good agreement, especially for Z-scores ≤ -2. DXR assessment using BoneXpert software seems to be feasible for monitoring of bone health in children with IF.

The limited screening value of insulin-like growth factor-I as a marker for alterations in body composition in very long-term adult survivors of childhood cancer.

BACKGROUND: The clinical relevance of low IGF-I levels, caused by cranial radiotherapy, in adult childhood cancer survivors has not been studied extensively. We evaluated whether IGF-I is a useful marker for altered body composition and growth hormone deficiency (GHD) in this group. PROCEDURE: We analyzed retrospective data from 610 adult childhood cancer survivors, retrieved from the late effects clinic. Median age at diagnosis was 6 years (interquartile range 3-11) and follow-up time was 18 years (13-24). We assessed IGF-I standard deviation scores (SDS), anthropometrical measures, growth hormone stimulation tests in patients with clinical signs of GHD, and measures of body composition (assessed by dual X-ray absorptiometry, Lunar Prodigy). RESULTS: In 58 cranially irradiated acute leukemia survivors (25 Gy (24-25)) and 56 locally irradiated brain tumor survivors (42 Gy (35-54)) we found significantly lower IGF-I SDS (P < 0.001), lower height SDS (P < 0.001), higher body mass index (P = 0.01), higher waist-hip ratio (WHR; P = 0.001), higher total fat percentage SDS (P < 0.001), and lower lean body mass SDS (P < 0.001), as compared to 452 not cranially irradiated survivors. IGF-I showed a weak inverse correlation with BMI (r = -0.12, P = 0.04), WHR (r = -0.15, P = 0.01), total fat percentage (r = - 0.14, P = 0.02), and a positive correlation with lean body mass (r = 0.15, P = 0.01). In patients with low IGF-I levels, IGF-I did not significantly differ between subjects with and without GHD as determined by GH-stimulation testing (P = 0.39). CONCLUSION: This study shows that IGF-I has limited value as a marker for alterations in body composition in adult childhood cancer survivors.

Periarticular osteoporosis: a useful feature in the diagnosis of early rheumatoid arthritis? Reliability and validity in a cross-sectional diagnostic study using dual-energy X-ray absorptiometry.

OBJECTIVES: To identify regions of interest (ROIs) relevant to periarticular osteoporosis in RA with low precision error and sufficient inter-rater reliability and to test diagnostic validity for RA. METHODS: Periarticular BMD was measured using dual-energy X-ray absorptiometry (DXA). Five ROIs were defined around MCP and/or PIP joints II-V, II-IV and mid-metacarpal to mid-phalangeal. They were evaluated for precision using the root mean square coefficient of variation (RMS-CV) and the intra-class correlation coefficient (ICC) for inter-reader reliability. To test validity, established RA patients (n = 25) and early arthritis patients (n = 25) were compared with healthy controls (n = 37) matched on sex, age and menopausal status using paired t-tests, ROC curves and scatterplots. RESULTS: The RMS-CV was 0.45-1.07%. The ICC was 0.99. Mean BMDs of the five ROIs ranged from 0.321 to 0.372 g/cm(2) in established RA, from 0.321 to 0.382 g/cm(2) in early arthritis and from 0.342 to 0.401 g/cm(2) in healthy controls. Mean differences ranged from 0.012 to 0.032 g/cm(2) for established RA and from 0.023 to 0.033 g/cm(2) for early arthritis patients compared with matched controls, with P < 0.05 for ROIs 1-5 in early arthritis and the whole hand in established RA. ROC curves indicated low discriminative power, with an area under the curve (AUC) of 0.61-0.64, and scatterplots showed great overlap between BMD values of patients and controls. CONCLUSIONS: Periarticular BMD measured with DXA seems not to be a useful diagnostic feature due to strong overlap of BMD values between healthy controls, established RA patients and early arthritis patients.