13C-Mixed Triglyceride Breath Test and Fecal Elastase as an Indirect Pancreatic Function Test in Cystic Fibrosis Infants.

BACKGROUND: The 'gold standard' test for the indirect determination of pancreatic function status in infants with cystic fibrosis (CF), the 72-hour fecal fat excretion test, is likely to become obsolete in the near future. Alternative indirect pancreatic function tests with sufficient sensitivity and specificity to determine pancreatic phenotype need further evaluation in CF infants. OBJECTIVE: Evaluation of the clinical utility of both the noninvasive, nonradioactive C-mixed triglyceride (MTG) breath test and fecal elastase-1 (FE1) in comparison with the 72-hour fecal fat assessment in infants with CF. METHODS: C-MTG breath test and the monoclonal and polyclonal FE1 assessment in stool was compared with the 72-hour fecal fat assessment in 24 infants with CF. Oral pancreatic enzyme substitution (PERT; if already commenced) was stopped before the tests. RESULTS: Sensitivity rates between 82% and 100% for CF patients with pancreatic insufficiency assessed by both the C-MTG breath test and the FE1 tests proved to be high and promising. The C-MTG breath test (31%-38%) as well as both FE1 tests assessed by the monoclonal (46%-54%) and the polyclonal (45%) ELISA kits, however, showed unacceptably low-sensitivity rates for the detection of pancreatic-sufficient CF patients in the present study. CONCLUSIONS: The C-MTG breath test with nondispersive infrared spectroscopy (NDIRS) technique, as well as both FE1 tests, are not alternatives to the fecal fat balance test for the evaluation of pancreatic function in CF infants during the first year of life.

Bile salt stimulated lipase: Inhibition by phospholipids and relief by phospholipase A2.

INTRODUCTION: Bile salt stimulated lipase (BSSL; Enzyme Commission (EC) number 3.1.1.13) has been a candidate triglyceridase for improving enzyme therapy for pancreatic insufficiency; however, its efficacy is near absent. We hypothesise that similarly to pancreatic lipase, BSSL is inhibited by phospholipids and this inhibition is relieved by Phospholipase A2 (PLA2; EC 3.1.1.4), and the present study was undertaken to explore this possibility. MATERIALS AND METHODS: Synthetic emulsions of triglyceride and phosphatidylcholine (PC) or lysophosphatidylcholine (LPC)/bile salt mixed micelles were used as a model of intestinal digestion-media. The effect of PLA2 treatment of systems containing PC on BSSL activity was also explored. Automatic titration at constant pH (pH-stat) and nuclear magnetic resonance (NMR) spectroscopy were used to measure the rate and identify products of lipolysis. RESULTS: PC was inhibitory to BSSL activity, while LPC became inhibitory only above an LPC/bile salt concentration ratio of 0.3. PLA2 treatment relieved the inhibition only below this ratio, despite its complete phospholipid-hydrolysing action. Thus, LPC had an inhibitory effect at higher concentrations. CONCLUSIONS: These results may implicate a change in the design of enzyme therapy in patients with pancreatic exocrine insufficiency. Supplementation of BSSL with PLA2 could improve patient health with adequate manipulation of phospholipid and lysophospholipid concentrations in the intestinal fluid.

Pediatric-to-adult Transition and Medication Adherence in Patients with Inflammatory Bowel Disease.

BACKGROUND: Medication nonadherence is common in inflammatory bowel disease and is associated with poor outcomes. There has been no study on pediatric-to-adult transition as a risk factor for nonadherence in inflammatory bowel disease, which has been demonstrated in other diseases. We aimed to assess whether transitioned (TR) patients have higher nonadherence rates than young adults (YAs) diagnosed in adulthood. METHODS: Consecutive ambulatory subjects were prospectively recruited and completed the validated Medication Adherence Reporting Scale (MARS), with the primary outcome being adherence differences between group age-matched TR and YA groups. Pediatric subjects were taken as the control group. Perceptions of medication-related necessity and concerns were assessed with the Beliefs about Medicines Questionnaire (BMQ). Nonadherers (defined as MARS ≤16) received the Inflammatory Bowel Diseases Pharmacist Adherence Counselling (IPAC) intervention and adherence change was reassessed after 6 months as a secondary outcome. RESULTS: Adherence in TR patients (n = 38, mean age 20.4, 13.2% nonadherent) was noninferior to and numerically better than YAs diagnosed in adulthood (n = 41, mean age 21.2, 24.4%). Nonadherence in the pediatric control group (n = 50, mean age 14.7) was 8.0%. YAs had significantly higher medication-related concerns (14.6 versus 11.9, P = 0.02) than the pediatric group. The IPAC intervention reduced nonadherence rates by 60% (P = 0.004). CONCLUSIONS: TR patients did not have worse adherence than YAs diagnosed in adulthood. Protective factors may include previous treatment in pediatric centers and the salient symptomatology of inflammatory bowel disease, whereas increasing concerns over medications contribute to nonadherence in YAs. Pharmacist-led counselling improves adherence in these patients.

Are We Overdoing Pediatric Lower Gastrointestinal Endoscopy?

INTRODUCTION: Lower gastrointestinal endoscopy (LGIE)/colonoscopy is frequently performed for rectal bleeding, recurrent abdominal pain, and the diagnosis of inflammatory bowel disease (IBD). Although these are common indications, the causes of isolated rectal bleeding and recurrent abdominal pain in the otherwise well child have not been described. METHODS: A retrospective analysis of patients who had had an LGIE/colonoscopy from January 2001 to December 2010 was performed. The following data were collected: demographic data, indication, distance reached, macroscopic findings, microscopic findings, diagnosis, additional procedures, and complications. RESULTS: There were a total of 999 colonoscopies. The colonoscopy was normal in 390 of 999 (39%). The commonest indication for colonoscopy was a diagnosis of suspected IBD, 449 of 999 (45%). IBD was confirmed in 282 of 449 (63%), but colonoscopy was normal in 143 of 449 (32%) of suspected IBD. Colonoscopy was performed for rectal bleeding in 197 of 999 (20%) of whom 141 of 197 (72%) were normal. There were 46 (5%) colonoscopies performed for recurrent abdominal pain, which were all normal. Our completion rate to the cecum and beyond was 521 of 999 (52%). Our perforation rate during the 10 years was 0.2%. CONCLUSIONS: Colonoscopy is a safe procedure in pediatrics; however, 39% of colonoscopies in this series were normal. Many of these could have been avoided by eliminating colonoscopy in patients with recurrent abdominal pain in the absence of other clinical features, conservative management with laxatives for those with fresh blood per rectum typical of anal fissures, and fecal calprotectin screening before endoscopy in patients with suspected IBD.

Differences in Outcomes between Early and Late Diagnosis of Cystic Fibrosis in the Newborn Screening Era.

OBJECTIVES: To evaluate children with cystic fibrosis (CF) who had a late diagnosis of CF (LD-CF) despite newborn screening (NBS) and compare their clinical outcomes with children diagnosed after a positive NBS (NBS-CF). STUDY DESIGN: A retrospective review of patients with LD-CF in New South Wales, Australia, from 1988 to 2010 was performed. LD-CF was defined as NBS-negative (negative immunoreactive trypsinogen or no F508del) or NBS-positive but discharged following sweat chloride < 60 mmol/L. Cases of LD-CF were each matched 1:2 with patients with NBS-CF for age, sex, hospital, and exocrine pancreatic status. RESULTS: A total of 45 LD-CF cases were identified (39 NBS-negative and 6 NBS-positive) with 90 NBS-CF matched controls. Median age (IQR) of diagnosis for LD-CF and NBS-CF was 1.35 (0.4-2.8) and 0.12 (0.03-0.2) years, respectively (P <.0001). Estimated incidence of LD-CF was 1 in 45 000 live births. Compared with NBS-CF, LD-CF had more respiratory manifestations at time of diagnosis (66% vs 4%; P <.0001), a higher rate of hospital admission per year for respiratory illness (0.49 vs 0.2; P = .0004), worse lung function (forced expiratory volume in 1 second percentage of predicted, 0.88 vs 0.97; P = .007), and higher rates of chronic colonization with Pseudomonas aeruginosa (47% vs 24%; P = .01). The LD-CF cohort also appeared to be shorter than NBS-CF controls (mean height z-score -0.65 vs -0.03; P = .02). CONCLUSIONS: LD-CF, despite NBS, seems to be associated with worse health before diagnosis and worse later growth and respiratory outcomes, thus providing further support for NBS programs for CF.

Variants in TRIM22 That Affect NOD2 Signaling Are Associated With Very-Early-Onset Inflammatory Bowel Disease.

BACKGROUND & AIMS: Severe forms of inflammatory bowel disease (IBD) that develop in very young children can be caused by variants in a single gene. We performed whole-exome sequence (WES) analysis to identify genetic factors that might cause granulomatous colitis and severe perianal disease, with recurrent bacterial and viral infections, in an infant of consanguineous parents. METHODS: We performed targeted WES analysis of DNA collected from the patient and her parents. We validated our findings by a similar analysis of DNA from 150 patients with very-early-onset IBD not associated with known genetic factors analyzed in Toronto, Oxford, and Munich. We compared gene expression signatures in inflamed vs noninflamed intestinal and rectal tissues collected from patients with treatment-resistant Crohn's disease who participated in a trial of ustekinumab. We performed functional studies of identified variants in primary cells from patients and cell culture. RESULTS: We identified a homozygous variant in the tripartite motif containing 22 gene (TRIM22) of the patient, as well as in 2 patients with a disease similar phenotype. Functional studies showed that the variant disrupted the ability of TRIM22 to regulate nucleotide binding oligomerization domain containing 2 (NOD2)-dependent activation of interferon-beta signaling and nuclear factor-κB. Computational studies demonstrated a correlation between the TRIM22-NOD2 network and signaling pathways and genetic factors associated very early onset and adult-onset IBD. TRIM22 is also associated with antiviral and mycobacterial effectors and markers of inflammation, such as fecal calprotectin, C-reactive protein, and Crohn's disease activity index scores. CONCLUSIONS: In WES and targeted exome sequence analyses of an infant with severe IBD characterized by granulomatous colitis and severe perianal disease, we identified a homozygous variant of TRIM22 that affects the ability of its product to regulate NOD2. Combined computational and functional studies showed that the TRIM22-NOD2 network regulates antiviral and antibacterial signaling pathways that contribute to inflammation. Further study of this network could lead to new disease markers and therapeutic targets for patients with very early and adult-onset IBD.

Novel de novo mutations of the interleukin-10 receptor gene lead to infantile onset inflammatory bowel disease.

BACKGROUND AND AIMS: Defects in the interleukin 10 (IL-10) signalling pathway have been shown to cause very early onset inflammatory bowel disease (IBD). We report a patient with severe infantile-onset IBD with a compound heterozygous IL-10 receptor alpha subunit (IL-10RA) mutation, one of which was paternally-inherited and the other occurring de novo. METHODS: Deep sequencing of IL-10, IL-10RA and IL-10 receptor beta subunit (IL-10RB) were performed. Peripheral blood mononuclear cell (PBMC) surface expression of IL-10RA was analysed by flow cytometry. IL-10 signalling pathway was examined by measuring phosphorylated STAT3 in PBMC cultured in the presence of IL-6 or IL-10. RESULT: We identified a missense mutation in exon 4 of IL-10RA (c.583T>C) in one allele and a nonsense mutation in exon 7 of IL-10RA (c.1368G>T) in the other allele. Neither mutation has been reported previously. The patient has functional IL-10RA deficiency despite normal IL-10RA expression. CONCLUSION: This represents the first case report of a de novo mutation of IL-10RA that is associated with very early onset severe IBD. Therefore, IL-10 pathway defect should be considered in patients with infantile-onset IBD even if the parents are non-consanguineous.

Cholestasis and meconium ileus in infants with cystic fibrosis and their clinical outcomes.

OBJECTIVE: To identify the incidence and outcomes of cholestasis and meconium ileus (MI) in infants with cystic fibrosis (CF). DESIGN: Retrospective cohort study. SETTING: Single-centre study. PATIENTS: From January 1986 to December 2011, 401 infants with CF (69 with MI) presented to our centre. MAIN OUTCOME MEASUREMENTS: (1) incidence of cholestasis, (2) identification of risk factors for cholestasis, (3) association between the presence of cholestasis and MI and the development of clinically significant CF-associated liver disease (CFLD) defined as multilobular cirrhosis with portal hypertension. RESULTS: Cholestasis occurred in 23 of 401 infants (5.7%). There was a significantly higher incidence of cholestasis in infants with MI (27.1%) compared to those without MI (1.2%) (p<0.001). Infants with MI had a 30.36-fold increased risk of developing cholestasis compared to those without MI (p<0.001). Cholestasis resolved in all children, at a median (range) age of 9.2 (0.8-53.2) months in the MI group and 10.2 (2.0-19.4) months in the non-MI group. The majority of cholestatic infants (87.0%) and infants with MI (92.8%) did not develop clinically significant CFLD, not significantly different than either the 93.9% of non-cholestatic infants nor the 93.7% infants without MI. CONCLUSIONS: Cholestasis is an uncommon condition in CF affecting only 5.7% of the screened newborn CF population. The greatest risk factor for developing cholestasis is the presence of MI. However, the presence of MI appears not to be associated with the development of CFLD. An effect of neonatal cholestasis on the development of CFLD cannot be excluded by this study.

Liver disease in cystic fibrosis.

The survival of patients with cystic fibrosis (CF) has progressively increased over recent decades, largely attributable to early diagnosis through newborn screening and advances in nutritional and respiratory care. As the life expectancy of patients with CF has improved, non-respiratory complications such as liver disease have become increasingly recognized. Biochemical derangements of liver enzymes in CF are common and may be attributed to a number of specific hepatobiliary abnormalities. Among them, Cystic Fibrosis-associated Liver Disease (CFLD) is clinically the most significant hepatic complication and is believed to have a significant impact on morbidity and mortality. However, there remains much conjecture about the extent of the adverse prognostic implications that a diagnosis of CFLD has on clinical outcomes. The purpose of this review is to give an overview of the current knowledge regarding liver disease in children with CF.

Prophylactic gastrectomy in a 16-year-old.

We performed a total gastrectomy in a 16-year-old asymptomatic CDH1 gene mutation carrier in whom two prior gastroscopies with biopsies were normal. The patient's mother died aged 39 years and her aunt died aged 21 years of gastric cancer. A germline CDH1 mutation (associated with hereditary diffuse gastric cancer) was initially identified in her mother at diagnosis and was later identified by predictive testing in this patient. Our patient is the youngest CDH1 carrier to date to have a prophylactic gastrectomy, and is several years below the age at which existing guidelines recommend consideration of gastrectomy. Multiple foci of early-stage carcinoma were found in her gastrectomy specimen. Given the family history of advanced gastric cancer in the late second decade, the unpredictable time course to development of advanced gastric cancer, and the futility of gastroscopic surveillance, we recommend consideration of prophylactic gastrectomy in adolescent asymptomatic CDH1 mutation carriers on an individual basis.

Evaluation of methods to assess reduced body fat in patients with anorexia nervosa.

OBJECTIVE: To evaluate skinfold anthropometry and dual-energy x-ray absorptiometry (DXA) to estimate percentage of body fat (%BF) in adolescent patients with anorexia nervosa (AN). METHODS: We examined 80 female AN patients (age 15.6 ± 1.4 years) and 31 healthy, normal weight sex- and age-matched controls with DXA and skinfold anthropometry to estimate %BF. Reference values for %BF of the same participants were obtained from a 4-compartment (4C) model, which was based on measurements of total body protein (with in vivo neutron activation), total body water (with deuterium dilution), and mineral content (with DXA). We compared the different methods to assess %BF with Bland-Altman analysis of agreement. RESULTS: In the AN group, average %BF was well predicted with DXA and skinfold measurements in combination with the Deurenberg equation based on 2 skinfolds (DXA 13.9 ± 6.2 %BF; skinfold 14.5 ± 4.3 vs 14.1 ± 6.8 %BF by the 4C model). In the control group, average %BF was closely predicted by skinfold measurements in combination with the Slaughter formula (26.1 ± 4.5 vs 25.2 ± 5.2 %BF by the 4C model) but was overestimated with DXA (31.3 ± 5.8 %BF). When compared with the 4C model, all methods under investigation showed considerable limits of agreement when predicting %BF in any given individual. CONCLUSIONS: In our group of patients with AN, the Deurenberg skinfold model and DXA were similar in performance; however, DXA overestimated %BF in healthy subjects.

Nutritional rehabilitation increases the resting energy expenditure of malnourished children with severe cerebral palsy.

AIM: The aim of this study was to measure resting energy expenditure (REE) and energy intake in children with quadriplegic cerebral palsy (CP), to relate these to anthropometric measurements, and to determine the influence of nutritional rehabilitation on REE. METHODS: Fifty-six children (20 females, 36 males; age range 3y 11mo-18y; mean age 10y; SD 3y 11mo) with CP (Gross Motor Function Classification System level V) participated in this cross-sectional study. Children were excluded if they had a known metabolic disorder, genetic syndrome, or chromosomal abnormality. Thirty-three of the children were tube fed and 23 were fed orally. A comparison group comprised 111 (42 females, 69 males) healthy children who had undergone anthropometric and REE measurements and were of similar age to the children with CP (4-19y). REE was measured by indirect calorimetry and energy intake was determined from weighed food records. RESULTS: The REE in the children with CP was low (79.5%) compared with that predicted and highly variable (SD 38.4%). Fat-free mass was the strongest predictor of REE, accounting for 27% of the variation. Energy intake as a percentage of REE in was greatly overestimated in oral-fed children with CP (293%). In a subset of children with CP (n=14), an increased energy intake by gastrostomy tube feeding resulted in an increase in REE from 70.0% to 101.9% of that predicted. INTERPRETATION: The REE of children with CP is low and variable and is not strongly related to any one anthropometric measurement. Food records in oral-fed children with CP are of little value owing to their inaccuracy. This study provided support for the hypothesis that the low REE found in malnourished children with CP is partly due to a low energy intake.

Improved survival in cystic fibrosis patients diagnosed by newborn screening compared to a historical cohort from the same centre.

BACKGROUND: Newborn screening (NBS) for cystic fibrosis (CF) is associated with improved early nutritional outcomes and improved spirometry in children. The aim of this study was to determine whether early diagnosis and treatment of CF with NBS in New South Wales in 1981 led to better clinical outcomes and survival into early adulthood. METHODS: Retrospective observational study comprising two original cohorts born in the 3 years before ('non-screened cohort', n=57) and after ('screened'; n=60) the introduction of NBS. Patient records were assessed at transfer from paediatric to adult care by age 19 years and survival was documented to age 25 years. RESULTS: Non-screened patients (n=38) when compared with screened patients (n=41) had a higher rate and lower age of Pseudomonas aeruginosa acquisition at age 18 years (p ≤ 0.01). Height, weight and body mass index (BMI) z scores (all p<0.01) and forced expiratory volume in 1 s (FEV(1))% were better in the screened group (n=41) (difference: 16.7 ± 6.4%; p=0.01) compared to non-screened (n=38) subjects on transfer to adult care. Each 1% increase in FEV(1)% was associated with a 3% (95% CI 1% to 5%; p=0.001) decrease in risk of death and each 1.0 kg/m(2) increase in BMI contributed to a 44% (95% CI 31% to 55%; p<0.001) decrease in risk of death. This accumulated in a significant survival difference at age 25 years (25 vs 13 deaths or lung transplants; p=0.01). CONCLUSION: NBS for CF leads to better lung function, nutritional status and improved survival in screened patients in early adulthood.

Isolated liver transplantation in children with cystic fibrosis--an Australian experience.

CF liver disease is an uncommon indication for pediatric LT. Determining optimal timing and type (isolated liver versus multi-organ) of transplantation for those with severe liver disease can be challenging and involves consideration of the extent of liver disease (PHT, synthetic dysfunction) and extrahepatic factors such as pulmonary function. We present the experience of isolated LT for CF at our center. Eight children received one allograft each (3.9% of all grafts). One- and four-yr survivals are both 75%. The two deaths occurred within the first two months after LT, and in both cases, invasive fungal infections were implicated, one following treatment for acute severe rejection. All had significant PHT, and six had synthetic dysfunction. All had roux-en Y biliary anastomoses and none developed long-term biliary complications. Seven had pulmonary colonization with Pseudomonas aeruginosa and six with fungus at time of transplantation. Mean pre-LT FEV1 was 80% (range 59-116%) predicted, and lung function post-LT was stable. Isolated LT in children with CF is successful in those with relatively preserved pulmonary function, which does not appear to deteriorate as a consequence. Roux-en Y biliary anastomosis and antifungal prophylaxis should be a part of management of these patients.

Different thermic effects of leptin in adolescent females with varying body fat content.

BACKGROUND & AIMS: Investigating the effect of leptin on energy expenditure in undernutrition might lead to a better understanding of the role of leptin in regulating body weight in humans. METHODS: 73 underweight female adolescents with anorexia nervosa (AN) were compared with 23 healthy normal weight (nwC), and 9 overweight girls (OW); 37 AN were followed during 7 months of weight recovery. Resting energy expenditure (REE, by indirect calorimetry), body composition (fat mass, FM; lean tissue mass, LTM; by Dual-Energy X-Ray Absorptiometry) and plasma hormones of leptin and 3,5,3'-Triiodothyronine (T(3)) were measured. RESULTS: In underweight, leptin, T(3) and REE adjusted for lean tissue mass (REE(LTM)) were decreased; in OW, FM and leptin were increased at unchanged T(3) and REE(LTM). There was a significant positive relation between FM and leptin at low and normal (AN, r(2) = 0.26; nwC, r(2) = 0.51, p < 0.001), but not at high adiposity. Leptin and REE(LTM) were positively associated in underweight (r(2) = 0.14, p = 0.001) but not in normal or overweight subjects. T(3) was linearly related to REE(LTM) over the whole range of adiposity (r(2) = 0.42, p < 0.001). With weight gain in AN (5.0 ± 3.5 kg) the relationship between leptin and REE(LTM) changed toward the conditions seen in normal weight controls. CONCLUSIONS: At low adiposity the interrelated fall of leptin and REE reflect an adaptive mechanism to preserve body weight. High leptin production associated with excessive adiposity was without effect on metabolic adaptation.

Body composition changes in female adolescents with anorexia nervosa.

BACKGROUND: Body weight provides limited information about nutritional status of patients with anorexia nervosa (AN). OBJECTIVES: Our objectives were to determine body composition (BC) changes, to find clinical predictors and endocrine correlates of total body protein (TBPr) depletion, and to compare results on fat mass (FM) obtained with anthropometry (skinfold measurements) and dual-energy X-ray absorptiometry (DXA) in patients with AN. DESIGN: Body weight, body mass index (BMI; in kg/m(2)), BC (with DXA and skinfold measurements), and TBPr [with in vivo neutron activation analysis (IVNAA)] was assessed in 50 AN patients (15.2 y) and 40 healthy sex- and age-matched controls. In 47 AN patients and 22 controls, hormone concentrations were measured. RESULTS: In AN patients, body weight (44.4 +/- 5.5 kg), BMI (16.7 +/- 1.6), and FM(DXA) (7.0 +/- 3.4 kg) were lower than in controls. Lean tissue mass by DXA (LTM(DXA)) was similar in AN patients and controls (35.7 +/- 4.3 compared with 35.8 +/- 4.5 kg), but TBPr was 87% of that of controls (8.1 +/- 1.0 compared with 9.2 +/- 1.2 kg; P < 0.001). Cortisol was high, testosterone was unchanged, and estradiol and insulin-like growth factor I were low. Severe protein depletion measured by IVNAA seen in 17 AN patients could not be identified with simpler methods. All except 1 of 26 AN patients with a BMI > 16.5 had normal TBPr. The difference in individual percentage of body fat measured with DXA and skinfold measurements came up to 9%. CONCLUSION: The severe protein depletion in 34% of AN patients was not accurately identified by LTM(DXA) or simpler methods, but a BMI > 16.5 indicated normal TBPr. Future studies need to compare DXA and skinfold measurements with a reference technique to assess FM in AN patients.

Total body protein in healthy adolescent girls: validation of estimates derived from simpler measures with neutron activation analysis.

BACKGROUND: Little recent and accurate information about body protein content in healthy adolescent girls is available. OBJECTIVE: The objective was to assess the total body nitrogen (TBN) and total body protein (TBPr) contents of fat-free mass (P:FFM) in a group of healthy adolescent girls and to validate previously published TBN prediction equations. DESIGN: TBN was measured with in vivo neutron activation analysis (TBNNAA). Bone mineral density and FFM were measured with dual-energy X-ray absorptiometry (FFMDXA), total body water and FFM were measured with bioimpedance analysis, and FFM was assessed by measuring skinfold thicknesses in 51 girls with a mean (+/- SD) age of 14.7 +/- 0.7 y. The validity of the TBN prediction equations was assessed with Bland-Altman analysis. RESULTS: TBNNAA in our adolescent group was higher (1.49 kg) than values reported in earlier studies of women (1.25 and 1.31 kg), and P:FFM was slightly higher (23%) than that documented in adults (19-21%). Previously published TBN equations showed either systematic bias or wide limits of agreement. CONCLUSION: A predictive equation derived from the present study population based on FFMDXA improves the prediction of TBN for groups of young girls but may not be helpful for individuals in clinical settings.

Reduced body protein in children with spastic quadriplegic cerebral palsy.

BACKGROUND: No studies have directly measured body protein or validated skinfold-thickness anthropometry and dual-energy X-ray absorptiometry (DXA) to assess body protein in children with spastic quadriplegic cerebral palsy (SQCP). OBJECTIVE: We aimed to measure and evaluate body protein and to determine whether skinfold-thickness anthropometry and DXA can predict body protein in children with SQCP. DESIGN: This was a cross-sectional study of 59 children (22 girls, 37 boys) aged 3.9-19.5 y with SQCP. The children underwent measurements of anthropometric indexes, lean tissue mass by DXA (LTM(DXA)), and total body protein by neutron activation analysis (TBP(NAA)). In addition, TBP was estimated from both skinfold-thickness anthropometry (TBP(SKIN)) and DXA (TBP(DXA)). The agreement of TBP(SKIN) and TBP(DXA) was tested against TBP(NAA) by using Bland and Altman plot analysis. RESULTS: Height and weight SD scores (x +/- SD: -3.1 +/- 1.6 and -4.8 +/- 5.3, respectively) were significantly lower than reference data in the children with SQCP (P < 0.001). TBP(NAA) for age and height was low in the children with SQCP (P < 0.001): 56.1 +/- 17.3% and 81.5 +/- 15.7%, respectively, of the values predicted from control data. TBP(SKIN) and TBP(DXA) were both highly correlated with TBP(NAA): r = 0.90, P < 0.001, and r = 0.91, P < 0.001, respectively. Despite these significant correlations, agreement analyses showed wide variation of up to 33.3% of the mean for both methods. CONCLUSIONS: Body protein in children with SQCP is significantly reduced for age and height. Skinfold anthropometry and DXA show wide variation in estimation of body protein compared with NAA in this group of children.