Air Displacement Plethysmography is an Accurate and Feasible Noninvasive Measure of Fat-Free Mass in Children With Intestinal Failure.

BACKGROUND: The nutritional status of children with intestinal failure (IF) can be difficult to determine using body weight and currently available anthropometric techniques. Air displacement plethysmography (ADP) is a noninvasive measure of whole-body composition that measures body mass and volume, with a calculation of percent body fat (%BF) and fat-free mass (FFM) that may be useful during the provision of specialized nutrition. OBJECTIVES: To evaluate the validity and feasibility of measuring body composition in children with IF using ADP compared with deuterium dilution (DD), as well as secondarily with other measures of body composition, namely bioelectrical impedance analysis (BIA), dual-energy X-ray absorptiometry (DXA), and four-site skinfold anthropometry. METHODS: We conducted a prospective cohort study of 18 children recruited through the Center for Advanced Intestinal Rehabilitation at Boston Children's Hospital. Patients 2-17 years of age with IF dependent on parenteral nutrition (PN) for more than 90 days were included. Spearman rank correlation and Bland-Altman limits of agreement (LOA) analysis were used to compare ADP to 4 alternative measures of body composition. RESULTS: Eighteen children with IF, median age 7.1 [interquartile range (IQR) 5.4-9.3] years, 9 female (50%), and median residual bowel length 31 (IQR 22-85) cm were enrolled. Median PN energy intake was 46 (IQR 39-49) kcal/kg/day. Incomplete bladder emptying lead to invalid measures of DD in 4 subjects. Spearman correlation coefficients for %BF were low to moderate between ADP and DD ( r = 0.29), DXA ( r = 0.62), BIA ( r = 0.50), and skinfold ( r = 0.40). Correlations for FFM were high between ADP and these other measures (range 0.95-0.98). Comparing ADP with DD and skinfold measures, Bland-Altman analysis showed small mean bias (-1.9 and +1.5 kg) and acceptable 95% LOA ranges (10.7 and 22.9 kg), respectively, with larger bias (-10.7 and -7.7 kg) and LOA ranges (38.7 and 45.2 kg) compared to DXA and BIA. %BF by ADP and skinfold thickness were moderately correlated ( r = 0.43) with low bias (-0.2%) but very wide LOA (25.7%). CONCLUSIONS: Body composition via ADP is feasible and valid in children with IF as a measure of FFM but appears less suitable for the measurement of %BF. The technique holds promise as a noninvasive measure of body composition to assess the efficacy of nutritional, medical, and surgical interventions.

Clinical Trial of the Protein Farnesylation Inhibitors Lonafarnib, Pravastatin, and Zoledronic Acid in Children With Hutchinson-Gilford Progeria Syndrome.

BACKGROUND: Hutchinson-Gilford progeria syndrome is an extremely rare, fatal, segmental premature aging syndrome caused by a mutation in LMNA yielding the farnesylated aberrant protein progerin. Without progerin-specific treatment, death occurs at an average age of 14.6 years from an accelerated atherosclerosis. A previous single-arm clinical trial demonstrated that the protein farnesyltransferase inhibitor lonafarnib ameliorates some aspects of cardiovascular and bone disease. This present trial sought to further improve disease by additionally inhibiting progerin prenylation. METHODS: Thirty-seven participants with Hutchinson-Gilford progeria syndrome received pravastatin, zoledronic acid, and lonafarnib. This combination therapy was evaluated, in addition to descriptive comparisons with the prior lonafarnib monotherapy trial. RESULTS: No participants withdrew because of side effects. Primary outcome success was predefined by improved per-patient rate of weight gain or carotid artery echodensity; 71.0% of participants succeeded (P<0.0001). Key cardiovascular and skeletal secondary variables were predefined. Secondary improvements included increased areal (P=0.001) and volumetric (P<0.001-0.006) bone mineral density and 1.5- to 1.8-fold increases in radial bone structure (P<0.001). Median carotid artery wall echodensity and carotid-femoral pulse wave velocity demonstrated no significant changes. Percentages of participants with carotid (5% to 50%; P=0.001) and femoral (0% to 12%; P=0.13) artery plaques and extraskeletal calcifications (34.4% to 65.6%; P=0.006) increased. Other than increased bone mineral density, no improvement rates exceeded those of the prior lonafarnib monotherapy treatment trial. CONCLUSIONS: Comparisons with lonafarnib monotherapy treatment reveal additional bone mineral density benefit but likely no added cardiovascular benefit with the addition of pravastatin and zoledronic acid. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifiers: NCT00879034 and NCT00916747.

Body Composition in Children with Chronic Illness: Accuracy of Bedside Assessment Techniques.

OBJECTIVE: To evaluate the accuracy of estimated fat mass and fat-free mass from bedside methods compared with reference methods in children with chronic illnesses. STUDY DESIGN: Fat mass and fat-free mass values were obtained by skinfold, bioelectrical impedance analysis (BIA), dual-energy x-ray absorptiometry (DXA), and deuterium dilution method in children with spinal muscular atrophy, intestinal failure, and post hematopoietic stem cell transplantation (HSCT). Spearman's correlation and agreement analyses were performed between (1) fat mass values estimated by skinfold equations and by DXA and (2) fat-free mass values estimated by BIA equations and by DXA and deuterium dilution methods. Limits of agreement between estimating and reference methods within ±20% were deemed clinically acceptable. RESULTS: Fat mass and fat-free mass values from 90 measurements in 56 patients, 55% male, and median age of 11.6 years were analyzed. Correlation coefficients between the skinfold-estimated fat mass values and DXA were 0.93-0.94 and between BIA-estimated fat-free mass values and DXA were 0.92-0.97. Limits of agreement between estimated and DXA values of fat mass and fat-free mass were greater than ±20% for all equations. Correlation coefficients between estimated fat-free mass values and deuterium dilution method in 35 encounters were 0.87-0.91, and limits of agreement were greater than ±20%. CONCLUSION: Estimated body composition values derived from skinfold and BIA may not be reliable in children with chronic illnesses. An accurate noninvasive method to estimate body composition in this cohort is desirable.

Clinical trial of a farnesyltransferase inhibitor in children with Hutchinson-Gilford progeria syndrome.

Hutchinson-Gilford progeria syndrome (HGPS) is an extremely rare, fatal, segmental premature aging syndrome caused by a mutation in LMNA that produces the farnesylated aberrant lamin A protein, progerin. This multisystem disorder causes failure to thrive and accelerated atherosclerosis leading to early death. Farnesyltransferase inhibitors have ameliorated disease phenotypes in preclinical studies. Twenty-five patients with HGPS received the farnesyltransferase inhibitor lonafarnib for a minimum of 2 y. Primary outcome success was predefined as a 50% increase over pretherapy in estimated annual rate of weight gain, or change from pretherapy weight loss to statistically significant on-study weight gain. Nine patients experienced a ≥50% increase, six experienced a ≥50% decrease, and 10 remained stable with respect to rate of weight gain. Secondary outcomes included decreases in arterial pulse wave velocity and carotid artery echodensity and increases in skeletal rigidity and sensorineural hearing within patient subgroups. All patients improved in one or more of these outcomes. Results from this clinical treatment trial for children with HGPS provide preliminary evidence that lonafarnib may improve vascular stiffness, bone structure, and audiological status.

Comparison of body composition assessment methods in pediatric intestinal failure.

OBJECTIVES: The aim of the study was to examine the agreement of multifrequency bioelectric impedance analysis (BIA) and anthropometry with reference methods for body composition assessment in children with intestinal failure (IF). METHODS: We conducted a prospective pilot study in children 14 years or younger with IF resulting from either short bowel syndrome or motility disorders. Bland-Altman analysis was used to examine the agreement between BIA and deuterium dilution in measuring total body water (TBW) and lean body mass (LBM), and between BIA and dual-energy x-ray absorptiometry (DXA) techniques in measuring LBM and fat mass (FM). FM and percent body fat (%BF) measurements by BIA and anthropometry were also compared in relation to those measured by deuterium dilution. RESULTS: Fifteen children with IF, median (interquartile range) age 7.2 (5.0, 10.0) years, and 10 (67%) boys, were studied. BIA and deuterium dilution were in good agreement with a mean bias (limits of agreement) of 0.9 (-3.2 to 5.0) for TBW (L) and 0.1 (-5.4 to 5.6) for LBM (kg) measurements. The mean bias (limits) for FM (kg) and %BF measurements were 0.4 (-3.8 to 4.6) kg and 1.7 (-16.9 to 20.3)%, respectively. The limits of agreement were within 1 standard deviation of the mean bias in 12 of 14 (86%) subjects for TBW and LBM, and in 11 of 14 (79%) for FM and %BF measurements. Mean bias (limits) for LBM (kg) and FM (kg) between BIA and DXA were 1.6 (-3.0 to 6.3) kg and -0.1 (-3.2 to 3.1) kg, respectively. Mean bias (limits) for FM (kg) and %BF between anthropometry and deuterium dilution were 0.2 (-4.2 to 4.6) and -0.2 (-19.5 to 19.1), respectively. The limits of agreement were within 1 standard deviation of the mean bias in 10 of 14 (71%) subjects. CONCLUSIONS: In children with IF, TBW and LBM measurements by multifrequency BIA method were in agreement with isotope dilution and DXA methods, with small mean bias and clinically acceptable limits of agreement. In comparison with deuterium dilution, BIA was comparable to anthropometry for FM and %BF assessments with small mean bias, but the limits of agreement were large. BIA is a reliable method for TBW and LBM assessments in population studies; however, its reliability in individual patients, especially for FM assessments, cannot be guaranteed.

The adult galactosemic phenotype.

BACKGROUND: Classic galactosemia is an autosomal recessive disorder due to galactose-1-phosphate uridyltransferase (GALT) deficiency. Newborn screening and early treatment do not completely prevent tremor, speech deficits, and diminished IQ in both sexes and premature ovarian insufficiency (POI) in women. Data on how individuals with galactosemia fare as adults will improve our ability to predict disease progression. METHODS: Thirty-three adults (mean age = 32.6 ± 11.7 years; range = 18-59) with classic galactosemia, confirmed by genotype and undetectable GALT enzyme activity, were evaluated. Analyses assessed associations among age, genotype, clinical features and laboratory measures. RESULTS: The sample included 17 men and 16 women. Subjects exhibited cataracts (21%), low bone density (24%), tremor (46%), ataxia (15%), dysarthria (24%), and apraxia of speech (9%). Subjects reported depression (39%) and anxiety (67%). Mean full scale IQ was 88 ± 20, (range = 55-122). All subjects followed a dairy-free diet and 75-80% reported low intake of calcium and vitamin D. Mean height, weight and body mass were within established norms. All female subjects had been diagnosed with POI. One woman and two men had had children. Logistic regression analyses revealed no associations between age, genotype or gender with IQ, tremor, ataxia, dysarthria, apraxia of speech or anxiety. Each 10- year increment of age was associated with a twofold increase in odds of depression. CONCLUSIONS: Taken together, these data do not support the hypothesis that galactosemia is a progressive neurodegenerative disease. However, greater attention to depression, anxiety, and social relationships may relieve the impact of this disorder in adults.

Timing of parenteral nutrition is associated with adequacy of nutrient delivery and anthropometry in critically ill children: A single-center study.

BACKGROUND: The optimal timing of supplemental parenteral nutrition (PN) use in the pediatric intensive care unit (ICU) is unclear. We aimed to describe patterns of PN use in the ICU and the association between the timing of PN initiation and macronutrient delivery and anthropometry. METHODS: We enrolled patients (aged <18 years) with an ICU stay >3 days were started on PN in the ICU. Initiation within 48 hours of admission was deemed as early, and duration <5 days was deemed as short. We used multivariable analysis to examine the association between PN timing and macronutrient delivery adequacy (percentage of the prescribed target that was actually delivered) and weight-for-age z-score (WAZ) over hospital stay. RESULTS: Ninety-five patients were included. Median (interquartile range [IQR]) time to initiate PN was 4 (1, 6) days, and in 33%, PN was initiated early. Median (IQR) PN duration was 8 (5, 14) days, and in 16.8%, duration was short. Median (IQR) adequacies for total energy and protein delivery were 55% (40, 74) and 72% (44, 81) in the early PN group compared with 29% (3, 50) and 31% (4, 47), respectively, in the late PN group (P < .001). The late PN group had a 0.50-unit greater decline in mean WAZ compared with the early PN group (95% CI, 0.11-0.89; P = .012). CONCLUSION: Late PN initiation was associated with significantly lower adequacy of macronutrient delivery and greater decline in WAZ in critically ill children. The relationship between PN timing patient outcomes must be further examined.

Effects of Sugar-Sweetened, Artificially Sweetened, and Unsweetened Beverages on Cardiometabolic Risk Factors, Body Composition, and Sweet Taste Preference: A Randomized Controlled Trial.

Background A 2018 American Heart Association science advisory indicated that, pending further research, artificially sweetened beverages (ASBs) may be an appropriate initial replacement for sugar-sweetened beverages (SSBs) during transition to unsweetened beverages (USBs). Methods and Results We randomly assigned 203 adults (121 males, 82 females; 91.6% retention), who habitually consumed SSBs, to 3 groups and delivered free SSBs, ASBs, or USBs to their homes for 12 months. Outcomes included serum triglyceride to high-density lipoprotein cholesterol ratio (primary), body weight, and sweet taste preference (experimental assessment, 0%-18% sucrose solutions). Change in serum triglyceride to high-density lipoprotein cholesterol ratio was not different between groups. Although overall change in weight also was not different between groups, we found effect modification (P=0.006) by central adiposity. Among participants in the highest tertile of baseline trunk fat but not other tertiles, weight gain was greater (P=0.002) for the SSB (4.4±1.0 kg, estimate±SE) compared with ASB (0.5±0.9 kg) or USB (-0.2±0.9 kg) group. Both sweetness threshold (-1.0±0.2% m/v; P=0.005) and favorite concentration (-2.3±0.4% m/v; P<0.0001) decreased in the USB group; neither changed in the SSB group. In the ASB group, sweetness threshold did not change, and favorite concentration decreased (-1.1±0.5% m/v; P=0.02). Pairwise comparison between the ASB and USB groups indicated a difference in sweetness threshold (P=0.015). Conclusions Replacing SSBs with noncaloric beverages for 12 months did not affect serum triglyceride to high-density lipoprotein cholesterol ratio. Among individuals with central adiposity, replacing SSBs with either ASBs or USBs lowered body weight. However, USBs may have the most favorable effect on sweet taste preference. Registration URL: https://www.clinicaltrials.gov; unique identifier: NCT01295671.

Blood and Hair Aluminum Levels, Vaccine History, and Early Infant Development: A Cross-Sectional Study.

OBJECTIVE: To evaluate relationships between whole blood (B-Al) and hair aluminum (H-Al) levels in healthy infants and their immunization history and development. METHODS: We conducted a cross-sectional study of 9- to 13-month-old children recruited from an urban primary care center, excluding those with a history of renal disease or receipt of either aluminum-containing pharmaceuticals or parenteral nutrition. Aluminum levels were measured using inductively coupled plasma-mass spectrometry. Correlation with Bayley Scales of Infant and Toddler Development, Third Edition (BSID) and vaccine-related aluminum load was assessed via linear regression models. RESULTS: The median age of 85 participants was 287 days. B-Al (median, 15.4 ng/mL; range, 0.9-952 ng/mL) and H-Al (median 42,542 ng/g; range, 2758-211,690 ng/g) were weakly correlated (Spearman ρ = 0.26; P = .03). There was no significant correlation between B-Al or H-Al and estimated aluminum load from vaccines. B-Al was not correlated with BSID composite or subscale scores. Although H-Al was not correlated with BSID scores in models including all data (n = 85), it was inversely correlated with motor composite (P < .02; Wald = 5.88) and the gross motor subscale (P = .04; Wald = 4.38) in models that excluded an extreme outlying H-Al value. CONCLUSIONS: Infant B-Al and H-Al varied considerably but did not correlate with their immunization history. Likewise, there was no correlation between B-Al and infant development or between H-Al and language or cognitive development. An inverse correlation between H-Al and BSID motor scores deserves further investigation.

Comprehensive nutritional and metabolic assessment in patients with spinal muscular atrophy: Opportunity for an individualized approach.

Optimal nutrition support is recommended for patients with spinal muscular atrophy (SMA). In a prospective study, we performed comprehensive nutritional assessments with the aim to guide best nutritional strategies for patients with SMA types II and III. We recorded a) anthropometry; b) macro- and micronutrient intakes; c) measured resting energy expenditure by indirect calorimetry; and d) body composition including dual X-ray absorptiometry. We enrolled a cohort of 21 patients aged 3 to 36 years of which 13 were female; 19 had SMA type II and 2 had SMA type III. The body mass index z-score ranged from -3 to 2.4. Forty-five percent of the cohort was either underfed or overfed, based on the difference between actual energy intake and measured resting energy expenditure. Vitamin D, E, K, folate and calcium intakes were low in a majority of the cohort. Forty-five percent of the cohort was either hypometabolic or hypermetabolic. Fat mass index (kg/m2) was significantly higher and lean body mass index (kg/m2) was significantly lower in the study cohort compared to population normalized values. Bone mineral density was low in 13 of 17 patients. In summary, we have described the prevalence of malnutrition, suboptimal feeding and alterations in body composition in children with SMA. A comprehensive nutritional assessment could guide individualized nutrition therapy in this vulnerable population.

Providing food to treat adolescents at risk for cardiovascular disease.

OBJECTIVE: Diet modification is recommended to treat childhood cardiovascular (CV) risk factors; however, the optimal dietary strategy is unknown. METHODS: In a randomized trial, the effect of a low-fat (LF) and a low-glycemic-load (LGL) reduced-calorie diet were examined in youth with overweight/obesity with CV risk factors. Using a novel intervention, we delivered LF or LGL meals and nutrition education to the home for 8 weeks (Intensive Phase), followed by 4 months Maintenance without food provision. Between-group differences in the change in insulin area under the curve (InsAUC) by oral glucose tolerance test and other risk factors were analyzed. RESULTS: Overall, participants (n = 27) showed substantial improvement during the Intensive Phase, including InsAUC (-59 ± 18.2 µU/ml × 120 min, P = 0.004), total cholesterol (-9.9 ± 3.6 mg/dl, P = 0.01), weight (-2.7 ± 0.5 kg, P < 0.001), waist circumference (-3.1 ± 0.8 cm, P < 0.001), HOMA-IR (-1.7 ± 0.4, P < 0.001), systolic blood pressure (-5 ± 1.4 mm Hg, P = 0.002), and CRP (-0.1 ± 0.1 mg/dl, P = 0.04). There were minimal between-group differences; the LF group showed greater declines in HDL (P = 0.005) and fasting glucose (P = 0.01) compared to the LGL group. Improvements waned during Maintenance. CONCLUSIONS: Home delivery of LF or LGL diets resulted in rapid and clinically important improvements in CV risk factors that diminished without food delivery and did not differ based on dietary intervention. If scalable, food provision may represent an alternative nutrition treatment strategy.

Intensively managed young children with type 1 diabetes consume high-fat, low-fiber diets similar to age-matched controls.

Despite significant emphasis on nutrition, older children with diabetes demonstrate poor dietary quality. We tested the hypothesis that dietary quality in young children with type 1 diabetes (T1D) would be better than age-matched children in the US population. Dietary data from children with T1D (n = 67) aged 2 to 12 years attending a pediatric diabetes clinic were compared with a nationally representative, age-matched sample from the National Health and Nutrition Examination Survey (NHANES; n = 1691). Multiple 24-hour dietary recalls were used. Recommended intakes were based on national guidelines, and dietary quality was assessed using the Healthy Eating Index-2005. More children with T1D were overweight or obese compared with children participating in NHANES (42% vs 30%, P = .04). Greater proportions of children with T1D met daily recommendations for vegetables (22% vs 13%, P = .03), whole grains (12% vs 5%, P = .005), and dairy (55% vs 36%, P = .001) compared with NHANES children, whereas similar proportions met daily fruit recommendations (40% vs 33%, P = .2). Less than one-third of all children limited total fat to recommended levels; children with T1D consumed more saturated fat than did NHANES children (14% vs 12% total energy intake, P = .0009). Fiber intakes were very low in both groups. Compared with NHANES children, children with T1D had higher Healthy Eating Index-2005 scores (59.6 vs 49.7, P = .0006) primarily because of lower intakes of added sugars. The nutritional intake of young children with T1D remains suboptimal in the contemporary era of diabetes management. Despite focused nutrition management, young children with T1D consume high-fat, low-fiber diets comparable with youth in the general population.

Maintenance of optimal vitamin D status in children and adolescents with inflammatory bowel disease: a randomized clinical trial comparing two regimens.

CONTEXT: Vitamin D promotes bone health and regulates the immune system, both important actions for pediatric patients with inflammatory bowel disease (IBD). The supplementation dose that would maintain optimal serum 25-hydroxyvitamin D concentration (25OHD ≥ 32 ng/mL) is unknown. OBJECTIVE: The objective of the study was to compare two supplementation regimens' efficacy and safety in maintaining optimal 25OHD in children with IBD. DESIGN: This was a randomized, not blinded, controlled trial. SETTING: The trial was conducted in the Boston Children's Hospital Clinical and Translational Study Unit. PARTICIPANTS: Sixty-three patients, aged 8-18 years with IBD and baseline 25OHD greater than 20 ng/mL were enrolled; 48 completed the study, and one withdrew for adverse events. INTERVENTION: Arm A received 400 IU of oral vitamin D2 daily (n = 32). Arm B received 1000 IU daily in the summer/fall and 2000 IU in the winter/spring (n = 31). MAIN OUTCOME: The main outcome was the probability of maintaining 25OHD of 32 ng/mL or greater in all trimonthly visits for 12 months. RESULTS: Three participants in arm A (9.4%) and three in arm B (9.7%) achieved the primary outcome (P = .97). The incidence of adverse events, all minor, did not differ. More participants in arm A developed C-reactive protein level of 1 mg/dL or greater (31% vs 10%, P = .04) and IL-6 greater than 3 pg/mL (54% vs 27%, P = .05). CONCLUSIONS: Daily oral vitamin D2 doses up to 2000 IU were inadequate to maintain optimal 25OHD but were well tolerated. The finding of lower incidence of elevated inflammatory markers and cytokines among participants receiving higher vitamin D2 doses merits further study.

Treatment of vitamin D insufficiency in children and adolescents with inflammatory bowel disease: a randomized clinical trial comparing three regimens.

CONTEXT: Vitamin D insufficiency [serum 25-hydroxyvitamin D (25OHD) concentration less than 20 ng/ml] is prevalent among children with inflammatory bowel disease (IBD), and its treatment has not been studied. OBJECTIVE: The aim of this study was to compare the efficacy and safety of three vitamin D repletion regimens. DESIGN AND SETTING: We conducted a randomized, controlled clinical trial from November 2007 to June 2010 at the Clinical and Translational Study Unit of Children's Hospital Boston. The study was not blinded to participants and investigators. PATIENTS: Eligibility criteria included diagnosis of IBD, age 5-21, and serum 25OHD concentration below 20 ng/ml. Seventy-one patients enrolled, 61 completed the trial, and two withdrew due to adverse events. INTERVENTION: Patients received orally for 6 wk: vitamin D(2), 2,000 IU daily (arm A, control); vitamin D(3), 2,000 IU daily (arm B); vitamin D(2), 50,000 IU weekly (arm C); and an age-appropriate calcium supplement. MAIN OUTCOME MEASURE: We measured the change in serum 25OHD concentration (Δ25OHD) (ng/ml). Secondary outcomes included change in serum intact PTH concentration (ΔPTH) (pg/ml) and the adverse event occurrence rate. RESULTS: After 6 wk, Δ25OHD ± se was: 9.3 ± 1.8 (arm A); 16.4 ± 2.0 (arm B); 25.4 ± 2.5 (arm C); P (A vs. C) = 0.0004; P (A vs. B) = 0.03. ΔPTH ± SE was -5.6 ± 5.5 (arm A); -0.1 ± 4.2 (arm B); -4.4 ± 3.9 (arm C); P = 0.57. No participant experienced hypercalcemia or hyperphosphatemia, and the prevalence of hypercalciuria did not differ among arms at follow-up. CONCLUSIONS: Oral doses of 2,000 IU vitamin D(3) daily and 50,000 IU vitamin D(2) weekly for 6 wk are superior to 2,000 IU vitamin D(2) daily for 6 wk in raising serum 25OHD concentration and are well-tolerated among children and adolescents with IBD. The change in serum PTH concentration did not differ among arms.

Hutchinson-Gilford progeria is a skeletal dysplasia.

Hutchinson-Gilford progeria syndrome (HGPS) is a rare segmental premature aging disorder that affects bone and body composition, among other tissues. We sought to determine whether bone density and structural geometry are altered in children with HGPS and whether relationships exist among these parameters and measures of skeletal anthropometry, body composition, and nutrition. We prospectively enrolled 26 children with HGPS (ages 3.1 to 16.2 years). Outcomes included anthropometric data; bone age; areal bone mineral density (aBMD) and body composition by dual-energy X-ray absorptiometry (DXA); volumetric bone mineral density (vBMD), strength-strain index (SSI), and bone structural rigidity calculated from radial transaxial peripheral quantitative computed tomographic (pQCT) images; serum bone biomarkers and hormonal measures; and nutrition assessments. Children with HGPS had low axial aBMD Z-scores by DXA, which improved after adjustment for height age, whereas differences in radial vBMD by pQCT were less striking. However, pQCT revealed distinct abnormalities in both novel measures of bone structural geometry and skeletal strength at the radius compared with healthy controls. Dietary intake was adequate, confirming that HGPS does not represent a model of malnutrition-induced bone loss. Taken together, these findings suggest that the phenotype of HGPS represents a unique skeletal dysplasia.

Impact of carbohydrate counting on glycemic control in children with type 1 diabetes.

OBJECTIVE: To study the association between parent carbohydrate counting knowledge and glycemic control in youth with type 1 diabetes. RESEARCH DESIGN AND METHODS: We assessed 67 youth ages 4-12 years with type 1 diabetes (duration >or=1 year). Parents estimated carbohydrate content of children's meals in diet recalls. Ratios of parent estimates to computer analysis defined carbohydrate counting knowledge; the mean and SD of these ratios defined accuracy and precision, respectively. A1C defined glycemic control. RESULTS: Greater accuracy and precision were associated with lower A1C in bivariate analyses (P < 0.05). In a multivariate analysis (R(2)= 0.25, P = 0.007) adjusting for child age, sex, and type 1 diabetes duration, precision (P = 0.02) and more frequent blood glucose monitoring (P = 0.04), but not accuracy (P = 0.9), were associated with lower A1C. A1C was 0.8% lower (95% CI -0.1 to -1.4) among youth whose parents demonstrated precision. CONCLUSIONS: Precision with carbohydrate counting and increased blood glucose monitoring were associated with lower A1C in children with type 1 diabetes.