A comparison of pubertal maturity and growth.

BACKGROUND: Growth and pubertal development have each been studied in detail, but rarely in conjunction. AIM: The study aim was to determine what somatic and pubertal development have in common and how they differ and to quantify the association between milestones for growth and for pubertal development (in terms of pubic hair and genitalia/breast, Age of Peak Testes Velocity, APTV and menarche) in relation both to chronological (CA) and bone age (RUS). SUBJECTS AND METHODS: The data analysed are from the 1st Zurich Longitudinal Growth Study, with 120 boys and 112 girls with almost complete data from birth to adulthood. RESULTS: Variability of pubertal milestones was somewhat reduced in terms of RUS, in particular in later phases. Pubic hair phase PH2 appeared ∼1 year after the onset of the pubertal spurt. Around the age of maximal deceleration (T9) an adult-like appearance of pubic hair, genitalia and breasts was reached in most cases. APTV occurred close to T8. Correlations were large between milestones for growth and PH stages and also with menarche or APTV. CONCLUSIONS: A successful modelling of testis growth led to a new pubertal milestone, APTV. The high correlations between the phenomenologically different domains "linear growth" and "pubertal development", and the high correlations between RUS and linear growth previously established allow the conclusion that these different domains develop along similar biological mechanisms, which are steered mainly by genetic factors.

A comparison of skeletal maturity and growth.

BACKGROUND: Somatic and bone development have each been studied in detail, but rarely in conjunction. AIM: The aim of this study was to determine what somatic and bone development have in common and how they differ. A second aim was to check for a pubertal spurt in bone age (BA) and to quantify it in a similar way as has been done for height. The Preece-Baines model is used to fit longitudinal data for BA. SUBJECTS AND METHODS: The data analysed are from the 1st Zurich Longitudinal Growth Study comprising 120 boys and 112 girls with almost complete data from birth to adulthood. RESULTS: Variability of somatic milestones was reduced in terms of BA and there was an aftergrowth after reaching adult RUS score 1000. A strong increase in the RUS score was seen at a late stage of the pubertal spurt (PS). Somatic milestones correlated with the RUS score attained at these ages and more so at an early stage of the PS. A PS for BA was clearly identified with a location at 14.2 years for boys and 12.2 years for girls. Age of peak bone development correlated highly with age of peak velocity of somatic variables. CONCLUSIONS: BA can be successfully modelled as a semi-quantitative entity. Bone development shows marked associations with somatic development, despite the fact that the latter reflects changes in size, while the former is essentially a maturity index and reflects changes in biochemical composition of tissues.

Health-related quality of life and behavior of triplets at adolescent age.

OBJECTIVES: To assess health-related quality of life (HRQoL) and behavior of triplets compared with matched singletons at adolescent age and to identify medical and sociodemographic predictors of outcome. STUDY DESIGN: Fifty-four triplets (19 sets, mean [SD] gestational age 32.0 [2.4] weeks, birth weight 1580 [450] g) and 51 gestational age-, birth weight-, and sex-matched singleton controls self-rated their HRQoL at age 14.5 (0.3) years. Proxy reports about HRQoL and behavior were obtained by parents and teachers. HRQoL was measured with the Kidscreen-52 questionnaire child and parent form, and behavior with the Achenbach Child Behavior Checklist. RESULTS: Self- and parent-reported HRQoL values was similar in both groups except for the dimensions "mood and emotions" and "autonomy," which were better (P = .001, P = .03) in triplets. Parents reported significantly less behavioral problems in triplets compared with controls. Compared with community norms, both HRQoL and behavior measures in triplets were in the normal range. Parent-reported HRQoL was predicted by dichorionicity. CONCLUSIONS: HRQoL and behavioral outcome in adolescent triplets was good in our study and was, in some aspects, better than in matched singleton controls. Dichorionicity is an important outcome determinant.

Impaired neuromotor outcome in school-age children with congenital hypothyroidism receiving early high-dose substitution treatment.

Congenital hypothyroidism (CH) can lead to intellectual deficits despite early high-dose treatment. Our study aimed to determine whether motor impairments can occur despite early high-dose treatment. Sixty-three children with CH and early (median age of onset of treatment 9 d), high-dose treatment (median starting dose of levothyroxine 14.7 µg/kg/d) were tested with the Zurich Neuromotor Assessment (ZNA) at a median age of 13.8 y (range 7.0-14.2 y). Median z-scores in the children with CH were -0.95 in the pure and -0.56 in the adaptive fine motor component, significantly lower than in the ZNA test norms (p < 0.001 and p = 0.01, respectively). The 26 children with athyreosis were more affected than the 33 children with dysgenesis, particularly in the pure motor (-1.55 versus -0.76, p = 0.03), adaptive fine motor (-1.31 versus 0.13, p < 0.01), and static balance task (-0.47 versus 0.67, p = 0.01). Boys performed worse than girls. Older age at onset of treatment was related to poorer adaptive fine motor performance. Movement quality (assessed by associated movements) was not affected. We conclude that severe CH can cause neuromotor deficits persisting into adolescence. These deficits cannot completely be reversed by postnatal treatment, but earlier age at treatment may reduce the degree of impairment.

The role of birthweight discordance in the intellectual and motor outcome for triplets at early school age.

AIM: We assessed motor and intellectual outcome in triplets at school age and investigated the predictive value of perinatal and demographic factors. METHODS: Seventy-one live-born newborn infants (24 triplet pregnancies) were prospectively enrolled at birth. At the age of 6 years, 58 children (31 males, 27 females; mean gestational age 31.2 wks [SD 2.2 wks]; mean birthweight 1622 g [SD 440 g]) returned for a neurodevelopmental examination. A comparison group for triplets born before 32 gestational weeks comprising 26 gestational age-, birthweight-, and sex-matched singletons was also recruited (mean gestational age 30.1 wk [SD 1.5 wk]; mean birthweight 1142 g [SD 210 g]; 12 males, 14 females). The Zurich Neuromotor Assessment was used to examine motor performance, and intellectual abilities were assessed with the Kaufman Assessment Battery for Children (K-ABC). RESULTS: Motor performance and movement quality in these individuals was significantly reduced compared with the test norms for all motor tasks (p<0.001) other than static balance. The mean values on the Mental Processing Composite (95.3, SD 8.4) and the Achievement Scale (90.1, SD 13.8) of the K-ABC were also lower than those in the test reference (p<0.05 and p<0.01 respectively). Triplets born at less than 32 weeks' gestation showed poorer pure motor and adaptive gross motor performance (both p<0.05) than, but similar intellectual performance to, the gestational age-, birthweight- and sex-matched singletons. Poor outcome was predicted by low socio-economic status and by intertriplet birthweight discordance (both p<0.01). INTERPRETATION: Triplets were at an increased risk of mild motor and intellectual impairments. This finding is important for tailoring therapeutic interventions for these children and for parental counselling. Very preterm triplets showed similar outcomes to the singleton comparison children, except that they had poorer motor performance. Low socio-economic status was a major risk factor for impaired intellectual development. In addition, birthweight discordance may also be considered a predictor for poor long-term motor and intellectual outcome in triplets.

Children with genetic disorders undergoing open-heart surgery: are they at increased risk for postoperative complications?

OBJECTIVES: Children with congenital heart disease and genetic disorders may be at increased risk for postoperative mortality and morbidity compared with children with congenital heart disease alone. The aim of the present study was to determine differences in postcardiopulmonary bypass outcome between these two groups. DESIGN: Prospective cohort study. SETTING: Tertiary university children's hospital. PATIENTS: We enrolled 211 infants (<1 yr) who underwent bypass surgery for congenital heart disease. Data on perioperative course were compared between infants with and without genetic disorders. Univariate analysis was followed by regression analysis to control for confounders. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: We enrolled 148 infants without and 63 infants with a genetic disorder. The majority of infants with genetic disorders had trisomy 21 (n = 32), six had microdeletion 22q11, and 25 had other genetic disorders. There was no significant difference in mortality between infants with and without genetic disorders. An underlying genetic disorder was an independent risk factor for renal insufficiency (p = .003) and reintubation (p = .02). Trisomy 21 was an independent risk factor for chylothorax (p = .01) and sepsis (p = .05). The length of hospital stay was longer in infants with genetic disorders other than trisomy 21 compared with infants with trisomy 21 (p = .009). CONCLUSIONS: Infants with congenital heart disease and genetic disorders are not at increased risk for postoperative mortality. However, a genetic disorder is a risk factor for reintubation and renal insufficiency, whereas infants with trisomy 21 have a higher risk of chylothorax and sepsis. Intensive care providers need to be aware of these differences in morbidity to improve management decisions and parental counseling.

Decrease in the prevalence of paediatric adiposity in Switzerland from 2002 to 2007.

OBJECTIVE: A national study in Switzerland in 2002 suggested nearly one in five schoolchildren was overweight. Since then, many programmes have been introduced in an attempt to control the problem. The aim of the present study was to determine the prevalence of childhood overweight in Switzerland five years later. DESIGN: In both studies a cross-sectional, three-stage, probability-proportional-to-size cluster sampling of schools throughout Switzerland was used to obtain a representative sample of approximately 2500 children aged 6-13 years. Height and weight were measured and BMI calculated. The BMI references from the Centers for Disease Control and Prevention were used to determine the prevalences of underweight (<5th percentile), overweight (>or=85th and <95th percentile) and obesity (>or=95th percentile). RESULTS: In 2007 the prevalences of underweight, overweight and obesity in boys were 3.5 %, 11.3 % and 5.4 %, respectively; in girls they were 2.6 %, 9.9 % and 3.2 %. Compared with 2002, there was a significant decrease in the prevalence of overweight in girls and of obesity in both genders. In contrast to 2002, where there were no differences, in 2007 the prevalence of paediatric obesity was significantly higher in communities with a population >100 000 compared with smaller communities (P < 0.05). CONCLUSIONS: In summary, over the past 5 years, the prevalence of adiposity has decreased in Swiss children. These findings suggest that increased awareness combined with mainly school-based programmes aimed at physical activity and healthy nutrition may have helped to control this public health problem. Future monitoring in Switzerland will determine if these findings are sustained.

Effects of valproic acid on sleep in children with epilepsy.

PURPOSE: Parents frequently report increased sleep duration in their children during treatment with valproic acid (VPA). We assessed sleep duration and sleep behavior before and after tapering VPA in children treated for more than 6 months. METHODS: Sleep variables were assessed by questionnaire, diary, and actigraphy (for 7 consecutive days and nights) before and 8-12 weeks after termination of VPA. RESULTS: Forty-six children (age range 1.7-17.4 years) completed the study. The questionnaire data showed no significant difference in bed and wake time, duration of sleep, and time to fall asleep before and after ending VPA treatment, although some qualitative measures on daytime sleepiness improved after tapering VPA. The actigraphy data revealed that the average sleep amount without VPA was reduced in 33 children (9 of them >30 min) and longer in 13 children (1 of them >30 min). The mean Assumed Sleep Time per Day decreased by 15.2 min or 9.5 min when the physiologic decrease of sleep duration within 0.3 years was considered. Also mean Actual Sleep Time per Day was significantly reduced after VPA termination (-15.2 min; after correction -10.7 min). The reduction was only significant in children older than age 6 years. DISCUSSION: Termination of VPA after long-term treatment leads to a significant reduction of sleep duration in children older than 6 years of age. The change was small in the majority, but considerable in a subgroup of children.

Children with congenital hypothyroidism: long-term intellectual outcome after early high-dose treatment.

We aim to determine long-term intellectual outcome of adolescents with early high-dose treated congenital hypothyroidism (CH). Sixty-three prospectively followed children with CH were assessed at age of 14 y with the Wechsler Intelligence Scale for Children-Revised and compared with 175 healthy controls. Median age at onset of treatment was 9 d (range 5-18 d) and median starting dose of levothyroxine (L-T4) was 14.7 microg/kg/d (range 9.9-23.6 microg/kg/d). Full-scale intelligence quotient (IQ) was significantly lower than in controls after adjustment for socioeconomic status (SES) and gender (101.7 versus 111.4; p < 0.0001). Children with athyreosis had a lower performance IQ than those with dysgenesis (adjusted difference 7.6 IQ scores, p < 0.05). Lower initial thyroxine (T4) levels correlated with poorer IQ (r = 0.27, p = 0.04). Lower SES was associated with poorer IQ, in particular in children with CH (interaction, p = 0.03). Treatment during childhood was not related to IQ at age 14 y. Adolescents with CH manifest IQ deficits when compared with their peers despite early high-dose treatment and optimal substitution therapy throughout childhood. Those adolescents with athyreosis and lower SES are at particular risk for adverse outcome. Therefore, early detection of intellectual deficits is mandatory in children with CH.

Diet determines features of the metabolic syndrome in 6- to 14-year-old children.

BACKGROUND/OBJECTIVES: Insulin resistance (IR) and hypertension are common in overweight children, and the adipocyte-derived hormones resistin, adiponectin, and leptin may modulate IR and blood pressure (BP). Few data exist in children on dietary determinants of IR, BP, or leptin, and no data exist on dietary determinants of resistin and adiponectin. Therefore, the objective of this study was to investigate dietary determinants of IR, BP, resistin, adiponectin, and leptin concentrations, as well as the interrelationship among these variables, in normal and overweight children. SUBJECTS/METHODS: In 6- to 14-year-old Swiss children (n=79), nutritional intake was assessed using two 24-hour-recalls and a one-day dietary record. Body mass index (BMI), body fat percentage (BF%), waist/hip ratio (W/H ratio), BP, glucose, insulin, resistin, adiponectin, and leptin were determined. IR was calculated using the quantitative insulin sensitivity check index (QUICKI). RESULTS: BMI, BF%, and W/H ratio were significant predictors of leptin and insulin, QUICKI, and systolic BP, but not resistin or adiponectin. Of the overweight and obese children, 40% were diagnosed pre-hypertensive or hypertensive. Total energy, fat, saturated fat, and protein intakes were significant predictors of fasting insulin and QUICKI, and total fat, saturated fat, and monounsaturated fat intakes were significant predictors of systolic BP, independent of BMI standard deviation score (BMI-SDS) and age. There were no associations between these dietary factors and leptin, adiponectin, or resistin. CONCLUSION: In children, dietary macronutrient composition is a predictor of IR and systolic BP, but not resistin, adiponectin, or leptin concentrations. Resistin and adiponectin concentrations are not correlated with IR or BP in this age range.

Randomised trial of oral versus sequential intravenous/oral cephalosporins in children with pyelonephritis.

The hypothesis was tested that oral antibiotic treatment in children with acute pyelonephritis and scintigraphy-documented lesions is equally as efficacious as sequential intravenous/oral therapy with respect to the incidence of renal scarring. A randomised multi-centre trial was conducted in 365 children aged 6 months to 16 years with bacterial growth in cultures from urine collected by catheter. The children were assigned to receive either oral ceftibuten (9 mg/kg once daily) for 14 days or intravenous ceftriaxone (50 mg/kg once daily) for 3 days followed by oral ceftibuten for 11 days. Only patients with lesions detected on acute-phase dimercaptosuccinic acid (DMSA) scintigraphy underwent follow-up scintigraphy. Efficacy was evaluated by the rate of renal scarring after 6 months on follow-up scintigraphy. Of 219 children with lesions on acute-phase scintigraphy, 152 completed the study; 80 (72 females, median age 2.2 years) were given ceftibuten and 72 (62 females, median age 1.6 years) were given ceftriaxone/ceftibuten. Patients in the intravenous/oral group had significantly higher C-reactive protein (CRP) concentrations at baseline and larger lesion(s) on acute-phase scintigraphy. Follow-up scintigraphy showed renal scarring in 21/80 children treated with ceftibuten and 33/72 with ceftriaxone/ceftibuten (p = 0.01). However, after adjustment for the confounding variables (CRP and size of acute-phase lesion), no significant difference was observed for renal scarring between the two groups (p = 0.2). Renal scarring correlated with the extent of the acute-phase lesion (r = 0.60, p < 0.0001) and the grade of vesico-ureteric reflux (r = 0.31, p = 0.03), and was more frequent in refluxing renal units (p = 0.04). The majority of patients, i.e. 44 in the oral group and 47 in the intravenous/oral group, were managed as out-patients. Side effects were not observed. From this study, we can conclude that once-daily oral ceftibuten for 14 days yielded comparable results to sequential ceftriaxone/ceftibuten treatment in children aged 6 months to 16 years with DMSA-documented acute pyelonephritis and it allowed out-patient management in the majority of these children.

Fructose intake is a predictor of LDL particle size in overweight schoolchildren.

BACKGROUND: High amounts of dietary fructose may contribute to dyslipidemia in adults, but there are few data in children. Childhood adiposity is associated with smaller LDL particle size, but the dietary predictors of LDL size in overweight children have not been studied. OBJECTIVES: We aimed to determine whether LDL particle size is associated with dietary factors and specifically with fructose intake in normal-weight and overweight children. DESIGN: In a cross-sectional study of normal-weight and overweight 6-14 y-old Swiss children (n = 74), dietary intakes were assessed by using two 24-h-recalls and a 1-d dietary record. Body mass index (BMI) and waist-hip ratio (WHR) were measured, and plasma lipid profile and LDL particle size were determined. RESULTS: Compared with the normal-weight group, overweight children had significantly higher plasma triacylglycerol concentrations, lower HDL-cholesterol concentrations, and smaller LDL particle size (P < 0.05). LDL particle size was inversely correlated to BMI SD scores and WHR (P = 0.007). Although there were no significant differences in total fructose intake, the overweight children consumed a significantly (P < 0.05) higher percentage of fructose from sweets and sweetened drinks than did the normal-weight children. After control for adiposity, the only dietary factor that was a significant predictor of LDL particle size was total fructose intake (P = 0.024). CONCLUSIONS: In school-age children, greater total and central adiposity are associated with smaller LDL particle size and lower HDL cholesterol. Overweight children consume more fructose from sweets and sweetened drinks than do normal-weight children, and higher fructose intake predicts smaller LDL particle size.

Assessment of iodine status using dried blood spot thyroglobulin: development of reference material and establishment of an international reference range in iodine-sufficient children.

CONTEXT: Thyroglobulin (Tg) may be a valuable indicator of improving thyroid function in children after salt iodization. A recently developed Tg assay for use on dried whole blood spots (DBS) makes sampling practical, even in remote areas. OBJECTIVE: The study aim was to develop a reference standard for DBS-Tg, establish an international reference range for DBS-Tg in iodine-sufficient children, and test the standardized DBS-Tg assay in an intervention trial. DESIGN, PARTICIPANTS, AND INTERVENTIONS: Serum Tg reference material of the European Community Bureau of Reference (CRM-457) was adapted for DBS and its stability tested over 1 yr. DBS-Tg was determined in an international sample of 5- to 14-yr-old children (n = 700) who were euthyroid, anti-Tg antibody negative, and residing in areas of long-term iodine sufficiency. In a 10-month trial in iodine-deficient children, DBS-Tg and other indicators of iodine status were measured before and after introduction of iodized salt. RESULTS: Stability of the CRM-457 Tg reference standard on DBS over 1 yr of storage at -20 and -50 C was acceptable. In the international sample of children, the third and 97th percentiles of DBS-Tg were 4 and 40 microg/liter, respectively. In the intervention, before introduction of iodized salt, median DBS-Tg was 49 microg/liter, and more than two thirds of children had DBS-Tg values greater than 40 microg/liter. After 5 and 10 months of iodized salt use, median DBS-Tg decreased to 13 and 8 microg/liter, respectively, and only 7 and 3% of children, respectively, had values greater than 40 microg/liter. DBS-Tg correlated well at baseline and 5 months with urinary iodine and thyroid volume. CONCLUSIONS: The availability of reference material and an international reference range facilitates the use of DBS-Tg for monitoring of iodine nutrition in school-age children.

Dietary intakes of fat and antioxidant vitamins are predictors of subclinical inflammation in overweight Swiss children.

BACKGROUND: In obese children, subclinical inflammation is often present and is correlated with the metabolic syndrome. Dietary factors, such as fatty acids and antioxidants, potentially modulate the association between adiposity and subclinical inflammation, but few data are available in children. OBJECTIVE: The aim of the study was to determine whether dietary fat or antioxidant intakes influence circulating tumor necrosis factor alpha (TNF-alpha), interleukin 6 (IL-6), C-reactive protein (CRP), and leptin concentrations in overweight children. DESIGN: In a cross-sectional study of 6-14-y-old normal-weight (n = 33), overweight (n = 19), and obese (n = 27) Swiss children, nutritional intakes were assessed from two 24-h dietary recalls and a 1-d dietary record. Percentage body fat from skinfold thicknesses, waist-hip ratio, and blood pressure were measured. Fasting blood samples were collected for the measurement of insulin, glucose, HDL-cholesterol, triacylglycerol, CRP, IL-6, TNF-alpha, and leptin concentrations. RESULTS: CRP, IL-6, and leptin increased significantly (P < 0.02) with increasing adiposity, independent of age; TNF-alpha did not increase. Total dietary fat and the percentage of energy from fat were significant predictors of CRP concentration, independent of body mass index (P < 0.05). Meat intake was a significant predictor of IL-6 and leptin, independent of body mass index (P < 0.05). Intakes of antioxidant vitamins (vitamins E and C and beta-carotene) were significant predictors of leptin (P < 0.05) but not of CRP, IL-6, or TNF-alpha. CONCLUSIONS: Overweight Swiss children as young as 6 y have elevated concentrations of inflammatory markers. Intakes of total fat and antioxidant vitamins are determinants of subclinical inflammation in this age group.

High thyroid volume in children with excess dietary iodine intakes.

BACKGROUND: There are few data on the adverse effects of chronic exposure to high iodine intakes, particularly in children. OBJECTIVE: The objective of the study was to ascertain whether high dietary intakes of iodine in children result in high thyroid volume (Tvol), a high risk of goiter, or both. DESIGN: In an international sample of 6-12-y-old children (n = 3319) from 5 continents with iodine intakes ranging from adequate to excessive, Tvol was measured by ultrasound, and the urinary iodine (UI) concentration was measured. Regressions were done on Tvol and goiter including age, body surface area, sex, and UI concentration as covariates. RESULTS: The median UI concentration ranged from 115 microg/L in central Switzerland to 728 microg/L in coastal Hokkaido, Japan. In the entire sample, 31% of children had UI concentrations >300 microg/L, and 11% had UI concentrations >500 microg/L; in coastal Hokkaido, 59% had UI concentrations >500 microg/L, and 39% had UI concentrations >1000 microg/L. In coastal Hokkaido, the mean age- and body surface area-adjusted Tvol was approximately 2-fold the mean Tvol from the other sites combined (P < 0.0001), and there was a positive correlation between log(UI concentration) and log(Tvol) (r = 0.24, P < 0.0001). In the combined sample, after adjustment for age, sex, and body surface area, log(Tvol) began to rise at a log(UI concentration) >2.7, which, when transformed back to the linear scale, corresponded to a UI concentration of approximately 500 microg/L. CONCLUSIONS: Chronic iodine intakes approximately twice those recommended-indicated by UI concentrations in the range of 300-500 microg/L-do not increase Tvol in children. However, UI concentrations >/=500 microg/L are associated with increasing Tvol, which reflects the adverse effects of chronic iodine excess.

Serum transferrin receptor and zinc protoporphyrin as indicators of iron status in African children.

BACKGROUND: Although transferrin receptor (TfR) and zinc protoporphyrin (ZnPP) are often used to define iron status in school-age children in developing countries, the diagnostic cutoffs for this age group are uncertain. OBJECTIVE: The objective was to determine the sensitivity and specificity of TfR and ZnPP in predicting iron deficiency in black and white children in Africa. DESIGN: Hemoglobin, C-reactive protein (CRP), serum ferritin (SF), TfR, and ZnPP were measured in children in Côte d'Ivoire and Morocco. We excluded children with elevated CRP and then used receiver operating characteristic (ROC) curves to evaluate TfR and ZnPP alone and in combination in screening for iron deficiency, defined as an SF concentration <15 mug/L, and iron deficiency anemia (IDA), defined as an SF concentration <15 mug/L and low hemoglobin. RESULTS: The sample included 2814 children aged 5-15 y. The sensitivity and specificity of TfR and ZnPP were limited by considerable overlap between iron-sufficient, nonanemic children and those with IDA. On the basis of ROC curves, we identified diagnostic cutoffs for TfR and ZnPP that achieved specificities and sensitivities of approximately 60-80%. Separate cutoffs for Côte d'Ivoire and Morocco gave the best performance; the cutoffs for both TfR and ZnPP were higher in Côte d'Ivoire. Moreover, a comparison of nonanemic, iron-sufficient subjects showed that Ivorian children had significantly higher TfR and ZnPP concentrations than did Moroccan children (P < 0.01). CONCLUSIONS: New diagnostic cutoffs for TfR and ZnPP, based on ROC curve analyses, may improve the performance of these indexes in defining iron status in children. Significant ethnic differences in TfR and ZnPP suggest that separate cutoffs may be needed for black and white children.

Very preterm infants show earlier emergence of 24-hour sleep-wake rhythms compared to term infants.

BACKGROUND: Previous studies show contradictory results about the emergence of 24-h rhythms and the influence of external time cues on sleep-wake behavior in preterm compared to term infants. AIMS: To examine whether very preterm infants (<32 weeks of gestational age) differ in their emergence of the 24-h sleep-wake rhythm at 5, 11 and 25 weeks corrected age compared to term infants and whether cycled light conditions during neonatal intermediate care affects postnatal 24-h sleep-wake rhythms in preterm infants. STUDY DESIGN: Prospective cohort study with nested interventional trial. SUBJECTS: 34 preterm and 14 control term infants were studied. During neonatal hospitalization, preterm infants were randomly assigned to cycled light [7 am-7 pm lights on, 7 pm-7 am lights off, n=17] or dim light condition [lights off whenever the child is asleep, n=17]. OUTCOME MEASURES: Sleep and activity behavior recorded by parental diary and actigraphy at 5, 11 and 25 weeks corrected age. RESULTS: Sleep at nighttime and the longest consolidated sleep period between 12 pm-6 am was longer (mixed model analysis, factor group: p=0.02, resp. p=0.01) and activity at nighttime was lower (p=0.005) at all ages in preterm compared to term infants. Cycled light exposed preterm infants showed the longest nighttime sleep duration. Dim light exposed preterm infants were the least active. CONCLUSIONS: Preterm infants show an earlier emergence of the 24-h sleep-wake rhythm compared to term infants. Thus, the length of exposure to external time cues such as light may be important for the maturation of infant sleep-wake rhythms. Trial registry number: This trial has been registered at www.clinicaltrials.gov (identifier NCT01513226).

The Zurich 3-step concept for the management of behavioral sleep disorders in children: a before-and-after study.

OBJECTIVES: Several strategies have been found to be effective for the treatment of childhood behavioral sleep disorders. One which has yet to be evaluated is the Zurich 3-step concept, which combines basic notions of the two-process model of sleep regulation (introducing a regular rhythm and adjusting bedtime to sleep need) with behavioral strategies. This uncontrolled before-and-after study describes our concept and its step-wise approach, assesses changes in sleep-wake variables and behavior problems, and also examines associations between changes in sleep-wake variables and behavior problems. METHODS: A total of 79 children with sleep problems (age range 6-47 months, 42% females) were included. Sleep problems were assessed by the Infant Sleep Questionnaire, sleep-wake variables by diary and actigraphy, and behavior problems of children ≥ 18 months by the Child Behavior Checklist. RESULTS: A significant decrease in nocturnal wake duration (Cohen's d = -0.34) and a significant increase in the duration of the longest continuous nocturnal sleep period (Cohen's d = 0.19) were found from before to after intervention (on average 2.7 months, SD 1.5). The variability for sleep onset and end time decreased, and actigraphically measured circadian rest-activity cycle measures improved. Parent-reported internalizing and total behavior problems also decreased (Cohen's d = 0.66). CONCLUSIONS: The findings of both objective and subjective assessment techniques suggest that the Zurich 3-step concept is effective. Thus, the intervention concept may be useful in clinical practice with sleep-disordered children.

Detection of overweight and obesity in a national sample of 6-12-y-old Swiss children: accuracy and validity of reference values for body mass index from the US Centers for Disease Control and Prevention and the International Obesity Task Force.

BACKGROUND: For defining overweight in children, reference values for body mass index (BMI) are available from the US Centers for Disease Control and Prevention (CDC) and the International Obesity Task Force (IOTF). However, these 2 sets of reference criteria differ, and their accuracy in classifying adiposity has not yet been validated in most countries. OBJECTIVE: We compared BMI criteria from the IOTF and the CDC with percentage of body fat (%BF) from multisite skinfold thicknesses (SFTs) for identification of overweight in 6-12-y-old Swiss children. DESIGN: In a representative sample (n = 2431), weight, height, and 4 SFTs were measured. Regression and receiver operating characteristic (ROC) curves were used to evaluate BMI as an indicator of adiposity. RESULTS: BMI and %BF were well correlated (r(2) = 0.74), and the areas under the ROC curves for overweight and obesity were 0.956-0.992. The sensitivity and specificity of the IOTF and CDC overweight criteria and of the CDC obesity criteria were high. The sensitivity of the IOTF obesity criteria was only 48% and 62% in boys and girls, respectively. Overall, the performance of the CDC criteria was superior. With the use of the CDC criteria, the prevalence of overweight in girls and boys was 19.1% and 20.3%, respectively. CONCLUSIONS: BMI is an excellent proxy measure of adiposity in 6-12-y-old children. In Swiss children, both BMI criteria accurately predict overweight, but the sensitivity of the IOTF obesity criteria is poor. They failed to detect one-half of the children identified as obese on the basis of %BF from SFTs.