Longitudinal associations between diet quality, sedentary behaviours and physical activity and risk of overweight and obesity in preschool children: The ToyBox-study.

BACKGROUND: Lifestyle behaviours related to diet and physical activity are associated with increased risk of obesity and evidence suggests that associations might be stronger when a synergetic effect is examined. OBJECTIVE: To examine the cross-sectional and longitudinal associations between diet, screen time (ST) and step recommendations and risk of overweight and obesity in European preschoolers participating in the ToyBox-study. METHODS: In this cluster-randomized clinical trial, 718 children (51.4% boys) from six European countries participated. Parents filled out questionnaires with information on socio-demographic status, step recommendations and ST. RESULTS: Longitudinal results indicate that participants having a low Diet Quality Index (DQI), not meeting ST and step recommendations at T0 and T1 had higher odds of having overweight/obesity at T1 (odds ratio [OR] = 1.116; 95% confidence interval [CI] = 1.104-2.562) than those children having a high DQI and meeting ST and step recommendations at T0 and T1. Similarly, participants having a high DQI, but not meeting ST and step recommendations at T0 and T1 had increased odds of having overweight/obesity (OR = 2.515; 95% CI = 1.171-3.021). CONCLUSIONS: The proportion of participants having a low DQI, not adhering to both step and ST recommendations was very high, and it was associated with a higher probability of having overweight and obesity.

Initial Effect of Recombinant Human Growth Hormone Treatment in a Patient with Löwe Syndrome.

OBJECTIVES: Löwe syndrome (the oculocerebrorenal syndrome of Löwe, OCRL, OMIM #309000, ORPHA: 534) is a very rare multisystem X-linked disorder characterized by ocular, kidney and nervous system anomalies. CASE PRESENTATION: We present the first Bulgarian genetically confirmed patient with OCRL. The patient had facial dysmorphism, cryptorchidism, congenital cataracts, nystagmus, delayed physical and mental development, and poor nutritional status. He had severe rickets, metabolic acidosis, hypokalaemia, hypophosphataemia, and low IGF-1 levels at the age of three, in addition to his developmental delay. The molecular-genetic analysis reported a pathogenic variant c.1124A>G, p.H375R in the OCRL gene. This variant was inherited from the mother, who was a carrier. Following the diagnosis of OCRL, treatment with potassium citrate, phosphate, and calcitriol was initiated, along with an increase in caloric intake. Following general physical and biochemical improvement, therapy with rhGH started 4 years ago, and current results are presented. CONCLUSIONS: The patient with Löwe syndrome who was presented with a 6-year follow-up demonstrates the complexity of rare disease cases and the value of multidisciplinary care together with growth hormone treatment for better results in these patients.

Treatment Burden of Weekly Somatrogon vs Daily Somatropin in Children With Growth Hormone Deficiency: A Randomized Study.

Context: Somatrogon is a long-acting recombinant human growth hormone treatment developed as a once-weekly treatment for pediatric patients with growth hormone deficiency (GHD). Objective: Evaluate patient and caregiver perceptions of the treatment burden associated with the once-weekly somatrogon injection regimen vs a once-daily Somatropin injection regimen. Methods: Pediatric patients (≥3 to <18 years) with GHD receiving once-daily somatropin at enrollment were randomized 1:1 to Sequence 1 (12 weeks of once-daily Somatropin, then 12 weeks of once-weekly somatrogon) or Sequence 2 (12 weeks of once-weekly somatrogon, then 12 weeks of once-daily Somatropin). Treatment burden was assessed using validated questionnaires completed by patients and caregivers. The primary endpoint was the difference in mean overall life interference (LI) total scores after each 12-week treatment period (somatrogon vs Somatropin), as assessed by questionnaires. Results: Of 87 patients randomized to Sequence 1 (n = 43) or 2 (n = 44), 85 completed the study. Once-weekly somatrogon had a significantly lower treatment burden than once-daily Somatropin, based on mean overall LI total scores after somatrogon (8.63) vs Somatropin (24.13) treatment (mean difference -15.49; 2-sided 95% CI -19.71, -11.27; P < .0001). Once-weekly somatrogon was associated with greater convenience, higher satisfaction with treatment experience, and less LI. The incidence of treatment-emergent adverse events (TEAEs) for Somatropin and somatrogon was 44.2% and 54.0%, respectively. No severe or serious AEs were reported. Conclusion: In pediatric patients with GHD, once-weekly somatrogon had a lower treatment burden and was associated with a more favorable treatment experience than once-daily Somatropin.

Breastfeeding and Overweight in European Preschoolers: The ToyBox Study.

The benefits of breastfeeding (BF) include risk reduction of later overweight and obesity. We aimed to analyse the association between breastfeeding practices and overweight/obesity among preschool children participating in the ToyBox study. Data from children in the six countries, participating in the ToyBox-study (Belgium, Bulgaria, Germany, Greece, Poland, and Spain) 7554 children/families and their age is 3.5-5.5 years, 51.9% were boys collected cross-sectionally in 2012. The questionnaires included parents' self-reported data on their weight, height, socio-demographic status, and infant feeding practices. Measurements of preschool children's weight and height were done by trained researchers using standard protocols and equipment. The ever breastfeeding rate in the total sample was 85.0% (n = 5777). Only 6.3% (n = 428) of the children from the general sample were exclusively breastfed (EBF) for the duration of the first six months. EBF for four to six months was significantly (p < 0.001) less likely among mothers with formal education < 12 years (adjusted Odds Ratio (OR) = 0.61; 95% Confidence interval (CI) 0.44-0.85), smoking throughout pregnancy (adjusted OR = 0.39; 95% CI 0.24-0.62), overweight before pregnancy (adjusted OR = 0.67; 95%CI 0.47-0.95) and ≤25 years old. The median duration of any breastfeeding was five months. The prevalence of exclusive formula feeding during the first five months in the general sample was about 12% (n = 830). The prevalence of overweight and obesity at preschool age was 8.0% (n = 542) and 2.8% (n = 190), respectively. The study did not identify any significant association between breastfeeding practices and obesity in childhood when adjusted for relevant confounding factors (p > 0.05). It is likely that sociodemographic and lifestyle factors associated with breastfeeding practices may have an impact on childhood obesity. The identified lower than desirable rates and duration of breastfeeding practices should prompt enhanced efforts for effective promotion, protection, and support of breastfeeding across Europe, and in particular in regions with low BF rates.

Complementary Feeding and Overweight in European Preschoolers: The ToyBox-Study.

Complementary feeding (CF) should start between 4-6 months of age to ensure infants' growth but is also linked to childhood obesity. This study aimed to investigate the association of the timing of CF, breastfeeding and overweight in preschool children. Infant-feeding practices were self-reported in 2012 via a validated questionnaire by >7500 parents from six European countries participating in the ToyBox-study. The proportion of children who received breast milk and CF at 4-6 months was 51.2%. There was a positive association between timing of solid food (SF) introduction and duration of breastfeeding, as well as socioeconomic status and a negative association with smoking throughout pregnancy (p < 0.005). No significant risk to become overweight was observed among preschoolers who were introduced to SF at 1-3 months of age compared to those introduced at 4-6 months regardless of the type of milk feeding. Similarly, no significant association was observed between the early introduction of SF and risk for overweight in preschoolers who were breastfed for ≥4 months or were formula-fed. The study did not identify any significant association between the timing of introducing SF and obesity in childhood. It is likely that other factors than timing of SF introduction may have impact on childhood obesity.

Type 1 Diabetes Mellitus - Risk Factor for Cardiovascular Disease Morbidity and Mortality.

Type 1 diabetes mellitus (T1DM) is a chronic disease that starts early in life and often leads to micro- and macrovascular complications. The incidence of the disease is lower than that of type 2 DM and varies in different countries and ethnic groups, and the etiological and pathogenetic factors are different from T2DM. The aim of this overview is to investigate the effect of T1DM on all-cause mortality and CVD morbidity and mortality. During the last decades, the treatment of T1DM has improved the prognosis of the patients. Still, the mortality rates are higher than those of the age- and sex-matched general population. With the prolonged survival, the macrovascular complications and cardiovascular diseases (CVD) appear as major health problems in the management of patients with T1DM. The studies on the CVD morbidity and mortality in this disease group are sparse, but they reveal that T1DM is associated with at least 30% higher mortality. In comparison to healthy people, CVDs are more common in T1DM patients and they occur earlier in life. Furthermore, they are a major cause for death and impaired quality of life in T1DM patients. The correlation between diabetic control and the duration of T1DM is not always present or is insignificant. Nevertheless, the early detection of the preclinical stages of the diseases and the risk factors for their development is important; similarly, the efforts to improve glycemic and metabolic control are of paramount importance.

Parental perceptions, attitudes and knowledge on European preschool children's total screen time: the ToyBox-study.

BACKGROUND: Preschool children spend a significant proportion of their waking hours being sedentary. Parents play a critical role in developing and shaping their children's lifestyle behaviours, particularly in the early years of life. This study aims to assess parental perceptions, attitudes and knowledge of their preschool children's sedentary behaviours and the association with children's television (TV)/video/DVDs viewing and total screen time. METHODS: Data were obtained from a sample of 4836 children (3.5-5.5 years), participating in the multi-centre ToyBox-study at baseline (T0) and at 1-year follow-up (T1) periods. Data on children's sedentary behaviours were collected via a standardized proxy-administered primary caregiver's questionnaire. RESULTS: Regarding total screen time, 66.6% of the children at T0 and 71.8% at T1 in the control group exceeded the recommendations, whereas the proportion in the intervention group varied from 69.7% at T0 to 72.5% at T1. The odds of exceeding total screen time recommendations were significantly higher when parental perceptions towards limiting the total screen time were negative [(both T0 and T1 and in the intervention and control groups (P < 0.05)]. Similarly, the odds of exceeding TV/video/DVDs viewing recommendations were significantly higher (both T0 and T1 is observed in both groups) when parental knowledge of recommendation were absent. CONCLUSIONS: Preschool children whose caregivers stated rules limiting their sedentary screen time were less likely to spend a high amount of time watching TV/video/DVDs. Interventions to increase parental practices may be a promising approach to decrease total screen time of preschool children but studies are needed to confirm this.

International Waist Circumference Percentile Cutoffs for Central Obesity in Children and Adolescents Aged 6 to 18 Years.

CONTEXT: No universal waist circumference (WC) percentile cutoffs used have been proposed for screening central obesity in children and adolescents. OBJECTIVE: To develop international WC percentile cutoffs for children and adolescents with normal weight based on data from 8 countries in different global regions and to examine the relation with cardiovascular risk. DESIGN AND SETTING: We used pooled data on WC in 113,453 children and adolescents (males 50.2%) aged 4 to 20 years from 8 countries in different regions (Bulgaria, China, Iran, Korea, Malaysia, Poland, Seychelles, and Switzerland). We calculated WC percentile cutoffs in samples including or excluding children with obesity, overweight, or underweight. WC percentiles were generated using the general additive model for location, scale, and shape (GAMLSS). We also estimated the predictive power of the WC 90th percentile cutoffs to predict cardiovascular risk using receiver operator characteristics curve analysis based on data from 3 countries that had available data (China, Iran, and Korea). We also examined which WC percentiles linked with WC cutoffs for central obesity in adults (at age of 18 years). MAIN OUTCOME MEASURE: WC measured based on recommendation by the World Health Organization. RESULTS: We validated the performance of the age- and sex-specific 90th percentile WC cutoffs calculated in children and adolescents (6-18 years of age) with normal weight (excluding youth with obesity, overweight, or underweight) by linking the percentile with cardiovascular risk (area under the curve [AUC]: 0.69 for boys; 0.63 for girls). In addition, WC percentile among normal weight children linked relatively well with established WC cutoffs for central obesity in adults (eg, AUC in US adolescents: 0.71 for boys; 0.68 for girls). CONCLUSION: The international WC cutoffs developed in this study could be useful to screen central obesity in children and adolescents aged 6 to 18 years and allow direct comparison of WC distributions between populations and over time.

Ion Transporters, Channelopathies, and Glucose Disorders.

Ion channels and transporters play essential roles in excitable cells including cardiac, skeletal and smooth muscle cells, neurons, and endocrine cells. In pancreatic beta-cells, for example, potassium KATP channels link the metabolic signals generated inside the cell to changes in the beta-cell membrane potential, and ultimately regulate insulin secretion. Mutations in the genes encoding some ion transporter and channel proteins lead to disorders of glucose homeostasis (hyperinsulinaemic hypoglycaemia and different forms of diabetes mellitus). Pancreatic KATP, Non-KATP, and some calcium channelopathies and MCT1 transporter defects can lead to various forms of hyperinsulinaemic hypoglycaemia (HH). Mutations in the genes encoding the pancreatic KATP channels can also lead to different types of diabetes (including neonatal diabetes mellitus (NDM) and Maturity Onset Diabetes of the Young, MODY), and defects in the solute carrier family 2 member 2 (SLC2A2) leads to diabetes mellitus as part of the Fanconi-Bickel syndrome. Variants or polymorphisms in some ion channel genes and transporters have been reported in association with type 2 diabetes mellitus.

Combined Longitudinal Effect of Physical Activity and Screen Time on Food and Beverage Consumption in European Preschool Children: The ToyBox-Study.

Lifestyle behavioral habits such as excess screen time (ST), a lack of physical activity (PA), and high energy-dense food consumption are associated with an increased risk of children being overweight or obese. This study aimed to (1) track longitudinal adherence to PA and ST recommendations at baseline (T0) and follow-up (T1) and (2) assess the association between changes in adherence to PA and ST recommendations and food and beverage consumption at follow-up. The present study included 2321 preschool children (3.5 to 6) participating in the multicenter ToyBox-study. A lineal mixed effects model was used to examine the association between different types of food and beverages and their relationship with changes in adherence to PA and ST recommendations. Approximately half of the children (50.4%) did not meet the PA and ST recommendations at both baseline and follow-up. However, only 0.6% of the sample met both PA and ST recommendations. Preschool children who met both recommendations consumed fewer fizzy drinks, juices, sweets, desserts, and salty snacks and consumed more water, fruits and vegetables, and dairy products than did those not meeting both recommendations. In conclusion, the proportion of European preschool children adhering to both PA and ST recommendations was very low and was associated with a low consumption of energy-dense foods.

Reproducibility and relative validity of a semiquantitative food frequency questionnaire in European preschoolers: The ToyBox study.

OBJECTIVES: The aim of this study was to examine the reproducibility and relative validity of a semiquantitative food frequency questionnaire (FFQ) in assessing food group estimates. METHODS: Food group estimates were assessed via a 37-item FFQ and a 3-d food record (FR). Pearson's correlation coefficients for log-transformed values were calculated to assess the reproducibility and Spearman's rank correlation coefficients for log-transformed values were calculated to assess the validity. Kindergartens from six European countries participated in the preparatory substudies of the ToyBox intervention study; data from preschool children 4 to 6 y of age (n = 196, reproducibility study; n = 324, validation study) were obtained. RESULTS: In the reproducibility study, positive Pearson's correlation coefficients for single and aggregated food groups ranged from 0.14 for pasta and rice to 0.90 for cooked vegetables. In the validation study, the FR gave higher estimates of 40 of the 50 food items (single and aggregated) examined compared with those obtained from the FFQ. Positive crude Spearman rank correlation coefficients ranged from 0.01 for total beverages (added sugar) and rice to 0.62 for tea. Corrections for the deattenuation effect did not improve observed correlations. Quartiles and tertiles were calculated for a small number of food groups (N = 14) owing to zero consumption in the rest of the groups. CONCLUSIONS: Moderately good reproducibility and low-moderate relative validity of the FFQ used in preschool children was observed. Relative validity, however, varied by food and beverage group; for some of the "key" foods/drinks targeted in the ToyBox intervention (e.g., biscuits), the validity was good. The findings should be considered in future epidemiologic and intervention studies in preschool children.

The Genetic and Molecular Mechanisms of Congenital Hyperinsulinism.

Congenital hyperinsulinism (CHI) is a heterogenous and complex disorder in which the unregulated insulin secretion from pancreatic beta-cells leads to hyperinsulinaemic hypoglycaemia. The severity of hypoglycaemia varies depending on the underlying molecular mechanism and genetic defects. The genetic and molecular causes of CHI include defects in pivotal pathways regulating the secretion of insulin from the beta-cell. Broadly these genetic defects leading to unregulated insulin secretion can be grouped into four main categories. The first group consists of defects in the pancreatic KATP channel genes (ABCC8 and KCNJ11). The second and third categories of conditions are enzymatic defects (such as GDH, GCK, HADH) and defects in transcription factors (for example HNF1α, HNF4α) leading to changes in nutrient flux into metabolic pathways which converge on insulin secretion. Lastly, a large number of genetic syndromes are now linked to hyperinsulinaemic hypoglycaemia. As the molecular and genetic basis of CHI has expanded over the last few years, this review aims to provide an up-to-date knowledge on the genetic causes of CHI.

Diagnosis and management of hyperinsulinaemic hypoglycaemia.

Hyperinsulinaemic hypoglycaemia (HH) is a heterogeneous condition with dysregulated insulin secretion which persists in the presence of low blood glucose levels. It is the most common cause of severe and persistent hypoglycaemia in neonates and children. Recent advances in genetics have linked congenital HH to mutations in 14 different genes that play a key role in regulating insulin secretion (ABCC8, KCNJ11, GLUD1, GCK, HADH, SLC16A1, UCP2, HNF4A, HNF1A, HK1, PGM1, PPM2, CACNA1D, FOXA2). Histologically, congenital HH can be divided into 3 types: diffuse, focal and atypical. Due to the biochemical basis of this condition, it is essential to diagnose and treat HH promptly in order to avoid the irreversible hypoglycaemic brain damage. Recent advances in the field of HH include new rapid molecular genetic testing, novel imaging methods (18F-DOPA PET/CT), novel medical therapy (long-acting octreotide formulations, mTOR inhibitors, GLP-1 receptor antagonists) and surgical approach (laparoscopic surgery). The review article summarizes the current diagnostic methods and management strategies for HH in children.

Clustering of energy balance-related behaviours and parental education in European preschool children: the ToyBox study.

Energy balance-related behaviours (EBRB) are established in childhood and seem to persist through to adulthood. A lower parental educational level was associated with unhealthy behavioural patterns. The aim of the study is to identify clusters of EBRB and examine their association with preschool children's BMI and maternal, paternal and parental education. A subsample of the ToyBox study (n 5387) conducted in six European countries was used. Six behavioural clusters ('healthy diet and low activity', 'active', 'healthy lifestyle', 'high water and screen time; low fruits and vegetables (F&V) and physical activity (PA)', 'unhealthy lifestyle' and 'high F&V consumers') emerged. The healthiest group characterised by high water and F&V consumption and high PA z scores ('healthy lifestyle') was more prevalent among preschool children with at least one medium- or higher-educated parent and showed markedly healthier trends for all the included EBRB. In the opposite, the 'unhealthy lifestyle' cluster (characterised by high soft drinks and screen time z scores, and low water, F&V and PA z scores) was more prevalent among children with lower parental, paternal and maternal education levels. OR identified that children with lower maternal, paternal and parental education levels were less likely to be allocated in the 'healthy lifestyle' cluster and more likely to be allocated in the 'unhealthy lifestyle' cluster. The 'unhealthy lifestyle' cluster was more prevalent among children with parents in lower parental educational levels and children who were obese. Therefore, parental educational level is one of the key factors that should be considered when developing childhood obesity prevention interventions.

Clinical presentation and treatment response to diazoxide in two siblings with congenital hyperinsulinism as a result of a novel compound heterozygous ABCC8 missense mutation.

BACKGROUND: Congenital hyperinsulinism (CHI) can present with considerable clinical heterogeneity which may be due to differences in the underlying genetic etiology. We present two siblings with hyperinsulinaemic hypoglycaemia (HH) and marked clinical heterogeneity caused by compound heterozygosity for the same two novel ABCC8 mutations. CASE PRESENTATION: The index patient is a 3-year-old boy with hypoglycaemic episodes presenting on the first day of life. HH was diagnosed and treatment with intravenous glucose and diazoxide was initiated. Currently he has normal physical and neurological development, with occasional hypoglycaemic episodes detected following continuous fasting on treatment with diazoxide. The first-born 8-year-old sibling experienced severe postnatal hypoglycaemia, generalised seizures and severe brain damage despite diazoxide treatment. The latter was stopped at 6-months of age with no further registered hypoglycaemia. Genetic testing showed that both children were compound heterozygotes for two novel ABCC8 missense mutations p.I60N (c.179T>A) and p.G1555V (c.4664G>T). CONCLUSIONS: These ABCC8 missense mutations warrant further studies mainly because of the variable clinical presentation and treatment response.

Establishing International Blood Pressure References Among Nonoverweight Children and Adolescents Aged 6 to 17 Years.

BACKGROUND: Several distributions of country-specific blood pressure (BP) percentiles by sex, age, and height for children and adolescents have been established worldwide. However, there are no globally unified BP references for defining elevated BP in children and adolescents, which limits international comparisons of the prevalence of pediatric elevated BP. We aimed to establish international BP references for children and adolescents by using 7 nationally representative data sets (China, India, Iran, Korea, Poland, Tunisia, and the United States). METHODS AND RESULTS: Data on BP for 52 636 nonoverweight children and adolescents aged 6 to 19 years were obtained from 7 large nationally representative cross-sectional surveys in China, India, Iran, Korea, Poland, Tunisia, and the United States. BP values were obtained with certified mercury sphygmomanometers in all 7 countries by using standard procedures for BP measurement. Smoothed BP percentiles (50th, 90th, 95th, and 99th) by age and height were estimated by using the Generalized Additive Model for Location Scale and Shape model. BP values were similar between males and females until the age of 13 years and were higher in males than females thereafter. In comparison with the BP levels of the 90th and 95th percentiles of the US Fourth Report at median height, systolic BP of the corresponding percentiles of these international references was lower, whereas diastolic BP was similar. CONCLUSIONS: These international BP references will be a useful tool for international comparison of the prevalence of elevated BP in children and adolescents and may help to identify hypertensive youths in diverse populations.

Circulating proinflammatory peptides related to abdominal adiposity and cardiometabolic risk factors in healthy prepubertal children.

OBJECTIVES: To analyze the circulating levels of proinflammatory peptides in healthy prepubertal children in relation to abdominal obesity, measured by waist circumference (WC), and to investigate their interactions with cardiometabolic risk factors. DESIGN AND METHODS: A cross-sectional study of 137 healthy prepubertal children with a mean age of 8.0±0.1 years divided into three groups according to their WC as a measure of abdominal obesity: 'normal-WC' children (25th-75th percentile, n=48), 'children at risk' (75th-90th percentile, n=39), and 'abdominally obese' (≥90th percentile, n=50) children. Auxological measurements and blood pressure (BP) were taken. Fasting levels of high-sensitivity C-reactive protein (hsCRP), interleukin 6 (IL6), tumor necrosis factor-α (TNF-α), glucose, insulin, and lipid profile were measured. Insulin resistance (IR) was assessed by homeostasis model assessment of IR (HOMA-IR). RESULTS: Abdominally obese children had significantly higher BP, insulin, HOMA-IR, total cholesterol and triglycerides (TG) compared with their normal-WC counterparts (P<0.05). HsCRP concentrations increased proportionally with the degree of abdominal obesity (r=0.443, P<0.0001), whereas IL6 and TNF-α were not significantly associated with any of the adiposity variables. After controlling for adiposity, hsCRP was significantly correlated with systolic BP (r=0.257, P=0.004), TNF-α levels were related to high-density lipoprotein cholesterol (HDL-C; r=-0.216, P=0.016) and TG (r=0.196, P=0.029), whereas the relationship between IL6 and HDL-C reduced its magnitude to an insignificant level (r=-0.173, P=0.055). CONCLUSIONS: Healthy prepubertal children with abdominal obesity have associated inflammatory and cardiometabolic alterations, interacting with each other.

Waist circumference percentile curves for Bulgarian children and adolescents aged 6-18 years.

BACKGROUND: Waist circumference (WC) is a simple, easily available anthropometric measurement, giving relevant information about fat distribution and reflecting the degree of central adiposity in children. It appears to be the main risk factor for the progress of the metabolic syndrome. Our aim was to develop age- and sex-specific WC percentile curves for Bulgarian children/adolescents and to compare them with those from other countries. METHODS: A representative cross-sectional study of 3,810 healthy Bulgarian children/adolescents (2,052 males) aged 6-18 years, conducted in 2006/07. Body weight, height and WC were measured and body mass index (BMI) was calculated. Sex- and age-specific WC percentile curves were constructed using the LMS method. RESULTS: WC increased with age in both sexes (P<0.0001), with higher values in boys at every age and percentile point. This difference became significant from age 11 years onwards (P<0.05). The boys' values continued to increase steeply after this age, while in girls we found a constant continuing increase until the age of 15. Thereafter WC began to decrease and level off. The WC percentile values in Bulgarian children were lower than in US children, higher than in British and Turkish children, and similar to those of their Cypriot peers. CONCLUSIONS: For the first time, WC percentile curves were constructed for Bulgarian children/adolescents. A unique standardized method for WC measurement in children is needed for more acceptable international comparisons.