Association between cardiorespiratory fitness level and insulin resistance in adolescents with various obesity categories.

BACKGROUND: An association between cardiorespiratory fitness (CRF) and insulin resistance in obese adolescents, especially in those with various obesity categories, has not been systematically studied. There is a lack of knowledge about the effects of CRF on insulin resistance in severely obese adolescents, despite their continuous rise. AIM: To investigate the association between CRF and insulin resistance in obese adolescents, with special emphasis on severely obese adolescents. METHODS: We performed a prospective, cross-sectional study that included 200 pubertal adolescents, 10 years to 18 years of age, who were referred to a tertiary care center due to obesity. According to body mass index (BMI), adolescents were classified as mildly obese (BMI 100% to 120% of the 95th percentile for age and sex) or severely obese (BMI ≥ 120% of the 95th percentile for age and sex or ≥ 35 kg/m2, whichever was lower). Participant body composition was assessed by bioelectrical impedance analysis. A homeostatic model assessment of insulin resistance (HOMA-IR) was calculated. Maximal oxygen uptake (VO2max) was determined from submaximal treadmill exercise test. CRF was expressed as VO2max scaled by total body weight (TBW) (mL/min/kg TBW) or by fat free mass (FFM) (mL/min/kg FFM), and then categorized as poor, intermediate, or good, according to VO2max terciles. Data were analyzed by statistical software package SPSS (IBM SPSS Statistics for Windows, Version 24.0). P < 0.05 was considered statistically significant. RESULTS: A weak negative correlation between CRF and HOMA-IR was found [Spearman's rank correlation coefficient (rs) = -0.28, P < 0.01 for CRFTBW; (rs) = -0.21, P < 0.01 for CRFFFM]. One-way analysis of variance (ANOVA) revealed a significant main effect of CRF on HOMA-IR [F(2200) = 6.840, P = 0.001 for CRFTBW; F(2200) = 3.883, P = 0.022 for CRFFFM]. Subsequent analyses showed that obese adolescents with poor CRF had higher HOMA-IR than obese adolescents with good CRF (P = 0.001 for CRFTBW; P = 0.018 for CRFFFM). Two-way ANOVA with Bonferroni correction confirmed significant effect of interaction of CRF level and obesity category on HOMA-IR [F(2200) = 3.292, P = 0.039 for CRFTBW]. Severely obese adolescents had higher HOMA-IR than those who were mildly obese, with either good or poor CRF. However, HOMA-IR did not differ between severely obese adolescents with good and mildly obese adolescents with poor CRF. CONCLUSION: CRF is an important determinant of insulin resistance in obese adolescents, regardless of obesity category. Therefore, CRF assessment should be a part of diagnostic procedure, and its improvement should be a therapeutic goal.

The smallest dislocated microduplication of Xq27.1 harboring SOX3 gene associated with XX male phenotype.

OBJECTIVES: Approximately 90% of "XX males" are positive for SRY. However, there are isolated cases of sex reversal associated to other genes in male-determining pathway. CASE PRESENTATION: We describe a 1.3-old patient with 46,XX karyotype, male phenotypic gender and cryptorchidism. Microarray analysis revealed a de novo 273 kb duplication in the Xq27.1 region that contains SOX3. FISH with probe specific to SOX3 confirmed a unique genomic location of this duplication, dislocated proximal to the centromere of the X chromosome. CONCLUSIONS: This rare genetic condition was described in few other isolated cases that have associated SOX3 genetic rearrangements and DSD. Microarray and genome-wide-sequencing presents important part in routine diagnostics, and in delineation of other sex-determination-pathway genes in sex reversal disorders.

ALTERNATING HYPOTHYROIDISM AND HYPERTHYROIDISM IN AN ADOLESCENT BOY - DO WE ALWAYS UNDERSTAND WHAT DRIVES THE SWITCH?

Alternating hypothyroidism and hyperthyroidism is a rare phenomenon, especially among pediatric patients. It is usually related to simultaneous, unbalanced presence of stimulating and blocking thyroid stimulating hormone receptor antibodies (TRAbs). Herein we describe thyroid stimulating hormone (TSH) and thyroid hormone fluctuations in an adolescent boy with negative TRAbs. A 12-year-old healthy boy exhibited alternating thyroid function, with several switches between hypothyroidism and hyperthyroidism during almost six years of follow-up. He had persistently elevated thyroid peroxidase antibodies, while TRAbs were repetitively negative. Due to a mild clinical presentation, most of the time he did not require any medication. This case contributes to the spectrum of alternating hypothyroidism and hyperthyroidism in the pediatric age and raises the question of mechanisms involved in fluctuating thyroid function. Therapeutic decisions should be individualized and guided by clinical manifestations and thyroid function tests, irrespective of the underlying pathophysiology.

TRANSIENT PSEUDOHYPOALDOSTERONISM SECONDARY TO URINARY TRACT INFECTION IN A MALE INFANT WITH UNILATERAL HYDRONEPHROSIS DUE TO PRIMARY OBSTRUCTIVE MEGAURETER: A CASE REPORT.

We present a case of transient form of type 1 pseudohypoaldosteronism (S-PHA) in a 1.5-month-old male infant who presented with lethargy, failure to thrive, severe hyponatremia (Na=118 mmol/L), hypochloremia (Cl=93 mmol/L) and fever due to urinary tract infection. Potassium levels were normal. Markedly elevated serum aldosterone level and elevated serum renin confirmed the diagnosis of pseudohypoaldosteronism. Renal ultrasound showed grade III hydronephrosis on the left kidney while contrast-enhanced voiding urosonography excluded the existence of vesicoureteral reflux, which raised suspicion of obstructive uropathy at the level of vesicoureteral junction. Serum sodium normalized after several days of intravenous fluids and antibiotic therapy, after which oral supplementation of sodium was introduced. The levels of 17-hydroxyprogesterone, adrenocorticotropic hormone, cortisol and thyroid-stimulating hormone were normal. Functional magnetic resonance urography conducted at the age of 3 months confirmed the diagnosis of primary congenital obstructive megaureter and the infant was referred to a pediatric surgeon. Although a rare occurrence, S-PHA can be a potentially life-threatening condition in infants if not recognized and treated appropriately. Therefore, serum concentrations of electrolytes should be obtained in every child diagnosed with obstructive anomaly of the urinary tract and/or acute cystopyelonephritis. On the other hand, every child diagnosed with S-PHA should be evaluated for obstructive anomaly of the urinary tract.

Establishing paediatric reference intervals for thyroid function tests in Croatian population on the Abbott Architect i2000.

INTRODUCTION: Evaluation of thyroid function is often requested and therefore defining paediatric reference intervals (RIs) is of vital importance. Currently, there is a distinct lack of paediatric RIs for thyroid function tests in Croatia. Thus, we established RIs for thyroid stimulating hormone (TSH), total triiodothyronine (TT3), total thyroxine (TT4), free triiodothyronine (FT3) and free thyroxine (FT4) in the Croatian paediatric population. MATERIALS AND METHODS: Reference intervals were calculated from 397 apparently healthy children, aged from 2 days to < 19 years. Serum samples were analysed for thyroid function tests on the Abbott Architect i2000. Age- and sex-specific 95% RIs with 90% confidence intervals were established according to Clinical and Laboratory Standards Institute guidelines. To express the magnitude of sex and age variation, standard deviation ratio (SDR) was calculated using two-level nested ANOVA. The criterion for considering partitioning reference values was set to SDR > 0.3. RESULTS: All thyroid function tests required age partitioning, confirmed by SDR above 0.3. There was no need for sex partitioning, confirmed by SDR below 0.3. Still, FT3 was partitioned due to visually noticeable sex related difference for the oldest group (12 years to < 19 years). CONCLUSION: This is the first study to establish RIs for thyroid function tests in the Croatian paediatric population. We propose RIs for widely used Abbott platform, thus giving laboratories method- and population-specific paediatric RIs for thyroid function tests that should improve clinical test interpretation.

CONTINUOUS GLUCOSE MONITORING AND TYPE 1 DIABETES MELLITUS CONTROL IN CHILD, ADOLESCENT AND YOUNG ADULT POPULATION - ARGUMENTS FOR ITS USE AND EFFECTS.

Sensors for continuous glucose monitoring (CGM) in intercellular fluid are used as a contemporary method to achieve better control in type 1 diabetes mellitus (DM), which is best shown through lower glycated hemoglobin (HbA1c) levels.The aim of this study was to assess how many of our patients used CGM (parents were solely financing all the cost of the device) and what was the effect of CGM on the control of DM. Data were retrospectively collected from medical records of patients actively treated at the Division of Endocrinology, Diabetology, Pulmonology and Allergology, Department of Pediatrics, Sestre milosrdnice University Hospital Center. The t-test was used for independent samples to compare the mean levels of HbA1c before and after the inclusion of CGM. CGM was used by 81 (32.1%) of our patients with type 1 DM, of which 43 met the inclusion criteria. The mean HbA1c level 6 months before the introduction of CGM was 8.2%±1.9 and after 12 months of CGM use it was 7.4%±1.2, which was a statistically significant improvement (p=0.026). Furthermore, our results demonstrated that the greatest improvement in HbA1c level was recorded in the groups of young adults (18-25 years) and youngest children (<12 years). We confirmed the efficacy of CGM in achieving better control of type 1 DM by significantly improving HbA1c levels in a population of highly motivated patients.

Time to the Peak, Shape of the Curve and Combination of These Glucose Response Characteristics During Oral Glucose Tolerance Test as Indicators of Early Beta-cell Dysfunction in Obese Adolescents

Objective: Characteristics of the glucose response during oral glucose tolerance test (OGTT) may reflect differences in insulin secretion and action. The aim was to examine whether timing of the glucose peak, shape of the glucose curve and their combination could be indicators of beta-cell dysfunction in obese/severely obese adolescents with normal glucose tolerance (NGT). Methods: Data from 246 obese/severely obese adolescents who completed OGTT were reviewed. Out of 184 adolescents with NGT, 174 could be further classified into groups based on timing of the glucose peak (early/30 minutes vs late/≥60 minutes) and shape of the glucose curve (monophasic vs biphasic). Groups were compared with respect to insulin sensitivity (whole body insulin sensitivity index - WBISI), early-phase insulin secretion (insulinogenic index - IGI) and beta-cell function relative to insulin sensitivity (oral disposition index - oDI). Results: Late glucose peak (p=0.004) and monophasic glucose curve (p=0.001) were both associated with lower oDI after adjustment for age, sex, puberty stage and body mass index z-score. Among obese/severely obese adolescents with NGT, those with coexistent late glucose peak and monophasic glucose curve had lower oDI than those with early glucose peak and biphasic glucose curve (p=0.002). Moreover, a combination of late glucose peak and monophasic glucose curve was the most powerful predictor of the lowest oDI quartile [odds ratio (OR): 11.68, 95% confidence interval: 3.048-44.755, p<0.001]. Conclusion: Late timing of the glucose peak, monophasic shape of the glucose curve and, in particular, a combination of those characteristics during OGTT may indicate early beta-cell dysfunction in obese/severely obese adolescents with NGT.

EFFECT OF GROWTH HORMONE THERAPY IN CHILDREN WITH PRADER-WILLI SYNDROME - OUR FIRST EXPERIENCES.

- Prader-Willi syndrome (PWS) is the most common cause of morbid obesity in childhood. It is the consequence of the lack of expression of genes on the paternally inherited 15q11.2-q13 region. Hyperphagia, obesity, short stature, psychomotor retardation and deterioration of behavior predominate in clinical presentation. Recombinant human growth hormone (rhGH) therapy, along with restriction of caloric intake, has become the mainstay in the management of PWS patients. Anthropometric parameters (height, body mass index (BMI)), therapy effect on carbohydrate and lipid metabolism, and occurrence of side effects were monitored in four children with PWS treated with rhGH for ≥2 years at doses of up to 1 mg/m2/day. During the follow-up, the height standard deviation score (SDS) increased in comparison with baseline values, and after ≥2 years of treatment with rhGH it was within the reference range for the general children population. BMI SDS decreased after the first year of treatment, but thereafter increased again; still, the level of BMI SDS was much better in comparison with most children with PWS of the same age and gender. RhGH therapy had no negative effect on glucose and lipid metabolism, nor caused any other adverse effect. Therapy including a customized diet for PWS, along with rhGH therapy, provided a satisfactory growth rate and prevented development of morbid obesity without side effects. This treatment approach would ensure transition of a greater number of PWS patients into adult care, where the multidisciplinary approach in care should be continued.

Regional differences in incidence and clinical presentation of type 1 diabetes in children aged under 15 years in Croatia.

AIM: To determine regional differences in the incidence, incidence trends, and clinical presentation of type 1 diabetes in children under the age of 15 years in Croatia in a 9-year period (1995-2003). METHODS: We included the patients who had been diagnosed with the disease and had started the insulin treatment before they were 15 years old. Regional differences between eastern, central, and southern Croatia were observed. The gross incidence was expressed by the number of newly diagnosed type 1 diabetes patients in 100000 children of the same age and sex per year, ie, for the 0-14 age group, and for the 0-4, 5-9, and 10-14 subgroups. RESULTS: The highest incidence was observed in southern Croatia (10.91 per 100000/y) and the lowest in central Croatia (8.64 per 100000/y), and in eastern Croatia the incidence was 8.93 per 100000/y. All three regions showed a growing incidence trend, which was significant only in eastern and southern Croatia. There was 35.9% of patients with diabetic ketoacidosis in eastern Croatia, 41.7% in central Croatia, and 31.28% in southern Croatia. CONCLUSION: Croatian regions show differences in the incidence, incidence trends, and disease presentation of type 1 diabetes. A further follow-up is needed to establish whether the regional differences are a consequence of the population dynamics in the observed period or they will continue to exist, pointing to differences in environmental risk factors.