Bumin Dündar

Prevalence of Metabolic Syndrome in Obese Children and Adolescents using Three Different Criteria and Evaluation of Risk Factors

Objective: To compare the prevalence of the metabolic syndrome (MS) in Turkish obese children and adolescents by using three different definitions and to assess the risk factors through a retrospective evaluation of anthropometric and laboratory parameters. Methods: Sixty hundred and fourteen obese patients (307 male, 307 female; mean age: 11.3±2.5 years) were included in the study. Medical history, physical examination, anthropometric measurements, results of biochemical and hormonal assays were obtained from the hospital records. MS was diagnosed according to the modified World Health Organization (WHO), Cook and the International Diabetes Federation (IDF) consensus criteria. Results: The prevalence of MS was found to be 39%, 34% and 33% according to the modified WHO, Cook and the IDF consensus criteria, respectively. MS prevalence in patients aged 12-18 years was significantly higher than that in patients between 7 and 11 years of age (p<0.05). Pubertal patients had a significantly higher MS prevalence than the non-pubertal cases (p<0.05). MS prevalence was also significantly higher in children who had a family history of heart disease, diabetes, obesity and hypertension as well as in those who had not been breast-fed (p<0.05). Conclusion: The use of the modified WHO criteria was found to result in a slightly higher prevalence rate for MS as compared to the other criteria. The prevalence of MS in our study population was higher than that reported in most previous studies in Turkey. A positive family history, puberty and not being breastfed in infancy were shown to be significant risk factors for MS in childhood. The prevalence of MS was found to be 39%, 34% and 33% according to the modified WHO, Cook and the IDF consensus criteria, respectively. MS prevalence in patients aged 12-18 years was significantly higher than that in patients between 7 and 11 years of age (p<0.05). Pubertal patients had a significantly higher MS prevalence than the non-pubertal cases (p<0.05). MS prevalence was also significantly higher in children who had a family history of heart disease, diabetes, obesity and hypertension as well as in those who had not been breast-fed (p<0.05). Conclusion: The use of the modified WHO criteria was found to result in a slightly higher prevalence rate for MS as compared to the other criteria. The prevalence of MS in our study population was higher than that reported in most previous studies in Turkey. A positive family history, puberty and not being breastfed in infancy were shown to be significant risk factors for MS in childhood. Conflict of interest:None declared.

Association between insulin resistance and oxidative stress parameters in obese adolescents with non-alcoholic fatty liver disease.

Objective: Non-alcoholic fatty liver disease (NAFLD) has become one of the most common chronic liver diseases in children. The aim of this study was to investigate the associations of oxidative stress with insulin resistance and metabolic risk factors in obese adolescents with NAFLD. Methods: Forty-six obese adolescents (23 girls and 23 boys, mean age: 12.8±2.2 years) and 29 control subjects (15 girls and 14 boys, mean age: 12.7±2.7 years) were enrolled in the study. The obese subjects were divided into two groups (NAFLD group and non-NAFLD group) based on the elevated alanine aminotransferase levels (>30 IU/L) and the presence or absence of liver steatosis detected by ultrasonography. Insulin resistance was evaluated by homeostasis model assessment (HOMA-IR) from fasting samples. Plasma total antioxidant status (TAS) and total oxidant status (TOS) level measurements (REL Assay Diagnostics) were done in all participants. The ratio of TOS to TAS was regarded as an oxidative stress index (OSI), an indicator of the degree of OS. Results: Fasting insulin levels and HOMA-IR values in the NAFLD group were significantly higher than in the non-NAFLD and control groups. TAS measurements were decreased in both obese groups (NAFLD and non-NAFLD) in comparison with the control group. TOS and OSI measurements were higher in the NAFLD group than in the non-NAFLD and control groups. OSI was positively correlated with fasting insulin (r=0.67, p=0.01) and HOMA-IR (r=0.71, p=0.02) in the NAFLD obese group. Conclusions: In this cross-sectional study, elevated OS markers in obese adolescents with NAFLD were associated with insulin resistance. This data suggest that an antioxidant therapy might have a potential for treating NAFLD associated with insulin resistance. Conflict of interest:None declared.

Leptin levels in boys with pubertal gynecomastia

BACKGROUND It has been reported that there is a relationship between circulating leptin and sex steroid hormones and leptin is able to stimulate estrogen secretion by increasing aromatase activity in adipose stromal cells and breast tissue. Leptin receptors have been also shown in mammary epithelial cells and it has been suggested that leptin is involved in the control of the proliferation of both normal and malignant breast cells. AIM To investigate circulating leptin levels in boys with pubertal gynecomastia. METHODS Twenty boys with pubertal gynecomastia who were in early puberty and had no obesity, and 20 healthy individuals matched for age, pubertal stage and body mass index (BMI) with the study group, were enrolled in the study. Body weight, height and left midarm circumference (MAC) and left arm triceps skinfold thickness (TSF) were measured and BMI was calculated. A fasting blood sample was collected and routine hormonal parameters including prolactin, beta-human chorionic gonadotropin (betaHCG), total and free testosterone, estradiol, luteinizing hormone (LH), follicle stimulating hormone (FSH), prolactin, androstenedione (AS) and dehydroepiandrosterone sulfate (DHEAS) levels were studied. Serum leptin levels were analyzed using radioimmunoassay. RESULTS The mean ages of the study and control group were not different (13.9 +/- 0.89 and 14.2 +/- 0.66, respectively). No significant difference was found for BMI, MAC and TSF values between the two groups. There was no significant difference for hormonal parameters including FSH, LH, total and free testosterone, estradiol, AS, DHEAS and estradiol/total testosterone ratio between boys with pubertal gynecomastia and the controls. Serum leptin levels were found significantly higher in the study group compared with the healthy controls (5.58 +/- 0.81 and 2.39 +/- 0.29 ng/ml, respectively; p <0.001). No correlation could be determined between serum leptin levels and hormonal parameters. CONCLUSION The presence of higher leptin levels in boys with pubertal gynecomastia indicates that leptin may be involved in the pathogenesis of pubertal gynecomastia. The role of circulating leptin in pubertal gynecomastia is probably related to increase in estrogen and/or estrogen/ androgen ratio by the stimulating effect of leptin on aromatase enzyme activity in both adipose and breast tissues, or a direct growth stimulating effect of leptin on mammary epithelial cells, or increase in sensitivity of breast epithelial cells to estrogen with inducing functional activation of estrogen receptors by leptin in breast tissue.

Adipokines in Breast Milk: An Update

Epidemiological surveys indicate that nutrition in infancy is implicated in the long-term tendency to obesity and that a longer duration of breastfeeding is associated with a protective effect against metabolic disorders later in life. However, the precise cause of this association is not well understood. Recent studies on the compounds present in human breast milk have identified various adipokines, including leptin, adiponectin, resistin, obestatin, nesfatin, ghrelin and apelins. Some of these compounds are involved in the regulation of food intake and energy balance. The presence of these adipokines in breast milk suggests that they may be responsible for the regulation of growth in early infancy and that they could influence the energy balance and development of metabolic disorders in childhood and adulthood.

Ghrelin and adiponectin levels in colostrum, cord blood and maternal serum

Background:  Ghrelin and adiponectin, which are considered to take part in the regulation of energy metabolism, have been found in breast milk and cord blood. The aims of this study were to determine ghrelin and adiponectin levels in colostrum, cord blood and maternal serum and to investigate the correlations between colostrum and cord blood levels of these peptides and the anthropometry of newborn infants and their mothers.

Long-Term Treatment with n-3 Polyunsaturated Fatty Acids as a Monotherapy in Children with Nonalcoholic Fatty Liver Disease

Objective: To investigate the efficacy and safety of n-3 polyunsaturated fatty acids (PUFA) treatment in obese children with nonalcoholic fatty liver disease (NAFLD). Methods: One hundred and eight obese (body mass index (BMI) >95th percentile for age and sex) adolescents with NAFLD were included in the study. Mean age of the subjects was 13.8±3.9 years (9-17 yrs). The diagnosis of NAFLD was based on the presence of liver steatosis with high transaminases. The subjects were randomly divided into two groups. Group 1 (PUFA group, n=52) received a 1000 mg dose of PUFA once daily for 12 months and lifestyle intervention. Group 2 (placebo group, n=56) received a recommended diet plus placebo and lifestyle intervention for 12 months. Insulin resistance was evaluated by homeostasis model assessment of insulin resistance (HOMA-IR) from fasting samples. Results: BMI, fasting insulin levels and HOMA-IR values in both groups decreased significantly at the end of the study. In group 1, 67.8% of the patients had a decrease from baseline in the prevalence of steatosis (p<0.001). Frequency of elevated alanine aminotransferase (ALT) levels (39.2% to 14.2%; p<0.01) and elevated aspartate aminotransferase (AST) levels (25% to 17.8%; p=0.01) decreased significantly in the PUFA group. Following a 12-month diet plus placebo and lifestyle intervention treatment, 40.3% (21) of the patients in the placebo group also showed a decrease in frequency of steatosis (p=0.04) and slight decreases in frequency of elevated ALT levels (38.4% to 28.8%; p=0.01) and AST levels (30.7% to 28.8%; p>0.05). Conclusion: Our results indicated that n-3 PUFA treatment is safe and efficacious in obese children with NAFLD and can improve ultrasonographic findings and the elevated transaminase levels.

Vanishing Testes: A Literature Review

Vanishing testes syndrome is often referred to as testicular regression syndrome (TRS) in the recent medical literature. The most characteristic histological findings are presence of a fibrovascular nodule with associated hemosiderin-laden macrophages and dystrophic calcification. Residual testicular tubules are found in less than 10% of cases, with prevalence being unrelated to age at surgery. Presence of seminiferous tubules and viable germ cells in testicular remnant tissue has been reported in some series. TRS theoretically carries a potential for malignant degeneration in the long term and therefore removal of any remnant is a common practice to eliminate this risk. However, no case series has reported germinal dysplasia or intratubular germ cell neoplasia in any of the specimens taken from these patients. Conflict of interest:None declared.

Helicobacter pylori infection in children with constitutional delay of growth and puberty.

Helicobacter pylori is a gastroduodenal pathogen strongly associated with chronic gastritis and duodenal ulceration. It is thought that H. pylori infection might be one of the causes of growth retardation in children. The aim of this study was to evaluate the seroprevalence of H. pylori in children with constitutional delay of growth and puberty (CDGP). H. pylori seropositivity was studied in 24 children with CDGP (22 M, 2 F) and 32 healthy age-matched children with normal pubertal development. Mean age of the children with CDGP was 14.53 +/- 1.12 yr and all of them had been diagnosed as CDGP after physical and laboratory assessment. H. pylori IgG positivity was detected in 16 of the 24 children with CDGP (66.6%) and 12 of 32 controls (37.5%) (p <0.05). This finding is consistent with the hypothesis that H. pylori infection could be one of the environmental factors causing CDGP.

Relationship Between Aspartate Aminotransferase-to-Platelet Ratio Index and Carotid Intima-Media Thickness in Obese Adolescents with Non-Alcoholic Fatty Liver Disease

Objective: There is increasing evidence for an association between non-alcoholic fatty liver disease (NAFLD) and an increased risk of cardiovascular morbidity and mortality. The aim of this study was to investigate the association between aspartate aminotransferase-to-platelet ratio index (APRI) and carotid intima-media thickness (IMT) in obese adolescents with NAFLD. Methods: Seventy-six obese adolescents and 36 lean subjects were enrolled in this cross-sectional single-centre study. The obese subjects were divided into two subgroups based on the presence or absence of fatty liver with high transaminase levels (NAFLD group and non-NAFLD group). Fasting blood samples were assayed for transaminase, glucose, and insulin levels. Insulin resistance was calculated by the homeostasis model assessment (HOMA-IR). Results: APRI values were higher in both obese groups (NAFLD and non-NAFLD) in comparison with the lean group. The NAFLD group had significantly higher APRI values than the non-NAFLD obese group and the lean group. Carotid IMT was higher in both obese groups (NAFLD and non-NAFLD) in comparison with the lean group. The NAFLD group had significantly higher measurements of carotid IMT than the non-NAFLD group and the lean group. APRI was positively correlated with most of the metabolic parameters (total cholesterol, low-density lipoprotein cholesterol, glucose, insulin, HOMA-IR) and with carotid IMT in the NAFLD obese group. Conclusions: This study demonstrated that a significant relationship exists between APRI and carotid IMT in obese adolescents with NAFLD. We suggest that an increased APRI score in obese adolescents with NAFLD can possibly serve to predict a more adverse cardiovascular risk profile. Conflict of interest:None declared.

Diverse Genotypes and Phenotypes of Three Novel Thyroid Hormone Receptor-α Mutations

CONTEXT Recently several patients with resistance to thyroid hormone (RTH)-α due to T3 receptor-α (TRα) mutations were identified. The phenotype of these patients consists of varying degrees of growth impairment, delayed bone, mental and motor development, constipation, macrocephaly, and near-normal thyroid function tests. OBJECTIVE The objective of the study was to describe the clinical phenotype of three new families with RTHα and thereby gain more detailed knowledge on this novel syndrome. DESIGN, SETTING, AND PARTICIPANTS RTHα was suspected in three index patients from different families. Detailed clinical and biochemical assessment and imaging and genetic analyses were performed in the patients and their relatives. In addition, functional consequences of TRα mutations were investigated in vitro. RESULTS We studied 22 individuals from three families and identified 10 patients with heterozygous TRα mutations: C380fs387X, R384H, and A263S, respectively. The frame-shift mutation completely inactivated TRα, whereas the missense mutations produced milder defects. These mutations were associated with decreasing severity of the clinical phenotype: the patient in family 1 showed severe defects in growth, mental, and motor development, whereas the seven patients in family 3 had only mild clinical features. The most frequent abnormalities were anemia, constipation, and a delay in at least one of the developmental milestones. Serum free T3 ranged from high-normal to high and serum free T4 and rT3 from normal to low. TSH levels were normal in all patients. CONCLUSIONS This large case series underlines the variation in the clinical phenotype of RTHα patients. RTHα should be suspected in subjects when even mild clinical and laboratory features of hypothyroidism are present along with high/high-normal free T3, low/normal free T4, and normal TSH.