A common variant near BDNF is associated with dietary calcium intake in adolescents.

Specific targets for most obesity candidate genes discovered by genomewide association studies remain unknown. Such genes are often highly expressed in the hypothalamus, indicating their role in energy homeostasis. We aimed to evaluate the associations of selected gene variants with adiposity and dietary traits. Anthropometric parameters, fat mass, dietary intake (total energy, fat, protein, carbohydrate, fiber, and calcium) and 10 gene variants (in/near TMEM18, SH2B1, KCTD15, PCSK1, BDNF, SEC16B, MC4R and FTO) were analyzed in 1953 Czech individuals aged 10.0 to 18.0 years (1035 nonoverweight and 918 overweight: body mass index [BMI] ≥90th percentile). Obesity risk alleles of TMEM18 rs7561317, SEC16B rs10913469, and FTO rs9939609 were related to increased body weight and BMI (P < .005). The FTO variant also showed a significant positive association with waist circumference and fat mass (P < .001). Overweight adolescents had a lower total energy intake (P < .001) but a higher percentage of fat (P = .009) and protein intake (P < .001) than the nonoverweight subjects. There was also a lower calcium intake in the overweight group (P < .001). An association with at least one component of dietary intake was found in 3 of 10 studied gene variants. The MC4R rs17782313 was associated negatively with protein (P = .012) and positively associated with fiber (P = .032) intakes. The obesity risk alleles of BDNF rs925946 and FTO rs9939609 were related to a lower calcium intake (P = .001 and .037). The effects of FTO and MC4R variants, however, disappeared after corrections for multiple testing. Our results suggest that the common BDNF variant may influence dietary calcium intake independent of BMI.

Glucose homeostasis and insulin resistance: prevalence, gender differences and predictors in adolescents.

BACKGROUND: Adolescence, due to transient pubertal insulin resistance (IR), is associated with a higher risk for disturbances of glucose metabolism. The aim of our study was 1) to investigate the prevalence of disturbances of glucose metabolism, 2) to define gender specific homeostasis model assessment of insulin resistance (HOMA-IR) thresholds associated with increased cardiometabolic risks and 3) to provide predictors of HOMA-IR. METHODS: The studied cohort consisted of Czech adolescents aged 13.0-17.9 years: 1,518 individuals of general population and three studied groups according weight category (615 normal weight, 230 overweight and 683 obese). The prevalence of IR, impaired fasting glucose (IFG) and type 2 diabetes was assessed. Risky HOMA-IR thresholds based on components of metabolic syndrome were investigated. HOMA-IR prediction was calculated taking into account age, blood pressure, multiple anthropometric, biochemical and hormonal parameters. RESULTS: In general population cohort, the prevalence of IFG and type 2 diabetes was 7.0% and <0.5%, respectively. Boys regardless of weight presented significantly higher levels of blood glucose and higher prevalence of IFG than girls. Obese boys were found more insulin resistant than obese girls. HOMA-IR thresholds of 3.6 for girls and 4.4 for boys were associated with increased cardiometabolic risks. For both genders, the model of HOMA-IR prediction was composed of age, BMI, ratio of free triiodthyronine to free thyroxine, gamma-glutamyltransferase activity and levels of triglycerides and sex hormone-binding globulin. CONCLUSIONS: The type 2 diabetes in adolescents, including those who were obese, was rarely diagnosed. Obese adolescent boys were at greater risk for IR and for IFG than obese girls. In adolescence, thresholds of HOMA-IR in contrast to predictors were found gender specific.

Metabolic syndrome in adolescents with polycystic ovary syndrome.

The aim of the presented study is to evaluate metabolic features in adolescents with polycystic ovary syndrome (PCOS) in comparison with age- and BMI-matched subjects. Forty-three adolescents with PCOS according to ESHRE criteria were prospectively evaluated and compared with 48 control subjects. Blood sampling was done in the early follicular phase of menstrual cycle, between 1st and 5th day, for plasma glucose, total and high-density lipoprotein (HDL)-cholesterol, triglycerides, insulin and C peptide. The diagnosis of metabolic syndrome was done according to IDF adolescent criteria. Adolescents with PCOS have increased low-density lipoprotein (LDL)-cholesterol (p < 0.002), decreased HDL-cholesterol (p <0.0007) and increased C peptide levels (p < 0.02) in comparison with healthy adolescents. Total cholesterol, triglycerides, fasting blood glucose, fasting insulin, HOMA-IR, waist-to-hip ratio, systolic and diastolic blood pressure did not differ between the groups. There was no difference when we compared the prevalence of adolescents with at least one feature of metabolic syndrome between PCOS (17 from 43) and healthy controls (27 from 48). In conclusion, adolescents with PCOS have less favourable blood lipid profiles with higher LDL-cholesterol and lower levels of HDL-cholesterol and are more insulin resistant than their healthy counterparts having higher fasting C peptide levels.

[A new simple method for estimating trunk and visceral fat by bioelectrical impedance: comparison with magnetic resonance imaging and dual X-ray absorptiometry in Czech adolescents]. / Nová jednoduchá metoda stanovení viscerálního a trunkálního tuku pomocí bioelektrické impedance: srovnání s magnetickou rezonancí a duální rentgenovou absorpciometrií u ceských adolescentu.

BACKGROUND: The enlargement of visceral fat (VF) in abdominal obesity is associated with increased cardiometabolic health risks in both adults and adolescents. A precise measurement of VF by sophisticated methods as computed tomography (CT) and magnetic resonance imaging (MRI) cannot be applied in routine clinical practice. The aim of our study was to compare estimates on visceral and trunk fat in adolescents obtained by a new bioimpedance analysis instrument (BIA)--Tanita AB-140 ViScan--with those obtained by MRI, dual X-ray absorptiometry (DEXA) and anthropometry. METHODS AND RESULTS: Investigated cohort: 39 adolescent secondary school students; median (lower quartile; upper quartile)--age: 16.4 (15.4; 17.4) years; body weight: 63.8 (54.1; 79.0) kg; BMI: 21.4 (19.5; 27.4) kg/m2. Investigated parameters: BMI, body circumferences and sagittal abdominal diameter (SAD), trunk, visceral and subcutaneous fat determined by BIA, MRI and DEXA. STATISTICS: Spearman's correlations. The assessment of trunk fat by BIA correlated with DEXA estimates (r = 0.979, p < 0.0001) and with abdominal fat measured by MRI (r = 0.930, p < 0.0001). The visceral fat amount derived from abdominal BIA exhibited lower, however significant correlation with visceral fat determined by MRI (r = 0.791, p < 0.001). The visceral fat area presumed by abdominal BIA significantly correlated with anthropometric parameters as abdominal circumference (r = 0.923, p < 0.0001), waist circumference (r = 0.913, p < 0.0001) and SAD (r= 0.891, p < 0.0001). CONCLUSIONS: The new method estimating abdominal fat by BIA represents a reliable tool for clinical evaluation of the trunk fat in adolescents. However, its advantages over anthropometric measurements in evaluation of VF require further validation studies.

[Reduction of abdominal obesity and cardiometabolic health risks in obese adolescents in response to a short-term spa weight management program]. / Redukce abdominální obezity a kardiometabolických rizik u obézních adolescentu krátkodobým lázenským redukcním programem.

BACKGROUND: Overweight and obesity is associated with metabolic and cardiovascular complications even in children and adolescents. Obesity in childhood represents a serious health problem, as an obese child frequently remains obese subject in adulthood. Obesity is also an important early risk factor for morbidity and mortality in adulthood. The aim of this study was to follow changes in selected anthropometric parameters and cardiometabolic risks in overweight and obese adolescents in response to a 4-week spa weight management program. METHODS AND RESULTS: The studied cohort included 342 adolescents (boys, n = 121, girls, n = 221); mean age (+/- SD) 14.9 +/- 1.4 years (range 13.0 to 17.9 years) with overweight or obesity, mean BMI (+/- SD) 30.1 +/- 4.4 kg/m2 who underwent a 4-week spa weight management program. Anthropometric (body height and weight, waist circumference, sagittal abdominal diameter, total body fat and intra-abdominal fat), clinical (blood pressure) and biochemical (total cholesterol, HDL and LDL cholesterol, triglycerides, glucose, insulin) parameters were studied. All examinations were conducted before and after a 4-week weight management program. Statistical evaluation of the data was performed by ANOVA. The data are expressed as means +/- SD. In response to treatment all subjects demonstrated significant decreases in initial body weight (-6.3 +/- 2.3 %), percent of total fat (-2.7 +/- 2.5 %), percent of trunk fat (-2.5 +/- 1.5 %), degree of enlargement in visceral fat stores (-2.1 +/- 2.8), as well as reductions in waist circumference (-4.7 +/- 3.2 cm) and sagittal abdominal diameter (-1.0 +/- 1.8 cm). Positive changes in lipid profile and decrease in insulin resistance as measured by HOMA-IR were also recorded together with significant reductions in both systolic and diastolic blood pressures. CONCLUSIONS: Short-term weight management program in adolescents led to significant reductions in body weight, trunk and visceral fat and cardiometabolic health risks.

Entrapment of beta-galactosidase in polyvinylalcohol hydrogel.

beta-Galactosidase isolated from Aspergillus oryzae was immobilized in lens-shaped polyvinylalcohol capsules (with activity 25 U g(-1)) giving 32% of its original activity. Immobilization did not change the pH optimum (4.5) of lactose hydrolysis. The relative enzyme activity during product inhibition testing was, in average, 10% higher for immobilized enzyme. No decrease of activity was observed after 35 repeated batch runs and during 530 h of continuous hydrolysis of lactose (10%, w/v) at 45 degrees C. The immobilized enzyme was stable for 14 months without any change of activity during the storage at 4 degrees C and pH 4.5.