Prevalence of metabolic syndrome in Brazilian children using three different sets of international criteria.

INTRODUCTION: Background: the aim of the present study was to compare the prevalence of metabolic syndrome in Brazilian children aged 6-10 years using three different international criteria. Methods: systolic and diastolic blood pressure (SBP and DBP), high-density lipoprotein (HDL) cholesterol, low-density lipoprotein (LDL) cholesterol, triglycerides, fasting glucose, and insulin levels were measured in 290 schoolchildren, and the presence of metabolic syndrome was analyzed according to the criteria established by Cook, Boney, and Ferreira. Results: the prevalence of metabolic syndrome was 2.27 % (Boney and Ferreira criteria) and 7.58 % (Cook criteria) for girls, and 3.8 % (Boney and Ferreira criteria) and 5.06 % (Cook criteria) for boys. Agreement in pairs showed a concordance of 57.5 % (Kappa = 0.57) between Boney and Cook criteria, and 65.2 % (Kappa = 0.65) between Cook and Ferreira. The greatest concordance found was 77 % (Kappa = 0.77) between Boney and Ferreira criteria, demonstrating a substantial agreement. Conclusion: prevalence according to Boney and Ferreira criteria was lower than according to Cook criteria. Therefore, we suggest the use of Cook criteria in clinical practice for the diagnosis of metabolic syndrome, since this criterion provided a wider diagnostic range, thereby reducing the risk of underdiagnosis.

INTRODUCCIÓN: Antecedentes: el objetivo del presente estudio fue comparar la prevalencia del síndrome metabólico en niños brasileños de 6 a 10 años de edad, usando tres diferentes criterios internacionales. Métodos: se midieron la presión arterial sistólica y diastólica, el colesterol de alta y baja densidad, los triglicéridos, la glucemia en ayunas y la insulinemia en 290 escolares, y se analizó la presencia del síndrome metabólico de acuerdo con los criterios de Cook, Boney y Ferreira. Resultados: las prevalencias del síndrome metabólico encontradas fueron del 2,27 % (criterios de Boney y Ferreira) y 7,58 % (criterios de Cook) para las niñas, y del 3,8 % (criterios de Boney y Ferreira) y 5,06 % (criterios de Cook) para los niños. La concordancia por pares fue del 57,5 % (Kappa = 0,57) entre los criterios de Boney y Cook, y del 65,2 % (Kappa = 0,65) entre los criterios de Cook y Ferreira. La mayor concordancia encontrada fue del 77 % (Kappa = 0,77) entre los criterios de Boney y Ferreira, demostrando una concordancia sustancial. Conclusiones: la prevalencia de acuerdo con los criterios de Boney y Ferreira fue inferior a la encontrada con los criterios de Cook. Por lo tanto, sugerimos el uso de los criterios de Cook en la práctica clínica para el diagnóstico del síndrome metabólico, ya que utilizando este criterio se obtiene un rango diagnóstico más amplio, reduciéndose así el riesgo del infradiagnóstico.

Tensiomyographic Markers Are Not Sensitive for Monitoring Muscle Fatigue in Elite Youth Athletes: A Pilot Study.

Objective: Tensiomyography (TMG) is an indirect measure of a muscle's contractile properties and has the potential as a technique for detecting exercise-induced skeletal muscle fatigue. Therefore, the aim of this study was to assess the sensitivity of tensiomyographic markers to identify reduced muscular performance in elite youth athletes. Methods: Fourteen male junior tennis players (age: 14.9 ± 1.2 years) with an international (International Tennis Federation) ranking position participated in this pre-post single group trial. They completed a 4-day high-intensity interval training (HIT) microcycle, which was composed of seven training sessions. TMG markers; countermovement jump (CMJ) performance (criterion measure of fatigue); delayed onset muscle soreness; and perceived recovery and stress were measured 24 h before and after the training program. The TMG measures included maximal radial deformation of the rectus femoris muscle belly (Dm), contraction time between 10 and 90% Dm (Tc) and the rate of deformation until 10% (V10) and 90% Dm (V90), respectively. Diagnostic characteristics were assessed with a receiver-operating curve (ROC) analysis and a contingency table, in which the area under the curve (AUC), Youden's index, sensitivity, specificity, and the diagnostic effectiveness (DE) of TMG measures were reported. A minimum AUC of 0.70 and a lower confidence interval (CI) >0.50 classified "good" diagnostic markers to assess performance changes. Results: Twenty-four hours after the microcycle, CMJ performance was observed to be significantly (p < 0.001) reduced (Effect Size [ES] = -0.68), and DOMS (ES = 3.62) as well as perceived stress were significantly (p < 0.001) increased. In contrast, Dm (ES = -0.35), Tc (ES = 0.04), V10 (ES = -0.32), and V90 (ES = -0.33) remained unchanged (p > 0.05) throughout the study. ROC analysis and the data derived from the contingency table revealed that none of the tensiomyographic markers were effective diagnostic tools for detecting impaired muscular performance in elite youth athletes (AUC, 95% CI, DE%; Dm: 0.46, 0.15-0.77, 35.7%; Tc: 0.29, 0.03-0.59, 35.7%; V10: 0.71, 0.27-1.00, 35.7%; V90: 0.37, 0.10-0.65, 35.7%). Conclusion: The tensiomyographic parameters that were assessed in this study were not sensitive enough to detect muscular performance changes in elite youth athletes.However, due to the preliminary nature of the study, further research is needed to investigate the sensitivity of TMG in this population.

Muscle mechanical properties of strength and endurance athletes and changes after one week of intensive training.

The study investigates whether tensiomyography (TMG) is sensitive to differentiate between strength and endurance athletes, and to monitor fatigue after either one week of intensive strength (ST) or endurance (END) training. Fourteen strength (24.1±2.0years) and eleven endurance athletes (25.5±4.8years) performed an intensive training period of 6days of ST or END, respectively. ST and END groups completed specific performance tests as well as TMG measurements of maximal radial deformation of the muscle belly (Dm), deformation time between 10% and 90% Dm (Tc), rate of deformation development until 10% Dm (V10) and 90% Dm (V90) before (baseline), after training period (post1), and after 72h of recovery (post2). Specific performance of both groups decreased from baseline to post1 (P<0.05) and returned to baseline values at post2 (P<0.05). The ST group showed higher countermovement jump (P<0.05) and shorter Tc (P<0.05) at baseline. After training, Dm, V10, and V90 were reduced in the ST (P<0.05) while TMG changes were less pronounced in the END. TMG could be a useful tool to differentiate between strength and endurance athletes, and to monitor fatigue and recovery especially in strength training.