Association of physical activity and sitting with metabolic syndrome and hyperglycemic clamp parameters in adolescents - BRAMS pediatric study.

Introduction: Obesity and metabolic syndrome (MetS) have immediate and long-term consequences on adolescent health and well-being. Among the available treatments for MetS in adolescents, behavioral interventions such as increasing physical activity (PA) are preferred. This study aimed to investigate the association of PA and sitting time with MetS and a complete set of metabolic health parameters. Methods: Data from the Pediatric Brazilian Metabolic Syndrome Study (BRAMS-P), a cross-sectional multicenter study conducted using a convenience sample of 448 Brazilian adolescents (10y-19y), were used. Sociodemographic and lifestyle information were collected using a standardized questionnaire. Daily PA and sitting time were estimated from the International PA Questionnaire. Anthropometric parameters, body composition, and blood pressure were measured by trained researchers. Blood lipids, uric acid, hepatic enzymes, creatinine, glycated hemoglobin, glucose, and insulin were measured in fasting blood samples, and the Homeostasis Model Assessment for Insulin Resistance was calculated. A subsample of 57 adolescents underwent the hyperglycemic clamp protocol. Results: The odds for metabolic syndrome were higher among adolescents who spent >8h sitting (OR (95%CI)=2.11 (1.02 - 4.38)), but not in those classified as active (OR (95%CI)=0.98 (0.42 - 2.26)). Adolescents who spent more time sitting had higher BMI, waist circumference, sagittal abdominal diameter, neck circumference, percentage of body fat, and worse blood lipid profile. The insulin sensitivity index was moderately and positively correlated with moderate-to-high PA in minutes per day (rho=0.29; p=0.047). Conclusion: Time spent sitting was associated with worse metabolic parameters and must be restricted in favor of adolescent health. Regular PA is associated with improved insulin sensitivity and may be encouraged not only in adolescents with obesity or metabolic disorders but also to prevent adverse metabolic outcomes in normal-weight adolescents.

Hypertriglyceridemic Waist Phenotype Indicates Insulin Resistance in Adolescents According to the Clamp Technique in the BRAMS Study.

OBJECTIVE: This study aimed to identify cutoff points for detecting hypertriglyceridemic waist phenotype (HTWP) in adolescents and to investigate the association of the HTWP with insulin resistance (IR) and metabolic syndrome components. METHODS: A multicentric cross-sectional study of 861 adolescents (10-19 years of age, 504 girls) was conducted. Pubertal stage, anthropometric, and laboratory parameters were assessed. IR was assessed by Homeostasis Model Assessment for Insulin Resistance (HOMA1-IR) index and hyperglycemic clamp (n = 80). HTWP was defined by the presence of increased plasma triglycerides (TGs) and increased waist circumference (WC) according to cutoff points obtained in ROC curve analysis given the HOMA1-IR index as a reference method. RESULTS: Cutoffs for WC and TGs, with a higher sum of sensitivity (S) and specificity (E), were, respectively: >84 cm (S:65.1%, E:71.9%) and >87 mg/dL (S:65.1%, E:73.4%) in pubertal girls; >88.5 cm (S:80.2%, E:60.2%) and >78 mg/dL (S:60.5%, E:53.2%) in postpubertal girls; >94 cm (S:73.1%, E:83.1%) and >79 mg/dL (S:61.5%, E:60.2%) in pubertal boys; and >99 cm (S:81.3%, E:78.7%) and >86 mg/dL in postpubertal boys (S:68.1%, E:60.7%). HTWP frequency was 27.5%. In the phenotype presence, after adjustment for age and pubertal stage, blood pressure and fasting glucose levels were elevated and high-density lipoprotein cholesterol was lower (p < 0.001). Adolescents with the HTWP showed more IR, evaluated both by the HOMA1-IR and by the clamp test (p < 0.003). CONCLUSION: The findings suggest HTWP as an IR status in adolescents. Cutoff point standardization for gender and pubertal stage, combined with the ease of application of the method, may allow their use for screening adolescents who would most benefit from lifestyle changes.