Background: The objective of the study was to investigate the response of 64Arg allele carriers of the ADRB3 gene (Trp64Arg polymorphism) in the anthropometric, cardiorespiratory and metabolic variables in overweight adolescents after a 12-week aerobic exercise and nutritional program.
Methods: A total of 92 overweight adolescents, 10-16 years old and of both genders, participated. Body composition, waist circumference (WC), pubertal stage status, blood pressure, glucose, insulin and lipid profile and direct maximal oxygen uptake were assessed at baseline and after 12 weeks of a training program. The homeostasis metabolic assessments [homeostasis model assessment of insulin resistance (HOMA-IR)] and quantitative insulin sensitivity check index (QUICKI) were determined and the Trp64Arg polymorphism of the ADRB3 gene was investigated by Taqman single nucleotide polymorphism (SNP) genotyping assays. Exercise sessions consisted of 100-min aerobic exercise and 20-min stretching, 3 times a week, totalizing 36 sessions. Multivariate analysis of variance (MANOVA), analysis of covariance (ANCOVA) and effect size were used for variables, with p<0.05 considered significant.
Results: In baseline, HOMA-IR was higher in carriers of the 64Arg allele and decreased more after 12 weeks than in non-carriers (p=0.01). The anthropometric, physical fitness and metabolic profiles had similar responses after training in carriers and non-carriers.
Conclusions: Overweight adolescents present changes in body composition and physical fitness, independent of Trp64Arg genotypes. However, a 12-week aerobic exercise and nutritional program promoted greater reductions in insulin resistance in carriers of the 64Arg allele.
Keywords: Trp64Arg; adolescents; overweight; polymorphism.