The Association of Genotype, and the Gene-Physical Activity Interaction Effect on Aerobic Fitness in Prepubertal, African American, Obese Children

Purpose: To determine the association of certain aerobic fitness and physical activity genotypes and the gene-physical activity interaction effect on aerobic fitness in pre-pubertal, African American, obese children. Methods: Subjects were 30 pre-pubertal, African American, obese children (9.5 ± 1.7 years) who were free of clinical disease. Height and weight were measured according to standard procedures. Body fat was assessed using dual energy x-ray absorptiometry, and DNA samples were collected using buccal swabs. Aerobic fitness was assessed using a cycle ergometer and the McMaster cycle protocol. ANOVAs were used to determine associations and interaction effects of the ACE, ADRB2, NOS3, IL6, IGF-1, and APO-E genes, physical activity and aerobic fitness. Results: Age, height, weight, body mass index, and waist circumference were significantly lower in girls compared to boys. Subjects averaged approximately 51 minutes of moderate-to-vigorous intensity activity per day, and girls were significantly more active than boys. There were no significant associations between the candidate genes and aerobic fitness level. P > 0.05). There were trends towards significance for the IL6 rs2069845 gene for absolute and relative VO_2peak measures (P = 0.078, and P = 0.094, respectively). There was also a trend toward significance for the ADRβ2 rs1042717 gene for leanVO_2peak (P = 0.092). Conclusions: In children, further research is needed that includes diverse populations and large sample sizes in order to more accurately assess the association and interaction effects of the candidate genes, physical activity and fitness.