Medicine & Science in Sports & Exercise:
E-25 Free Communication/Poster - Diet, Exercise and Hormonal Responses: JUNE 3, 2011 7:30 AM - 12:30 PM: ROOM: Hall B
1The George Washington University School of Public Health and Health Services, Washington, DC. 2Children's National Medical Center, Washington, DC.
(No relationships reported)
Defining the inter-relatedness between moderate-to-vigorous physical activity (MVPA), obesity, and type 2 diabetes is complicated by the fact that obesity lies in the biologic pathway between MVPA and metabolic risk, thereby minimizing the true magnitude of contribution from lifestyle behaviors.
PURPOSE: To examine the independent association between MVPA and the odds of insulin resistance (IR) among obese Latino youth living in Washington, DC.
METHODS: Subjects (N=113; 57 male/56 female) were obese (BMI ≥95th percentile) children aged 7 to 15 years who were enrolled in a community-based obesity intervention program. Baseline information on current physical activity and sedentary time was gathered by self-report. Baseline clinical assessments of body composition, resting energy expenditure (REE), as well as glucose, insulin, and free fatty acid (FFA) responses to an oral glucose tolerance test (OGTT) were performed after an overnight fast in a Clinical Research Center. Insulin resistance was defined as a 2-h post-challenge insulin concentration greater than 64 μU·mL-1 (the median value). Analyses were conducted on the total sample and then were stratified by the median age (</≥11.7 years).
RESULTS: Surprisingly, reported sedentary behavior was identical between groups (Sedentary Index=10.6±6.4 vs.10.7±6.3 for those with and without IR, respectively). Fasting insulin and 2-h glucose levels were significantly higher, and MVPA levels were significantly lower in participants with IR compared to those without (p<0.05). After simultaneous adjustment for these variables using logistic regression, MVPA demonstrated a null association with the odds of IR among children <11.7 years (OR=1.00; 95% CI:(0.98-1.04)]; however among the older children, the odds of IR were 5% lower for each unit increase in the MVPA index [OR=0.95;95%CI:(0.92-0.98)].
CONCLUSIONS: The importance of MVPA in lowering odds of IR, independent of obesity, impaired glucose tolerance, and sedentary behavior is underscored by these findings. These benefits may be most apparent in older Latino children, however, and likely reflect the modifying effects of puberty on the study associations of interest.
Supported by NIH Grants K23-RR022227 (NMM) and MO1-RR-020359 awarded by the National Center for Research Resources (NCRR).