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- Title
Exercise dose and diabetes risk in overweight and obese children: a randomized controlled trial.
- Authors
Davis CL; Pollock NK; Waller JL; Allison JD; Dennis BA; Bassali R; Meléndez A; Boyle CA; Gower BA; Davis, Catherine L; Pollock, Norman K; Waller, Jennifer L; Allison, Jerry D; Dennis, B Adam; Bassali, Reda; Meléndez, Agustín; Boyle, Colleen A; Gower, Barbara A
- Abstract
<bold>Context: </bold>Pediatric studies have shown that aerobic exercise reduces metabolic risk, but dose-response information is not available.<bold>Objectives: </bold>To test the effect of different doses of aerobic training on insulin resistance, fatness, visceral fat, and fitness in overweight, sedentary children and to test moderation by sex and race.<bold>Design, Setting, and Participants: </bold>Randomized controlled efficacy trial conducted from 2003 through 2007 in which 222 overweight or obese sedentary children (mean age, 9.4 years; 42% male; 58% black) were recruited from 15 public schools in the Augusta, Georgia, area.<bold>Intervention: </bold>Children were randomly assigned to low-dose (20 min/d; n = 71) or high-dose (40 min/d; n = 73) aerobic training (5 d/wk; mean duration, 13 [SD, 1.6] weeks) or a control condition (usual physical activity; n = 78).<bold>Main Outcome Measures: </bold>The prespecified primary outcomes were postintervention type 2 diabetes risk assessed by insulin area under the curve (AUC) from an oral glucose tolerance test, aerobic fitness (peak oxygen consumption [VO2]), percent body fat via dual-energy x-ray absorptiometry, and visceral fat via magnetic resonance, analyzed by intention to treat.<bold>Results: </bold>The study had 94% retention (n = 209). Most children (85%) were obese. At baseline, mean body mass index was 26 (SD, 4.4). Reductions in insulin AUC were larger in the high-dose group (adjusted mean difference, -3.56 [95% CI, -6.26 to -0.85] × 10(3) μU/mL; P = .01) and the low-dose group (adjusted mean difference, -2.96 [95% CI, -5.69 to -0.22] × 10(3) μU/mL; P = .03) than the control group. Dose-response trends were also observed for body fat (adjusted mean difference, -1.4% [95% CI, -2.2% to -0.7%]; P < .001 and -0.8% [95% CI, -1.6% to -0.07%]; P = .03) and visceral fat (adjusted mean difference, -3.9 cm3 [95% CI, -6.0 to -1.7 cm3]; P < .001 and -2.8 cm3 [95% CI, -4.9 to -0.6 cm3]; P = .01) in the high- and low-dose vs control groups, respectively. Effects in the high- and low-dose groups vs control were similar for fitness (adjusted mean difference in peak VO2, 2.4 [95% CI, 0.4-4.5] mL/kg/min; P = .02 and 2.4 [95% CI, 0.3-4.5] mL/kg/min; P = .03, respectively). High- vs low-dose group effects were similar for these outcomes. There was no moderation by sex or race.<bold>Conclusion: </bold>In this trial, after 13 weeks, 20 or 40 min/d of aerobic training improved fitness and demonstrated dose-response benefits for insulin resistance and general and visceral adiposity in sedentary overweight or obese children, regardless of sex or race.<bold>Trial Registration: </bold>clinicaltrials.gov Identifier: NCT00108901.
- Publication
JAMA: Journal of the American Medical Association, 2012, Vol 308, Issue 11, p1103
- ISSN
0098-7484
- Publication type
journal article
- DOI
10.1001/2012.jama.10762