(14-10-12) Exercise dose and diabetes risk in overweight and obese children: a randomized controlled trial.

Davis CL, Pollock NK, Waller JL, Allison JD, Dennis BA, Bassali R, Mel??ndez A,
Boyle CA, Gower BA.
Source
Georgia Prevention Center, Institute for Public and Preventive Health,
Department of Pediatrics, Medical College of Georgia, 1120 15th St, Ste 1640,
Augusta, GA 30912, USA. [email protected]
Abstract
CONTEXT:
Pediatric studies have shown that aerobic exercise reduces metabolic risk, but
dose-response information is not available.
OBJECTIVES:
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.
DESIGN, SETTING, AND PARTICIPANTS:
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.
INTERVENTION:
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).
MAIN OUTCOME MEASURES:
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.
RESULTS:
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) ??U/mL; P = .01) and the low-dose group (adjusted mean
difference, -2.96 [95% CI, -5.69 to -0.22] ?? 10(3) ??U/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.
CONCLUSION:
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.

Source:
JAMA. 2012 Sep 19;308(11):1103-12.

News

---

In evidenza

"L'informazione presente nel sito serve a migliorare, e non a sostituire, il rapporto medico-paziente."

Per coloro che hanno problemi di salute si consiglia di consultare sempre il proprio medico curante.