Successful overweight prevention in adolescents by increasing physical activity: a 4-year randomized controlled intervention.
BACKGROUND
Population-based studies directed at promoting physical activity in youth have shown limited success in obesity prevention.


OBJECTIVE
To assess whether an intervention integrating environmental changes to induce sustained changes in physical activity, prevents overweight in adolescents.


METHODS
Four-year randomized trial started in 2002 in eight middle schools of Eastern France. The intervention, randomized at school level, was designed to promote physical activity by changing attitudes through debates and attractive activities, and by providing social support and environmental changes encouraging physical activity.


METHODS
Nine hundred and fifty four 12-year-old six-graders.


METHODS
Body mass index (BMI), body composition, physical activity by questionnaire, plasma lipids and glucose, insulin resistance.


RESULTS
Intervention students had a lower increase in BMI (P=0.01) and age- and gender-adjusted BMI (P<0.02) over time than controls. The differences across groups of the age- and gender-adjusted BMI changes (95% confidence interval (CI)) were -0.29 (-0.51; -0.07) kg/m2 at 3 years, -0.25 (-0.51; 0.01) kg/m2 at 4 years. An interaction with baseline weight status was noted. The intervention had a significant effect throughout the study in initially non-overweight adolescents (-0.36 (-0.60;-0.11) kg/m2 for adjusted BMI at 4 years), corresponding to a lower increase in fat mass index (P<0.001). In initially overweight adolescents, the differences observed across groups at 2 years (-0.40 (-0.94; 0.13) kg/m2 for adjusted BMI) did not persist over time. At 4 years, 4.2% of the initially non-overweight adolescents were overweight in the intervention schools, 9.8% in the controls (odds ratio=0.41 (0.22; 0.75); P<0.01). Independent of initial weight status, compared with controls, intervention adolescents had an increase in supervised physical activity (P<0.0001), a decrease of TV/video viewing (P<0.01) and an increase of high-density cholesterol concentrations (P<0.0001).


CONCLUSIONS
Enhancing physical activity with a multilevel program prevents excessive weight gain in non-overweight adolescents. Our study provides evidence that prevention of obesity in youth is feasible.
Simon
C
C
Louis Pasteur University of Strasbourg, Strasbourg, France. chantal.simon@medecine.u-strasbg.fr
Schweitzer
B
B
Oujaa
M
M
Wagner
A
A
Arveiler
D
D
Triby
E
E
Copin
N
N
Blanc
S
S
Platat
C
C
D000293:Adolescent; D001786:Blood Glucose / Q000378:metabolism; D001823:Body Composition; D050218:Body Fat Distribution; D015992:Body Mass Index; D002648:Child; D005081:Exercise Therapy / Q000379:methods*; D005260:Female; D006801:Humans; D007333:Insulin Resistance / Q000502:physiology; D008055:Lipids / Q000097:blood; D008297:Male; D050177:Overweight / Q000517:prevention & control*; D016896:Treatment Outcome
D001786:Blood Glucose; D008055:Lipids