Article Evaluates School-Based Intervention to Lower Incidence of Disordered Weight-Control Behaviors in Young Adolescents

Date published: September 17, 2007

"The present study adds novel empirical evidence in support of the viability of integrating obesity and eating disorders prevention initiatives," state the authors of an article published in the September
2007 issue of Archives of Pediatric and Adolescent Medicine. Eating disorders have substantial negative health consequences for affected adolescents. In addition, disordered weight-control behaviors, including self-induced vomiting or use of laxatives or diet pills to control weight (which are often precursors to eating disorders) have been positively associated with overweight in adolescents. A recent analysis of the Planet Health obesity prevention intervention conducted in middle-school students found an unexpected benefit: after 2 years in intervention schools, girls' risk of reporting disordered weight-control behaviors halved, compared with girls in control schools. This article reports on a study to determine the effect of Planet Health implemented in a randomized effectiveness trial on incidence of disordered weight-control behaviors in middle-school girls and boys. The present study extended beyond previous research on Planet Health by including a larger sample, more recent data, and data for boys.

The authors used a group-randomized design in which middle schools were the unit of randomization and students were the unit of analysis.
Thirteen Massachusetts middle schools were stratified by type (parochial or public), and public schools were further stratified by racial and ethnic composition (75% white or higher or less than 75% white). Schools were then randomly assigned as either an intervention (Planet Health, a curriculum that includes health messages that focus on physical activity, television viewing, and consumption of fruits, vegetables, and
fats) or as a control. All students in the 13 schools who were in sixth or seventh grade at baseline were eligible to participate. A total of
1,451 eligible students who completed the follow-up questionnaire and did not report disordered weight-control behaviors at baseline formed the total analytical sample.

The authors found that

* After 2 school years, 3.6% of girls in control schools, compared with 1.2% of girls in intervention schools, reported new disordered weight-control behaviors.

* The odds of adopting a disordered weight-control behavior were reduced by two-thirds in girls in intervention schools compared with girls in control schools.

* In models that also controlled for grade, race and ethnicity, and overweight, the magnitude of the effect estimate associated with the intervention for girls remained stable, changing less than 10%, but the confidence interval widened to include the null value of 1.0.

* No protective effects of the intervention were observed for boys.

The authors conclude that "new research efforts will need to identify protective strategies for early adolescent boys also and to understand the mechanism of Planet Health and other strategies in school settings that integrate obesity and eating disorders prevention."

Austin SB, Kim J, Wiecha J, et al. 2007. School-based overweight preventive intervention lowers incidence of disordered weight-control behaviors in early adolescent girls. Archives of Pediatric and Adolescent Medicine 161(9):865-869. Abstract available at
http://archpedi.ama-assn.org/cgi/content/abstract/161/9/865

Readers: More information is available from Bright Futures at http://brightfutures.aap.org/web http://www.brightfutures.org/nutrition/index.html
http://www.brightfutures.org/physicalactivity/about.htm
http://nutrition.utk.edu/max_resources/maximize

Information is also available from the following MCH Library resources:

- Overweight in Children and Adolescents (knowledge path) at http://www.mchlibrary.info/KnowledgePaths/kp_overweight.html

- School Health (selected resources) at
http://www.mchlibrary.info/guides/schoolhealth.html

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