School-Based Obesity Prevention: Research, Challenges, and Recommendations

Article excerpt

The epidemic of obesity is worsening in the United States (1) despite serious health and social consequences. (2) The economic costs incurred by the problem and its treatments are steep (3) and may be underestimated. (4) The prevalence of American children classified as "at risk for overweight" or "overweight" has tripled in the past 20 years (5) and currently exceeds >30%. (2) The serious and lifelong health complications of excess body weight suggest that providing resources for primary prevention in children is advantageous. Schools are an important venue for primary prevention because approximately 6 hours a day are spent in the school environment, 1-2 meals are consumed there, and resources such as school nurses and physical education programs are already in place. (6)

Evaluation of the prevention research already conducted in school-based populations provides information useful to school health officials. The research methods of the randomized controlled trial (RCT) is judged to be the most rigorous of the research world. Findings produced in these types of studies are most likely to be reproducible in other settings. Therefore, the purpose of this paper is to review the school-based RCTs aimed at reducing body weight or preventing weight gain. First, basic childhood obesity assessment is reviewed, followed with an overview of the successful school-based RCTs. Challenges and future recommendations are then discussed.

DEFINITIONS

In children and adults, body mass index (BMI) has been shown to be a valid measure of adiposity. The Centers for Disease Control and Prevention (CDC) recommend using gender- and age-based BMI (weight [kg]/ height (2) [m]) percentiles to evaluate children for overweight and at risk overweight. (1) The CDC identifies 2 levels of overweight for children: (1) at risk for overweight defined as a BMI between the 85th and 95th percentiles and (2) overweight defined as [greater than or equal to] the 95th percentile. (7) The CDC avoids using the term "obesity" when referring to overweight in children and adolescents because children are growing and could be stigmatized if categorized as obese. Internationally and in adults, a BMI of 25 or higher, and a BMI of 30 or higher define overweight and obesity, respectively. (8) At the population level, the term childhood obesity is used; thus, this paper uses the term obesity synonymously with overweight in children.

INTEGRATIVE LITERATURE REVIEW

Identification of the relevant literature began by performing a literature search for the years 1985-2004 in MED-LINE, CINAHL, PsycINFO, and the Cochrane Database of Systematic Reviews. Initially, the key words searches included "obesity," "prevention," and "child." Subsequently, the key word "obesity" is replaced with "weight management." Thirteen peer-reviewed articles were found in CINAHL, 12 in PsycINFO, 140 in MEDLINE, and 6 in the Cochrane Systematic Literature Review. Other sources of articles included bibliographies of identified papers and review articles, as well as recent book chapters on obesity prevention in children and adolescents. Additional searches were conducted on the Web sites of professional organizations and governmental agencies. Every attempt was made to include all the studies that met the inclusion criteria.

Publications of studies with BMI as an outcome measure were reviewed. Criteria for including studies consisted of the following: (1) RCTs, (2) studies including BMI for age and gender as an outcome, (3) studies conducted in US schools during the school day, (4) studies with children in elementary, middle, or high school, and (5) publication in a peer-reviewed journal.

THEORETICAL PERSPECTIVE

Bandura's (9) social cognitive theory (SCT) was the theoretical perspective cited most often. This framework suggests that an individual can summon self-efficacy, or thoughtful motivation, planning, and action to stimulate behavior change. …