Interventions to prevent obesity in children and adolescents: a systematic literature review.

Objective: Preventive measures to contain the epidemic of obesity have become a major focus of attention. This report reviews the scientific evidence for medical interventions aimed at preventing obesity during childhood and adolescence. Design: A systematic literature review involving selection of primary research and other systematic reviews. Articles published until 2004 were added to an earlier ( 2002) review by the Swedish Council on Technology Assessment in Health Care. Methods: Inclusion criteria required controlled studies with follow-up of at least 12 months and results measured as body mass index, skinfold thickness or the percentage of overweight/obesity. Children could be recruited from normal or high-risk populations. Results: Combining the new data with the previous review resulted in an evaluation of 24 studies involving 25 896 children. Of these, eight reported that prevention had a statistically significant positive effect on obesity, 16 reported neutral results and none reported a negative result ( sign test; P = 0.0078). Adding the studies included in five other systematic reviews yielded, in total, 15 studies with positive, 24 with neutral and none with negative results. Thus, 41% of the studies, including 40% of the 33 852 children studied, showed a positive effect from prevention. These results are unlikely to be a random chance phenomenon ( P = 0.000061). Conclusion: Evidence shows that it is possible to prevent obesity in children and adolescents through limited, school-based programs that combine the promotion of healthy dietary habits and physical activity