Long-term effect of a school-based physical activity program (KISS) on fitness and adiposity in children: a cluster-randomized controlled trial

Abstract

Background: School-based intervention studies promoting a healthy lifestyle have shown favorable immediate health effects. However, there is a striking paucity on long-term follow-ups. The aim of this study was therefore to assess the 3 yr-follow-up of a cluster-randomized controlled school-based physical activity program over nine month with beneficial immediate effects on body fat, aerobic fitness and physical activity.

Methods and findings: Initially, 28 classes from 15 elementary schools in Switzerland were grouped into an intervention (16 classes from 9 schools, n = 297 children) and a control arm (12 classes from 6 schools, n = 205 children) after stratification for grade (1st and 5th graders). Three years after the end of the multi-component physical activity program of nine months including daily physical education (i.e. two additional lessons per week on top of three regular lessons), short physical activity breaks during academic lessons, and daily physical activity homework, 289 (58%) participated in the follow-up. Primary outcome measures included body fat (sum of four skinfolds), aerobic fitness (shuttle run test), physical activity (accelerometry), and quality of life (questionnaires). After adjustment for grade, gender, baseline value and clustering within classes, children in the intervention arm compared with controls had a significantly higher average level of aerobic fitness at follow-up (0.373 z-score units [95%-CI: 0.157 to 0.59, p = 0.001] corresponding to a shift from the 50th to the 65th percentile between baseline and follow-up), while the immediate beneficial effects on the other primary outcomes were not sustained.

Conclusions: Apart from aerobic fitness, beneficial effects seen after one year were not maintained when the intervention was stopped. A continuous intervention seems necessary to maintain overall beneficial health effects as reached at the end of the intervention.

Trial registration: ControlledTrials.com ISRCTN15360785.

Figure 1. Flow of individual participants through study with outcome measures.

Post-intervention results have been published elsewhere .

Figure 2. Schematic illustration of the differences for the four primary outcomes between the intervention and the control group at baseline, after nine months physical activity intervention, and three years after cessation of the intervention.

Post-intervention results derive from previously published results with different sample sizes (for body fat (n = 485 at post-intervention/n = 293 at follow-up); fitness (n = 472/n = 281); physical activity (n = 303/n = 145); quality of life (n = 427/n = 191)). ^asignificantly different values in favour of the intervention group compared to the control group.