Efficacy of school-based intervention programs in reducing overweight: A randomized trial

Abstract

Childhood obesity represents a serious public health problem and this study evaluates the effectiveness of a 6-month educational intervention on lifestyle, nutrient adequacy, and diet quality in the school setting in improving the knowledge and behavior of primary school children regarding correct eating habits. The strategy was implemented over a 6-month period and participants were randomly assigned to either the intervention group (n = 200) or the non-intervention group (control group, n = 197). Participants had a mean body mass index of 18.3 ± 2.7 kg/m² and its variation in the intervention group (-2.7 ± 0.5 kg/m²) was significantly different from that in the control group (3.41 ± 0.8 kg/m²). In the experimental group, there were significant differences between the proportion of children who were overweight, underweight, normal weight, or obese before and after intervention (p < 0.05). The best results were seen in the female sex, and after the intervention, there were no more girls with obesity. Furthermore, there were significant waist circumference decrement effects in the intervention group compared to the control group (p < 0.05). Finally, many of the participating children acquired healthy eating habits. Therefore, the quantitative results obtained suggest that a school intervention program represents an effective strategy to prevent and improve the problem of childhood overweight and obesity.

Keywords: BMI; children obesity; overweight; school-based intervention; waist circumference.

Figure 1

Scheme of the participants in the study.

Figure 2

Changes in BMI, percentile over time. Box and whiskers representation of body mass index (BMI: weight in kilograms divided by height in meters squared) of intervention group (A) and control children (B), recorded at baseline (T0), at 6 months from baseline (T1, at the completion of the intervention). The sample was also divided between girls and boys. In this representation, the central box covers the middle 50% of the data values, between the upper and lower quartiles. The bars extend out to the extremes, while the central line is at the median. p-values were obtained by Student's paired t-test.

Figure 3

Percentage of overweight, underweight, normal weight or with obesity children pre (T0) and post (T1) intervention. The sample was also divided between girls and boys and different age groups.

Figure 4

Changes in waist circumference over time. Box and whiskers representation of waist circumference of intervention group (A) and control children (B), recorded at baseline (T0) and 6 months from baseline (T1, at the completion of the intervention). The sample was also divided according to gender. In this representation, the central box covers the middle 50% of the data values, between the upper and lower quartiles. The bars extend out to the extremes, while the central line is at the median. Those values which are beyond 1.5 times the interquartile range beyond the central box are plotted as individual points. p-values were obtained by Student's paired t-test.