Effectiveness of a School-Based Multimodal Intervention on Promoting Healthy Lifestyle Behaviours Among Schoolchildren. Previene-Cádiz Study.

Background Childhood obesity is a global health concern with significant implications for long-term health outcomes. To address this issue, this study aimed to evaluate the effectiveness of a school-based multimodal intervention targeting healthy lifestyle behaviours among schoolchildren in the province of Cádiz. Methods: A quasi-experimental design was employed to compare outcomes between the experimental and control groups. The study sample consisted of 833 schoolchildren between 8 and 9 years of age who were enrolled in the third grade of primary education from 25 schools in the province of Cádiz. The intervention adopted a multimodal approach, targeting students, their families, and educational institutions, and was implemented over a 6-month period. The students participated in a healthy educational programme of 10 sessions and were provided with two workbooks to use at home with their families. Additionally, parents attended three training courses aimed at improving their children's lifestyle behaviours. The intervention aimed to achieve significant improvements in body composition, physical fitness, physical activity levels, sedentary behaviours, dietary patterns, and sleep patterns. Two statistical tests were conducted to compare groups before and after the intervention. First, the Mann‒Whitney U test was used for numerical variables, and second, the delta of the study variables was calculated, and a difference‒in-differences analysis was performed. Numerical delta variables were analysed via the Mann‒Whitney U test, and categorical delta variables were analysed via the chi‒square test. Results: The results suggested that the intervention produced moderate and variable effects in promoting healthier lifestyle behaviours among schoolchildren. While improvements were noted in the experimental group compared with the control group, these improvements did not fully meet the initial expectations. Conclusions: This outcome underscores the need for further research and adjustments in implementation, such as the integration of specialised external personnel to support teachers, embedding the intervention into the school curriculum, and extending its duration throughout an entire academic year. This study contributes valuable insights into childhood obesity prevention and intervention strategies, paving the way for future research aimed at promoting the health and well-being of children worldwide.