Effect of an online lifestyle intervention on the BMI z-score of Mexican school children: a protocol for an outcome assessor-blinded pilot randomized controlled trial during the COVID-19 pandemic

Introduction: School closures due to the COVID-19 pandemic represent a risk factor for the development of childhood obesity, due to the increase in unhealthy behaviors. Online lifestyle interventions in schoolchildren could help to mitigate this problem. However, to our knowledge, no randomized controlled trials have been conducted to prevent obesity in schoolchildren during COVID-19. The aim of this study is to evaluate the effect of a 4-month online lifestyle intervention on the BMI Z-score of Mexican schoolchildren during the COVID-19 pandemic in an intervention group compared to a control group. Material and Methods: This is a protocol for an outcome assessor-blinded pilot randomized controlled trial. Schoolchildren from a public elementary school in Hermosillo, Sonora, Mexico will be invited to participate. Participants will be randomized to an intervention group (online lifestyle intervention) or a control group. The intervention will include online sessions of nutrition education and physical activity (60 minutes per session, 30 minutes for nutrition education and 30 minutes for physical activity) and nutrition information for parents. The control group will receive a digital brochure with nutrition recommendations at the beginning of the study and access to the program materials at the end of the study. The measurements will be performed at baseline and at 4 months. The primary outcome will be the BMI Z-score. Secondary outcomes will be waist circumference, body fat percentage, nutrition knowledge, lifestyle parameters, participation, retention and acceptance of the intervention. The changes on the outcomes will be analyzed using an intention to treat analysis. The protocol was approved by the Research Ethics Committee of the University of Sonora Nursing Department and registered in Clinical Trials. Conclusion: To our knowledge, the study will provide the first evidence of the evaluation of online interventions for the prevention of obesity in schoolchildren derived from a randomized controlled trial, which could be useful in the fight against childhood obesity.