Schoolwide Intervention May Improve Obesity Outcomes Over Time

A novel, school-based intervention to prevent childhood obesity has the potential to lower abdominal adiposity measurements, with earlier initiation of the program producing more substantial improvements over time, according to a new, randomized study from Spain.

With data showing that the onset of cardiovascular disease risk factors in childhood can predict outcomes later in life, the sooner prevention in the form of education can begin, the better, researchers argue.

“Seventy-five percent of adult obesity starts in childhood,” senior author Valentin Fuster, MD, PhD (Icahn School of Medicine at Mount Sinai, New York, NY), told TCTMD, adding that one of his main goals is making the subject of health mandatory in primary schooling around the globe. “It's time that we pay attention to the children. To me, the best impact itself in the future will be when we start education in children.”

The SI! Program tested in the study, which was published in the August 6, 2024, issue of the Journal of the American College of Cardiology with first author Gloria Santos-Beneit, PhD (Fundación SHE, Barcelona, Spain), is one example of how children might be taught about subjects tied to cardiovascular disease prevention, he said. The age-adapted curriculum includes four components designed to bring awareness to modifiable risk factors: diet, physical activity, body and heart, and emotions management. It is administered in a multilevel fashion, targeting children through their families, teachers, and school environment.

The cluster randomized study was conducted in 48 elementary schools in Madrid, Spain, in which half the schools served as controls and half were assigned to use the SI! program between September 2014 and July 2020. In total, 1,771 children were included (52.6% boys; mean age at recruitment 6.3 years).

At 3 years, the researchers showed smaller increases in adiposity, as measured by body mass index (BMI), waist-to-height ratio (WHtR), and waist circumference (WC) among the children randomized to schools offering the intervention compared with controls. The differences were maintained for WHtR and WC at 6 years, but not for BMI.

At 6 years, children who received the intervention in grades 1-3 or grades 1-6 had significant benefits compared with controls regarding the WC and WHtR endpoints, but this was not observed for children who received the intervention in grades 4-6, indicating that earlier intervention is more effective.

Additionally, they calculated a knowledge-attitudes-habits (KAH) score for each child based on the four components of the intervention, which ranged from 0 to 96 points, with a higher score denoting a healthier understanding. They found no significant between-group differences in KAH score between children from SI! schools or controls at either 3 or 6 years.

Mixed Responses

Lauding the investigators for pulling off a 6-year study among elementary school students, Justin Ryder, PhD (Lurie Children's Hospital and Northwestern Feinberg School of Medicine, Chicago, IL), told TCTMD the findings should be caveated by several design flaws.

First, he said, the cluster randomized design doesn’t allow for a look at individual-level outcomes. “I would want to know how many kids were prevented from having obesity, rather than looking at a whole school and looking at it that way,” he said. “That, from a clinical perspective, is going to be more important to me than what happened on the school level.”

Ryder also questioned the use of looking at BMI using a z-score approach, which has been demonstrated to not be a great tool for assessing longitudinal change in weight for children, as opposed to percentiles.

“I don't think that they accounted for all the things in the statistical analysis that they needed to do to have a valid statistical analysis of their design,” he said, “and the problem with that is it can create a lot of error. . . . It's really hard to determine if their outcomes are real or not.

“For me, the jury is still out on whether or not this was really an effective study or not,” Ryder added. “Their premise and their purpose here is very important. I just have challenges with some of the approaches and more of the backend.” 

In an accompanying editorial, Carl J. Lavie, MD (Ochsner Clinical School-The University of Queensland School of Medicine, New Orleans, LA), Ian J. Neeland, MD (University Hospitals Cleveland Medical Center, Case Western University School of Medicine, OH), and Francisco B. Ortega, PhD (University of Granada, Spain), focused on other aspects.

Writing that the trial stands out from other similar studies for its large size, long length, and research question addressing optimal timing, the editorialists say the SI! intervention is positioned to “provide an excellent start to prevent CVD earlier—a paradigm shift indeed.”

Further, they say, “this approach may be important worldwide, including in very high-risk children and adolescents in the United States, where children from families with low income or low parental education, as well as Hispanic and non-Hispanic Black children, are at particularly high risk of obesity and its complications.”

Notably, Fuster said he would not generalize the results of this study to populations outside of Spain given that the study cohort was primarily white. “But I can say that in similar studies we have done in different groups, we have learned that socioeconomically the best results are in the highest socioeconomic states,” he said.

The study team is planning to continue following these children to assess longer-term outcomes, and developing another study to determine the effects of repeating the intervention over time.