February 22, 2023
3 min read
Adding more physical education classes in grades one to nine could help lower the prevalence of obesity among school-aged children, according to a study published in Obesity.
From 2011 to 2018, Slovenia enacted a nationwide program named Healthy Lifestyle that added two to three additional physical education classes per week for students in more than 200 schools in the country. The researchers found that students who participated in the additional classes had a larger reduction in BMI than nonparticipants, and the BMI decrease grew as students participated in the intervention for a longer time.
“There are two important messages,” Gregor Starc, PhD, assistant professor in the faculty of sport at University of Ljubljana in Slovenia, told Healio. “The first one is that school-based interventions to increase physical activity can be effective in reducing obesity prevalence, but such interventions should be longer than two years. The second — in our regard the more important message — is that introducing one hour of high-quality school physical education every day could reverse the childhood obesity epidemic.”
Researchers analyzed findings from Healthy Lifestyle, a program that allocated two additional physical education classes per week for students in grades one to six and three additional classes for students in grades seven to nine. The additional classes meant that participants attended a physical education class during every school day. There were 216 schools in Slovenia that opted to participate in the program. All students at participating schools were invited to take part in the intervention as an elective course. Height, weight and triceps skinfold measurements were obtained from the Slovenian national fitness surveillance system. Children in the 85th to 94th percentile for age- and sex-specific BMI were considered to have overweight, and those in the 95th percentile or higher were defined as having obesity. Researchers compared data from intervention participants with a control group of children who attended participating schools but did not take part in the intervention.
BMI reductions grow with longer intervention participation
There were 29,152 children in the intervention group and 34,473 children in the control group at baseline. The overall prevalence of obesity in the 216 participating schools declined after the intervention began for schools that joined before or after 2016. Due to delays and reduced financing in 2016, schools joining that year did not have a change in obesity prevalence, according to the researchers.
In a generalized estimating equations analysis, the intervention group had an increasingly lower mean BMI compared with the control group. The difference in BMI between the intervention and control groups peaked at 3 years for girls with normal weight (beta = 0.937; 95% CI, 0.845-1.029) and girls with obesity (beta = 1.417; 95% CI, 0.959-1.875) and at 4 years for girls with overweight (beta = 1.151; 95% CI, 0.785-1.517). Among boys, the difference in BMI change between intervention and control participants plateaued at 3 years for those with normal weight (beta = 0.851; 95% CI, 0.766-0.935), overweight (beta = 0.766; 95% CI, 0.542-0.989) and obesity (beta = 0.889; 95% CI, 0.461-1.316).
Starc said the findings were not surprising as the decision to implement the intervention was based on previous research testing out how many physical education lessons per week were needed to improve physical fitness in children.
“We tested different combinations and it turned out that the only combination that reliably works is having five lessons of 45-minute physical education per week, implemented by specialist physical education teachers,” Starc said. “Combinations with fewer lessons and classroom teachers with less competencies in PE teaching were much less effective.”
Intervention linked to obesity reversal at 3 years or longer
Researchers assessed the transition of 4,063 children with obesity at baseline to overweight or normal weight by the number of years participants were enrolled in the intervention. Girls with obesity participating in the intervention for 2 years (Cramer’s V coefficient = 0.072; P = .016), 3 years (Cramer’s V coefficient = 0.12; P = .002), 4 years (Cramer’s V coefficient = 0.122; P = .024) or 5 years (Cramer’s V coefficient = 0.154; P = .033) were more likely to transition to overweight or normal weight than girls with obesity in the control group. For boys with obesity, only those participating in the intervention for 3 years (Cramer’s V coefficient = 0.092; P = .011) or 5 years (Cramer’s V coefficient = 0.157; P = .027) were more likely to lower their BMI to overweight or normal weight than those in the control group. The number of children needed to treat to reverse one obesity case declined as duration of the intervention increased, with the lowest number needed to treat being 17 for girls and 12 for boys at 5 years.
“The number needed to treat for obesity reversal decreased as the intervention duration increased, emphasizing the need for long-term physical activity programs,” the researchers wrote. “Policymakers and funding bodies should be aware that obesity is a chronic condition that needs to be dealt with over a longer timeframe and that easy solutions and immediate effects are neither realistic nor sustainable.”
Starc said it is crucial for similar interventions to be studies and adapted in other countries to validate the findings.
For more information:
Gregor Starc, PhD, can be reached at [email protected]