The goal of this study was to evaluate the impact of the Active Teen Leaders Avoiding Screen-time (ATLAS) intervention for adolescent boys, an obesity prevention intervention using smartphone technology.
ATLAS was a cluster randomized controlled trial conducted in 14 secondary schools in low-income communities in New South Wales, Australia. Participants were 361 adolescent boys (aged 12–14 years) considered at risk of obesity. The 20-week intervention was guided by self-determination theory and social cognitive theory and involved: teacher professional development, provision of fitness equipment to schools, face-to-face physical activity sessions, lunchtime student mentoring sessions, researcher-led seminars, a smartphone application and Web site, and parental strategies for reducing screen-time. Outcome measures included BMI and waist circumference, percent body fat, physical activity (accelerometers), screen-time, sugar-sweetened beverage intake, muscular fitness, and resistance training skill competency.
Overall, there were no significant intervention effects for BMI, waist circumference, percent body fat, or physical activity. Significant intervention effects were found for screen-time (mean ± SE: –30 ± 10.08 min/d; P = .03), sugar-sweetened beverage consumption (mean: –0.6 ± 0.26 glass/d; P = .01), muscular fitness (mean: 0.9 ± 0.49 repetition; P = .04), and resistance training skills (mean: 5.7 ± 0.67 units; P < .001).
This school-based intervention targeting low-income adolescent boys did not result in significant effects on body composition, perhaps due to an insufficient activity dose. However, the intervention was successful in improving muscular fitness, movement skills, and key weight-related behaviors.
While we agree with Wake and Lycett [1], that population-level interventions are needed to address the global obesity pandemic, a number of their comments regarding the ATLAS RCT [2] are inaccurate and misleading. To start, Wake and Lycett questioned the use of sub-group analyses that were not specified a priori. Although not updated in the clinical trials registry, our sub-group analyses for overweight/obese students were decided a priori and described in our protocol paper [3]. Recent recommendations arising from the seminal diabetes prevention trial known as HEALTHY [4], suggest that the primary outcome analysis in school- based trials should perhaps be conducted with participants in the highest risk subgroup (i.e., participants overweight/obese at baseline). As overweight/obese youth have the greatest need for intervention, sub-group analyses for these individuals are worthy of exploration.
Wake and Lycett questioned the cost-benefit of the ATLAS intervention and reported crude calculations suggesting that our approach would reach only 20% of the eligible population. As noted by the authors in the same paragraph, ATLAS was an efficacy trial, not a translation trial and therefore it was not necessary or appropriate to include all eligible students. Based on our power calculation, it was determined that 350 participants were needed (25 students from 14 schools). Wake and Lycett suggest that we were only able to recruit 42% of our intended population. However, we exceeded our recruitment target by recruiting 361 participants. Regarding the cost-benefit of the ATLAS intervention, the face-to-face component of the intervention (i.e., 33 hours) was integrated into schools' existing school sport programs and delivered by teachers. From this perspective, the cost-effectiveness of our intervention is likely high, as is the case with most school-based interventions[5].
As noted by Wake and Lycett, the intervention effects for our primary outcomes were not statistically significant, yet they failed to comment on the improvements in resistance training skill competency. Short-term improvements in body composition and fitness can be achieved in physical activity programs. However, due to the lack of long-term follow-up in our trial (and most others), evidence regarding the maintenance of such effects is largely absent. Unlike changes in body composition, physical activity and fitness, improvements in movement skills are retained over the longer-term. Therefore, these improvements should be given due credit, as they may facilitate lifelong physical activity participation, which is important for a myriad of reasons.
On a final note, Wake and Lycett appear to have selectively reported our conclusion. In the first sentence of our conclusion in the abstract we state "This school-based intervention targeting low-income adolescent boys did not result in significant effects on body composition." Furthermore, after re-stating our aim in the discussion, we state "No significant intervention effects were observed overall for body composition". The text reported by Wake and Lycett was taken from the 'What this study adds' section. We do not assume that obesity prevention interventions alone will provide the 'silver bullet' for the current obesity pandemic. However, we continue to advocate for theoretically sound school-based programs.
References
1) Wake M, Lycett K: Let's call it as it is: On results, reach, and resolution in population-based obesity trials. Pediatrics 2014, 134(3):e846-e847.
2) Smith JJ, Morgan PJ, Plotnikoff RC, Dally KA, Salmon J, Okely AD, Finn TL, Lubans DR: Smart-phone obesity prevention trial for adolescent boys in low-income communities: The ATLAS RCT. Pediatrics 2014, 134(3):e723-e731.
3) Smith JJ, Morgan PJ, Plotnikoff RC, Dally KA, Salmon J, Okely A, D.,, Finn TL, Babic M, Skinner G, Lubans DR: Rationale and study protocol for the 'Active Teen Leaders Avoiding Screen-time' (ATLAS) group randomized controlled trial: An obesity prevention intervention for adolescent boys from schools in low-income communities. Contemp Clin Trials 2014, 37(1):106-119.
4) Marcus MD, Hirst K, Kaufman F, Foster GD, Baranowski T: Lessons learned from the HEALTHY primary prevention trial of risk factors for type 2 diabetes in middle school youth. Curr Diab Rep 2013, 13(1):63-71.
5) Wu S, Cohen D, Shi Y, Pearson M, Sturm R: Economic analysis of physical activity interventions. Am J Prev Med 2011, 40(2):149-158.
Conflict of Interest:
None declared