In both developed and developing countries, the prevalence of overweight and obesity in children has risen substantially in recent decades, with a global increase of 47% since the 1980s.1
This trend is concerning to experts because of the numerous comorbidities that have been linked to overweight and obesity in children, including poor mental health, chronic diseases such as asthma, and cardiovascular risk factors such as hypertension.2 In addition, overweight and obesity are associated with significant healthcare costs, including an estimated $113.9 billion in the United States annually.3
Noting the increasing interest in potential interventions for the prevention or management of weight gain in children and adolescents, the authors of a 2017 systematic review examined evidence regarding these types of strategies implemented in various nonclinical settings for youth aged 2 to 19 years in many parts of the world.
A total of 56 studies (randomized controlled trials, quasi-experimental studies, and natural experiments) met the selection criteria, such as a minimum follow-up duration of 12 months (6 months for school-based interventions) and the inclusion of a control group. Studies also had to include at least 1 of the following primary outcomes: body mass index (BMI), BMI percentile, BMI Z score, waist circumference, body fat percentage, skinfold thickness, or prevalence of overweight or obesity.
Interventions were based in the following settings: school or after-school setting (n=41) studies, preschool (n=6), community (n=7), and home (n=2). According to the results, the most effective approaches were school-based and involved both diet and exercise components, as well as a home element. Of these interventions, there were 24 randomized controlled trials (RCTs), 15 quasi-experimental studies, and 2 natural experiments. Several examples of these studies are highlighted here:
- In 1 RCT, 342 kindergarten students were assigned to a control group or an intervention that included 45 minutes of daily, game-based physical activity and techniques such as games and stories to teach the children about nutrition.4 At the 1-year follow-up, the BMI of intervention participants had decreased significantly more than that of control patients (−0.73 kg/m2 vs −0.33 kg/m2; P =.005).
- A cluster randomized trial conducted across 16 primary schools in Spain used an educational intervention that “encouraged self-efficacy in health-related decisions and involved families through presentations and newsletters,” as described in the review.5 At the 6-year follow-up, a smaller increase in BMI was observed in the intervention group vs controls (2.79 kg/m2 vs 3.85 kg/m2; P =.023).
- An RCT involving 253 adolescent girls in Brazil employed an intervention consisting of enhanced physical education classes, nutrition lessons, and workshops.6 At 6 months, a significant effect was observed in the intervention group for waist circumference (difference −2.28 cm; P =.01) but not BMI.
- A cluster randomized trial of 318 children in the UK used 20 weekly lessons on nutrition and physical activity.7 Ten weeks postintervention, there was a significant reduction in BMI Z score (difference −0.24; P =.04), but not waist circumference or BMI.
- In a quasi-experimental study conducted in 6 middle schools in Italy, an intervention that included environmental aspects such as educational posters and reinforcement techniques such as text messaging was linked to a significantly lower BMI Z score at 2 years (difference, −0.18; P = .003).8
The small number of studies conducted in other settings produced less consistent results, partly as a result of heterogeneity in characteristics and design. The 5 RCTs conducted in preschool settings, however, showed moderate evidence for the effectiveness of physical activity interventions alone, as well as strategies that combined diet and physical activity.
Endocrinology Advisor discussed these findings with the following experts: review coauthor Sara Bleich, PhD, professor of public health policy at the Harvard TH Chan School of Public Health, Boston, Massachusetts; and Roy Kim, MD, MPH, head of pediatric endocrinology at the Cleveland Clinic Children’s hospital in Ohio.
Endocrinology Advisor: In summary, what are the main takeaways of this review?
Roy Kim, MD, MPH: Among their findings is that school-based prevention programs tended to be more successful than programs based in the other settings. The results also suggest that among school-based programs, those that combine diet and physical activity, rather than focusing on 1 approach alone, tend to be more successful at preventing overweight and obesity. Furthermore, success was also promoted by the inclusion of a home-based component to the school program.
Endocrinology Advisor: In light of these findings, and in general, how can healthcare providers support efforts to prevent overweight and obesity in children?
Sara Bleich, PhD: This review did not focus on the clinical setting. Given our finding that school-based interventions combining diet and physical activity are more effective, healthcare providers can support efforts to prevent childhood obesity by adopting complementary strategies. For example, health systems, and particularly those targeting children, should consider modifying their food and beverage options to support healthy choices and incorporating play areas where children can be active, such as playgrounds.
Endocrinology Advisor: What are the direct or indirect treatment implications for clinicians?
Dr Bleich: During each clinical encounter, healthcare providers should encourage healthy behaviors among children and their families that can help reduce obesity risk; for example, not drinking sugary beverages and reducing screen time. There is no single factor that can solve the problem of childhood obesity, but interactions with healthcare providers that encourage healthy habits are 1 important piece of the puzzle.
Dr Kim: Their review omits primary care settings; the findings do not diminish the importance of other interventions to prevent overweight and obesity, many of which occur in primary care settings. The study was not designed to assess the role of prenatal care to promote healthy weight during pregnancy, for example, or other early life interventions.
Endocrinology Advisor: What should be the focus of future research on this topic?
Dr Bleich: Future research should examine how integrating information about a child’s community into the electronic medical record can help healthcare providers provide more meaningful advice about reducing obesity risk. For example, if there are no safe parks near a child’s home, a healthcare provider might encourage indoor games that promote physical activity.
Dr Kim: Additional studies should focus on longer-term results, include settings in developing countries, and identify what aspects of the diet and physical activity interventions are most effective. Research should also focus on interventions to reach toddlers and preschool age children, as early intervention is likely going to be more effective and durable.
- Ng M, Fleming T, Robinson M, et al. Global, regional, and national prevalence of overweight and obesity in children and adults during 1980–2013: a systematic analysis for the Global Burden of Disease Study 2013. Lancet. 2014;384(9945):766-781.
- Bleich SN, Vercammen KA, Zatz LY, Frelier JM, Ebbeling CB, Peeters A. Interventions to prevent global childhood overweight and obesity: a systematic review. Lancet Diabetes Endocrinol. 2018;6(4):332-346.
- Tsai AG, Williamson DF, Glick HA. Direct medical cost of overweight and obesity in the USA: a quantitative systematic review. Obes Rev. 2011;12(1):50-61.
- Nemet D, Geva D, Pantanowitz M, Igbaria N, Meckel Y, Eliakim A. Long term effects of a health promotion intervention in low socioeconomic Arab- Israeli kindergartens. BMC Pediatrics. 2013;13:45.
- Llargués E, Recasens MA, Manresa J-M, et al. Four-year outcomes of an educational intervention in healthy habits in schoolchildren: the Avall 3 Trial. Eur J Public Health. 2017;27(1):42-47.
- Leme AC, Lubans DR, Guerra PH, Dewar D, Toassa EC, Philippi ST. Preventing obesity among Brazilian adolescent girls: six-month outcomes of the Healthy Habits, Healthy Girls-Brazil school-based randomized controlled trial. Prev Med. 2016;86:77-83.
- Fairclough SJ, Hackett AF, Davies IG, et al. Promoting healthy weight in primary school children through physical activity and nutrition education: a pragmatic evaluation of the CHANGE! randomised intervention study. BMC Public Health. 2013;13:626.
- Ermetici F, Zelaschi RF, Briganti S, et al. Association between a school-based intervention and adiposity outcomes in adolescents: the Italian “EAT” project. Obesity. 2016;24(3):687-695.