The World Health Organization defines overweight and obesity as abnormal or excessive fat accumulation that may impair health and manifesting with excess weight and increased body volume.1 It has been labelled a XXI century epidemic on account of its impact on morbidity and mortality, quality of life and health care costs. Childhood obesity is a risk factor, given its frequent association with comorbidities both in childhood and adulthood. Thus, it is associated with type 2 diabetes mellitus, high blood pressure, dyslipidaemia, fatty liver disease, psychiatric disorders and others in the paediatric age group. Furthermore, obesity in adolescence is associated with a higher risk of obesity and increased morbidity and mortality in adulthood associated with stroke, ischaemic heart disease, tumours, etc.2 In addition, we have been witnessing an alarming increase in the prevalence of overweight and obesity in the past few decades, with a cohort effect in the epidemic, that is, obesity in younger generations is more prevalent and has earlier onset. In Spain, this phenomenon has been particularly pronounced, with prevalences that exceed those of most other European countries. The extent of the problem is considerably smaller in Anglo-Saxon and Scandinavian countries compared to Mediterranean countries. The ALADINO3 study found a prevalence of overweight of 14–26% in boys and 13–25% in girls, depending on the cut-off point applied, while the prevalence of obesity was 11–20% in boys and 11–15% in girls. According to the 2014 Health Survey of Catalonia, based on data reported by parents, the prevalence of overweight in children aged 6–12 years was 18.7%, the same for both sexes, and the prevalence of obesity was 11.7% (13.5% in boys and 9.9% in girls).4 These results are consistent with those of previous studies that had already found an increased prevalence of childhood obesity, such as the EnKid study.5

In this context, any preventive measures or interventions aimed at reducing overweight and obesity at early ages become critically important.

One of the multiple initiatives carried out to attempt to curb this epidemic was the development of the Clinical Practice Guideline (CPG) on the Prevention and Treatment of Childhood and Adolescence Obesity of the Spanish National Health System (Sistema Nacional de Salud [SNS]) in 2009.6 Since the intervention strategies that are being implemented now seem unable to control the increase of obesity and overweight, a critical review of the most recent evidence seems necessary in order to update the recommendations of CPGs.

The aim of our study was to perform an updated review of the literature on obesity and overweight in children and adolescents. More specifically, we intended to update part of the literature review in the aforementioned CPG,6 focusing on the criteria for referral from primary care (PC) to specialty care, and the evidence available on the management of overweight and obesity taking into account effectiveness and safety criteria. We excluded prevention and pharmacological and surgical treatment from the review. In addition, we included an analysis on some of the most recently developed interventions that could be effective on the target population, such as the use of information and communication technologies (ICTs).

We conducted a systematic review (SR) of the literature, replicating the literature search methodology used in the CPG of the SNS. We selected the questions of the CPG related to the criteria for referral from PC to specialty care (SC), and nonpharmacological and nonsurgical clinical interventions (Table 1). The literature search prioritised the identification of SRs and other critical summaries of the scientific literature, such evaluation reports on health technologies. We used the major updates on CPGs published recently by the National Institute for Health and Care Excellence (NICE)7,8 as a reference. We conducted searches in the Cochrane Database of Systematic Reviews (The Cochrane Library), MEDLINE and Scopus databases.

We mainly considered documents in Spanish, English and French. We searched for publications from January 2009 to December 2014. A description of the methodology used can be found in an earlier version of this document.9 Details on the search criteria can be obtained by consulting with the authors. The search was completed replicating the searches performed for the remaining questions of the SNS CPG, as we considered that most questions included nonspecific criteria and thus allowed the identification of documents that would answer the search questions for other CPG questions. We tried to replicate the inclusion and exclusion criteria of the original CPG during data collection. Once we had selected the documents, we developed evidence tables and assessed the quality of the evidence using the Scottish Intercollegiate Guidelines Network (SIGN) system10 (Table 2). We have attempted to summarise the primary outcomes based on body mass index (BMI) as changes in BMI expressed in standard deviations (SDs) or changes in the standardised score (z-score), effect size (ES) or kg/m2, when possible. We strived to summarise the rest of the primary or secondary outcomes for each question individually (for example, the lipid profile, duration of physical activity, sedentary time, etc.).

The initial literature search identified 3.703 documents after excluding duplicates (Fig. 1). After reading the titles and abstracts, we selected 134 documents, reading the full text of 55. Finally, 44 documents were included in the review and four others were added, two from secondary sources, and the NICE CPGs, which are considered the gold standard of CPGs. Appendix A, which is available online, details the included publications.

Figure 1.

Literature search.

(0.21MB).

The review of the evidence and the updated NICE CPG for children was published in 2013,7 and the 2014 update8 includes recommendations for both prevention and management and targets both the paediatric and the adult population. The literature review in this CPG included 41 studies, of which 30 were randomised controlled trials (RCTs) and 11 real-life clinical trials. The recommendations of the NICE guideline focus on the development and implementation of “lifestyle weight management” programmes based on the best available evidence. This approach is based on a multicomponent intervention that includes physical activity, diet, behaviour change and family involvement.

Our study shows that multicomponent interventions on obesity and overweight in children and adolescents that include dietary, physical activity, sedentary time reduction and behavioural change interventions applied simultaneously achieve better outcomes than isolated interventions. Intensive interventions delivered by professionals with previous training on the subject in PC settings with consultation with SC are most effective. Furthermore, withdrawal of sugary drinks from the diet showed a short-term effect on BMI reduction. Outcomes also improve when families are involved, especially in younger children, and when socioeconomic status and other individual factors are taken into account. Further research is needed to evaluate the role of ICTs and to analyse the association between obesity and sleep duration.

The interpretation of the results of this review must take its limitations into account. We replicated the SNS CPG6 inclusion and exclusion criteria, although we prioritised SRs over other types of study. Therefore, we may have omitted some RCTs or other experimental studies. The considerable heterogeneity of the outcome measures analysed in the included studies precluded a quantitative summary of the results and hindered their comparison. In fact, some studies that analysed the validity and reliability of the outcome measures and the interventions performed in childhood obesity studies underscored the heterogeneity and wide variability of outcome measures, the challenges to the extrapolation of results, the different type and duration of interventions, and how these barriers prevent reaching generalisable conclusions in most instances.14,15 Last of all, this SR focused on interventions in the clinical setting and excluded pharmacological and surgical interventions. Still, our intent was to update the evidence in interventions delivered in PC settings, which is where most overweight or obese children and adolescents receive care. Finally, the information analysed in this SR has improved the existing LE on the effectiveness of multicomponent interventions compared to isolated interventions, and provides information that may help identify factors associated with lack of adherence and participation in interventions, as well as some of the potential adverse effects of interventions.

There is a clear need to standardise the criteria for the classification of weight, height and BMI and for referral to SC.11 There is no consensus on the reference values to be used, and this has negative repercussions on the analysis and assessment of the problem. In this sense, it would probably be beneficial to increase agreement compared to the current status quo.

One of the interventions that may be effective is the withdrawal of sugary drinks from the diet.16 Similarly, both the reduction of the energy density of foods and of portion sizes were associated with favourable outcomes.17 In any case, multicomponent interventions are most effective. However, many of the reviewed studies highlighted the poor adherence to treatment, and it is likely that adherence is even lower in real-life clinical practice. This is one of the main factors that contribute directly to treatment failure. The review also supports the beneficial impact of formal and standardised training of the providers that deliver the intervention with the purpose of improving outcomes.

On the other hand, the implementation of interventions should take into account individual factors and the fact that there is a significant socioeconomic gradient in obesity.18 The burden of morbidity, the decreased life expectancy and the health care costs caused by obesity in the adult population are rooted in the early stages of life; a more effective approach would be to tackle the health inequalities in childhood obesity, that is, the “causes of the causes”.19

Based on the findings of our review, we recommend the implementation of multicomponent programmes delivered by professionals with special training, with family involvement, and addressing aspects analysed in this review such as behaviour and individual and sociodemographic factors (LE=1++; 4). Lack of adherence is one of the reasons why interventions fail, and the criteria for diagnosis, the outcome measures and the type and duration of interventions should be standardised and improved (LE=1+, 2++). Further research is needed on the evaluation of emerging ICT tools, as well as to develop a consensus on specific criteria for referral to SC tailored to the National Health System (LE=1+).

The authors have no conflict of interests to declare.