Controlling childhood obesity: A systematic review on strategies and challenges

Abstract

Background:

Childhood obesity is a global health problem with short- and long-term health consequences. This systematic review presents a summary of the experiences on different family-, school-, and clinic-based interventions.

Materials and Methods:

Electronic search was conducted in MEDLINE, PubMed, ISI Web of Science, and Scopus scientific databases. We included those studies conducted among obese individuals aged up to 18 years. Our search yielded 105 relevant papers, 70 of them were conducted as high quality clinical trials.

Results:

Our findings propose that school-based programs can have long-term effects in a large target group. This can be related to this fact that children spend a considerable part of their time in school, and adopt some parts of lifestyle there. They have remarkable consequences on health behaviors, but as there are some common limitations, their effects on anthropometric measures are not clear. Due to the crucial role of parents in development of children's behaviors, family-based interventions are reported to have successful effects in some aspects; but selection bias and high dropout rate can confound their results. Clinic-based interventions revealed favorable effects. They include dietary or other lifestyle changes like increasing physical activity or behavior therapy. It seems that a comprehensive intervention including diet and exercise are more practical. When they have different designs, results are controversial.

Conclusion:

We suggest that among different types of interventional programs, a multidisciplinary approach in schools in which children's family are involved, can be the best and most sustainable approach for management of childhood obesity.

INTRODUCTION

The epidemic of childhood obesity is no more limited to high-income countries,[1,2,3,4,5,6,7,8] and has become as one of the most important global health problems of the 21^th century.[9] The World Health Organization (WHO) experts have estimated that there are 43 million overweight children under the age of 5 and by 2020 more than 60% of global disease burden will be the result of obesity related disorders.[2,10] Childhood obesity is associated with several short term and long-term health hazards as cardiovascular diseases, hypertension, type 2 diabetes, fatty liver disease, orthopedic problems, low self-esteem, etc.[11,12] Childhood obesity can reduce life expectancy by 2-5 years.[2] Moreover, the increasing trend of obesity has enormous economic outcomes.[13] Two main underlying causes of excess weight are genes and environment.[14,15] Although both genes and environment have a role in an obesity epidemic, gene defects needs to time to show their phenotype; so obesogenic environment is responsible for obesity.[11]

Primordial/primary prevention of pediatrics obesity and establishment of a healthy lifestyle behaviors from early life are the favored against the epidemic of obesity at the global level.[16]

Effective interventions for prevention and control of childhood obesity should be considered for different aspects.[11,17,18,19,20,21,22,23,24] Experts recommend specific eating and physical activity (PA) behaviors through counseling.[14] Along with clinic-based interventions, researchers have attempted to manage obesity by virtue of family, community, school, and after school programs. Based on Cochrane review of obesity prevention programs in children, most of the well-designed interventions had positive results especially in 6-12-year-old children.[25] Clearly targeted interventions for children and population-based approach for adolescents may be useful and make economic sense. The purpose of this investigation was to systematically review the effects of various clinical-, family-, and community-based interventions targeting the control of childhood obesity and make a suggestion for future interventions.

MATERIALS AND METHODS

Literature search

Relevant literature reporting the interventions for controlling excess weight in children and adolescents was identified through electronic search of papers published from 2000 to 2012 in MEDLINE, PubMed, ISI Web of Science, and Scopus. Keywords such as “childhood obesity”, “overweight,” “weight disorder,” “intervention,” “treatment,” “management,” “control,” “PA,” “nutrition,” “behavior therapy,” and “diet therapy” were used. The searches yielded 1768 articles.

Study selection and eligibility criteria

Having removed duplicates, the relevant papers were selected in three phases. In the first and second phases, titles and abstracts of papers were screened and irrelevant papers were excluded. In the last phase, the full text of recruited papers was explored deeply to select only relevant papers. All these three screening phases were done by two independent reviewers (RK and FA). Discrepancies were resolved by consultation and consensus.

Studies were included if they met the following criteria: Studies on 2-18-year-old children; community, family, school, and clinic interventions or a combination of them; English language; and conducted among obese or overweight children and adolescents. Systematic reviews, meta-analysis, and editorials were excluded. Articles were firstly assessed on their abstracts and 234 were removed.

Data extraction and abstraction

The required information that was extracted from all eligible papers was as follow:

• (i)General characteristics of the study (first author's name, publication year, study year, study design, sampling method,
• (ii)Characteristics of the study population (age and sex of studied participants and sample size, follow-up),
• (iii)Type and duration of the intervention, measure(s) used to assess child weight, and
• (iv)Main finding. One reviewer (FA) extracted the data while another (RK) randomly selected 10% of them and checked their extracted data.

The selection process of our systematic review is presented in Figure 1.

Figure 1.

Flow chart of study selection process

RESULTS

The interventions were categorized as school-based, family-based, and clinic-based programs as described below:

School-based programs

A summary of the school-based obesity prevention and control programs is presented in Table 1. In brief, such interventions are suggested to be feasible and effective;[26] because students spend a considerable part of their time in school,[27] moreover teachers and peers can be engaged in such programs.[28] These kinds of programs can improve health behaviors in a large target group. They are characterized by nutritional education and changes in dietary habits, as well as increase in PA through structured programs.[29] Findings of various studies proposed that the effects of such interventions will be preserved for several years after intervention.[30,31,32] This effect has been of special concern about consuming fruits and vegetables, and healthy snacks, as well as increased PA. Nevertheless, the impact of school-based programs on obesity prevention is controversial and remains to be determined by large studies with long-term follow-up research. Some studies have not evaluated the effect of intervention on anthropometric measures,[27,33,34] but they have shown positive impacts on eating and activity behaviors. The most common limitation of these studies is presenting self-reported data, non-randomized selection of schools, short duration of study, and not masking the interventional groups.

Table 1.

School-based weight control studies

Family-based programs

Reaching a healthy weight is not successful unless children have support for making healthy behavior choices; obviously, providers of this support are families. Family is an applicable target for health promoting interventions. Family-based intervention programs are considered as one of the most successful methods for obesity treatment or prevention.[59] Engaging parents in childhood obesity prevention programs may make weight loss easier for children; because they can provide confirmatory conditions to help their children to choose healthy behaviors, furthermore they are important role models for their children.[60] It is difficult for parents to know and accept that their child has excess weight, and that recommended diets would not have adverse health effect for their children;[61] therefore, they often do not comprehend the necessity of obesity prevention. Families are able to construct children's lifestyle habits, perhaps through their “parenting style” and management of “family functioning.”[62] Table 2 shows family-based interventions for management of childhood obesity. As it demonstrates, most of these programs were successful in decreasing body mass index (BMI) z-score and some health consequences of overweight. After participation of parents in these kinds of programs, their children consumed more fiber and were less sedentary. In some cases, significant decrease in fat mass is documented, as well.[63,64] It has shown that low parental confidence predicts dropout rate from family-based behavioral treatment.[65] The main limitation of family-based studies is the small sample size, high dropout rate, no follow-up data, and selection of motivated families.

Table 2.

Family-based studies for controlling childhood obesity

Clinic-based programs

Table 3 presents a summary of clinic-based weight management programs conducted in the pediatric age group. Although most researchers have tried low calorie-low fat diets for treating obesity, experts have recommended to consider a diet with balanced macronutrients.[14] Nevertheless, different dietary changes have been tried to control excess weight in children and adolescents. High protein (HP) diets seems to make more satiety, but two studies did not confirm their advantage versus standard diets.[90,91]

Table 3.

Clinic-based weight control studies for children and adolescents

In studies in which diet, exercise or both of them were taken into account, nutrition plus PA had more effect on anthropometric indices.[99,103,124] One study showed that combination of aerobic and strength training along with diet therapy results in BMI decrease in comparison with strength training plus diet recommendation.[127] A successful experience is reported about the favorable effects of zinc supplementation on anthropometric and metabolic indices.[102,133]

Obesity behavioral therapy has different parts such as motivational interviewing, goal setting, positive reinforcement, monitoring, and cognitive restructuring.[134] Most of behavioral therapies had positive consequences on weight, BMI, or dietary and PA habits.[92,98,107,108,116]

All interventions that consisted of nutrition, exercise, and counseling had significant effects on body weight or other obesity-related factors[84,93,96,100,101,105,109,111,112,113,114,115,117,118,120,128,135] except for a study, which had beneficial effects only on obesity related behaviors.[97] The main limitation of some of these studies is lack of comparison with the control group, and short-term follow-up of participants, and the uncertain sustainability of such kinds of interventions.

DISCUSSION

This review evaluated three different approaches in childhood obesity management. As the design of most studies is a clinical trial, it makes their comparison easier. Schools are a safe place for learning healthy skills and continuing them during life. Most (29/32) of the papers reported a positive effect of school-based intervention on dietary habits or anthropometric measures. One of negative effects of this kind intervention is discrimination resulted from stigmatization. This may persuade them to get involved in healthier lifestyle or might have opposite results. All of the studies conducted in the family setting (n = 26), had favorable results on obesity criteria. Although some of them had negligible effects. Clinic-based intervention had different methods but almost the same results.

Some studies had no effects on anthropometric index. However, they had resulted in dietary habits or physical fitness improvement.[35,36,46,55,72,97,78,132] One explanation for this can be self-reported dietary intake and PA data. On the other words, children may not pay attention to the instruction they were given.

Teachers can train students how to choose nutritious and low-calorie foods. In addition, exercise training can be reinforced in the school curriculum.[14] Most students with excess weight prefer to eat fatty, sweetened, and salty snacks; they also choose fast foods as their first meal preference. If attendants get involved in obesity prevention programs, they can provide an environment for children to purchase healthy snacks and foods. Families can also make a circumstance which facilitates dietary and behavioral changes. Furthermore, if parents recognize the importance of weight control, they will be motivated to persuade their children for weight control. Families, especially mothers, are the best paradigm for children to learn a healthful eating pattern and activity habits.[136] Through family meals, children can eat more whole grains, fruits, vegetables, low fat milk, and consume less sweets and unhealthy fats. Parents should involve kids in preparing food to make a positive effect on their attitudes toward obesity prevention. It seems that the family has a key role in long-term weight control.[71] It has been shown that if family confidence is low, rate of dropout from weight loss programs will increase.[65] In this regard, providing parenting styles and skills as well as child management strategies are really critical.[81,137] Principally clinic-setting programs have brought nutrition, PA, and education or counseling together to achieve their goals and they have demonstrated long lasting results.[138] Most experts advise a low calorie low fat diet for obesity management; but they may have side-effects such as binge eating.[139] Actually weight loss is allowed in severe obesity and in other cases weight maintenance is an appropriate policy.[114] Some studies recommend HP or low carbohydrate diets because they cause more satiety.[140] A review article revealed that low carbohydrate ad libitum diets are as effective as calorie restricted diets.[140] In addition, a Cochrane review showed that low fat diets have no extra advantages in comparison with other diets with calorie restriction.[141] Another review article revealed moderate effect of exercise on adiposity and not on BMI.[142] Clearly, PA is efficient when lasts for more than 60 min, is moderate to vigorous, and is done in all weekdays.[134] As low calorie diets are harmful for growth, and complying with them is difficult, some studies suggested that vigorous exercise can be a suitable substitute for diet therapy.[137,139] As always emphasized, to be effective, PA should be considered as an enjoyable fun, and should be integrated into daily lifestyle. Obesity causes mental problems in children and adolescents,[118] so behavior therapy seems to be vital. It sounds that group treatment is more successful than individual ones;[75,79] specifically when parents are engaged. Counselors should persuade children and adolescents to eat breakfast, to have structured meal plan to increase consumption of fruits, vegetables, and family meals, as well as to decrease the intake of sweetened beverages, calorie-dense foods, and eating out, as well as reducing the sedentary behaviors and the screen time.[14,91] Counselors also need to teach families about healthy shopping and cooking habits. Unfortunately, most studies did not show favorable effects, many of them had small sample sizes or had short-term follow-up or lacked of the control group. Managing extra group support sessions or using technologies such as E-mail or SMS for monitoring weight losers can be a good idea.[63,92,143]

CONCLUSION

The findings suggest that among different types of interventional programs for management of childhood obesity, a multidisciplinary approach in schools in which children's family are involved, can be the most feasible and effective approach. As teachers and parents are the best role models, it will be easier to accustom children with healthy dietary, PA, and behavioral habits. Future studies are needed to determine the long-term effects and sustainability of different programs.

AUTHORS’ CONTRIBUTION

FAS contributed in the conception of the work, conducting the review, revising the draft, approval of the final version of the manuscript, and agreed for all aspects of the work. RK contributed in the conception and design of the work, drafting and revising the draft, approval of the final version of the manuscript, and agreed for all aspects of the work.