Promoting Health in Pediatric Obesity: A Decade’s Research of Physical Activity’s Influence on Cardiometabolic Parameters

Background

Physical activity is seen as one of the key factors in the prevention of overweight and obesity and in the reduction of cardiometabolic risk in children and adolescents. Good physical fitness in childhood brings health benefits, especially cardiovascular and respiratory. According to literature, overweight and obesity in childhood also correlate with low levels of physical fitness [1]. Furthermore, higher levels of cardiometabolic activity significantly reduce the cardiometabolic risk in adult life, even among people with abdominal obesity that appeared during childhood [2].

Physical Activity in Children

PHYSICAL ACTIVITY IN CHILDREN AND CARDIOMETABOLIC INDICATORS:

Behaviors associated with physical activity are perceived as one of the key factors in the prevention of overweight and obesity and for the reduction of cardiometabolic risk [14]. Several mechanisms have been proposed to mediate the protective effect of physical activity and physical fitness on cardiometabolic risk, namely, anti-inflammatory effects, increased insulin sensitivity, higher glucose uptake independent of insulin, an improved lipid profile, and the function of hormones and enzymes involved in fat metabolism [15]. The lack of physical activity involves lower aerobic capacity and mental health, reduced glucose tolerance, higher fasting insulin levels, and increased risk factors for cardiovascular diseases [16]. Moderate or intense activity is associated with high cardiopulmonary capacity, a healthier lipid profile [17] and blood pressure, and lower insulin resistance [18]. It also affects hemodynamic variables along with psychological and socio-affective aspects [19]. High-intensity physical activity has a positive effect on metabolic profiles regardless of weight loss and energy expenditure [6]. It is suggested that exercise reduces blood pressure and serum glucose levels [17]. It can improve insulin sensitivity, functions of vascular endothelium, glycemic control, and blood pressure [20]. Also, exercise contributes to a reduced risk of non-alcoholic fatty liver disease and facilitate improvements in the event of chronic inflammation [21]. Regular exercise has a significant impact on cardiovascular capacity in people with type 2 diabetes. It reduces insulin resistance, and thus improves glycemic control and decreases cardiovascular risk factors [22]. In their meta-analysis, Ho et al point out that physical activity interventions and combined interventions (diet and exercise) can lead to weight loss and improved metabolism in the pediatric population with obesity or overweight. Combined interventions can determine greater improvements in high-density lipoprotein cholesterol (HDL-C), fasting glucose, and insulin levels within 6 months [21]. Researchers who have implemented those interventions in adolescents with overweight or obesity have reported an improvement in body composition, along with a decrease in systolic blood pressure (SBP), alanine transaminase, glucose, homeostasis model assessment of insulin resistance (HOMA-IR), glycated hemoglobin (HbA1c), total cholesterol, low-density lipoprotein cholesterol (LDL-C), and triglycerides, and an increase in HDL-C [23].

CHILDHOOD OBESITY:

With reference to the literature, obesity is not just the result of reversible poor eating habits, lack of movement, or other personal choices, although these undoubtedly effectively worsen this condition. Obesity is a chronic disease that results in changes in human anatomy, physiology, and metabolism [24,25]. The Obesity Medicine Association defines obesity as “a chronic, recurrent, multi-factor neurobehavioral disease in which adipose tissue growth promotes adipose tissue dysfunction and abnormal body fat mass resulting in adverse metabolic, biomechanical, and psychosocial (stigmatization) health consequences” [25,26]. The main factor is food, especially foods such as fat or sugar-sweetened drinks. An abundance of food, low physical activity, and several other environmental factors interact with the genetic susceptibility of humans to produce a positive energy balance. Most of this excess energy is stored as fat in enlarged and often more numerous fat cells, but some lipids can infiltrate other organs, such as the liver (ectopic fat). The formation of obesity is influenced by the interaction of genetics, epigenetics, metagenomics, and the environment [27]. The traditional treatment of obesity as a result of excessive or high-calorie consumption is insufficient [28]. The omission or depreciation of the role of the gastrointestinal tract in the etiology of obesity, which in turn is influenced by many factors, such as digestive enzymes, bile acids, microflora, intestinal hormones, and neural signals, none of which is under voluntary control, is a fairly common mistake [29]. Energy consumption through physical activity has been found to be relatively low [30]. Chamorro et al [31] point to circadian diseases and lack of sleep, and Claes et al [32] point to mental stress as contributing factors to obesity. Therefore, overeating and reduced physical activity may be symptoms rather than primary causes of obesity [33]. The complex causes of obesity are associated with lower biases related to weight disorders and less guilt [26]. Enlarged fat cells and ectopic fat produce and secrete a variety of metabolic, hormonal, and inflammatory products that cause damage to organs, such as the arteries, heart, liver, muscles, and pancreas [34].

There are significant individual differences in body weight and body fat within each environment, suggesting that obesity is influenced by complex interactions between genetic, developmental, behavioral, and environmental influences [27]. The prevalence of childhood obesity is increasing worldwide and is currently a global public health problem [35–37]. In 2020, a total of 39 million children under the age of 5 had overweight or obesity [38]. The problem of overweight and obesity also includes adolescence and adult life, causing a number of health problems, which are increasing with age [39]. Persons with obesity face not only increased risk of serious medical complications but also a pervasive and resilient form of social stigma. This phenomenon can cause significant harm to affected individuals, including physical and psychological results [26]. Childhood and adolescence are both critical moments, not only for the formation of habits in adult life. Behavior during this period is also associated with medical conditions at a later age [40]. Evidence suggests that obesity in children can persist throughout the whole life, reducing the quality of life and its expected length [19]. Preventing obesity and forming healthy habits at a young age is crucial for establishing long-term healthy behaviors. The acquisition of habits of a healthy lifestyle in childhood depends both on the individual and his or her socio-psychological environment [41].

OBESITY IN CHILDREN AND CARDIOMETABOLIC MARKERS:

Childhood obesity is associated with co-existing physical and mental diseases, including adverse cardiometabolic effects, such as high blood pressure, dyslipidemia, and insulin resistance [42,43]. Obesity is strongly connected with elevated concentrations of circulating inflammatory markers, such as C-reactive protein (CRP) [10]. Studies have shown that children and adolescents with low levels of cardiopulmonary capacity who have overweight or obesity have an increased risk of developing cardiovascular diseases or metabolic syndrome during puberty or in adulthood [1,14,44,45]. Children with overweight or obesity are more likely to develop cardiovascular problems in the form of type 2 diabetes, hypertension, myocardial infarction, coronary heart disease, dyslipidemia, and stroke [35,36,46]. Increased overweight and obesity is associated with hepatic steatosis, a high level of cholesterol, glucose intolerance, insulin resistance, interference with the menstrual cycle, and balance disorders [23,41,47]. Children with obesity are exposed to harmful short- and long-term health effects, thus showing metabolic syndrome components, such as changes in the lipid profile of the plasma [17], hypertension, insulin resistance, and impaired glucose metabolism [11,12,17,21]. Furthermore, their vascular structures deteriorate, which contributes to an adverse reconstruction of the heart, resulting in an abnormal cardiovascular response [41]. Damage to the endothelium, which leads to atherosclerosis, can develop during puberty [45]. Early endothelial dysfunction has been reported in children and adolescents with obesity, with a significantly greater thickness of the carotid median membrane than in persons with normal body mass [46].

A sedentary lifestyle with other factors can cause the accumulation of adipose tissue [18]. A high percentage of visceral fat in the abdominal cavity has been shown to exacerbate hyperlipidemia and hypertension, and it considerably contributes to insulin resistance [35]. An extensive capillary network surrounding the fat tissue affects strain on the heart by increasing the blood volume and cardiac output [35]. When adipose tissue gathers in excessive amounts in the body, several metabolic changes begin to occur [15]. Research has shown that children with obesity are more likely to develop adverse lipid and glycemic profiles than are other children. It is additionally associated with an increase in fatty streaks in the endothelium of arteries in children, which can lead to the development of atherosclerotic plaques in adulthood [15]. Adipose tissue is a source of interleu-kin-6, which results in the formation of a chronic inflammation that can trigger acute coronary syndrome, as well as a source of lipoprotein lipase, estrogen, angiotensinogen, adiponectin, leptin, insulin-3 binding protein, and tumor necrosis factor α1. Fat tissue produces and secretes peptides and proteins called adipocytokines, which are involved in inflammation and immune responses [19]. In the case of obesity, the concentrations of different adipocytokines are high and are associated with hypertension (angiotensinogen), inhibition of fibrinolysis (plasminogen activator inhibitor-1), insulin resistance (tumor necrosis factor-α, interleukin-6, and resistine), and the onset or progression of atherosclerotic lesions (CRP). Adiponectin, which has anti-inflammatory and anti-atherosclerotic properties, is inversely proportional to the body mass index (BMI) and the percentage of adipose tissue [19]. Leptin, a hormone secreted by fat tissue, inhibits food intake, stimulating energy expenditure [11].

The main purpose of this review was to determine the existing relationship between physical activity, its forms, and selected cardiovascular indicators among children with obesity. This study includes publications from the last 10 years, which makes the accumulated knowledge current and helps the understanding of the research problem.

In this study, we assumed that the state of health among children perceived through the prism of measuring and analyzing cardiometabolic indicators is associated with various forms of physical activity with varying intensity and duration. We also state that the moderator of this compound is the BMI indicators and how the undertaken physical activity affects them, allowing noticeable changes in, among others, cholesterol and glucose levels. In addition, types of physical activity have a diverse impact on BMI.

The problem of childhood obesity is constantly increasing. It is important to try to counteract this. Therefore, the present study is based on an analysis of current studies that indicate the impact of activities among children with normal body weight and obesity on their cardiovascular health, as well as body weight, BMI, and biochemical parameters of the blood. To increase the understanding of childhood obesity and its importance in the relationship between physical activity and cardiometabolic indicators, the conceptual framework that guided the study is presented in Figure 1.

The initial information forms the basis for the next parts of the article, in which the integration review method, detailed rules for its implementation, characterized results of tests qualified for basic analysis, as well as discussion, conclusions, limitations and gaps, broader context, and recommendations for future research will be presented.

Material and Methods

To comprehensively understand the analyzed problem, an integrative review was conducted. The integrative review method allows for combining data from both theoretical and empirical literature, and takes into account the results obtained during studies based on various research projects [48–50]. The use of different data sources enable us to specifying current knowledge on a certain subject and contribute to the holistic understanding of the research subject [50] through identifying, analyzing, and synthesizing the results of independent studies [49].

The review was based on an integrative review framework developed by Whittemore and Knafl [48], made up of 5 stages: problem identification, literature search, data evaluation, data analysis, and the presentation of results [48]. The integrative review begins with a description of the problem, which is addressed in the review, as well as with a definition of the purpose of the review [48]. At this stage, it is important to consider the concept, target population, healthcare problem, and types of empirical research. In the next stage, the literature necessary for a deeper understanding of the problem was searched, having regard for a variety of bibliographical databases and the table of contents review of journals containing publications about a given subject [48]. Subsequently, data obtained from several publications and literature were evaluated in terms of methodological quality. Whittemore and Knafl propose the coding of sources in terms of methodological or theoretical rigor, along with the usefulness of data on a 2-point scale (high or low) [48]. The findings relevant for the review should be distinguished from the reports obtained at a later stage. The results are compared and synthesized, whereas at the final stage they are presented with the conclusions. To draw conclusions, the results should be synthesized. The conclusions of the integration reviews can be presented in the form of a table or scheme. By providing clear evidence to support the conclusions, a logical chain of evidence is created, which allows the reader to make sure that the conclusions of the review do not go beyond evidence [48].

The quality assessment was carried out by the lead author, and the results were discussed with two other investigators who had experience with the review methodology. Discrepancies between authors were resolved during discussions. The summary and content of the article were re-analyzed, so that the authors could exchange comments with each other. Critical evaluation of the studies considered issues such as the compatibility of the study design with its research objective, the risk of bias, if applicable, the quality of reporting, generalizability, and possible repeatability. The different types of studies required the application of separate criteria for each of them. Critically evaluated studies were classified as strong and moderately strong. There were no studies that were assessed as weak. The review mainly qualified articles with significant or moderate methodological quality; however, several works with lower percentages (50–58%) were separated. The authors of the review thus wanted to ensure high reliability of the results and final conclusions.

Electronic databases, including PubMed, Scopus, Web of Science and EBSCO, were searched in accordance with the guidelines of Preferred Reporting Items for Systematic Review and Meta Analyses (PRISMA). During searching for keywords, there should be a balance between a search that will be comprehensive enough to cover everything about the theme defined in the research question, and precise enough to capture only these results that are particularly important. The presented project used Medical Subject Headings (MeSH), which is a thesaurus of the controlled vocabulary of the National Library of Medicine, used to index articles in the MEDLINE®/PubMed MeSH database. The search used a combination of the MeSH terms (or equivalents) and the following keywords: “physical activity”, “children”, “BMI”, and “cardiometabolic indicators”, which were connected by the Boolean operators “and” and “or”. The criteria for the inclusion and exclusion of articles are shown in Table 2.

We used Rayyan software to review and select the publications [51], which is a tool designed for conducting literature reviews. Articles were verified independently by two authors (MG & AF), and any discrepancies were discussed. The selection of articles for the analysis lasted a total of 2747 min (110 sessions). During the review, various types of research were identified, such as randomized control studies, quasi-experimental studies, case series, and cohort studies; hence, the we assessed the methodological quality by using the following check-lists: Critical Appraisal of a Meta-analysis or Systematic Review (Center of Evidence-Based Management, CEBMa), Critical Appraisal of a Cross-Sectional Study (survey, CEBMa), Critical Appraisal of a Cohort or Panel Study (CEBMa), Randomized Controlled Trial Standard Checklist (Critical Appraisal Skills Programme, Critical Appraisal Check-list for Quasi-Experimental Studies (non-randomized experimental studies) (Joanna Briggs Institute), and Critical Appraisal Checklist for Case Series (Joanna Briggs Institute). Based on the points obtained from individual check-lists, methodological quality was presented in the form of a percentage assessment. The selection of checklists was guided by the theoretical assumptions of David Sackett as the basis for their preparation, along with the experience of the team of the developing institution (ie, Oxford CEBM, Joanna Briggs Institute), clarity of detailed criteria, and their adequacy to the type of scientific evidence assessed. Furthermore, the option of free access to check-lists was recognized as a criterion.

We prepared special timetable to show the process of making an integrative review (each stage has a date assigned; Figure 2).

The assessment of methodological quality was determined using recognised checklist criteria, to help to determine the confidence with which the study results could be interpreted in the synthesis of this review. The minimum threshold to qualify a publication for further analysis was 50% of the possible points, although most of the qualified publications are studies of higher methodological quality. It should be noted, however, that these figures are intended only to illustrate the comparative quality of the articles, recognizing that items do not necessarily carry equal weight and are prone to subjectivity. In summary, strengths of all articles included clear aims and rationale for the research, rigorous analysis of the data appropriate to its quality, often involving multiple analysts, and discussion of results based on empirical findings. A major weakness of the studies was the underrepresentation of designs with a blinded control group.

Assessment of the reliability of the sources was made during analysis of the full texts of the articles, particularly when there were discrepancies in their assessment (MG, AF). In determining the final consensus on the eligibility of publications for analysis, the following were considered: the authors’ qualifications to present the information, whether the source of the data was peer-reviewed, and whether the information was subject to risk of error.

Results

A preliminary search yielded 1874 records, 856 of which were duplicates. The results came from 4 databases: PubMed (253 articles), Scopus (476 articles), Web of Science (552 articles), and EBSCO (593 articles). The database of articles was not complemented with manual searches. After further analysis of 1018 records, 673 summaries and articles were excluded, including 514 irrelevant articles, as well as 103 articles that were removed because of wrong research group, 44 articles due to the lack of full text, and 12 articles owing to more than 10 years from publication. Authors during the first selection were based on titles and abstracts. Moreover, at a subsequent stage, whole articles were read. Finally, the subject of the analysis was a total of 345 articles, and 55 articles were included in the review. The schedule for the selection of records and articles according to PRISMA [52] is shown in Figure 3.

Among the qualified articles, 20 concerned cross-sectional studies; 10 were clinical trials; 6, randomized clinical trials (RCT); 3, multicenter clinical trials; 5, cohort studies; 3, systematic reviews; 3, meta-analyses; 2, longitudinal studies; 1, a quasi-experimental study; 1, a pilot study; 1, a feasibility study; 1, a latent profile analysis; and 1, a comparative study.

The type of study has an important impact on the results and their interpretation. Among the primary studies, the most valuable results were those from a RCT, which demonstrate the effect of an experimental agent under controlled conditions over a specified period of time. Of the studies selected for review, 19 out of 55 are based on RCT methodology. The study of processes (eg, of illness or recovery) was possible from a prospective perspective, which was ensured by cohort studies, longitudinal studies, which account for 5 out of 55 papers analyzed. Retrospective studies based on the recollection of circumstances and events by the respondents have a higher risk of error, accounting for 2 studies out of 55 analyzed. Cross-sectional studies make it possible to assess the state of affairs at a given point in time and, depending on the methods used to evaluate variables (objective, subjective) and the methods used to qualify people for the study, the results are of varying value. A number of cross-sectional surveys can be used to make inferences about a process, but this is not the same as continuous surveys. This type of outcome dominates (20 out of 55) in this integrative review. The results of studies based on the opinions of respondents require very careful interpretations.

The results of secondary studies, namely, systematic reviews and especially meta-analyses, are a source of integrated knowledge with the highest probability of being consistent with reality. This type of study accounts for 6 of the 55 papers included in the integrative review. In summary, this paper considers the type of studies whose results provide a moderate to high level of credibility [53].

The results of the analyzed research came from 29 countries: Spain (8), USA (8), Brazil (7), United Kingdom (4), Germany (4), Greece (4), Italy (4), Iran (3), Australia (3), Chile (3), Hungary (3), Poland (2), Sweden (2), Norway (2), Austria (2), Canada (2), South Africa (2), Nigeria (1), Ghana (1), Egypt (1), Netherlands (1), Belgium (1), France (1), Serbia (1), New Zealand (1), Turkey (1), Portugal (1), Romania (1), and Japan (1). More than half of the studies analyzed (35/55) were conducted in Europe, indicating a metabolic direction in the empirical search to exemplify selected health behaviors. On the other hand, the wide geographical distribution of the studies allows for a greater diversity of results, including the consideration of many factors related to physical activity, such as cultural or economic factors.

The analysis and synthesis of the empirical information contained in the articles shortlisted for the review was based on the approach described by Thomas and Harden [54]. The thematic synthesis performed by the author of the article (DZ) who had not previously participated in the literature review involved coding “line by line” information related to the research question posed earlier. Subsequently, the extracted key information was combined into related topic areas that were unique to the baseline content, but were within the defined scope of the review, namely, relationships between physical activity (or lack thereof), forms of physical activity, and cardiometabolic factors in relation to the obese child population. To minimize bias, the authors MG and AF met to discuss the proposed themes of the detailed synthesis of the information contained in the 55 articles, and the reliability, accuracy, and relevance of the information qualified for the final analysis was assessed. An iterative process was used to reach consensus on the final synthesis sub-themes. Another author (DZ) independently extracted and reviewed data from 5 randomly selected studies to ensure consistency with the primary studies. DZ also blindly assessed the fit between the baseline content and the unique directions extracted. There was 100% agreement.

The present integrative review looked for an association between physical activity and cardiometabolic indices in children with obesity. The conducted analysis made it possible to capture many factors related to physical activity. The results of the cited studies were analyzed in terms of the topic of the paper, the method used, the reliability, the group size and age of the study participants, and the time of publication, defining, on the basis of the aforementioned thematic synthesis, the main relationships of physical activity and diet with cardiometabolic factors in children with obesity.

The present integrative review looked for an association between physical activity and cardiometabolic indices in children with obesity, which, to clarify the presentation of results, was included in a recommended question with a population, intervention, comparison, outcome (PICO) structure [55]. In other words, in children with obesity, how does physical activity versus no physical activity affect cardiometabolic indices? The conducted analysis made it possible to capture many factors related to physical activity:

Discussion

LIMITATIONS AND GAPS:

This integrative review has limitations due to the varying methodological quality of the included studies. Studies with a lack of blinding can be considered one of the main limitations among these studies, although this is quite common in non-pharmacological studies. Studies that include physical activity and no comparative intervention bring other relevant information regarding, for example, body weight, BMI, triglycerides, blood LDL-cholesterol and glucose, HbA1c, CRP, and HOMA-IR index. The demonstration of similar associations/relationships in selected articles provides data for the analysis of several components, even in a small sample. In our integrative review, several studies considering the relationship between physical activity and blood pressure were excluded, as they were ultimately considered not thematically relevant to the topic at hand. In addition, children and adolescents were included regardless of baseline BMI or the way physical activity was measured, which may have a distracting effect on the results of studies classified for analysis.

This integrative review also has strengths, which are worth mentioning. The process of selecting articles was done according to strict criteria, taking into account different types of studies, in order to be sensitive to preliminary research reports carried out in a less strong research protocol. In addition, the issue under consideration is part of a contemporary world health problem: the growing phenomenon of child and adolescent obesity and its significant health consequences. In the future, funding and infrastructure for the development of organized and spontaneous physical activity should be provided at the national and supranational level, beyond the narrow scope of sports policies. Broad and personally targeted promotion of daily physical activity with reference to scientific research demonstrating the importance of AP for health and well-being is needed. In addition, it seems necessary to develop a strategy at a global level to return to pre-pandemic activity, taking into account the stigma left by the pandemic on children and adolescents.

BROADER CONTEXT:

Evidence-based knowledge of the impact of physical activity on individual health [84], as well as understanding of its impact on public health [85–87] has increased recently. Evidence is emerging to suggest that participation in physical activity can have benefits beyond physical health [88]. However, among child and adolescent populations, there is a global epidemic of insufficient physical activity [89,90] and obesity [91], further exacerbated by the effects of the COVID-19 pandemic [92]. Given the importance of physical activity for physical as well as mental health, and the emerging evidence that exercise can have beneficial outcomes for many diseases including COVID-19, it is recommended that governments be more involved in promoting ways to increase physical activity and reduce sedentary behavior, and to consider the broad context of epidemiological restriction decisions [93].

Participation in organized team and individual physical activity plays an important role, primarily in supporting vigorous physical activity, but also in community-wide physical activity among children. The negative effects of pandemics should be mitigated by increasing the participation of young people in various forms of organized physical activity, with an emphasis on structured individual physical activity [94], revitalizing supportive peer relationships, increasing motivation for physical activity through its attractiveness, flexibility regarding place and time of implementation, and increasing recreational infrastructure in the immediate environment [95], or implementing the use of family-based behavioral interventions [96].

RECOMMENDATIONS FOR FUTURE RESEARCH:

The integrative review showed the need for a standardized scheme based on measurable indicators to monitor the effectiveness of physical activity promotion programs. We should continuously search for new, specific, and highly differentiated laboratory markers indicating the impact of physical activity on cardiovascular function, the endocrine system, or the well-being of children and adolescents. It also seems reasonable and cognitively quite intriguing to search for cultural [97] and genetic influences on physical activity and health consequences in children.

Conclusions

Healthy behaviors undertaken in childhood are essential for the improvement of physical fitness, bone condition, cardiometabolic health, cognitive performance, and mental health. Additionally, healthy habits are important in preventing chronic diseases in adulthood. The analysis of the thematic literature allowed for identifying factors related to physical activity. As presented, numerous studies describing the relationships between physical activity and cardiometabolic indicators, as well as overweight, require constant monitoring in the changing conditions of the socio-economic environment, as they have a profound impact on all spheres of human life and health.