Abstract
Background:
Multiple modifiable lifestyle factors are well-known contributors to many health problems.
Objectives:
This study aims to determine the association between latent class analysis (LCA) of modifiable lifestyle risk factors with being overweight and/or obese for children and/or adolescents.
Methods:
Articles were selected from six databases, without limitation regarding language or date. The review included studies that identify latent classes of modifiable lifestyle risk factors [e.g., physical activity (PA), diet, sedentary behavior (SB), and/or unhealthy behavior] by LCA to determine the association between latent classes with being overweight and/or obese. The methodology of the selected studies was evaluated using the JBI Critical Appraisal Checklist for Analytical Cross-Sectional Studies. Owing to the heterogeneity between latent classes of modifiable lifestyle risk factors with obesity and/or being overweight, the results are described narratively.
Results:
Using a selection process in two phases, nine articles were included. All of the included studies were of high methodological quality. The studies were conducted in six different countries: the USA, Brazil, Canada, Portugal, Italy, and Australia. Sample sizes ranged from 166 to 18.587 children and adolescents, and in terms of age (range 5–19 years). Across study clusters characterized by low consumption of fruit and vegetables, and high consumption of fatty foods, sugar snack foods, sweets, chips and fries, low PA (<1 hour each day), and high SB (screen time and TV >2 hours/day), sleep time (<10 hours/day) were positively associated with being overweight and/or obese.
Conclusion:
Overall there is good evidence to support that the modifiable lifestyle risk factors clustered together by LCA should be novel targets for the treatment of obesity and its associated comorbidities.
Introduction
Being overweight and/or obesity (Ow/Ob) among children and adolescents are major public health problems that have increased in prevalence in almost all countries since 1990,1,2 with the WHO reporting 41 million overweight children aged under five in 2016 worldwide. 3 Ow/Ob in childhood are predictors of the risk of obesity, morbidity, and mortality in adulthood4–7 and are associated with the development of various comorbidities 8 (e.g., dyslipidemia, nonalcoholic steatohepatitis, type 2 diabetes mellitus, obstructive sleep apnea, hypertension, and polycystic ovary syndrome), as well as psychosocial problems, including discrimination, social isolation, and low self-esteem, which can themselves affect health, education, and quality of life. 8
To prevent comorbidities and morbidity in adult life, it is necessary to intervene to reduce obesity 9 through the joint analysis of lifestyle behaviors and their interrelationships,10–13 especially physical activity (PA), sedentary lifestyles, and dietary behavior.1,14 Socioeconomic status, age, gender, ethnicity, sleep duration, depression, symptoms of anxiety, and behavioral problems should be taken into account,9,15,16 as they may be associated with the risk of developing obesity. In addition, parenting style and parental support, 17 low levels of parental education, 11 social inequality and gender differences, 18 types of friendships, adolescent sex, and race/ethnicity should also be considered. 19
Some statistical tools, such as cluster analysis (CA), factorial analysis, and latent class analysis (LCA), are used to classify lifestyle factors as more or less healthy.13,20 LCA has advantages over the other methods due to using an unobserved (latent) variable based on the responses of a set of observed variables (continuous, nominal, and ordinal), grouping homogeneous and mutually exclusive individuals (cases and units) into classes.13,21–25
LCA identifies the lowest number of latent classes and then associates the observed symptoms, for example, lifestyle factors, with behavioral patterns that exist within a heterogeneous population.26,27 The different health behaviors often cannot be directly measured; that is, they are latent variables and the LCA serves as an ideal analytical method because it takes into account the observable variables and the unobservable variables (latent), with the objective of identifying classes with homogeneous behaviors.
LCA has been used in several studies to explore modifiable lifestyle risk factors associated with being Ow/Ob, such as diet, PA, substance use, sexual behavior, stress, sleep,23,28 neurocognitive processes associated with self-regulation, decision-making, goal-directed behavior, 29 and asthma phenotypes. 30 LCA has been used with other modifiable lifestyle risk factors, such as alcohol use, 31 risk factors for suicide,23,27,28 and impulsivity, anxiety, depression, drug use, and alcohol dependence. 32
Thus, knowledge of lifestyle risk factors through LCA is relevant, as it can indicate whether the risk factors together have synergistic effects and can negatively affect health, thereby supporting preventive health interventions. LCA can also be part of implementing strategies that will maximize the impact of public health. 22 We hypothesized (1) that LCA would identify at least one pattern characterized by obesogenic behaviors (unhealthy food, physical inactivity, or a sedentary lifestyle) and (2) that these isolated or clustered patterns may be associated with the development of Ow/Ob in children and adolescents.
Therefore, the aim of this study was to identify latent classes of obesogenic behaviors in children/adolescents based on the clustering of the modifiable lifestyle risk factors of PA, diet, sedentary behavior and/or unhealthy behavior (SB/UB), and then determine the association between these latent classes and Ow/Ob.
Methods
Protocol and Registration
This systematic review was reported following the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) checklist. 33 The protocol underpinning this review is available through the PROSPERO database (see registration no. CRD42019132083).
Eligibility Criteria
Inclusion criteria
For inclusion, studies had to meet the following requirements:
Study design: Nonexperimental designs (observational, cohort studies, surveys, cross-sectional, and longitudinal) were considered. Population: Studies with samples of children aged <11 years, and/or adolescents aged 12–18 years (or a mean within these ranges) at baseline were included. Information was reported by the children/adolescents aged >12 years or their parents, mother–child pairs, participating families, or parents or caregivers of children <12 years. Comparison: Studies could target multiple behaviors in any combination. Language and date: Studies that were published in any language or date were considered. Types of measurement tools: Studies that identified latent classes of modifiable lifestyle risk factors (e.g., diet, PA, and SB/UB) by LCA and estimation [item-response probabilities, greater likelihood >0.50, or probability (%)].
34
Outcome: Primary outcomes: We included studies reporting LCA based on the clustering of modifiable lifestyle risk factors: diet, PA, and SB/UB. Secondary outcomes: We included studies that determined the association between latent classes with Ow/Ob. Variety of obesity measures: body weight status was determined using age- and gender-specific BMI percentiles (Ow BMI ≥85th percentile to 95th percentiles, Ob 95th percentile), BMI z-scores, BMI standard deviation scores (SDSs) (Ow one standard deviation above the average and Ob two standard deviations above the average), BMI cut-off points. BMI was calculated as weight in kilogram divided by the square of height in meters (BMI = weight (kg)/(height (meter))
2
).
35
The primary criteria used to define being Ow/Ob include overweight: BMI ≥85th percentile to 95th percentile, BMI = one standard deviation above the average; obesity: BMI = 95th percentile, BMI = two standard deviations above the average, and considered overweight if their BMI z-score was between the 85th and 95th percentile and obese if their BMI z-score was above the 95th percentile. 35
Supplementary Appendix Table SA1 contains modifiable lifestyle risk factors, variables, used as the latent class indicators.
Exclusion criteria
Experimental designs (e.g., randomized controlled trial [RCT], interrupted time series, and pretest–post-test)
Studies with samples consisting of adults, elderly, pregnant, and nonhealthy subjects (people with type 2 diabetes, hypertension patients, and eating disorders)
Studies that do not use the LCA based on the clustering of modifiable lifestyle risk factors: diet, PA, and SB/UB
Studies that do not use the LCA and do not use estimation [item-response probabilities, greater likelihood >0.50, or probability (%)]
Studies that do not correlate modifiable lifestyle risk factors with obesity parameters
Studies that do not identify at least three latent classes of modifiable obesogenic behaviors in lifestyle risk factors diet, PA, and SB/UB.
Supplementary Appendix Table SA2 contains the articles excluded and the reasons for exclusion.
Information Sources and Search Strategy
Detailed individual search strategies for each of the following electronic databases were performed: Cochrane Library, Lilacs, Eric, Livivo, Pubmed/Medline, and Social Care Online databases. We performed a gray literature search on Google Scholar. In addition to the electronic search, a hand search was made, and reference lists of the selected articles were screened.
Search terms and Boolean operators with the list of medical subject headings (MeSH), keywords, and/or other controlled vocabulary terms used in searches of the PubMed and the other electronic databases were used. Database-specific search terms included the keywords “latent class analysis,” “obesity,” “childhood,” “children,” “adolescents,” “diet,” and relevant synonyms. All electronic searches were conducted from their earliest records up to March 1, 2019 and updated until May 1, 2019.
Supplementary Appendix Table SA3 contains the search terms, search strategy, and databases.
Study Selection
We selected the articles in two phases. In phase l, two authors (R.L. and F.D.C.) independently reviewed the titles and abstracts for all of the references. During this phase, any articles that did not meet the eligibility criteria described earlier in the inclusion and exclusion criteria section were excluded. In phase 2, they applied the same selection criteria to the full text of the articles to determine which ones to include. The same two authors independently reviewed all full-text articles. When they needed help making a final decision, a third author (E.K. or M.A.A.A.) participated in the review process. Supplementary Appendix Table SA2 contains the articles excluded and the reasons for exclusion.
Data Collection Process and Data Items
Two authors (R.L., F.D.C.) extracted data from the selected studies, including author, year of publication, location, and information reported; population, sample size characteristics (boys, girls, and total), and weight status prevalence; LCA based on the clustering of modifiable lifestyle risk factors; findings variables (latent class indicators) and main conclusion. A third author (E.K.) cross-checked all the retrieved information.
Risk of Bias in Individual Studies
Risk of bias in individual studies included articles was conducted by the JBI-MAStARI (JBI Critical Appraisal Checklist for Analytical Cross-Sectional Studies). The questionnaire consists of eight questions that were answered with yes, no, unclear, or not applicable. 36 In the JBI-MAStARI, two criteria listed in the instrument were deemed irrelevant to the nature of the studies. We classified the studies as follows: high methodological quality (>5 times a score of “yes”), moderate methodological quality (3–4 times a score of “yes”), or low methodological quality (0–2 times a score of “yes”). 37 Supplementary Appendix Table SA4 contains the risk of bias of the selected studies by JBI-MAStARI.
Summary Measures
We considered as outcome of the association modifiable lifestyle risk factors (diet, PA, and SB/UB) identified by LCA and association with Ow/Ob. Variables used as the latent class indicators, identified by item-response probabilities.
Synthesis of Results
Owing to heterogeneity relating between assessment of associations of modifiable lifestyle risk factors (diet, PA, and SB/UB) and BMI, it was not possible to perform a meta-analysis, and thus results are described narratively. It was not possible to assess publication bias through funnel plots, as no statistical data synthesis could be performed.
Results
Study Selection
Of the 1114 identified articles, 9 were included and the results from these studies were weighted. A flowchart of the process of study identification and selection is shown in Figure 1.

Flowchart of the literature search and selection criteria.
Study Characteristics
All the studies were published between 2011 and 2019. No language restriction was set, although all the articles included were published in English. The studies collected information on modifiable lifestyle risk factors from children, adolescents, and their parents.
The studies were conducted in six different countries, with the majority being from North and South America (USA,38,40–42 Brazil, 46 and Canada 44 ), two from Europe (Portugal 43 and Italy 45 ) and one from Australia. 39
Sample sizes ranged from 16642 to 18,58744 children and adolescents. With the exception of one study 39 that included children aged 6–7 years, the ages of the children and adolescents in these studies ranged from 5 to 19 years. The sample sizes were moderate to large, with one study using a sample of <500, 42 four studies using samples between 500 and 1000,38,41,43,45 and four studies including >1000 participants.39,40,44,46
The total sample from the nine selected studies included 38,512 children and adolescents (19,419 boys and 19,093 girls). The samples of eight studies comprised boys and girls, and one study exclusively consisted of girls. 42 The total sample of the American countries was n = 35,111,38,40–42,44,46 of the European countries was n = 1569,43,45 and n = 1832 for Australia. 39 A summary of the descriptive characteristics of the included studies is provided in Table 1.
Summary of the Characteristics of the Included Studies
BMI was computed using the standard formula [body mass (kg)/height (m) 2 ]. Height and weight were self-reported and used to calculate BMI (kg/m2). Overweight and obesity were defined at cutpoints of 25 and 30 kg/m2, respectively. Or children were classified as overweight if their BMI z-score was between the 85th–95th percentile and obese if their BMI z-score was above the 95th percentile.
SB = board games, playing with dolls, playing with toy cars, watching TV, listening to music, using smartphone/tablet, using computer, play videogames.
HF/HS snacks, high-fat and/or high-sugar snacking; LCA, latent classes analysis; Ow/Ob, overweight and/or obesity; PA, physical activity; SA, screen-based sedentary activities self-reports; SB/UB, sedentary behavior and/or unhealthy behavior.
Brief food frequency questionnaires38,40,43 were among the most commonly used methods to assess individual long-term dietary intake of foods and nutrients in the studies. These are appropriate for investigating dietary patterns on the basis of frequencies. Dietary intake data were most commonly collected using a one 24-hour, 39 questions adapted from the CDC's, 41 24 hours-Drecall—3, 42 Canada's Food Guide serving sizes, 44 ASSO-FHQ (Food Habits Questionnaire), 45 and Web-CAAFE (Food Intake and Physical Activity of Schoolchildren). 46
The type, duration, and frequency of the PA intervention varied among the studies. Studies focused on daily hard activities lasting >30 or ±60 minutes per day,38–41,43–46 traditional sports, 38 fitness activities and other sports, 45 physical activities, varsity sports, and intramural. 44 Of these, studies used an objective measure: Questions adapted from CDC's,38,40,41 Australian guidelines, 39 moderate to vigorous physical activity (MVPA) daily recommendations, 43 Canada's Physical Activity Guidelines for Children and Youth, 44 ASSO-PASAQ (Physical Activity, Smoke, and Alcohol Questionnaire) 45 and Web-CAAFE. 46
Studies used an objective measure for SB/UB: The American Academy of Pediatrics (AAP),38,40 Australian guidelines, 39 Questions adapted from the CDC,41,42 Recommendations by the National Sleep Foundation and screen time by questionnaire, 43 Canadian Sedentary Behaviour Guidelines, 44 ASSO-PASAQ, 45 and Web-CAAFE. 46
Supplementary Appendix Table SA5 contains the methods to assess PA, diet, and SB/UB.
Primary Outcome: LCA Based on the Clustering of Modifiable Lifestyle Risk Factors (Diet, PA, and SB/UB)
Table 1 presents the nine studies that examined the relationships among modifiable lifestyle risk factors derived from LCA.
LCA involves testing sequential models to identify the optimal number of latent classes 39 (Supplementary Appendix Table SA6). The number of clusters from LCA observed across the studies varied among two, 43 three,39–41,46 four,42,44 and five.66,73
All the studies examined associations between modifiable lifestyle risk factor outcomes for boys and girls combined, whereas one examined the association between PA and SB separately for boys and girls. 46
Diet correlates of clusters
All the studies indicated the frequency with which each child or adolescent consumed several different types of foods per day (≥daily consumption).
Dietary behavior (what the children or adolescents consumed) was measured: in Australia 39 (consumption of fruits and vegetables, high-fat food, and high-sugar drinks); in Portugal 43 (consumption of fruits and vegetables); in Italy 45 (inadequate meals and inadequate food habits); in Canada 44 (consumption of fast food, breakfast, snacks, and sugar); in Brazil 46 (consumption of beans, pizza/hamburgers/hot dogs, maize/potatoes/breakfast cereals, cheese bread, fries/nuggets, and sugar/candies/chocolate/lollipops/ice cream; in the USA38,40–42 (consumption of fruits and vegetables, fatty foods, sugar/sweets, fries/chips, and breakfast).
Six studies analyzed the consumption of fruit and vegetables designated: Healthy eating, 38 Healthy,39,40 Healthy dietary behaviour, 41 Lifestyle, dieting and extreme dieting 42 and better diet quality. 43 The practice of eating breakfast every day was analyzed in two studies and the classes named were healthy dietary behaviour 41 and health conscious. 44
The classes designated: high-sedentary, high-fat and/or high-sugar snacks, not weight conscious, 38 sedentary, 39 unhealthy eaters, 39 unhealthful, 40 nondieters, 42 traditional school athletes, 44 inactive screenagers, 44 and mixed 46 involved the increased consumption of obesogenic foods, including intake of snacks, sweets, junk food, fast food, chips, candies, chocolate, ice cream, pizza, hamburgers, hot dogs, salty high-fat snack foods, high-sugar snack foods, and sugary drinks, among others.
PA correlates of clusters
All the studies indicated the frequency with each children or adolescents engaged in at least one kind of exercise, PA, participated on a sports team, varsity sport, or intramural activities per day.
PA was measured (whether the children or adolescents engaged in at least the following): in Australia 39 (one PA per day); in Portugal and in Italy: (moderate PA each day,43,45 and participated on at least one sports team 39 ); in USA, Brazil, and Canada: (practiced PA each day,38–42,44,46 participated in intramural activities, 44 varsity sports, 44 participated on at least one sports team,38,41 and performed strength training at least three times per week 39 ).
The classes designated: active, 38 healthy, 39 healthful, 40 healthy, 41 and lifestyle 42 involved 1- and 2-hour physical activities per day, and 4 or more days per week. And the classes designated: high-sedentary, 38 sedentary, 39 typical, 41 unhealthy PA, 42 sedentary and insufficiently active, 71 involved <1 hour PA each day.
SB/UB correlates of clusters
All the studies indicated the number of hours each children or adolescent spent in SB/UB per day. SB/UB included analysis by (1) weight perception, related behaviors, weight-loss behavior 44 ; (2) screen time/watching/streaming TV38–41,43–46; (3) playing video or computer games40,46; (4) using the internet/computer (surfing the internet) 44 ; (5) sleep time43–45 ; (6) use of laxatives/enemas, diuretics, diet pills, or appetite suppressants, smoking cigarettes, tobacco, marijuana use, or self-induced vomiting 42 ; (7) listening to music, using smartphone/tablet. 46
Secondary Outcome: Association between Modifiable Lifestyle Risk Factors with Childhood Ow/Ob Risk
Table 1 summarizes the nine studies identified that have examined associations between the cluster of modifiable lifestyle risk factors and weight status or BMI.
In all the studies, children and adolescents were classified as Ow/Ob according to the BMI cutoff points,43,44 BMI z-score, 46 or BMI percentiles.38,40–42,45 The total sample of the nine selected studies included 38,512 children and adolescents: 27,069 (70.28%) classified as normal and 11,443 (29.72%) as Ow/Ob.
Across five study clusters characterized by low consumption of fruit and vegetables38–41,43 and high consumption of fatty foods, sugary snack foods, sweets, chips and fries,38–40 low PA (<1 hour each day)38–41,43 and high SB/UB (screen time and TV >2 hours/day),38–41,43 and sleep time (<10 hours/day) 43 were positively associated with Ow/Ob.
In the study by Balantekin et al., 42 the greatest percentage of girls with Ow/Ob (38%) were found in the cluster “Extreme Dieters,” with these being more likely to report attempting to reduce weight, dieting (eliminating snacking, sweets, and junk foods and reducing calories and the amount of food), increased exercise and unhealthy behaviors (use of laxatives/enemas, diuretics, diet pills, or appetite suppressants, smoking cigarettes, or self-induced vomiting).
In two studies, unhealthy lifestyles were positively associated with Ow/Ob, as well as alcohol use44,45 and tobacco, 45 marijuana use, 45 more SB (>2 hours/day watching TV44,45 and surfing the internet 45 ) and unhealthy eating (inadequate meals and food habits 45 and the consumption fast food and snacks 44 ).
Risk of Bias in Individual Studies
All studies presented high quality based on the tool JBI-MAStARI (Supplementary Appendix Table SA4).
Discussion
The results of this review indicate that the risk for Ow/Ob in children and adolescents can be influenced by the grouping of obesogenic behaviors (diet, PA, and SB/UB) and that the clusters presented in the studies, however distinct and complex, demonstrated the occurrence of healthy and unhealthy behaviors.
Ow/Ob is defined as the imbalance between energy intake and energy expenditure and apparently arises from the complex interaction of hereditary, social, socioeconomic, and, mainly, behavioral factors.47,48 Although genetic factors have an influence on body weight, it is believed that behavioral factors, such as dietary factors, decreased PA, and increased sedentary leisure time, affect the early development of Ow/Ob.48,49
Therefore, it was decided to synthesize the studies that analyzed these modifiable lifestyle risk factors according to more important and modifiable determinants for the control of obesity and chronic diseases 50 (diet, PA, and SB/UB) using LCA, since this statistic is used to identify subgroups of children and adolescents with different patterns of health-related risk behaviors 2 and the risk of developing Ow/Ob.
LCA is preferred in studies that include heterogeneous populations because it can identify the source of heterogeneity 51 and it allows the joint analysis of many variables, 2 thus allowing it to identify similar patterns of responses, classifying homogeneous subgroups with similar characteristics of behaviors. 52
Different studies may give the same name to a dietary pattern, although this does not mean that the variates observed in these patterns were the same. There are possible variations due to the heterogeneity and specificity of the population (such as geographic, economic, and cultural characteristics), although several similarities could be observed. 53
In this review, the studies in the table demonstrated that independent of the name given to the clusters, the main characteristics of obesogenic risk behaviors were low weekly consumption of fruit and vegetables,38–41,43 high consumption of fatty food, sugary snack foods, sweets, chips and fries,38–40 low PA (<1 hour each day),38–41,43 high SB [screen time and TV (2+ hours/day)],38–40,43 and reduced sleep time (<10 hours/day). 43 These were positively associated with Ow/Ob.
In relation to diet, the results of this review are consistent with the worldwide trend toward Ow/Ob risk, with reports of a higher frequency of consuming obesogenic foods (rich in lipids, carbohydrates, bakery products, of animal origin, soft drinks, and sweets) and reduced consumption of fruits and vegetables, as highlighted by the WHO. 54
Studies carried out in several countries show the same trend of increasing consumption of potentially obesogenic foods (rich in sugar, such as breads, cakes, and cookies) by children and adolescents, for example, in the USA,28,55 Brazil, 56 Mexico, 57 and European countries (regions in Italy, Estonia, Cyprus, Belgium, Sweden, Hungary, Germany, and Spain).15,58
Food choices associated with increased Ow/Ob risk may be affected by a number of factors. A study conducted in the USA by French et al. 59 and another in China, Indonesia, Malaysia, and South Korea by Kelly et al. 60 indicate that television contributes to higher energy intake or increased dietary fat because food advertising is predominately related to fast food or convenience foods, most often sugary drinks, with low advertising rates for vegetables and fruits.
Cairns et al. 61 concluded that the predominant advertising presence for food and beverages of low nutritional value for children occurs in both developed and low-income countries. Skidmore et al. 62 emphasized that food choice is often affected by the distance and type of food establishments available, and Wang et al. 63 report that living in areas of low socioeconomic status leads to less access to supermarkets, resulting in the consumption of less healthy food.
In relation to PA, the results of this review showed that, in addition to an obesogenic diet, the prevalence of obesity was higher in the groups that presented PA (<1 hour each day) lower than the levels recommended by the WHO in 2019, 64 which recommends the practice of 60 minutes daily of MVPA for children and adolescents. PA level is likely determined by a complex mixture of biological, social, cultural, and environmental factors. 65
PA has several long-term benefits, with Janz et al. 66 and Baxter-Jones et al. 67 reporting that the practice of PA in childhood promoted positive effects on bone mineral density in adulthood. However, especially when performed with moderate to vigorous intensity, PA is favorably associated with multiple health indicators, 68 a greater effect on reducing cardiac risk and decreasing adiposity through BMI. 69 Dorling et al. 70 indicated that PA presented greater efficacy when combined with dietary interventions, as exercise has effects on the regulation of appetite.
Noonan et al. 71 highlighted in their study that a way to encourage the regular practice of PA would be through school activities and social activities oriented around the family, as parents can help promote these healthy behaviors. DeWeese et al. 28 reported that, in addition to access to public and private recreational environments, such as parks or gyms for leisure activities, urbanization should also be effective in facilitating active transportation for individuals and thus affect eating and PA behaviors.
Considering SB, the results of this review showed that, in addition to an obesogenic diet and a low level of PA, the prevalence of obesity was higher in groups that presented SB [screen time—such as computer use, video games, and viewing other electronic media and TV (2+ hours/day)]. SB can be conceptualized as behavior that is distinct from any level of PA, with mild and moderate intensities that include sitting, lying down, watching television, and other forms of entertainment based on screen time 72 and characterized by an energy expenditure of ≤1.5 METS in a seated or reclined posture. 73
Currently, children and adolescents have easy access to SB in their leisure time, especially TV viewing and electronic games, with more time spent in SB leading to less time spent in PA. 74 Wu et al. 75 concluded in their review that a higher frequency of PA or less SB equates to better health-related quality of life and a lower percentage of Ow/Ob. 76
SB may be dependent on culture, socioeconomic status, and/or lifestyle. Cui et al. 77 showed that Chinese children whose parents set rules for watching TV were less likely to be TV users. In contrast, it was also shown that easy access to TV, such as a TV in the bedroom, internet at home or in cyber cafes, or often watching TV with parents, were all associated with a higher probability of presenting SB (≥2 hours/day). 77 Janssen et al. 78 concluded that, from 7 to 15 years old, this SB tends to increase with age, so that by 15 years of age, typical sedentary time exceeded 75% of the waking day.
Current studies in several countries show the same tendency for SB. For example, regarding Japanese children, Ishii et al. 74 highlighted that on weekdays and weekends, children spent the most time watching TV, followed by online games. The study of Velde et al. 79 showed the same tendency in nine European countries (Austria, Belgium, Denmark, Iceland, the Netherlands, Norway, Portugal, Spain, and Sweden). The study from Biddle et al. 80 showed the same for Scottish adolescents, for whom television occupied the greatest amount of leisure time.
To reduce screen time and promote interactive games, the AAP 81 recommends (1) limiting screen time for children <2 years of age; (2) limiting the total amount of entertainment screen time to 1–2 hours a day; (3) not watching TV during meals; (4) not putting a TV in the bedroom; (5) daily interactive play for children, ideally with parental involvement; and (6) monitoring the media that children are using and accessing, including any sites they visit and social media sites that they may be using.
The results of this review showed that there are some UBs, such as the use of laxatives/enemas, diuretics, self-induced vomiting, diet pills, appetite suppressants, smoking cigarettes, binge drinking, and excessive sleep time, which are associated with the prevalence of Ow/Ob.
Over the previous 5 years, new technologies and easy access to them have contributed to a rapid increase in average screen-time exposure for children and adolescents. 82 Studies highlight that the longer children and adolescents spend in screen time (TV/videogame time) daily, the greater the sleep problems they may develop, such as, shorter sleep duration, with consequences on working memory and emotional control, 83 sleep efficiency, and verbal cognitive performance, 84 as well as behavioral health problems. 82
In this review, the studies of Pereira et al. 43 and Magee et al. 39 associated the risk of Ow/Ob with sleep time (<10 hours/day). These data are consistent with systematic reviews that point to a positive association between screen time (TV/video game time) and sleep problems,85,86 with one of the consequences being sleep deprivation leading to fatigue, tiredness, and a greater propensity for SB and less PA. 87
Studies also show the association of cigarette smoking, and alcohol use, with the increased risk of obesity by adolescents, 88 alcohol, tobacco, and other drug use, with increased BMI 89 and, in the study by Liu et al., 90 alcohol use was significantly associated with increased BMI in adolescents, although they found no significant association between illicit drug use and BMI.
The ideal is the joint identification of several modifiable risk factors, comparing them with other risk factors in terms of possible health benefits, and taking into account the specific context of each country and age group. 91 The promotion of lifestyle modifications, including behavioral treatments, diet modification, and PA, can be the basis of primary/secondary prevention/treatment of pediatric obesity.64,92
Strengths and Limitations of Review
One of the main strengths of this review is its analysis of studies that used the grouping of diet, PA, SB/UB, and their associations with Ow/Ob in children and adolescents. From an extensive search in different databases and with previously defined inclusion criteria, potential studies were identified; however, as these studies were heterogeneous, it was not possible to perform a meta-analysis and, therefore, the results were narratively described.
Studies have explored risk factors for Ow/Ob alone (e.g., diet and PA)93,94; therefore, another strength of this review was the analysis considering the fact that obesogenic behaviors are not unique, with this joint analysis leading to a better understanding of which risk behaviors are the greatest predictors of Ow/Ob. This provides support so that future interventions can be adapted to these specific groups, considering behavioral differences.
Another aspect that sets this review apart is that some studies also examined other health behaviors, such as smoking or alcohol use and, particularly, sleep. Therefore, this review can provide important insights for the direction of public health initiatives aimed at combating obesity.
This review has several limitations. First, it is well known that the use of a cross-sectional design does not achieve the confidence level that meta-analyses of randomized clinical trials reach. Second, the studies did not take into account the differences of age and gender in the analysis of obesogenic behaviors. Finally, the studies included in this review were heterogeneous.
Conclusions: Implications for Future Research
This systematic review indicates that children and adolescents who adhere to dietary patterns composed of obesogenic foods are more likely to develop obesity, especially associated with low PA and excessive SB (especially screen time). It is suggested that to improve the understanding of modifiable lifestyle risk factors, future studies using LCA should use CA separately for age, gender, and environmental patterns, as this would provide more complete information for future interventions. Longitudinal studies could also be carried out, accompanying these children and adolescents to comprehend the changes in these obesogenic behaviors.
Footnotes
Authors' Contributions
All authors were involved in analyzing the studies, reviewing and interpreting the results, and writing the article.
Acknowledgment
We are grateful to the Postdoctoral National Program-Coordenação de Aperfeiçoamento de Pessoal de Nível Superior Coordination for the Improvement of Higher Education Personnel CAPES (PNPD/CAPES) (Programa Nacional de Pós Doutorado, PNPD-CAPES) that granted Rafaela Liberali a postdoctoral scholarship.
Funding Information
No funding was received for this article.
Author Disclosure Statement
No competing financial interests exist.
References
Supplementary Material
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