Correlates of childhood obesity in Athens, Greece

Prolonged screen watching behavior is associated with high blood pressure among children and adolescents: a systematic review and dose-response meta-analysis

BACKGROUND

Numerous cardio-metabolic risk factors influence screen-related behaviors in children and adolescents. Numerous studies with inconsistent results revealed a relationship between blood pressure and screen time in the children and adolescents. This systematic review and meta-analysis summarized the data regarding the relationship between screen time and hypertension (HTN) in children and adolescents.

METHODS

We examined three electronic databases, including Scopus, PubMed, and Embase to find the recent research on the relationship between screen time and HTN up to 19 July 2022. Twenty papers were included in the final two-class and dose-response meta-analysis. We conducted subgrouping to identify the source of heterogeneity.

RESULTS

The highest category of screen time increased the odds of HTN by 8% [odds ratio (OR): 1.15; 95% confidence interval (CI): 1.08, 1.23; P < 0.001; I2 = 83.20%] and 1.9 mmHg increase in systolic blood pressure [weighted mean difference (WMD): 1.89; 95% CI: 0.18-3.62; P = 0.030; I2 = 83.4]. However, there was no significant difference in diastolic blood pressure. Moreover, screen time in hypertensive children and adolescents was 0.79 h (47.4 min) higher than normotensive subjects (WMD: 0.79; 95% CI: 0.02, 1.56; P = 0.046; I2 = 92.8). A departure from linearity was observed between increased screen time [digital video discs, personal computers, and video games and HTN (Pnonlinearity = 0.049).

CONCLUSION

This systematic meta-analysis review is the first to demonstrate a positive correlation between screen time and HTN in children and adolescents.

Childhood obesity risk increases with increased screen time: a systematic review and dose-response meta-analysis

BACKGROUND

The role of screen time in promoting obesity among children has been reported in previous studies. However, the effects of different screen types and the dose-response association between screen time and obesity among children is not summarized yet. In the current meta-analysis we systematically summarized the association between obesity and screen time of different screen types in a dose-response analysis.

METHODS

A systematic search from Scopus, PubMed and Embase electronic databases was performed. Studies that evaluated the association between screen time and obesity up to September 2021 were retrieved. We included 45 individual studies that were drawn from nine qualified studies into meta-analysis.

RESULTS

The results of the two-class meta-analysis showed that those at the highest category of screen time were 1.2 times more likely to develop obesity [odds ratio (OR) = 1.21; confidence interval (CI) = 1.113, 1.317; I2 = 60.4%; P < 0.001). The results of subgrouping identified that setting, obesity status and age group were possible heterogeneity sources. No evidence of non-linear association between increased screen time and obesity risk among children was observed (P-nonlinearity = 0.310).

CONCLUSION

In the current systematic review and meta-analysis we revealed a positive association between screen time and obesity among children without any evidence of non-linear association. Due to the cross-sectional design of included studies, we suggest further studies with longitudinal or interventional design to better elucidate the observed associations.

Screen time increases overweight and obesity risk among adolescents: a systematic review and dose-response meta-analysis

Background

Adolescence is a critical period in human life, associated with reduced physical activity and increased sedentary behaviors. In this systematic review and dose-response meta-analysis, we evaluated the association between screen time and risk of overweight/obesity among adolescents.

Methods

A systematic search in electronic databases, including PubMed, Embase, and Scopus was performed up to September 2021. All published studies evaluating the association between screen time and risk of overweight/obesity among adolescents were retrieved. Finally, a total of 44 eligible studies were included in the meta-analysis.

Results

The results of the two-class meta-analysis showed that adolescents at the highest category of screen time were 1.27 times more likely to develop overweight/obesity (OR = 1.273; 95% CI = 1.166–1.390; P < 0.001; I-squared (variation in ES attributable to heterogeneity) = 82.1%). The results of subgrouping showed that continent and setting were the possible sources of heterogeneity. Moreover, no evidence of non-linear association between increased screen time and risk of overweight/obesity among adolescents was observed (P-nonlinearity = 0.311).

Conclusion

For the first time, the current systematic review and meta-analysis revealed a positive association between screen time and overweight/obesity among adolescents without any dose-response evidence.

Trial registration

The protocol of the current work has been registered in the PROSPERO system (Registration number: CRD42021233899).

Supplementary Information

The online version contains supplementary material available at 10.1186/s12875-022-01761-4.

Associations between meal and snack frequency and overweight and abdominal obesity in US children and adolescents from National Health and Nutrition Examination Survey (NHANES) 2003–2012

The association between eating frequency (EF) and adiposity in young populations is inconsistent. This cross-sectional study examined associations of EF, meal frequency (MF) and snack frequency (SF) with adiposity measures in US children aged 6–11 years (n 4346) and adolescents aged 12–19 years (n 6338) participating in the National Health and Nutrition Examination Survey 2003–2012. Using data from two 24-h dietary recalls, all eating occasions providing ≥210 kJ of energy were divided into meals or snacks based on contribution to energy intake (≥15 or <15 %), self-report and time (06.00–09.00, 12.00–14.00 and 17.00–20.00 hours or others). When analysed without adjustment for the ratio of reported energy intake:estimated energy requirement (EI:EER), all measures of EF, MF and SF showed inverse or null associations with overweight (BMI≥85th percentile of BMI-for-age) and abdominal obesity (waist circumference≥90th percentile) in both children and adolescents. After adjustment for EI:EER, however, EF and SF, but not MF, showed positive associations in children, irrespective of the definition of meals and snacks. In adolescents, after adjustment for EI:EER, positive associations were observed for EF (abdominal obesity only), SF based on energy contribution and MF based on self-report, whereas there was an inverse association between MF based on energy contribution and overweight. In conclusion, higher SF and EF, but not MF, were associated with higher risks of overweight and abdominal obesity in children, whereas associations varied in adolescents, depending on the definition of meals and snacks. Prospective studies are needed to establish the associations observed here.

Decreasing the number of small eating occasions (<15 % of total energy intake) regardless of the time of day may be important to improve diet quality but not adiposity: a cross-sectional study in British children and adolescents

Evidence of associations between meal frequency (MF) and snack frequency (SF) and diet and obesity in young populations is limited. This cross-sectional study examined MF and SF in relation to dietary intake and adiposity measures in British children aged 4-10 years (n 818) and adolescents aged 11-18 years (n 818). Based on data from a 7-d weighed dietary record, all eating occasions were divided into meals or snacks on the basis of contribution to energy intake (≥15 or <15 %) or time (06.00-10.00, 12.00-15.00 and 18.00-21.00 hours or others). All measures of MF and SF showed positive associations with energy intake, except for MF based on energy contribution in children. Irrespective of the definition of snacks, SF was associated with higher intakes of soft drinks, confectionery and total sugar, lower intakes of cereals, fish, meat, protein, PUFA, starch and dietary fibre, and a lower diet quality (assessed by the Mediterranean diet score, except for SF based on energy contribution in adolescents). MF based on time, but not based on energy contribution, was associated with higher intakes of confectionery and total sugar, lower intakes of fish, protein, PUFA and starch, and, only in children, a lower diet quality. All measures of MF and SF showed no association with adiposity measures. In conclusion, this cross-sectional study in British children and adolescents suggests that decreasing the number of small eating occasions (<15 % of total energy intake) regardless of the time of day may be important to improve diet quality but not adiposity.

Prevalence of overweight/obesity in relation to dietary habits and lifestyle among 7-17 years old children and adolescents in Lithuania

BACKGROUND

Until recently increasing prevalence of overweight and obesity among pediatric population in Europe and worldwide contributes to major well-known risks for metabolic consequences in later life. The aim of this study was to determine the prevalence of overweight/obesity among children and adolescents in Lithuania and assess its association with energy balance related behaviors as well as familial demographic and socioeconomic factors.

METHODS

Cross-sectional study included 3990 7-17 years old schoolchildren from 40 schools of Kaunas region, Lithuania. Study participants underwent anthropometric measurements. Body mass index (BMI) was evaluated according to International Obesity Task Force (IOTF) criteria for children and adolescents. Children and adolescents and their parents filled in the questionnaires on parental sociodemographic characteristics, dietary habits, TV watching time, and family socioeconomic status.

RESULTS

The prevalence of underweight, overweight, and obesity among boys and girls was 6.9 and 11.7 % (P < 0.05), 12.6 and 12.6 % (P > 0.05), and 4.9 and 3.4 % (P < 0.05), respectively. Obesity was significantly more prevalent in the 7-9 years old group (6.7 and 4.8 % in boys and girls, respectively, P < 0.05). Lower meals frequency and breakfast skipping were directly associated with overweight/obesity (P < 0.05); however, physical inactivity was not associated with higher BMI. Children's overweight/obesity was directly associated with lower paternal education and unemployment (OR 1.30, P = 0.013 and OR 1.56, P = 0.003, respectively).

CONCLUSIONS

The prevalence of overweight and obesity among 7-17 years old Lithuanian children and adolescents was more prevalent in younger age, still being one of the lowest across the European countries. Meals frequency, breakfast skipping, paternal education and unemployment as well as a family history of arterial hypertension were found to be associated with children's and adolescents' overweight/obesity.

Conceptual framework of a simplified multi-dimensional model presenting the environmental and personal determinants of cardiometabolic risk behaviors in childhood

Clinical manifestations of cardiometabolic risk (CMR) may be set early in childhood due to unfavorable behaviors or lifestyle patterns related to diet and physical activity. Several factors may determine the adoption of such lifestyle-related behaviors, which researchers have tried to cluster under certain frameworks or models. In this context, the framework developed and proposed by this review gathers all the present knowledge regarding these determining factors to date and groups them into three main categories related to personal characteristics and the social and physical environment. Based on the proposed framework, a large variety of personal, social and physical environmental factors can positively or negatively influence CMR-related behaviors (either directly or indirectly via their interrelations), thus leading to decreased or increased risk, respectively. This framework could be of great value to public health policy makers and legislators for designing and implementing interventional programs tailored to the needs of susceptible population groups who are most in need for such initiatives. Targeting the correlates as potential determinants of CMR-related behaviors, and not just on the behaviors themselves, has been shown previously to be the most effective approach for tackling health issues related to CMR starting from early life stages.

Physical activity, diet and BMI in children aged 6-8 years: a cross-sectional analysis

OBJECTIVE

To assess relationships between current physical activity (PA), dietary intake and body mass index (BMI) in English children.

DESIGN AND SETTING

Longitudinal birth cohort study in northeast England, cross-sectional analysis.

PARTICIPANTS

425 children (41% of the original cohort) aged 6-8 years (49% boys).

MAIN OUTCOME MEASURES

PA over 7 days was measured objectively by an accelerometer; three categories of PA were created: 'active' ≥60 min/day moderate-to-vigorous-intensity PA (MVPA); 'moderately active' 30-59 min/day MVPA; 'inactive' <30 min/day MVPA. Dietary intake over 4 days was measured using a prospective dietary assessment tool which incorporated elements of the food diary and food frequency methods. Three diet categories were created: 'healthy', 'unhealthy' and 'mixed', according to the number of portions of different foods consumed. Adherence to the '5-a-day' recommendations for portions of fruit and vegetables was also assessed. Children were classified as 'healthy weight' or 'overweight or obese' (OW/OB) according to International Obesity Taskforce cutpoints for BMI. Associations between weight status and PA/diet categories were analysed using logistic regression.

RESULTS

Few children met the UK-recommended guidelines for either MVPA or fruit and vegetable intake, with just 7% meeting the recommended amount of MVPA of 60 min/day, and 3% meeting the 5-a-day fruit and vegetable recommendation. Higher PA was associated with a lower OR for OW/OB in boys only (0.20, 95% CI 0.04 to 0.88). There was no association detected between dietary intake and OW/OB in either sex.

CONCLUSIONS

Increasing MVPA may help to reduce OW/OB in boys; however, more research is required to examine this relationship in girls. Children are not meeting the UK guidelines for diet and PA, and more needs to be done to improve this situation.

Associations of eating frequency with adiposity measures, blood lipid profiles and blood pressure in British children and adolescents

Several epidemiological studies in adults have suggested a favourable effect of frequent eating on blood lipid profiles, but evidence in younger populations is lacking. In the present cross-sectional study, we examined the associations of eating frequency (EF) with metabolic risk factors in British children aged 4-10 years (n 818) and adolescents aged 11-18 years (n 818). Dietary intake was assessed using a 7 d weighed dietary record. EF was calculated based on all eating occasions, except for those providing < 210 kJ of energy. Metabolic risk factors examined were total, HDL-cholesterol and LDL-cholesterol concentrations, TAG concentration, BMI z-score, waist:height ratio (WHtR; only adolescents), and systolic and diastolic blood pressures. Adjustment was made for age, sex, social class, physical activity levels, intakes of protein, fat, total sugar and dietary fibre, ratio of reported energy intake to estimated energy requirement (EI:EER) and BMI z-score (except for BMI z-score and WHtR). In children, EF was inversely associated with total cholesterol and LDL-cholesterol concentrations (n 324, P= 0·01 and 0·04, respectively). Conversely, EF was positively associated with BMI z-score in adolescents (P= 0·004). There were no associations between EF and other metabolic risk factors. In analyses in which only plausible energy reporters (EI:EER: 0·72-1·28) were included, similar results were obtained, except for an inverse association between EF and diastolic blood pressure in children. In conclusion, a higher EF is associated with lower total cholesterol and LDL-cholesterol concentrations in children but with a higher BMI z-score in adolescents.

Identification of lifestyle patterns associated with obesity and fat mass in children: the Healthy Growth Study

OBJECTIVE

To investigate possible associations of lifestyle patterns with obesity and fat mass in children.

DESIGN

Cross-sectional epidemiological study. Principal component analysis was used to identify lifestyle patterns.

SETTING

Primary schools from four regions in Greece.

SUBJECTS

A total of 2073 schoolchildren (aged 9-13 years).

RESULTS

Children in the fourth quartile of the lifestyle pattern combining higher dairy foods with more adequate breakfast consumption were 39·4%, 45·2% and 32·2% less likely to be overweight/obese and in the highest quartile of sum of skinfold thicknesses and fat mass, respectively, than children in the first quartile of this pattern. Similarly, children in the fourth quartile of a lifestyle pattern comprising consumption of high-fibre foods, such as fruits, vegetables and wholegrain products, were 27·4% less likely to be in the highest quartile of sum of skinfold thicknesses than children in the first lifestyle pattern quartile. Finally, children in the fourth quartile of a lifestyle pattern characterized by more time spent on moderate-to-vigorous physical activity and more frequent meals were 38·0%, 26·3% and 29·5% less likely to be overweight, centrally obese and in the highest quartile of fat mass, respectively, than their peers in the first quartile of this lifestyle pattern (all P < 0·05).

CONCLUSIONS

The current study identified three lifestyle patterns (i.e. one pattern comprising higher dairy consumption with a more adequate breakfast; a second pattern characterized by increased consumption of high-fibre foods; and a third pattern combining higher physical activity levels with more frequent meals), which were all related with lower odds of obesity and/or increased fat mass levels. From a public health perspective, promotion of these patterns among children and their families should be considered as one of the components of any childhood obesity preventive initiative.

Eating frequency and overweight and obesity in children and adolescents: a meta-analysis

OBJECTIVES

To determine the effect of eating frequency on body weight status in children and adolescents.

METHODS

In this meta-analysis, original observational studies published to October 2011 were selected through a literature search in the PubMed database. The reference list of the retrieved articles was also used to identify relevant articles; researchers were contacted when needed. Selected studies were published in English, and they reported on the effect of eating frequency on overweight/obesity in children and adolescents. Pooled effect sizes were calculated using a random effects model.

RESULTS

Ten cross-sectional studies and 1 case-control study (21 substudies in total), comprising 18 849 participants (aged 2-19 years), were included in the analysis. Their combined effect revealed that the highest category of eating frequency, as compared with the lowest, was associated with a beneficial effect regarding body weight status in children and adolescents (odds ratio [OR] = 0.78, log OR = -0.24, 95% confidence interval [CI] -0.41 to -0.06). The observed beneficial effect remained significant in boys (OR = 0.76, log OR = -0.27, 95% CI -0.47 to -0.06), but not in girls (OR = 0.96, log OR = -0.04, 95% CI -0.40 to 0.32) (P for sex differences = 0.14).

CONCLUSIONS

Higher eating frequency was associated with lower body weight status in children and adolescents, mainly in boys. Clinical trials are warranted to confirm this inverse association, evaluate its clinical applicability, and support a public health recommendation; more studies are also needed to further investigate any sex-related differences, and most importantly, the biological mechanisms.

Selected eating behaviours and excess body weight: a systematic review

The relationship between obesity and the intake of macronutrients and specific foods is uncertain. Thus, there is growing interest in some eating behaviours because they may reflect the joint effect of several foods and nutrients and, thus, increase the likelihood of finding a link to obesity. This study examined the association between selected eating behaviours and excess weight in the general population throughout a systematic review of publications written in English, Spanish or Portuguese identified in a PubMed search up to 31 December 2010. We included 153 articles, 73 of which have been published since 2008. Only 30 studies had a prospective design; of these, 15 adjusted for sociodemographic variables, physical activity and energy or food intake. Moreover, definitions of eating behaviours varied substantially across studies. We found only small or inconsistent evidence of a relationship between excess weight and skipping breakfast, daily eating frequency, snacking, irregular meals, eating away from home, consumption of fast food, takeaway food intake, consumption of large food portions, eating until full and eating quickly. In conclusion, this review highlights the difficulty in measuring human behaviour, and suggests that a more systematic approach is needed for capturing the effects of eating behaviours on body weight.

Systematic review of sedentary behaviour and health indicators in school-aged children and youth

Accumulating evidence suggests that, independent of physical activity levels, sedentary behaviours are associated with increased risk of cardio-metabolic disease, all-cause mortality, and a variety of physiological and psychological problems. Therefore, the purpose of this systematic review is to determine the relationship between sedentary behaviour and health indicators in school-aged children and youth aged 5-17 years. Online databases (MEDLINE, EMBASE and PsycINFO), personal libraries and government documents were searched for relevant studies examining time spent engaging in sedentary behaviours and six specific health indicators (body composition, fitness, metabolic syndrome and cardiovascular disease, self-esteem, pro-social behaviour and academic achievement). 232 studies including 983,840 participants met inclusion criteria and were included in the review. Television (TV) watching was the most common measure of sedentary behaviour and body composition was the most common outcome measure. Qualitative analysis of all studies revealed a dose-response relation between increased sedentary behaviour and unfavourable health outcomes. Watching TV for more than 2 hours per day was associated with unfavourable body composition, decreased fitness, lowered scores for self-esteem and pro-social behaviour and decreased academic achievement. Meta-analysis was completed for randomized controlled studies that aimed to reduce sedentary time and reported change in body mass index (BMI) as their primary outcome. In this regard, a meta-analysis revealed an overall significant effect of -0.81 (95% CI of -1.44 to -0.17, p = 0.01) indicating an overall decrease in mean BMI associated with the interventions. There is a large body of evidence from all study designs which suggests that decreasing any type of sedentary time is associated with lower health risk in youth aged 5-17 years. In particular, the evidence suggests that daily TV viewing in excess of 2 hours is associated with reduced physical and psychosocial health, and that lowering sedentary time leads to reductions in BMI.

Obesity and associated cardiovascular risk factors among schoolchildren in Greece: a cross-sectional study and review of the literature

OBJECTIVE

To examine the prevalence and determinants of obesity and associated cardiovascular risk factors in a sample of Greek children.

METHODS

This is a cross-sectional, school-based study of 780 students (9.2 +/- 1.8 years old, 415 boys) conducted in Eastern Attica, the greater area of the city of Athens. The study protocol included anthropometric, blood pressure (BP), and biochemical measurements, as well as dietary and lifestyle habits assessment. A review of Greek studies on childhood obesity was also performed.

RESULTS

Approximately 22% of the participants were overweight and 8% were obese, which is in accordance with the results of 24 previous Greek studies showing the childhood overweight/obesity prevalence in the range of 30%. Overweight/obese children compared with normal-weight children had higher BP, lower high-density lipoprotein cholesterol (HDL-C), and higher triglycerides (p < 0.05 for all). Parental weight, consumption of sweets and fast-food, and decreased physical activity were independent determinants of being overweight/obese. Furthermore, overweight/obesity predicted the presence of high BP, low HDL-C, and high triglycerides.

CONCLUSION

A close association was revealed between obesity and metabolic abnormalities, underlining the need for early screening and intervention in overweight children in order to address the emerging childhood obesity epidemic in Greece.

Relative contribution of energy intake and energy expenditure to childhood obesity: a review of the literature and directions for future research

BACKGROUND

Understanding the relative importance of overconsumption and physical inactivity to excess weight gain among children and adolescents can contribute to the development and evaluation of interventions and policies to reduce childhood obesity. However, whether energy intake or expenditure is the dominant contributor to childhood obesity is a subject of debate. To date, no study has systematically reviewed the literature on this subject.

METHODS

We searched PubMed and Ovid Medline (January 1970 to January 2010) for potentially relevant English-language abstracts and obtained full-text articles for the abstracts, which passed the initial inclusion-exclusion criteria. Reference lists of full-length articles were hand searched to identify additional studies potentially relevant for inclusion. Relevant studies were characterized into one of the following three categories: cross-sectional studies with a nationally representative sample, cross-sectional studies among population subgroups and longitudinal studies.

RESULTS

This review identified 26 studies examining factors related to energy intake, energy expenditure and obesity among children and adolescents. Cross-sectional and longitudinal studies suggest that the primary determinant of energy imbalance at both the population and the individual levels is not definitive. Our findings further suggest that there is wide variation in data quality between studies. Future research in this area should aim to improve the accuracy of measures of energy intake, expenditure and their net balance over time; capitalize on under-utilized, non-traditional data sources, which have not been widely used; use modeling techniques to synthesize studies of shorter follow-up period and different outcome measures; and examine the unique determinants of energy imbalance among demographic groups at higher risk for obesity.

CONCLUSIONS

On the basis of the current evidence, there is no consensus on the main driver of secular trends on weight gain among US children and adolescents. More research and better methods are needed to identify the relative contribution of energy intake and energy expenditure to obesity in the pediatric population.

Consumption of vegetables, cooked meals, and eating dinner is negatively associated with overweight status in children

OBJECTIVE

To evaluate potential associations between diet- and physical activity-related lifestyle patterns and obesity indices in a cohort of children.

STUDY DESIGN

Dietary and physical activity information and anthropometric indices were collected from 1138 children (53% girls; age, 11.2 ± 0.7 years). Dietary intake was evaluated with two 24-hour recalls, which were analyzed for nutrient and food intake, eating frequency, and meal quality. Principal component analysis was used to extract salient lifestyle patterns.

RESULTS

Five lifestyle behavioral patterns were identified. The "dinner, cooked meals and vegetables pattern," a multidimensional lifestyle pattern including the consumption of vegetables, cooked meals, and eating dinner, was negatively associated with all obesity indices, even after adjustment for potential confounders and exclusion of low energy reporters. A "high fiber pattern," representing high consumption of whole-grain cereals, legumes, and low intake of sugar-sweetened beverages was negatively correlated with obesity indices; when the analysis included only acceptable energy reporters, these associations became non-significant, except for triceps skinfolds.

CONCLUSIONS

Our findings are supportive of the synergistic or conditional effects of distinct lifestyle-related behaviors on obesity. Although these results are hypothesis-generating and need replication, they suggest potential preventive approaches, interventional approaches, or both to combat childhood obesity.

Epidemiology and predisposing factors of obesity in Greece: from the Second World War until today

Over the last 30 years overweight and obesity among adults and children have been on the rise, and since 1997 WHO has designated obesity as a major public health problem. In Greece both adult and childhood obesity is now recognized as an epidemic problem, probably more important than in other European countries. The issue is more serious in male adolescents and adults. There is also a tendency for weight increase along the last 30 years. Metabolic syndrome and type 2 diabetes mellitus are also rising rapidly in the Greek population. The reasons for this epidemic in Greece are not clear. Possible explanations could emerge from the delayed but sharp economic evolution of the country, as well as the abandonment of the traditional Mediterranean diet. Other predisposing factors in Greek children are parental obesity, frequent television viewing, low rates of breastfeeding and, in adolescent girls, smoking and alcohol consumption. Emerging measures are needed to confront this epidemic.