Overweight and obesity in Portuguese children: prevalence and correlates

Characteristic Sleep Patterns and Associated Obesity in Adolescents

Poor sleep adversely affects health and may cause obesity. Poor sleep includes short sleep duration, low quality of sleep, and sleep discrepancy. Although most studies have focused on the association between sleep duration and obesity, poor sleep is a significant risk factor for obesity. Adolescents have characteristic sleep patterns which correspond to poor sleep. Adolescents sleep late due to various biological and psychosocial factors; also, they wake up early to be on time for school. This causes them to sleep less. To make up for this sleep debt, adolescents sleep more on non-school days, which causes sleep discrepancies. Therefore, since adolescents have characteristic sleep patterns, an in-depth investigation is needed to identify whether poor sleep is a risk for obesity. This article presents an overview of the characteristic sleep patterns of adolescents, and reviews studies on the association of each sleep pattern with obesity.

Defining Optimal Cut-Points for Cardiorespiratory Fitness Associated With Overweight/Obesity in Children: A School-Based Study

The main purpose of the study was to define optimal criterion-referenced cut-points for cardiorespiratory fitness (CRF) associated with overweight/obesity. In this cross-sectional study, participants were 1,612 children aged 7–14 years (mean age ± SD = 9.7 ± 2.4 years; 52.5% girls). CRF was assessed by the Maximal multistage 20-m shuttle run test, from which maximal oxygen uptake (VO₂max) was estimated. Anthropometric indices included body-mass index (BMI), waist circumference (WC), and waist-to-height ratio (WHtR). Receiver operating characteristic (ROC) curves were performed to determine cut-off points. In boys, the optimal cut-off points of CRF in defining overweight/obesity for BMI, WC, and WHtR were 44.6, 46.4, and 46.9 mlO₂/kg/min. The areas under the curves (AUC) were 0.83 (95% CI 0.78–0.88, p < 0.001), 0.77 (95% CI 0.71–0.83, p < 0.001), and 0.90 (95% CI 0.86–0.93, p < 0.001). In girls, the optimal cut-off points were 41.0, 40.8, and 40.7 mlO₂/kg/min for BMI, WC, and WHtR, with the AUCs of 0.86 (95% CI 0.82–0.90, p < 0.001), 0.83 (95% CI 0.79–0.88), and 0.88 (95% CI 0.84–0.93, p < 0.001). In conclusion, our newly developed cut-off points for CRF assessed by the Maximal multistage 20-m shuttle run test may adequately detect primary school-aged boys and girls with general and abdominal obesity.

Relationship between waist circumference and cardiorespiratory fitness in Chinese children and adolescents: Results from a cross-sectional survey

Background

This article assessed the relationship between waist circumference (WC) and cardiorespiratory fitness (CRF) of children and adolescents aged 7–18 years.

Methods

Using a stratified cluster random sampling method, 92,574 children and adolescents (47,364 males and 45,210 females) were extracted. CRF was measured by performance in the 20 m shuttle run test (20mSRT) and the subsequent estimation of maximal oxygen consumption (V˙O_2max) using the Léger equations. Participants were divided into five groups of WC percentiles and three groups of CRF percentiles by the Lambda Mu Sigma (LMS). The correlation between WC and CRF was examined by one-way ANOVA and curvilinear regression analysis.

Results

WC increased with age, while V˙O_2max showed an age-related decline. Controlling for gender, urban, and rural factors, for children and adolescents aged 10–12, 13–15, and 16–18 years, the V˙O_2max Z-score of the normal WC group was significantly higher than the very low WC group (P < 0.05). Controlling for gender, urban, and rural factors, for participants aged 7–18 years, the V˙O_2max Z-score of the normal WC group was significantly higher than the high WC group and the very high WC group (P < 0.05).

Conclusions

It generally shows a “parabolic” trend between WC-Z and V˙O_2max-Z. The CRF among children and adolescents in the normal WC group is significantly higher than that in the low and the high WC groups.

Sex differences in younger school age children’s body weight categories

The issue of inadequate or excessive children’s body weight, particularly in relation to their health, is also discussed by Czech experts in physical anthropology, auxology, paediatrics, endocrinology, etc. Overweight and obesity occur already at a younger school age, and some domestic and foreign sources report a higher prevalence in boys.

The objective of this study was to describe distribution range in body weight categories among Czech children of younger school age (6 to 11 years) taking into account age and sex.

Our research was carried out at 23 primary schools in 5 regions of the Czech Republic between 2014 and 2018. The research group consisted of 2,099 children aged 6 to 11 years (boys n = 1,015, 48.4%; girls n = 1,084, 51.6%). Probands were subjected to the standard anthropometric examination with body weight being assessed using the following assessment standards: the Czech national growth references, Nationwide Anthropological Survey of Czech Children and Adolescents (NAS), World Health Organisation (WHO) growth standards, and International Obesity Task Force (IOTF) references were used. Statistical tests were carried out at a significance level of p ≤ 0.05; residual analysis.

According to all three assessment standards, the highest prevalence of children with normal body weight was in both sexes; 45.8% of girls and 48.4% of boys, using the Czech assessment reference. Overweight and obesity were more predominant in boys (7.9% and 8.7%) than in girls (7.7% and 7.5%). One point seven percent of boys and girls were equally underweight, whereas the percentage of girls (22.3%) with reduced body weight was higher than in boys (20.3%). A significant difference between boys and girls was found in the category of reduced body weight in nine-year-old children. Using internationally recommended BMI references, more children fell into the category of normal body weight. Significant differences, in accordance with IOTF, between the number of severely underweight boys and girls were observed in 7-year-olds, slightly underweight in 9- and 11-year-olds, and overweight in 7-year-olds. In accordance with the WHO growth standards, significant differences appeared between eight-year-olds and eleven-year-olds obese boys and girls.

Our research study revealed the prevalence in younger school age children body weight categories. Different BMI references were used to classify body weight. Significant differences between the number of boys and girls were observed in certain weight categories in seven-year-old, eight-year-old, nine-year-old and eleven-year-old children. Thus, the study confirmed the presence of differences in the number of boys and girls in specific body weight categories.

Cross-sectional associations between objectively measured sleep characteristics and body mass index in European children and adolescents

BACKGROUND

Short sleep duration has been found to be associated with a higher risk for overweight and obesity. However, previous studies have mainly relied on subjective measures of sleep duration and other sleep characteristics (eg quality, timing) have often been neglected. Therefore, we aimed to investigate associations between several, mainly objectively measured sleep characteristics and body mass index (BMI). Further, we aimed to identify distinct sleep subtypes based on these sleep characteristics and to study their association with BMI.

METHODS

Children aged 9-16 years participating in the European I.Family study (N = 559, 51.2% girls, 32.9% overweight/obese) wore an accelerometer for one week on their wrist and recorded their daily wake-up and lights-off times in a sleep diary. Information on sleep duration, sleep efficiency and sleep latency was derived. To identify sleep subtypes, we conducted a latent class analysis using all five sleep variables. Associations between single sleep variables, sleep subtype and age- and sex-specific BMI z-score were investigated using linear mixed-effects regression models to accommodate clustering among siblings.

RESULTS

No statistically significant associations were observed between the single sleep variables (sleep duration, sleep efficiency, sleep latency, wake-up and lights-off times) and BMI z-score. Four sleep subtypes were identified and children were assigned to one of the groups based on their highest probability for latent group membership: "early birds" (17.5% of the sample), "short sleep duration" (14.7%), "optimal sleep" (47.6%) and "poor sleep quality" (20.2%). Sleep subtype was not associated with BMI z-score.

CONCLUSIONS

Using objective sleep data, we did not find convincing evidence for associations between the sleep variables under investigation and BMI.

Secular Trends of Underweight, Overweight, and Obesity in Children and Adolescents from Ukraine

Overweight and obesity, as well as underweight in children and adolescents, pose a significant public health issue. This study aimed to investigate the secular trend of the incidence of underweight, overweight, and obesity in children from Ukraine in 2013/2014 and 2018/2019. The studies were conducted in randomly selected primary and secondary schools in Ukraine. In total, 13,447 children (6468 boys and 6979 girls) participated in the study in 2013/2014 and 18,144 children (8717 boys and 9427 girls) participated in 2018/2019. Measurements of body weight and height were performed in triplicate. Underweight, overweight, and obesity were diagnosed according to the standards of the World Health Organization (WHO). In the group of girls, a significant difference between 2013/2014 and 2018/2019 measurements was found only among 7-year-olds. The percentage of girls at this age exceeding the body mass index (BMI) norm was lower in the 2018/2019 study. In boys, a significant difference was also found in 7-year-olds, and, as in girls, a lower share of overweight and obesity was found in 2018/2019. But for the ages of 12, 13, and 15, the significant differences had a different character-more overweight or obese boys were found in the 2018/2019 study. The proportion of underweight children was similar for the majority of age groups in both genders and did not differ in a statistically significant way.

Body mass index and potential correlates among elementary school children in Jordan

PURPOSE

Childhood obesity and overweight are on the rise worldwide, and Jordanian children are no exception to this rule. Childhood Obesity has major implications on the physical and mental health of individuals, and it can often develop into adult obesity. Obesity/overweight correlates have not been researched extensively in the Middle East region, where Jordan is central. This region is undergoing tremendous changes because of wars, globalization, and the influx of refugees. The cultural and eating habits of the people are changing along with demographical changes. Thus, timely research is required to assess the current health state of this dynamic society. The main goal of this study is to understand the environmental and cultural factors that are associated with Body Mass Index (BMI) z score in elementary school children in Jordan.

METHODS

A total of 1260 children enrolled in this descriptive, cross-sectional study. The study used a parental self-reporting questionnaire that contains possible factors associated with BMI, zBMI, demographics, and other pertinent information.

RESULTS

Several factors have been associated with higher zBMI among elementary school children: if a child owns a smartphone (p = 0.0037), uses electronics to play ([Formula: see text]), uses electronics for longer hours ([Formula: see text]), eats food while using electronics or watching TV ([Formula: see text] and [Formula: see text], respectively), sleeps less hours in weekends ([Formula: see text]), was breastfed for lower number of months ([Formula: see text]), lives in rural areas ([Formula: see text]), goes to a private school ([Formula: see text]) and is a male ([Formula: see text]).

CONCLUSION

Investigating characteristics and environmental determinants of childhood obesity play an essential role in establishing effective intervention program and reduce future risks of morbidity.

LEVEL OF EVIDENCE

Level V, descriptive (cross-sectional) study.

Secular Changes in Body Build and Body Composition in Czech Preschool Children in the Context of Latent Obesity

Changes in lifestyle can be significantly reflected in growth and development. Adaptations to reduced levels of physical activity, together with non-corresponding nutritional intakes, can result in body build and body composition changes at an early age. The present cross-sectional study aimed to evaluate the secular trend of modifications of body composition and body mass index (BMI) in Czech preschoolers over the last two to three decades. Boys and girls (386 boys and 372 girls) aged 4 to 6 years in 2014–2019 were measured. Outcome data were compared with the reference sample of preschoolers from 1990: 911 boys and 896 girls. Body height, BMI, and percentage of body fat, muscle, and bone mass were evaluated. Height and BMI have not changed. Body fat increased in both genders (p < 0.01), and contrarily, a significant reduction of muscle and skeletal mass was revealed (p < 0.001). Significant changes in body composition and unchanged BMI indicate the development of latent obesity during the last few decades. Due to latent obesity in a recent cohort, the differences in the prevalence of overweight and obesity markers according to BMI and fat percentage were tested. The prevalence of overweight and obesity was higher by 7.2% in boys, and by 6.5% in girls, as compared to children evaluated according to only their BMI results. Secular changes in preschoolers’ physical builds over the last 25 years are not reflected in body height and BMI, but in body composition. Insufficient development of active, lean body mass proportionally compensated by increased fat mass was also indicated.

Overweight and Obesity in Children of Immigrant Versus Native Parents: Exploring a Local Setting in Portugal

In Portugal, the majority of immigrants come from Portuguese-speaking countries. Among children, overweight and obesity are serious public health concerns, but a few studies include children with immigrant background. This study aimed to estimate the prevalence of overweight and obesity and risk of abdominal obesity in school-age children and to explore potential determinants, considering the origin of the children’s parents (both mother and father are non-Portuguese, only one Portuguese, and both are Portuguese). A cross-sectional study included a random sample of 789 children (5–11 years old, 49.2% of males and 50.8% female) attending public primary schools in Barreiro, district of Setubal, Portugal. Fieldwork occurred from 20th April to 3rd July 2009. Data concerning socioeconomic, eating habits, and sports outside school were obtained through a questionnaire applied to the children’s person in charge. Anthropometric measures were collected by certified technicians. One-third of the children presented overweight and obesity (33.7%, 95% CI [30.0; 37.7]) and risk of abdominal obesity (16.4%, 95% CI [13.6; 19.7]) without differences according to parents’ origin. Children with immigrant background presented higher consumption of low-priced, high-sugar, and high-fat foods, with a worse situation for girls. Females from both non-Portuguese parents also practiced less sports outside school than those where one or two parents are Portuguese. Thus, promoting and monitoring a healthy diet and physical activity in this group should be prioritized in this local setting.

Sleep and obesity among children: A systematic review of multiple sleep dimensions

The objectives were to systematically investigate the multiple dimensions of sleep and their association with overweight or obesity among primary school-aged children. CINHAL, PsycINFO, SPORTDiscus, Medline, Cochrane, Embase, and PubMed databases were searched for papers reporting on an association between children's sleep and weight status. Studies on clinical populations, published in languages other than English, without objectively measured weight status, or where weight status was reported outside the outlined age bracket (5-13 years) were excluded. A total of 34  248 citations were extracted from our systematic search protocol, of which 112 were included for detailed review. Compared with sleep duration, of which 86/103 articles found a significant inverse association between sleep duration and measured weight status, few studies examined other dimensions of sleep, such as quality, efficiency and bed/wake times, and relationship with weight status. Where studies existed, variation in defining and measurement of these dimensions restricted comparison and potentially influenced discrepancies across results. Overall, the findings of this review warrant the need for further research of the outlined dimensions of sleep. Future research would benefit from clarity on definitions across the different dimensions, along with the use of valid and reliable tools.

Costs and benefits of a school-based health intervention in Portugal

School-based programmes for preventing childhood obesity have been shown to be effective in improving eating habits and nutritional status, but few intervention programmes with a controlled design have included an economic evaluation. In this study, we conducted a cost-consequence analysis to evaluate the costs and the health benefits of the 'Planning Health in School' programme (PHS-pro) implemented in the Northern region of Portugal to 449 children of 10-14 years old. Previous study has showed that after PHS-pro, several anthropometric measures significantly improved in the intervention group (height, waist circumference and waist-height ratio) compared with the control group, followed by significant improvements on soft drinks, fruit and vegetables daily consumptions. Costs were estimated according the two phases of the programme: designing and preparation of schools, and school setting implementation, and included all the direct costs on human and material resources. PHS-pro total costs were estimated as 7915.53€/year with an intervention cost of 36.14€/year/child attending the programme. This is much lower than the direct costs for treating an obese adult in Portugal, which was calculated as 3849.15€/year. A scale-up costing projection for implementing the PHS-pro to a larger young population was estimated to be even lower: 18.18€/year/child. This cost-consequence analysis provided evidence that the PHS-pro was economically feasible especially if compared with the medical costs for treating adult obesity. The PHS-pro can be a beneficial investment and may give a promising contribution to addressing overweight over childhood and adolescence, which are developmental stages that determine adulthood chronic diseases.

The mediation effect of anthropometry and physical fitness on the relationship between birthweight and basal metabolic rate in children

BACKGROUND

Birthweight (BW) has been associated with anthropometry, body composition and physical fitness during growth and development of children. However, less is known about the mediation effect of those variables on the relationship between BW and basal metabolic rate (BMR) in children.

OBJECTIVE

To analyse the mediation effect of anthropometry, body composition and physical fitness on the association between BW and BMR in children.

METHODS

In total, 499 children (254 boys, 245 girls) aged 7-10 years were included. Anthropometry (weight, height, head, waist and hip circumferences), body composition (skinfolds thickness, body fat percentage), physical fitness (handgrip strength, flexibility, muscular endurance, muscular explosive power, agility, running speed) and BMR were evaluated. The analyses were conducted by: single-mediator analysis (SMA) and multi-mediator analysis (MMA).

RESULTS

The SMA indicates height, head, waist and hip circumferences and handgrip strength as significant mediators of BW on BMR for boys and height, hip circumference and handgrip strength as significant mediators of BW on BMR for girls. In MMA for girls, there were significant indirect effects for height, hip circumference and handgrip strength, with 79.08% of percent mediation. For boys, the head and waist circumferences mediation had a significant indirect effect, with 83.37% of percent mediation.

CONCLUSION

The anthropometric variables associated with BW were body height, head, hip and waist circumferences for boys and body height and hip circumference for girls. The current study provides new evidence that height and handgrip strength during childhood mediated the relationship between BW and BMR.

Correlates of Overweight in Children and Adolescents Living at Different Altitudes: The Peruvian Health and Optimist Growth Study

Background and Aim

Overweight prevalence in children and adolescents shows great variability which is related to individual-level and environmental-level factors. The present study aimed to determine the prevalence of and factors associated with overweight in Peruvian children and adolescents living at different altitudes.

Methods

8568 subjects, aged 6-16 y, from the sea level, Amazon, and high-altitude regions were sampled. Overweight was identified using BMI; biological maturation and physical fitness were measured; school characteristics were assessed via an objective audit.

Results

Overweight prevalence decreased with age (28.3% at 6 y to 13.9% at 16 y); it was higher in girls (21.7%) than boys (19.8%) and was higher at the sea level (41.3%), compared with Amazon (18.8%) and high-altitude (6.3%) regions. Approximately 79% of the variance in overweight was explained by child-level characteristics. In Model 1, all child-level predictors were significant (p < 0.001); in Model 2, six out of nine added school-level predictors (number of students, existence of policies and practices for physical activity, multisports-roofed, duration of Physical Education classes, and extracurricular activities) were significant (p < 0.001); in Model 3, subjects living at high altitudes were less likely to be overweight than those living at the sea level.

Conclusions

Child- and school-level variables played important roles in explaining overweight variation. This information should be taken into account when designing more efficient strategies to combat the overweight and obesity epidemic.

Relationship Between Obesity, Physical Activity, and Cardiorespiratory Fitness Levels in Children and Adolescents in Bosnia and Herzegovina: An Analysis of Gender Differences

This study aimed to examine: (i) the level of physical activity (PA), obesity indices and cardiorespiratory fitness (CRF) among boys and girls in primary school, and (ii) to determine the association of obesity indices and PA with CRF for the total number of participants, and then separately for boys and girls. 753 sixth to ninth grade girls and boys aged 10-14 years took part in this cross-sectional study. The PA was assessed by the "Physical Activity Questionnaire - Children" and CRF was assessed by the Maximal multistage a 20 m shuttle run test. Body mass index (BMI), waist circumferences (WC), and waist to height ratio (WHtR) were considered as obesity indices. Multiple linear regression analyses were performed to explore correlates of CRF. The results obtained showed the prevalence of general overweight and obesity was 25.5% in our sample which was lower than that in the regional estimate (e.g., ∼28%) for Eastern Europe. Among all participants, CRF was associated with male sex, older age, a lower WC percentile, higher WHtR, and higher level of PA. The model accounted for 24% of the variance. CRF was associated with older age and higher level of PA among girls and boys. Lower WC percentile was a significant determinant of CRF among boys. In conclusion, general overweight/obesity was not independently associated with CRF. Those with better CRF were more likely to be male and older, had a higher level of PA and lower central adiposity. These findings emphasize the importance of supporting school age children to take a part in programmed physical activity regardless of their body composition.

Prevalence of metabolic syndrome among university students: A systematic review

Introduction: Metabolic syndrome (MS) is defined as a set of conditions including high blood pressure, dyslipidemia, glucose intolerance and visceral obesity. In recent years, an increase of obesity in university students has been observed, although the accurate prevalence of MS is unknown.Objective: To determine the prevalence of MS in university students between January 2000 and January 2016.Materials and methods: A systematic review of studies published in the PubMed, LILACS, ScienceDirect, UpToDate, Imbiomed, SciELO and Google Scholar databases was performed. To ensure the highest number of papers, different combinations of words related to MS were used in Spanish, English, and Portuguese.Results: A total of 16 studies met the inclusion criteria. Students from different health, social and human sciences careers from America, Asia and Europe participated in said studies. The prevalence of MS ranged from 0 to 19.2% according to NCEP-ATP III.Conclusions: The prevalence of MS varies widely across studies. It is important to expand MS research, as this would allow designing specific interventions for high-risk groups in the university context.

Association between body mass index and individual characteristics and the school context: a multilevel study with Portuguese children

OBJECTIVE

The aim of this study was to examine the association between individual and school context characteristics with the body mass index of Portuguese children.

METHODS

The sample comprised 1641 children (847 boys) aged 6-10 years from the North and Central regions of Portugal. Regarding the individual characteristics, age, gender, city of residence, levels of physical activity, and physical fitness were assessed. Concerning the school context characteristics, the surrounding environment, school size, presence of recreational characteristics and space, and presence of a sports court and of physical education classes were considered. Children's body mass index was the dependent variable. The multilevel analysis was carried out in HLM 7.0 software.

RESULTS

The predictors of the child and the school context explained, respectively, 97.3% and 2.7% of the total body mass index variance. Regarding the individual characteristics, older children, boys, and those who had lower performance at the 1-mile run/walk, curl-up, push-up, and higher performance in trunk lift tests showed higher BMI. Further, urban schools with higher recreational spaces were positively associated with children's body mass index.

CONCLUSION

School context variables have a reduced effect on body mass index variation compared to the children's biological and behavioral characteristics. The authors therefore encourage strategies that aim to increasing children's physical fitness levels to help prevent excess weight.

Relationship between sleep duration and childhood obesity: Systematic review including the potential underlying mechanisms

AIM

The prevalence of obesity is continually increasing worldwide. Determining risk factors for obesity may facilitate effective preventive programs. The present review focuses on sleep duration as a potential risk factor for childhood obesity. The aim is to summarize the evidence on the association of sleep duration and obesity and to discuss the underlying potential physiological and/or pathophysiological mechanisms.

DATA SYNTHESIS

The Ovid MEDLINE, Scopus and Cochrane Central Register of Controlled Trials (CENTRAL) databases were searched for papers using text words with appropriate truncation and relevant indexing terms. All studies objectively measuring sleep duration and investigating the association between sleep duration and obesity or factors (lifestyle and hormonal) possibly associated with obesity were included, without making restrictions based on study design or language. Data from eligible studies were extracted in tabular form and summarized narratively. After removing duplicates, 3540 articles were obtained. Finally, 33 studies (including 3 randomized controlled trials and 30 observational studies) were included in the review.

CONCLUSION

Sleep duration seems to influence weight gain in children, however, the underlying explanatory mechanisms are still uncertain. In our review only the link between short sleep duration and the development of insulin resistance, sedentarism and unhealthy dietary patterns could be verified, while the role of other mediators, such as physical activity, screen time, change in ghrelin and leptin levels, remained uncertain. There are numerous evidence gaps. To answer the remaining questions, there is a need for studies meeting high methodological standards and including a large number of children.

Perceptions and behaviours towards high body weight among adults in Northeast China

OBJECTIVE

To determine the prevalence of high weight at different characteristics, understand the perceptions and behaviours towards high body weight, and determine potential influencing factors of body weight misperception among high-weight adults in Jilin Province.

DESIGN

A cross-sectional survey with complex sampling design was conducted. We described the prevalence and perception of high body weight.

SETTING

Northeast China in 2012.

SUBJECTS

Adults (n 20 552) aged 18-79 years.

RESULTS

Of overweight individuals, 37·4 % considered themselves as 'normal weight', 4·8 % reported themselves as being 'very thin' and only 53·1 % were aware of their own weight being 'overweight'. About 1·8 % of both male and female obese individuals perceived themselves as 'very thin'. Only 29·1 % of obese people thought of themselves as 'too fat'. Nearly 30·0 % of centrally obese men and women perceived that their waist circumference was about right and they were of 'normal weight'; 5·7 % of the centrally obese even perceived themselves as being 'very thin'. Only 51·8 and 12·5 % of centrally obese individuals reported themselves to be 'overweight' or 'too fat'. Body weight misperception was more common in rural residents (OR; 95 % CI: 1·340; 1·191, 1·509). The prevalence of body weight misperception increased with age (middle age: 1·826; 1·605, 2·078; old people: 3·101; 2·648, 3·632) and declined with increased education level (junior middle school: 0·628; 0·545, 0·723; senior middle school: 0·498; 0·426, 0·583; undergraduate and above: 0·395; 0·320, 0·487).

CONCLUSIONS

Body weight misperception was common among adults from Jilin Province.

Correlates of children's compliance with moderate-to-vigorous physical activity recommendations: a multilevel analysis

This study aimed to investigate the association between individual and school characteristics associated with the number of school days children comply with moderate-to-vigorous physical activity (MVPA) recommendations. Sample comprises 612 Portuguese children, aged 9-11 years, from 23 schools. Time spent in MVPA was measured by accelerometry, while individual-level correlates were obtained by anthropometry and questionnaires. School-level variables were collected by questionnaire, and accelerometer wear time and season were also considered. Maximum likelihood estimates of model parameters were obtained via a multilevel analysis with children as level-1, and school as level-2. Children who spent more time in sedentary activities and girls were less likely to comply with MVPA/daily. More mature children and those who use active transportation to school were more likely to attain the PA recommendation. Furthermore, greater accelerometer wear time and spring season increased the chance to achieve the recommended MVPA. In terms of school-level correlates, a greater number of available facilities was negatively associated with children MVPA compliance. Given the set of variables, our results showed that individual characteristics seem to be more relevant for children's compliance rates with PA/day than school context variables, which should be taken into account in the implementation of school policies and practices.

Profiling physical activity, diet, screen and sleep habits in Portuguese children

Obesity in children is partly due to unhealthy lifestyle behaviours, e.g., sedentary activity and poor dietary choices. This trend has been seen globally. To determine the extent of these behaviours in a Portuguese population of children, 686 children 9.5 to 10.5 years of age were studied. Our aims were to: (1) describe profiles of children’s lifestyle behaviours; (2) identify behaviour pattern classes; and (3) estimate combined effects of individual/socio-demographic characteristics in predicting class membership. Physical activity and sleep time were estimated by 24-h accelerometry. Nutritional habits, screen time and socio-demographics were obtained. Latent Class Analysis was used to determine unhealthy lifestyle behaviours. Logistic regression analysis predicted class membership. About 78% of children had three or more unhealthy lifestyle behaviours, while 0.2% presented no risk. Two classes were identified: Class 1-Sedentary, poorer diet quality; and Class 2-Insufficiently active, better diet quality, 35% and 65% of the population, respectively. More mature children (Odds Ratio (OR) = 6.75; 95%CI = 4.74–10.41), and boys (OR = 3.06; 95% CI = 1.98–4.72) were more likely to be overweight/obese. However, those belonging to Class 2 were less likely to be overweight/obese (OR = 0.60; 95% CI = 0.43–0.84). Maternal education level and household income did not significantly predict weight status (p ≥ 0.05).