Reliability of anthropometric measurements in European preschool children: the ToyBox-study

The ToyBox-study aims to develop and test an innovative and evidence-based obesity prevention programme for preschoolers in six European countries: Belgium, Bulgaria, Germany, Greece, Poland and Spain. In multicentre studies, anthropometric measurements using standardized procedures that minimize errors in the data collection are essential to maximize reliability of measurements. The aim of this paper is to describe the standardization process and reliability (intra- and inter-observer) of height, weight and waist circumference (WC) measurements in preschoolers. All technical procedures and devices were standardized and centralized training was given to the fieldworkers. At least seven children per country participated in the intra- and inter-observer reliability testing. Intra-observer technical error ranged from 0.00 to 0.03 kg for weight and from 0.07 to 0.20 cm for height, with the overall reliability being above 99%. A second training was organized for WC due to low reliability observed in the first training. Intra-observer technical error for WC ranged from 0.12 to 0.71 cm during the first training and from 0.05 to 1.11 cm during the second training, and reliability above 92% was achieved. Epidemiological surveys need standardized procedures and training of researchers to reduce measurement error. In the ToyBox-study, very good intra- and-inter-observer agreement was achieved for all anthropometric measurements performed.

Process evaluation design and tools used in a kindergarten-based, family-involved intervention to prevent obesity in early childhood. The ToyBox-study

Process evaluation (PE) is used for the in-depth evaluation of the implementation process of health promotion programmes. The aim of the current paper was to present the PE design and tools used in the ToyBox-intervention. The PE design was based on a three-step approach, including the identification of ToyBox-specific PE elements (step 1), the development of PE tools and harmonization of procedures (step 2), and the implementation of PE using standardized protocol and tools across the intervention countries (step 3). Specifically, to evaluate the implementation of the intervention, teachers' monthly logbooks were recorded (dose delivered, fidelity, dose received); post-intervention questionnaires were completed by parents/caregivers and teachers (dose received); participation and attrition rates were recorded (recruitment, reach); and audit questionnaires and retrospective information on weather conditions were collected (physical and social environment within which the intervention was implemented). Regarding the teachers' training sessions, the researchers who performed the trainings completed evaluation forms and documented teachers' attendance after each training (dose delivered, fidelity, dose received) and teachers completed evaluation forms after each training (dose received). The PE performed in the ToyBox-intervention may contribute in the evaluation of its effectiveness, guide the revision of the intervention material and provide insights for future health promotion programmes and public health policy.

Tools, harmonization and standardization procedures of the impact and outcome evaluation indices obtained during a kindergarten-based, family-involved intervention to prevent obesity in early childhood: the ToyBox-study

The ToyBox-intervention is a kindergarten-based, family-involved intervention targeting multiple lifestyle behaviours in preschool children, their teachers and their families. This intervention was conducted in six European countries, namely Belgium, Bulgaria, Germany, Greece, Poland and Spain. The aim of this paper is to provide a descriptive overview of the harmonization and standardization procedures of the baseline and follow-up evaluation of the study (and substudies). Steps related to the study's operational, standardization and harmonization procedures as well as the impact and outcome evaluation assessment tools used are presented. Experiences from the project highlight the importance of safeguarding the measurement process to minimize data heterogeneity derived from potential measurement error and country-by-country differences. In addition, it was made clear that continuing quality control and support is an important component of such studies. For this reason, well-supported communication channels, such as regular email updates and teleconferences, and regular internal and external meetings to ensure smooth and accurate implementation were in place during the study. The ToyBox-intervention and its harmonized and standardized procedures can serve as a successful case study for future studies evaluating the efficacy of similar interventions.

Concepts and strategies on how to train and motivate teachers to implement a kindergarten-based, family-involved intervention to prevent obesity in early childhood. The ToyBox-study

The key person for the implementation of kindergarten-based behavioural interventions is the kindergarten teacher. When conducting intervention studies in kindergartens, training sessions are needed to train and motivate kindergarten teachers for programme implementation. This paper presents the systematic development of the teachers' trainings executed in the ToyBox-intervention - a kindergarten-based and family-involved obesity prevention programme for children aged 4-6. Based on concepts for the education of kindergarten teachers, on general strategies for successful programme implementation and on the ToyBox programme-specific requirements, the aims of the teachers' trainings were defined and an overall concept was deduced. Regarding the concept for the ToyBox teachers' training sessions, it is concluded that the training modules should focus on presenting information on the practical implementation of the intervention. Furthermore, these modules should also include self-efficacy enhancing components and should give kindergarten teachers opportunities to share experiences. Regarding the didactic methods applied in the ToyBox teachers' training sessions, constructivist learning approaches that facilitate active participation, reflective thinking and personal involvement were implemented. Emphasis was put not only on the content but especially on the didactic methods of teachers' trainings in order to enhance devotion to, and quality and sustainability of the ToyBox-intervention.

Conception via in vitro fertilization and delivery by Caesarean section are associated with paediatric asthma incidence

BACKGROUND

The association between perinatal factors and asthma inception is under rigorous investigation. Nevertheless, evidence of a correlation between asthma, conception via in vitro fertilization (IVF) and delivery through Caesarean section (C-section) is inconclusive.

OBJECTIVE

We aimed to assess the relation of asthma incidence with IVF and C-section, after controlling for several potential confounding factors.

METHODS

Parent-reported wheeze in the last 12 months (current), wheeze ever, physician-diagnosed asthma, method of conception, and type of delivery were recorded from questionnaires filled in by the parents of 2016 Greek children aged 9-13, (the Healthy Growth Study population). Some perinatal data were recorded from children's medical records and others were reported by parents; anthropometric measurements were also conducted in children.

RESULTS

IVF was correlated with physician-diagnosed asthma (OR = 2.25; 95% CI = 1.11-4.56), but not with current/ever wheeze after adjustment for potential confounding factors. After adjustment, C-section was also associated with asthma (OR = 1.39; 95% CI = 1.04-1.87), but not with current/ever wheeze. When the association of both IVF and C-section with asthma was examined in the same multivariate logistic regression model, it was weakened to borderline significance (OR = 2.04; 95% CI = 1-4.15 and OR = 1.34; 95% CI = 1-1.81 respectively).

CONCLUSIONS AND CLINICAL RELEVANCE

Conception via IVF and delivery by C-section may predispose children to future asthma development. Either variable could also exert a confounding effect on the link of the other to asthma; this may partially be accountable for inconsistencies in the findings of pertinent studies.

Vitamins and iron blood biomarkers are associated with blood pressure levels in European adolescents. The HELENA study

OBJECTIVES

Previous research showed that low concentration of biomarkers in the blood during adolescence (i.e., iron status; retinol; and vitamins B6, B12, C, and D) may be involved in the early stages of development of many chronic diseases, such as hypertension. The aim was to evaluate if iron biomarkers and vitamins in the blood are associated with blood pressure in European adolescents.

METHODS

Participants from the Healthy Lifestyle in Europe by Nutrition in Adolescence cross-sectional study (N = 1089; 12.5-17.5 y; 580 girls) were selected by complex sampling. Multilevel linear regression models examined the associations between iron biomarkers and vitamins in the blood and blood pressure; the analyses were stratified by sex and adjusted for contextual and individual potential confounders.

RESULTS

A positive association was found in girls between RBC folate concentration and systolic blood pressure (SBP) (β = 3.19; 95% confidence interval [CI], 0.61-5.77), although no association between the vitamin serum biomarkers concentrations and diastolic blood pressure (DBP) was found. In boys, retinol was positively associated with DBP (β = 3.84; 95% CI, 0.51-7.17) and vitamin B6 was positively associated with SBP (β = 3.82; 95% CI, 1.46-6.18). In contrast, holotranscobalamin was inversely associated with SBP (β = -3.74; 95% CI, -7.28 to -0.21).

CONCLUSIONS

Levels of RBC folate and vitamin B6 in blood may affect BP in adolescents. In this context, programs aimed at avoiding high BP levels should promote healthy eating behavior by focusing on the promotion of vegetable proteins and foods rich in vitamin B12 (i.e., white meat and eggs), which may help to achieve BP blood control in adolescents.

High fat diets are associated with higher abdominal adiposity regardless of physical activity in adolescents; the HELENA study

BACKGROUND & AIMS

Failure to attain fat balance may contribute to obesity development even without excessive energy intake. The objective of this study was to examine the associations of dietary macronutrient distribution with abdominal adiposity in adolescents and to evaluate whether these relationships were attenuated by physical activity.

METHODS

A total of 224 Spanish adolescents (51% females, 14.9 ± 1.2 years) were included in the study. Abdominal adiposity in three regions, truncal and total body fat mass (FM) and lean mass (LM) were measured by dual-energy X-ray absorptiometry and thereafter FM index (FMI = FM/height(2)) and FMI/LMI ratio were calculated. The energy derived from fat intake was assessed by two non-consecutive 24 h recalls. Total physical activity (PA) and time spent in moderate-to-vigorous PA (MVPA) and vigorous PA were objectively measured by accelerometry.

RESULTS

We observed that the percent of energy derived from fat intake was significantly associated with FMI and FMI/LMI ratio (Ps = 0.001) and greater amounts of truncal (P = 0.001) and abdominal adiposity in the three regions regardless of age, sex and height (all P ≤ 0.005). The strength of the relationships was not substantially altered by further adjustment for PA, vigorous PA or moderate-to-vigorous PA (Ps ≤ 0.005).

CONCLUSIONS

The percent of energy derived from dietary fat intake is strongly and linearly associated with total, truncal and abdominal adiposity independently of PA in adolescents. These observations implicate the amount of dietary fat intake as a specific risk factor in the excess of abdominal adiposity in adolescence.

Criterion validity of the Physical Activity Questionnaire for Schoolchildren (PAQ-S) in assessing physical activity levels: the Healthy Growth Study

AIM

The aim of this paper was to evaluate the criterion validity of the Physical Activity Questionnaire for Schoolchildren (PAQ-S).

METHODS

The current study is a subcohort of the Healthy Growth Study, a large-scale cross-sectional study. 202 schoolchildren aged 9-13 years from Greece completed the PAQ-S and wore an accelerometer for 4 consecutive days. Time spent moderate (MPA), moderate to vigorous (MVPA) and vigorous (VPA) physical activity was calculated based on PAQ-S and accelerometer data.

RESULTS

The average time spent on MPA and MVPA as derived from PAQ-S and from accelerometers were significantly moderately correlated (r=0.462, P<0.001 and r=0.483, P<0.001, respectively). No significant correlation was detected between PAQ-S and accelerometer-measured time spent performing VPA (rho=0.150, P=0.057). Intraclass Correlation Coefficient (ICC) indicated a moderate agreement between PAQ-S and accelerometer in estimating MPA (ICC=0.592, P<0.001) and MVPA (ICC=0.581, P<0.001). Bland-Altman analysis revealed a small mean difference (the "bias"), between the two methods, in estimating MPA, although this difference was found to be significantly higher than zero ("bias"=27.4% of the accelerometer-measured mean score, P=0.006). On the other hand, Bland-Altman analysis revealed a large mean difference in estimating MVPA and VPA ("bias"=84.2% and 357% of the accelerometer-measured mean score for MVPA and VPA, respectively and P<0.001). The high correlation coefficient between the average and difference values between all physical activity scores derived from accelerometers and PAQ-S, indicate a systematic overestimation of physical activity time with increasing physical activity for PAQ-S.

CONCLUSION

The validity of PAQ-S for the estimation of MPA and MVPA was found to be slightly similar self-reported measures for schoolchildren. Therefore, this questionnaire could be used as a tool for physical activity assessment in large population studies.

Associations of physical activity and sedentary time with weight and weight status among 10- to 12-year-old boys and girls in Europe: a cluster analysis within the ENERGY project

BACKGROUND

Moderate-to-vigorous physical activity (MVPA) plays an important role in childhood overweight prevention. Sedentary time appears to be independently associated with overweight, but most research has been done in adults.

OBJECTIVE

The objective of this study were to identify subgroups of children based on their MVPA and sedentary time, and explore differences in body mass index (BMI), waist circumference and overweight prevalence between among these subgroups.

METHODS

A sample of 766 10- to 12-year-old children (52.9% girls, 11.6 ± 0.8 years) were recruited from Hungary (n = 158), Belgium (n = 111), the Netherlands (n = 113), Greece (n = 169) and Switzerland (n = 215). Children wore an accelerometer to measure MVPA and sedentary time.

RESULTS

Cluster analysis revealed four clusters in both gender groups showing an unhealthy pattern (low MVPA/high sedentary time), a healthy pattern (high MVPA/low sedentary time), a low mixed pattern (low MVPA/low sedentary time) and a moderate to high mixed pattern (moderate to high MVPA/moderate sedentary time). In girls, the high MVPA/low sedentary time cluster had a significantly lower BMI (P ≤ 0.05), a lower waist circumference (P ≤ 0.01) and the lowest percentage of overweight (P ≤ 0.10) compared with the other three clusters. In boys, both clusters with higher activity levels had a significantly lower BMI (P ≤ 0.001) and waist circumference (P ≤ 0.001) than the two low activity clusters, independent of sedentary time.

CONCLUSION

Engagement in more MVPA and less sedentary time is associated with a more favourable weight status among 10- to 12-year-old girls. Among boys, MVPA seems most important for weight status, while sedentary time appears to be less relevant.

Influencing factors of sedentary behavior in European preschool settings: an exploration through focus groups with teachers

BACKGROUND

Sedentary behavior refers to activities involving sitting down and reclining (eg, watching TV, using the computer) and has been associated with different health outcomes. In preschool, children are sedentary for 50% to 80% of the time, in the classroom as well as during recess. Because of the absence of qualitative studies examining influencing factors of preschoolers' sedentary behavior in preschool settings, this study explored teachers' opinions on potentially influencing factors of this behavior.

METHODS

Eighty-seven teachers of 4- to 6-year-old preschoolers from 6 European countries participated in a total of 18 focus groups between October 2010 and January 2011. Key findings were reported separately by country, and were independently analyzed by 2 researchers using qualitative content analysis.

RESULTS

Teachers perceive the lack of play space and small classroom size as being influential factors on preschoolers' sedentary behavior; increasing play equipment and using teachers' prompts are mentioned as ways to stimulate children to be less sedentary on the playground. Computer use is reported to be more common in preschool than watching TV.

CONCLUSION

Interventions should focus on increasing teachers' awareness of how sedentary preschoolers are during the preschool day. Teachers also should be informed about strategies to decrease sedentariness in the classroom and on the playground.

Measured sedentary time and physical activity during the school day of European 10- to 12-year-old children: the ENERGY project

OBJECTIVES

This study aims to describe the time devoted to sedentary and physical activities at school in five European countries and to examine differences according to country, sex, ethnicity, parental education and weight status.

DESIGN

cross-European cross-sectional survey.

METHODS

Primary schoolchildren (n=1025) aged 10-12 years in Belgium, Greece, Hungary, the Netherlands, and Switzerland wore accelerometers for at least six consecutive days. Only weekdays were used for this study to calculate the percentages of school-time spent in sedentary activities and moderate to vigorous intensity activity. Trained research assistants measured height and weight. Sex and date of birth were self-reported by the child and parental education and ethnicity were parent-reported.

RESULTS

European schoolchildren spent on average 65% of their time at school in sedentary activities and 5% on moderate to vigorous intensity activities, with small differences between countries. Girls spent a significant larger amount of school-time in sedentary activities (67%) than boys (63%; p<0.0001), and spent less time in moderate to vigorous intensity activities (4% versus 5%; p<0.001). Overweight children spent significantly less time in moderate to vigorous intensity activities (4%) than normal weight children (5%,p < 0.01) [corrected]. Parental education or ethnicity were not associated with time spent in sedentary or physical activities.

CONCLUSIONS

European schoolchildren spend a small amount of their school-time in moderate to vigorous intensity activities and a large amount in sedentary activities, with small but significant differences across countries. Future interventions should target more physical activities and less sedentary time at school particularly in girls.

Associations between eating meals, watching TV while eating meals and weight status among children, ages 10-12 years in eight European countries: the ENERGY cross-sectional study

Background

To assess the association of eating meals, and never watching TV while eating meals, with weight status among children, ages 10–12 years across Europe.

Methods

7915 children (mean age: 11.5 years) in eight European countries (Belgium, Greece, Hungary, the Netherlands, Norway, Slovenia, Spain and Switzerland) completed a questionnaire at school. Data on meals eaten the day before questionnaire administration and the frequency of eating meals while watching TV were collected. Height and weight of the children were objectively assessed. Multinomial and binary regression analyses were conducted to test associations of eating meals (adjusted for gender and ethnicity) and never watching TV while eating meals (adjusted for gender, ethnicity and total TV time) with overweight/obesity, and to test for country- and socio-demographic differences.

Results

The proportions of children reporting eating breakfast, lunch and dinner were 85%, 96%, and 93% respectively, and 55%, 46% and 32% reported to never watch TV at breakfast, lunch and dinner respectively. The children who ate breakfast (OR = 0.6 (95% CI 0.5-0.7)) and dinner (OR = 0.4 (95% CI 0.3-0.5)), had lower odds of being overweight compared to those who did not. The children who never watched TV at lunch (OR = 0.7 (95% CI 0.7-0.8)) and dinner (OR = 0.8 (95% CI 0.7-0.9)) had lower odds of being overweight compared to those who watched TV at the respective meals.

Conclusions

The odds of being overweight was lower for children who ate breakfast and dinner compared to those who did not eat the respective meals. The odds of being overweight was lower for children who reported to never watch TV at lunch and dinner compared to those who did. A focus towards meal frequency and watching TV during meals in longitudinal and interventions studies in prevention of overweight and obesity, may contribute to a better understanding of causality.

[Egg intake and cardiovascular risk factors in adolescents: role of physical activity; the HELENA study]

INTRODUCTION

Cardiovascular diseases (CVDs) represent the main cause of morbi-mortality in western countries. Serum cholesterol levels have been related to cardiovascular disease (CVD). Egg intake has been indirectly related to the risk of developing CVD because of its high cholesterol content.

OBJECTIVE

The aim of the present study was to examine the association between egg intake and CVD risk factors in adolescents, assessing the possible influence of physical activity.

METHODS

We studied 380 adolescents enrolled in the HELENA (HEalthy Lifestyle in Europe by Nutrition in Adolescence) study. Food intake was estimated by 2 nonconsecutive 24 h recalls. We measured adiposity indicators, lipid profile, blood glucose and insulin levels, insulin resistance, blood pressure and cardiorespiratory fitness. A CVD risk score was computed as a measure of the overall CVD risk profile. Physical activity was objectively measured by accelerometry. Sexual development was examined. Socioeconomic and smoking statuses were obtained by questionnaire. The association between egg intake and CVD risk factors was examined using a multilevel analysis adjusted for potential confounders.

RESULTS

Egg intake was not associated with lipid profile, adiposity, insulin resistance, blood pressure, cardiorespiratory fitness or the integrated CVD risk score. This lack of association was not influenced by physical activity.

CONCLUSIONS

The findings of the present study suggest that egg intake is not associated with a less favorable lipid or CVD risk profile in adolescents. This lack of association is not influenced by the level of physical activity.

Neck circumference: a useful screening tool of cardiovascular risk in children

OBJECTIVE

Early identification of cardiovascular risk factors consists an essential target for public health. The current study aims to examine the association between neck circumference and several cardiovascular risk factors and to compare it with well-established anthropometric indices.

METHODS

Demographic, anthropometric (body weight and height, waist, hip and neck circumference [WC, HC and NC, respectively]), biochemical (total cholesterol, high-density lipoprotein [HDL] cholesterol, low-density lipoprotein [LDL] cholesterol, triglycerides [TG], fasting plasma glucose and serum insulin), clinical (pubertal stage, systolic and diastolic blood pressure [SBP and DBP, respectively]) and lifestyle (dietary intake, physical activity level) data were collected from 324 children (51.5% boys; 48.5% girls) aged 9-13 in Greece. Body mass index z-score (BMI z-score), waist-to-hip ratio (WHR), waist-to-height ratio (WHtR), homeostasis model assessment (HOMA-IR), quantitative insulin sensitivity check index (QUICKI) and fasting glucose to insulin ratio (FGIR) were calculated.

RESULTS

All indices (BMI z-score, NC, WC, HC, WHR and WHtR) were correlated with SBP, HDL and insulin-related indices (insulin, HOMA-IR, QUICKI and FGIR) and all indices except WHR with TG. LDL was correlated with BMI z-score, WC, WHR and WHtR, whereas DBP was correlated with BMI z-score, WC, HC and WHtR. In multivariate analysis, HDL, TG, SBP, insulin, HOMA-IR, QUICKI and FGIR were associated with all anthropometric indices; DBP with WC, HC, NC and WHtR; LDL with BMI z-score, WC, HC and WHtR.

CONCLUSIONS

NC is associated with most cardiovascular disease risk factors. These associations are comparable with those observed for BMI z-score, WC, HC, WHR and WHtR. NC could be a simple, alternative screening tool of cardiovascular risk in children.

Self-reported TV and computer time do not represent accelerometer-derived total sedentary time in 10 to 12-year-olds

Screen-time activities are often used as proxies for sedentary time. We studied associations of self-reported television (TV), computer and total screen-time with accelerometer-derived total sedentary time in European children (10-12 years). Analyses showed significant positive associations between TV, computer and total screen-time with total sedentary time for the total sample, however, the explained variance was low and stratified analyses only revealed a significant positive association between total screen-time and total sedentary time in boys and between computer time and total sedentary time in Dutch children. This suggests that self-reported TV and computer time do not adequately reflect total sedentary time in schoolchildren.

Levels of physical activity and sedentary time among 10- to 12-year-old boys and girls across 5 European countries using accelerometers: an observational study within the ENERGY-project

Background

The study aim was to objectively assess levels of sedentary time, light, moderate and vigorous physical activity (PA) among 10-12 year olds across five European countries and to examine differences in sedentary time and PA according to gender and country.

Methods

686 children (mean age = 11.6 ± 0.8 years, 53% girls, mean BMI = 19.0 ± 3.4 kg/m²) from Belgium, Greece, Hungary, the Netherlands and Switzerland wore Actigraph accelerometers and had at least 2 weekdays with minimum 10 h-wearing time and 1 weekend day with minimum 8 h-wearing time. Data were analyzed using multivariate analyses of covariance.

Results

Girls spent significantly more time sedentary (500 minutes/day) than boys (474 minutes/day) and significantly less time in light (267 minutes/day) and moderate-to-vigorous PA (32 minutes/day) than boys (284 minutes/day; 43 minutes/day respectively; p < 0.001). 4.6% of the girls and 16.8% of the boys met moderate-to-vigorous PA recommendations of at least 60 minutes/day. Greek boys were more sedentary (510 minutes/day; all at p < 0.05) than other boys. Dutch girls were less sedentary (457 minutes/day; all at p < 0.05) than other girls. Swiss girls displayed more moderate-to-vigorous PA (43 minutes/day; at p < 0.05) than other girls.

Conclusions

Large proportions of children across different European countries did not meet PA recommendations and spent a lot of time sedentary. Mean time spent in moderate-to-vigorous PA was significantly lower than the recommended 60 minutes. Obesity prevention programmes focusing on both decreasing sedentary time and increasing light, moderate and vigorous PA are needed for European children, particularly girls.

A systematic approach for the development of a kindergarten-based intervention for the prevention of obesity in preschool age children: the ToyBox-study

The increasing childhood obesity epidemic calls for appropriate measures and effective policies to be applied early in life. Large-scale socioecological frameworks providing a holistic multifactorial and cost-effective approach necessary to support obesity prevention initiatives in this age are however currently missing. To address this missing link, ToyBox-study aims to build and evaluate a cost-effective kindergarten-based, family-involved intervention scheme to prevent obesity in early childhood, which could potentially be expanded on a pan-European scale. A multidisciplinary team of researchers from 10 countries have joined forces and will work to realize this according to a systematic stepwise approach that combines the use of the PRECEDE-PROCEED model and intervention mapping protocol. ToyBox-study will conduct systematic and narrative reviews, secondary data analyses, focus group research and societal assessment to design, implement and evaluate outcome, impact, process and cost effectiveness of the intervention. This is the first time that such a holistic approach has been used on a pan-European scale to promote healthy weight and healthy energy balance-related behaviours for the prevention of early childhood obesity. The results of ToyBox-study will be disseminated among key stakeholders including researchers, policy makers, practitioners and the general population.

Study protocol of physical activity and sedentary behaviour measurement among schoolchildren by accelerometry--cross-sectional survey as part of the ENERGY-project

Background

Physical activity and sedentary behaviour among children should be measured accurately in order to investigate their relationship with health. Accelerometry provides objective and accurate measurement of body movement, which can be converted to meaningful behavioural outcomes. The aim of this study was to evaluate the best evidence for the decisions on data collection and data processing with accelerometers among children resulting in a standardized protocol for use in the participating countries.

Methods/Design

This cross-sectional accelerometer study was conducted as part of the European ENERGY-project that aimed to produce an obesity prevention intervention among schoolchildren. Five countries, namely Belgium, Greece, Hungary, Switzerland and the Netherlands participated in the accelerometer study. We used three different Actigraph models-Actitrainers (triaxial), GT3Xs and GT1Ms. Children wore the device for six consecutive days including two weekend days. We selected an epoch length of 15 seconds. Accelerometers were placed at children's waist at the right side of the body in an elastic belt.

In total, 1082 children participated in the study (mean age = 11.7 ± 0.75 y, 51% girls). Non-wearing time was calculated as periods of more than 20 minutes of consecutive zero counts. The minimum daily wearing time was set to 10 hours for weekdays and 8 hours for weekend days. The inclusion criterion for further analysis was having at least three valid weekdays and one valid weekend day. We selected a cut-point (count per minute (cpm)) of <100 cpm for sedentary behaviour, <3000 cpm for light, <5200 cpm for moderate, and >5200 cpm for vigorous physical activity. We also created time filters for school-time during data cleaning in order to explore school-time physical activity and sedentary behaviour patterns in particular.

Discussion

This paper describes the decisions for data collection and processing. Use of standardized protocols would ease future use of accelerometry and the comparability of results between studies.