Influence of physical fitness on cardio-metabolic risk factors in European children. The IDEFICS study.

OBJECTIVE: The aim of the study was to assess the associations of individual and combined physical fitness components with single and clustering of cardio-metabolic risk factors in children. SUBJECTS/METHODS: This 2-year longitudinal study included a total of 1635 European children aged 6-11 years. The test battery included cardio-respiratory fitness (20-m shuttle run test), upper-limb strength (handgrip test), lower-limb strength (standing long jump test), balance (flamingo test), flexibility (back-saver sit-and-reach) and speed (40-m sprint test). Metabolic risk was assessed through z-score standardization using four components: waist circumference, blood pressure (systolic and diastolic), blood lipids (triglycerides and high-density lipoprotein) and insulin resistance (homeostasis model assessment). Mixed model regression analyses were adjusted for sex, age, parental education, sugar and fat intake, and body mass index. RESULTS: Physical fitness was inversely associated with clustered metabolic risk (P<0.001). All coefficients showed a higher clustered metabolic risk with lower physical fitness, except for upper-limb strength (ß=0.057; P=0.002) where the opposite association was found. Cardio-respiratory fitness (ß=-0.124; P<0.001) and lower-limb strength (ß=-0.076; P=0.002) were the most important longitudinal determinants. The effects of cardio-respiratory fitness were even independent of the amount of vigorous-to-moderate activity (ß=-0.059; P=0.029). Among all the metabolic risk components, blood pressure seemed not well predicted by physical fitness, while waist circumference, blood lipids and insulin resistance all seemed significantly predicted by physical fitness. CONCLUSION: Poor physical fitness in children is associated with the development of cardio-metabolic risk factors. Based on our results, this risk might be modified by improving mainly cardio-respiratory fitness and lower-limb muscular strength.

Objectively measured physical activity in European children: the IDEFICS study.

OBJECTIVES: To provide sex- and age-specific percentile values for levels of physical activity (PA) and sedentary time of European children aged 2.0-10.9 years from eight European countries (Sweden, Germany, Hungary, Italy, Cyprus, Spain, Belgium and Estonia). METHODS: Free-living PA and sedentary time were objectively assessed using ActiGraph GT1M or ActiTrainer activity monitors in all children who had at least 3 days' worth of valid accelerometer data, with at least 8 h of valid recording time each day. The General Additive Model for Location Scale and Shape was used for calculating percentile curves. RESULTS: Reference values for PA and sedentary time in the European children according to sex and age are displayed using smoothed percentile curves for 7684 children (3842 boys and 3842 girls). The figures show similar trends in boys and girls. The percentage of children complying with recommendations regarding moderate-to-vigorous physical activity (MVPA) is also presented and varied considerably between sexes and country. For example, the percentage of study participants who were physically active (as assessed by MVPA) for 60 or more minutes per day ranged from 2.0% (Cyprus) to 14.7% (Sweden) in girls and from 9.5% (Italy) to 34.1% (Belgium) in boys. CONCLUSION: This study provides the most up-to-date sex- and age-specific reference data on PA in young children in Europe. The percentage compliance to MVPA recommendations for these European children varied considerably between sexes and country and was generally low. These results may have important implications for public health policy and PA counselling.

Adherence to the obesity-related lifestyle intervention targets in the IDEFICS study.

BACKGROUND/OBJECTIVES: To address behaviours associated with childhood obesity, certain target values are recommended that should be met to improve children's health. In the IDEFICS (Identification and prevention of Dietary- and lifestyle-induced health Effects in Children and infantS) study such lifestyle recommendations were conveyed as six key messages. Here, we investigate the adherence of European children to these messages. METHODS: The IDEFICS intervention was based on the intervention mapping approach with the following six targets: increase water consumption (to replace sugar-containing beverages), increase fruit/vegetable consumption, reduce daily screen time, increase daily physical activity, improve the quality of family life and ensure adequate sleep duration. Internationally recommended target values were applied to determine the prevalence of children meeting these targets. RESULTS: In a cohort of 18,745 children participating in the IDEFICS baseline survey or newly recruited during follow-up, data on the above lifestyle behaviours were collected for a varying number of 8302 to 17,212 children. Information on all six behaviours was available for 5140 children. Although 52.5% of the cohort was classified in the highest category of water consumption, only 8.8% met the target of an intake of fruits/vegetables five times a day. The prevalence of children adhering to the recommendation regarding total screen time-below 1 h for pre-school children and 2 h for school children-was 51.1%. The recommended amount of at least 60 min of moderate-to-vigorous physical activity per day was fulfilled by 15.2%. Family life of the child measured by various indicators was considered as satisfactory in 22.8%. Nocturnal sleep duration of 11 (10) hours or more in pre-school (school) children was achieved by 37.9%. In general, children in northern countries and younger children showed better adherence to the recommendations. Only 1.1% of the children adhered to at least five of these recommendations. CONCLUSIONS: Current adherence of children to lifestyle recommendations to prevent childhood obesity is low where observed differences with respect to country, age and gender call for targeted intervention.

Impact of methodological decisions on accelerometer outcome variables in young children.

BACKGROUND: The impact of accelerometer-related methodological decisions relating to the assessment of physical activity and sedentary time has not been conclusively determined in young children. OBJECTIVES: To determine the effects of epoch and cutoff points on the assessment of physical activity and sedentary time and to determine the accelerometer wear time required to achieve reliable accelerometer data in children. DESIGN: Children were recruited from centres at Ghent, Glasgow, Gothenburg and Zaragoza. METHODS: Physical activity was assessed for 1 week in 86 children (41 girls, 45 boys; mean age 7±2 years) by uniaxial accelerometry. The epoch was set at 15 s and reintegrated to 30 and 60 s. Time spent sedentary and in moderate and vigorous physical activity (MVPA) was assessed using a range of cutoff points. Number of days required to achieve 80% reliability was predicted using the Spearman-Brown Prophecy formula. RESULTS: The Reilly cutoff points (<1100 counts per min (CPM)) indicated less sedentary time per day when comparing 15 vs 30 s and 15 vs 60 s epochs: 570±91 vs 579±93 min and 570±91 vs 579±94 min, respectively; P<0.05. Pate cutoff points (>420 counts per 15 s) reported more MVPA time per day compared with Sirard (890 counts per 15 s) and Puyau cutoff points (>3200 counts per min) using 15 s epoch: 78 (4-197) min (median (range) vs 18 (1-80) min and 24 (1-100) min, respectively; P<0.001. Compliance with guidelines of at least 60 min MVPA was 84, 78 and 73% for Pate cutoff points using 15, 30 and 60 s epochs, respectively, but 0% for Sirard and Puyau cutoff points across epochs. The number of days required to achieve 80% reliability for CPM, sedentary and MVPA time was 7.4-8.5 days. CONCLUSION: Choice of epoch and cutoff point significantly influenced the classification of sedentary and MVPA time and observed compliance to the MVPA guidelines.

The IDEFICS validation study on field methods for assessing physical activity and body composition in children: design and data collection.

OBJECTIVE: To describe the design, measurements and fieldwork of the IDEFICS (Identification and prevention of dietary- and lifestyle-induced health effects in children and infants) physical activity and body composition validation study, and to determine the potential and limitations of the data obtained. DESIGN: Multicentre validation study. SUBJECTS: A total of 98 children from four different European countries (age: 4-10 years). METHODS: An 8-day measurement protocol was carried out in all children using a collaborative protocol. Reference methods were the doubly labelled water method for physical activity, and a three- and a four-compartment model for body composition. Investigated field methods were accelerometers, a physical activity questionnaire and various anthropometric measurements. RESULTS: For the validation of physical activity field methods, it was possible to gather data from 83 to 89 children, laying the basis for age- and sex-specific results. The validation of body composition field methods is possible in 64-80 children and allows sex-specific analyses but has only limited statistical power in the youngest age group (<6 years). The amount of activity energy expenditure (AEE) varied between centres, sexes and age groups, with boys and older children having higher estimates of AEE. After normalisation of AEE by body weight, most group-specific differences diminished, except for country-specific differences. CONCLUSION: The IDEFICS validation study will allow age- and sex-specific investigation of questions pertaining to the validity of several field methods of body composition and physical activity, using established reference methods in four different European countries. From the participant analyses it can be concluded that the compliance for the investigated field methods was higher than that for the reference methods used in this validation study.

The IDEFICS community-oriented intervention programme: a new model for childhood obesity prevention in Europe?

BACKGROUND AND OBJECTIVES: The European Union-as well as other parts of the world-faces a major challenge of increasing incidence of overweight/obesity. In particular, the increase in childhood obesity gives rise to a strong imperative for immediate action. Yet, little is known about the effectiveness of community interventions, and further research in this field is needed. There is, however, a growing consensus that such research should start from the paradigm that the current living environments tend to counteract healthy lifestyles. Questioning these environments thoroughly can help to develop new pathways for sustainable health-promoting communities. Against this background, the IDEFICS (Identification and prevention of dietary- and lifestyle-induced health effects in children and infants) study developed and implemented innovative community-oriented intervention programmes for obesity prevention and healthy lifestyle primarily in children aged 2-10 years in eight European countries: Sweden, Estonia, Germany, Belgium, Hungary, Italy, Spain and Cyprus. MATERIALS AND METHODS: The IDEFICS community-oriented intervention study mobilised an integrated set of interventional efforts at different levels of society, with the aim of facilitating the adoption of a healthy obesity-preventing lifestyle. The overall programme has been composed of 10 modules: three at community level, six at school level and one for parents. The main focus was on diet, physical activity and stress-coping capacity. The sphere of action encompassed both children and their (grand) parents, schools, local public authorities and influential stakeholders in the community. All materials for the interventions were centrally developed and culturally adapted. RESULTS: So far, the following has been achieved: focus group research, literature review and expert consultations were done in an early phase as a basis for the development of the intervention modules. The intervention mapping protocol was followed as guide for structuring the intervention research. The overall intervention programme's duration was 2 years, but a longer-term follow-up programme is under development. CONCLUSIONS: This large-scale European effort is expected to contribute significantly to the understanding of this major public health challenge.

Differential outcome of the IDEFICS intervention in overweight versus non-overweight children: did we achieve 'primary' or 'secondary' prevention?

BACKGROUND: The aim of this study was to explore whether the IDEFICS intervention had a differential effect on 11,041 children's weight trajectories depending on their baseline body mass index status. METHODS: Two subgroups of children are considered in the present analysis: those who were overweight or obese prior to the intervention and those who were neither overweight nor obese. RESULTS: Among children in all eight countries who did not have prevalent overweight or obesity (OWOB) at baseline, 2 years later, there was no significant difference between intervention and control groups in risk of having developed OWOB. However, we observed a strong regional heterogeneity, which could be attributed to the presence of one distinctly outlying country, Belgium, where the intervention group had increased risk for becoming overweight. In contrast, among the sample of children with prevalent OWOB at baseline, we observed a significantly greater probability of normalized weight status after 2 years. In other words, a protective effect against persistent OWOB was observed in children in intervention regions compared with controls, which corresponded to an adjusted odds ratio of 0.76 (95% confidence interval: 0.58, 0.98). DISCUSSION: This analysis thus provided evidence of a differential effect of the IDEFICS intervention, in which children with overweight may have benefited without having been specifically targeted. However, no overall primary preventive effect could be observed in children without initial overweight or obesity.

Behavioural effects of a community-oriented setting-based intervention for prevention of childhood obesity in eight European countries. Main results from the IDEFICS study.

OBJECTIVE: The objective of this paper is to evaluate the behavioural effects, as reported by the parents of the participating boys and girls, of the IDEFICS (Identification and prevention of Dietary- and lifestyle-induced health EFfects In Children and infantS) intervention. METHODS: The effectiveness of the IDEFICS intervention was evaluated through a cluster-controlled trial in eight European countries (control and intervention communities in each country) including more than 16,000 children. The 2- to 9.9-year-old children in the intervention group were exposed to a culturally adapted intervention that aimed to prevent childhood obesity through the community, schools/kindergartens and family. Parents completed questionnaires to measure water, soft drink and fruit juice intake; fruit and vegetable intake; daily TV viewing and other sedentary behaviours; daily physical activity levels and strengthening of the parent-child relationships at baseline and follow-up (2 years later). Mixed models with an additional random effect for country were used to account for the clustered study design, and results were stratified by sex. RESULTS: The pan-European analysis revealed no significant time by condition interaction effects, neither for boys nor girls, i.e. the analysis revealed no intervention effects on the behaviours of the IDEFICS children as reported by their parents (F = 0.0 to 3.3, all p > 0.05). Also very few significances were found in the country-specific analyses. Positive intervention effects were only found for sport club participation in Swedish boys, for screen time in weekends for Spanish boys and for TV viewing in Belgian girls. CONCLUSION: Although no expected intervention effects as reported by the parents on diet, physical activity and sedentary behaviours could be shown for the overall IDEFICS cohort, a few favourable intervention effects were found on specific behaviours in some individual countries. More in-depth analyses of the process evaluation data are needed to obtain more insight into the relationship between the level of exposure to the intervention and its effect.

Effect of the IDEFICS multilevel obesity prevention on children's sleep duration.

BACKGROUND: According to recent findings, short sleep duration is associated with overweight in children. However, primary prevention efforts aimed at achieving adequate sleep among children are scarce. Therefore, the 'Identification and prevention of Dietary-induced and lifestyle-induced health EFfects In Children and infantS' (IDEFICS) study implemented a multilevel intervention that included sleep duration as a key behavioural target. The aim of this study is to evaluate sleep duration among children participating in the IDEFICS study. METHODS: The IDEFICS nocturnal sleep intervention was included as part of stress reduction educational messages aimed at parents and children. Sleep was assessed by a parental 24-h recall (only weekdays; n = 8,543) and by a diary (weekdays and weekends separately; n = 4,150). Mixed linear models tested the intervention effect on sleep duration change between baseline when children were 2-9.9 years of age (2007/2008) and follow-up (2009/2010). Logistic mix models were used to study the intervention effect on the presence of TV in the children's bedroom (one of the intervention messages; n = 8,668). Additionally, parents provided qualitative data regarding exposure to the intervention. RESULTS: About 51.1% of the parents in the intervention regions reported awareness of the sleep intervention. A small intervention effect was seen on weeknight sleep duration in that the decrease in sleep duration over 2 years was smaller in the intervention (15 min) as compared with control regions (19 min) (p = 0.044). There was no overall intervention effect on weekend sleep duration or on the presence of a TV in the bedroom. A small significant time effect between baseline and follow-up was found on bedroom TV presence depending on self-reported intervention exposure (3% increase in TV presence in exposed versus 6.6% increase in non-exposed). Children without a TV in the bedroom had longer nocturnal sleep duration. DISCUSSION: The sleep component of the intervention did not lead to clinically relevant changes in sleep duration. Future interventions aimed at young children's sleep duration could benefit from more specific and intense messaging than that found in the IDEFICS intervention. Future research should use objective measures of sleep duration as well as intermediate outcomes (sleep knowledge, sleep environment and sleep practices).

Implementation of the IDEFICS intervention across European countries: perceptions of parents and relationship with BMI.

OBJECTIVES: The primary aim of the present study was to obtain insight into parents' perception of the IDEFICS intervention at the school or preschool/kindergarten and community levels and whether they received specific materials related to the intervention. The secondary aim was to analyse whether parents who reported higher levels of exposure to the IDEFICS intervention had children with more favourable changes in body mass index (BMI) z-scores between baseline and after 2 years of intervention. METHODS: Process evaluation of the IDEFICS intervention investigated the implementation of the 2-year intervention in the intervention communities. Intervention group parents (n = 4,180) in seven countries (Belgium, Cyprus, Estonia, Germany, Italy, Spain and Sweden) answered questions about their exposure to the IDEFICS study. To analyse the relationship between exposure and BMI z-score, a composite score was calculated for exposure at the setting and at the community levels. RESULTS: The frequency of parental exposure to the IDEFICS messages not only through the community but also through the (pre)school/kindergarten was lower than what was intended and planned. The dose received by the parents was considerably higher through the (pre)school/kindergarten settings than that through the community in all countries. Efforts by the settings or communities related to fruit and vegetable consumption (range 69% to 97%), physical activity promotion (range 67% to 91%) and drinking water (range 49% to 93%) were more visible and also realized more parental involvement than those related to TV viewing, sleep duration and spending time with the family (below 50%). Results showed no relation of parental exposure at the setting or the community level on more favourable changes in children's BMI z-scores for the total sample. Country-specific analyses for parental exposure at the setting level showed an expected positive effect in German girls and an unexpected negative effect in Italian boys. CONCLUSION: Parental exposure and involvement in the IDEFICS intervention in all countries was much less than aimed for, which might be due to the diverse focus (six key messages) and high intensity and duration of the intervention. It may also be that the human resources invested in the implementation and maintenance of intervention activities by the study centres, the caretakers and the community stakeholders were not sufficient. Higher levels of parental exposure were not related to more favourable changes in BMI z-scores.

Effectiveness of the IDEFICS intervention on objectively measured physical activity and sedentary time in European children.

BACKGROUND: This paper reports on the effectiveness of the prevention of dietary- and lifestyle-induced health effects in children and infants (IDEFICS) intervention on objectively measured physical activity (PA) and sedentary time (ST) in 2- to 9.9-year-old European boys and girls. METHODS: The intervention was evaluated after 2 years through a non-randomized cluster-controlled trial in eight European countries (one control and one intervention community per country). All children in the intervention group received a culturally adapted childhood obesity prevention programme through the community, schools/kindergartens and family. A random sub-sample of children participating in the IDEFICS study wore an accelerometer at baseline and follow-up for at least 3 days (n = 9,184). Of this sample, 81% provided valid accelerometer data at baseline (n = 7,413; 51% boys; 6.21 ± 1.76 years; boys: 617 ± 170 cpm day(-1) ; girls 556 ± 156 cpm day(-1) ) and 3,010 children provided valid accelerometer data at baseline and during the follow-up survey 2 years later. RESULTS: In boys and girls, no significant differences in PA and ST were found between intervention and control groups over 2 years. Strong temporal effects were found in the total sample of boys and girls: the percentage of time spent in light PA per day decreased by 4 percentage points in both boys and girls between baseline and follow-up (both: p < 0.001), while time spent in ST per day increased by 4 percentage points in both sexes over time (both: p < 0.001). Percentage of time spent in moderate-to-vigorous PA per day remained stable over time in boys and girls. CONCLUSION: Despite the socio-ecological approach and implementation of a culturally adapted intervention in each country, no effects of the IDEFICS intervention were found on children's objectively measured PA and ST. Behavioural interventions for children may need to enhance specificity and intensity at the family level using other behaviour change techniques and more direct strategies to reach parents.