Analysis of the association of leptin and adiponectin concentrations with metabolic syndrome in children: Results from the IDEFICS study.

BACKGROUND AND AIMS: Adipokines may play a role in the pathogenesis of the metabolic syndrome (MetS) in children. We aimed to evaluate the association of leptin, adiponectin, and its ratio (L/A ratio) with the metabolic syndrome (MetS) in a subsample of the IDEFICS (Identification and prevention of Dietary- and lifestyle-induced health EFfects In Children and infantS) cohort. METHODS AND RESULTS: Leptin, adiponectin and MetS parameters were measured in a subsample of 1253 children (3-9.9 years) participating to the IDEFICS study, grouped as: Non-OW (underweight/normal weight) and OW/Ob (overweight/obese). MetS was defined using the sex- and age-specific cut-offs based on the distribution of MetS components in the IDEFICS cohort. The prevalence of the MetS among OW/Ob was 24.8% and 27.1% in boys and girls respectively, whereas ≤2% among Non-OW. OW/Ob had significantly higher leptin and L/A ratio as compared to Non-OW. Significantly higher leptin was found in OW/Ob with MetS as compared with OW/Ob without MetS. Significantly lower adiponectin was observed only in OW/Ob girls as compared to Non-OW. A 1SD increase in leptin and L/A ratio z-scores or a 1SD decrease in adiponectin z-score were significantly associated with higher risk of MetS. After adjustment for BMI or body fat mass (BFM) the association remained significant only for leptin. CONCLUSION: We showed that in European children, higher leptin concentration is associated with MetS, even after adjusting for BMI or BFM, confirming an early role of leptin in MetS, while the association of adiponectin with MetS seems be mediated by body fat in this age range.

The impact of familial, behavioural and psychosocial factors on the SES gradient for childhood overweight in Europe. A longitudinal study.

BACKGROUND: In highly developed countries, childhood overweight and many overweight-related risk factors are negatively associated with socioeconomic status (SES). OBJECTIVE: The objective of this study is to investigate the longitudinal association between parental SES and childhood overweight, and to clarify whether familial, psychosocial or behavioural factors can explain any SES gradient. METHODS: The baseline and follow-up surveys of the identification and prevention of dietary and lifestyle induced health effects in children and infants (IDEFICS) study are used to investigate the longitudinal association between SES, familial, psychosocial and behavioural factors, and the prevalence of childhood overweight. A total of 5819 children (50.5% boys and 49.5% girls) were included. RESULTS: The risk for being overweight after 2 years at follow-up in children who were non-overweight at baseline increases with a lower SES. For children who were initially overweight, a lower parental SES carries a lower probability for a non-overweight weight status at follow-up. The effect of parental SES is only moderately attenuated by single familial, psychosocial or behavioural factors; however, it can be fully explained by their combined effect. Most influential of the investigated risk factors were feeding/eating practices, parental body mass index, physical activity behaviour and proportion of sedentary activity. CONCLUSION: Prevention strategies for childhood overweight should focus on actual behaviours, whereas acknowledging that these behaviours are more prevalent in lower SES families.

Efficacy of neck circumference to identify metabolic syndrome in 3-10 year-old European children: Results from IDEFICS study.

BACKGROUND AND AIMS: Several studies demonstrated that larger neck circumference (NC) in children and adolescents may help to identify obesity and cardio-metabolic abnormalities. We aimed to evaluate the correlation between NC and metabolic syndrome (MetS) risk factors and to determine the utility of this anthropometric index to identify MetS in European children. METHODS AND RESULTS: The present cross-sectional analysis includes 15,673 children (3-10 years) participating in the IDEFICS study. A continuous MetS (cMetS) score was calculated summing age and sex standardized z-scores of specific MetS risk factors. Receiver Operating Characteristic analysis, stratified by one-year age groups, was used to determine the ability of NC to identify children with unfavorable metabolic profile, corresponding to cMetS score ≥ 90th percentile. The areas under the curve values for NC associated with cMetS score values ≥ 90th percentile were significantly greater in girls than in boys (p < 0.001), except for 5 < 6 years group. For boys, optimal NC cut-off values ranged from 26.2 cm for the lowest age group (3 < 4 years), up to 30.9 cm for the highest age group (9 < 10 years). In girls, corresponding values varied from 24.9 cm to 29.6 cm. CONCLUSION: The study demonstrated the efficacy of NC in identifying European children with an unfavorable metabolic profile.

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.

Effects of a community-oriented obesity prevention programme on indicators of body fatness in preschool and primary school children. Main results from the IDEFICS study.

BACKGROUND/OBJECTIVES: Childhood obesity is a major public health concern but evidence-based approaches to tackle this epidemic sustainably are still lacking. The Identification and prevention of Dietary- and lifestyle-induced health EFfects In Children and infantS (IDEFICS) study investigated the aetiology of childhood obesity and developed a primary prevention programme. Here, we report on the effects of the IDEFICS intervention on indicators of body fatness. SUBJECTS/METHODS: The intervention modules addressed the community, school and parental level, focusing on diet, physical activity and stress-related lifestyle factors. A cohort of 16,228 children aged 2-9.9 years - about 2000 per country - was equally divided over intervention and control regions. (Participating countries were Sweden, Germany, Estonia, Hungary, Cyprus, Italy, Spain and Belgium.) We compared the prevalence of overweight/obesity and mean values of body mass index z-score, per cent body fat and waist-to-height ratio over 2 years of follow-up. Mixed models adjusting for age and socioeconomic status of the parents and with an additional random effect for country accounted for the clustered study design. RESULTS: The prevalence of overweight and obesity increased in both the intervention and control group from 18.0% at baseline to 22.9% at follow-up in the control group and from 19.0% to 23.6% in the intervention group. The difference in changes between control and intervention was not statistically significant. For the cohort as a whole, the changes in indicators of body fatness did not show any clinically relevant differences between the intervention and control groups. Changes in favour of intervention treatment in some indicators were counterbalanced by changes in favour of the control group in some other indicators. CONCLUSIONS: Over the 2-year-observation period, the IDEFICS primary prevention programme for childhood obesity has not been successful in reducing the prevalence of overweight and obesity nor in improving indicators of body fatness in the target population as a whole.

Does the FTO gene interact with the socioeconomic status on the obesity development among young European children? Results from the IDEFICS study.

BACKGROUND: Various twin studies revealed that the influence of genetic factors on psychological diseases or behaviour is more expressed in socioeconomically advantaged environments. Other studies predominantly show an inverse association between socioeconomic status (SES) and childhood obesity in Western developed countries. The aim of this study is to investigate whether the fat mass and obesity-associated (FTO) gene interacts with the SES on childhood obesity in a subsample (N = 4406) of the IDEFICS (Identification and prevention of Dietary- and lifestyle-induced health EFfects In Children and infantS) cohort. METHODS: A structural equation model (SEM) is applied with the latent constructs obesity, dietary intakes, physical activity and fitness habits, and parental SES to estimate the main effects of the latter three variables and a FTO polymorphism on childhood obesity. Further, a multiple group SEM is used to explore whether an interaction effect exists between the single nucleotide polymorphism rs9939609 within the FTO gene and SES. RESULTS: Significant main effects are shown for physical activity and fitness (standardised [betacrc ](s) = -0.113), SES ([betacrc ](s) = -0.057) and the FTO homozygous AA risk genotype ([betacrc ](s) = -0.177). The explained variance of obesity is ~9%. According to the multiple group approach of SEM, we see an interaction between SES and FTO with respect to their effect on childhood obesity (Δχ(2) = 7.3, df = 2, P = 0.03). CONCLUSION: Children carrying the protective FTO genotype TT seem to be more protected by a favourable social environment regarding the development of obesity than children carrying the AT or AA genotype.

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.

Percentile reference values for anthropometric body composition indices in European children from the IDEFICS study.

INTRODUCTION: To characterise the nutritional status in children with obesity or wasting conditions, European anthropometric reference values for body composition measures beyond the body mass index (BMI) are needed. Differentiated assessment of body composition in children has long been hampered by the lack of appropriate references. OBJECTIVES: The aim of our study is to provide percentiles for body composition indices in normal weight European children, based on the IDEFICS cohort (Identification and prevention of Dietary- and lifestyle-induced health Effects in Children and infantS). METHODS: Overall 18,745 2.0-10.9-year-old children from eight countries participated in the study. Children classified as overweight/obese or underweight according to IOTF (N=5915) were excluded from the analysis. Anthropometric measurements (BMI (N=12 830); triceps, subscapular, fat mass and fat mass index (N=11,845-11,901); biceps, suprailiac skinfolds, sum of skinfolds calculated from skinfold thicknesses (N=8129-8205), neck circumference (N=12,241); waist circumference and waist-to-height ratio (N=12,381)) were analysed stratified by sex and smoothed 1st, 3rd, 10th, 25th, 50th, 75th, 90th, 97th and 99th percentile curves were calculated using GAMLSS. RESULTS: Percentile values of the most important anthropometric measures related to the degree of adiposity are depicted for European girls and boys. Age- and sex-specific differences were investigated for all measures. As an example, the 50th and 99th percentile values of waist circumference ranged from 50.7-59.2 cm and from 51.3-58.7 cm in 4.5- to <5.0-year-old girls and boys, respectively, to 60.6-74.5 cm in girls and to 59.9-76.7 cm in boys at the age of 10.5-10.9 years. CONCLUSION: The presented percentile curves may aid a differentiated assessment of total and abdominal adiposity in European children.

Blood pressure reference values for European non-overweight school children: the IDEFICS study.

OBJECTIVES: To provide oscillometric blood pressure (BP) reference values in European non-overweight school children. DESIGN: Cross-sectional analysis from the IDEFICS study (www.ideficsstudy.eu) database. METHODS: Standardised BP and anthropometric measures were obtained from children aged 2 to 10.9 years, participating in the 2007-2008 and 2009-2010 IDEFICS surveys. Age- and height-specific systolic and diastolic pressure percentiles were calculated by GAMLSS, separately for boys and girls, in both the entire population (n=16,937) and the non-overweight children only (n=13,547). The robustness of the models was tested by sensitivity analyses carried out in both population samples. RESULTS: Percentiles of BP distribution in non-overweight children were provided by age and height strata, separately for boys and girls. Diastolic BP norms were slightly higher in girls than in boys for similar age and height, while systolic BP values tended to be higher in boys starting from age 5 years. Sensitivity analysis, comparing BP distributions obtained in all children with those of non-overweight children, showed that the inclusion of overweight/obese individuals shifted the references values upward, in particular systolic BP in girls at the extreme percentiles. CONCLUSIONS: The present analysis provides updated and timely information about reference values for BP in children aged 2 to <11 years that may be useful for monitoring and planning population strategies for disease prevention.

Country-specific dietary patterns and associations with socioeconomic status in European children: the IDEFICS study.

BACKGROUND/OBJECTIVES: Children from lower socioeconomic status (SES) may be at higher risk of unhealthy eating. We described country-specific dietary patterns among children aged 2-9 years from eight European countries participating in the IDEFICS study and assessed the association of dietary patterns with an additive SES indicator. SUBJECTS/METHODS: Children aged 2-9 years from eight European countries were recruited in 2007-2008. Principal component analysis was applied to identify dietary country-specific patterns. Linear regression analyses were applied to assess their association with SES. RESULTS: Two to four dietary patterns were identified in the participating regions. The existence of a 'processed' pattern was found in the eight regions. Also, a 'healthy' pattern was identified in seven of the eight regions. In addition, region-specific patterns were identified, reflecting the existing gastronomic and cultural differences in Europe. The 'processed' pattern was significantly inversely associated with the SES additive indicator in all countries except Sweden, whereas the 'healthy' pattern was positively associated with SES in the Belgian, Estonian, German and Hungarian regions, but was not significant in the Italian, Spanish and Swedish regions. CONCLUSIONS: A 'processed' pattern and a 'healthy' pattern were found in most of the participating countries in the IDEFICS study, with comparable food item profiles. The results showed a strong inverse association of SES with the 'processed' pattern, suggesting that children of parents with lower SES may be at higher risk of unhealthy eating. Therefore, special focus should be given to parents and their children from lower SES levels when developing healthy eating promotion strategies.

Validity of 24-h recalls in (pre-)school aged children: comparison of proxy-reported energy intakes with measured energy expenditure.

BACKGROUND & AIMS: Little is known about the validity of repeated 24-h dietary recalls (24-HDR) as a measure of total energy intake (EI) in young children. This study aimed to evaluate the validity of proxy-reported EI by comparison with total energy expenditure (TEE) measured by the doubly labeled water (DLW) technique. METHODS: The agreement between EI and TEE was investigated in 36 (47.2% boys) children aged 4-10 years from Belgium and Spain using subgroup analyses and Bland-Altman plots. Low-energy-reporters (LER), adequate-energy-reporters (AER) and high-energy-reporters (HER) were defined from the ratio of EI over TEE by application of age- and sex-specific cut-off values. RESULTS: There was good agreement between means of EI (1500 kcal/day) and TEE (1523 kcal/day) at group level though in single children, i.e. at the individual level, large differences were observed. Almost perfect agreement between EI and TEE was observed in thin/normal weight children (EI: 1511 kcal/day; TEE: 1513 kcal/day). Even in overweight/obese children the mean difference between EI and TEE was only -86 kcal/day. Among the participants, 28 (78%) were classified as AER, five (14%) as HER and three (8%) as LER. CONCLUSION: Two proxy-reported 24-HDRs were found to be a valid instrument to assess EI on group level but not on the individual level.

Influence of breastfeeding on blood-cell transcript-based biomarkers of health in children.

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT: The expression of specific genes in peripheral blood cells (PBCs) may be used as biomarkers of the metabolic status. High levels of expression of CPT1A, SLC27A2, INSR, LEPR, FASN and PPARα in PBCs are indicative of a lower risk for the insulin resistant or dyslipidaemic state associated with obesity in children. Breastfeeding seems to confer protective effects against obesity and its related metabolic problems. WHAT THIS STUDY ADDS: Children who had been breastfed showed higher expression levels of SLC27A2, FASN, PPARα and INSR in PBCs compared with formula-fed subjects. The relationship of the PBC transcript levels of SLC27A2, INSR, FASN and PPARα with insulin resistance and dyslipidaemia may be dependent on the type of infant feeding (breast vs. formula). The transcript levels of the mentioned biomarkers could be useful to distinguish the formula-fed children who are at higher risk of metabolic alterations. BACKGROUND: Blood-cell transcripts have showed to be good biomarkers of metabolic alterations and their use in early detection and prevention of future disorders is promising. OBJECTIVE: This study aimed to examine the relation between previously proposed transcriptional biomarkers of metabolic health (SLC27A2, CPT1A, FASN, PPARα, INSR, LEPR) in peripheral blood cells and the type of infant feeding in a subset of children from the IDEFICS (Identification and Prevention of Dietary- and Lifestyle-Induced Health Effects in Children and Infants) cohort. SUBJECTS: A total of 237 children aged 2-9 years from eight European countries were studied. RESULTS: Breastfed children showed higher expression levels of SLC27A2, FASN, PPARα and INSR, and lower risk of being overweight and of having high plasma triglyceride levels vs. formula-fed children. Besides, overweight formula-fed children presented higher HOMA-index than overweight breastfed children (1.90 vs. 1.62); however, this negative effect was absent in formula-fed children with high expression of SLC27A2. Moreover, formula-fed children with low expression of SLC27A2, FASN, PPARα and INSR presented higher triglyceride levels than subjects with high expression of these genes (77.7 mg dL(-1) vs. 44.8 mg dL(-1) ). This difference was absent in breastfed children. CONCLUSIONS: Protective effects of breastfeeding are reflected in higher expression levels of SLC27A2, FASN, PPARα and INSR in blood cells. These biomarkers may also serve to discriminate the formula-fed children that are at higher risk of metabolic alterations.

Validation of anthropometry and foot-to-foot bioelectrical resistance against a three-component model to assess total body fat in children: the IDEFICS study.

OBJECTIVE: To compare different field methods for estimating body fat mass with a reference value derived by a three-component (3C) model in pre-school and school children across Europe. DESIGN: Multicentre validation study. SUBJECTS: Seventy-eight preschool/school children aged 4-10 years from four different European countries. METHODS: A standard measurement protocol was carried out in all children by trained field workers. A 3C model was used as the reference method. The field methods included height and weight measurement, circumferences measured at four sites, skinfold measured at two-six sites and foot-to-foot bioelectrical resistance (BIA) via TANITA scales. RESULTS: With the exception of height and neck circumference, all single measurements were able to explain at least 74% of the fat-mass variance in the sample. In combination, circumference models were superior to skinfold models and height-weight models. The best predictions were given by trunk models (combining skinfold and circumference measurements) that explained 91% of the observed fat-mass variance. The optimal data-driven model for our sample includes hip circumference, triceps skinfold and total body mass minus resistance index, and explains 94% of the fat-mass variance with 2.44 kg fat mass limits of agreement. In all investigated models, prediction errors were associated with fat mass, although to a lesser degree in the investigated skinfold models, arm models and the data-driven models. CONCLUSION: When studying total body fat in childhood populations, anthropometric measurements will give biased estimations as compared to gold standard measurements. Nevertheless, our study shows that when combining circumference and skinfold measurements, estimations of fat mass can be obtained with a limit of agreement of 1.91 kg in normal weight children and of 2.94 kg in overweight or obese children.

Parental perceptions of and concerns about child's body weight in eight European countries--the IDEFICS study.

OBJECTIVES: To evaluate parental perceptions of and concern about child's body weight and general health in children in a European cohort. DESIGN: Cross-sectional multi-centre study in eight European countries. PARTICIPANTS: 16,220 children, ages 2-9 years. METHODS: Parents completed a questionnaire regarding children's health and weight and concern about overweight and underweight. Objective children's weight categories from the International Obesity Task Force were used. Logistic regression models were utilized to identify predictors of accurate weight perception. RESULTS: Parental weight perception corresponded overall to children's mean body mass index (BMI) z-scores, with important exceptions. About one-third of the total indicated concern about underweight, paradoxically most often parents of children in the overweight or obesity categories. In 63%, parents of children in the overweight category marked 'proper weight'. The strongest predictor for accurate parental weight perception for children with overweight and obesity was BMI z-score (odds ratio [OR] = 7.2, 95% confidence interval [CI] 6.1-8.7). Compared to Southern Europe, ORs for accurate parental weight perception were 4.4 (95% CI 3.3-6.0) in Northern Europe and 3.4 (95% CI 2.7-4.2) in Central Europe. CONCLUSION: Parents of children categorized as being overweight or obese systematically underestimated weight. Parents differed regionally regarding accurate weight perception and concern about overweight and underweight.

Socioeconomic factors and childhood overweight in Europe: results from the multi-centre IDEFICS study.

UNLABELLED: What is already known about this subject Overweight and obesity can be linked to different parental socioeconomic factors already in very young children. In Western developed countries, the association of childhood overweight and obesity and parental socioeconomic status shows a negative gradient. Ambiguous results have been obtained regarding the association between socioeconomic factors and childhood overweight and obesity in different countries and over time. What this study adds European regions show heterogeneous associations between socioeconomic factors and overweight and obesity in a multi-centre study with highly standardized study protocol. The strength of association between SES and overweight and obesity varies across European regions. In our study, the SES gradient is correlated with the regional mean income and the country-specific Human development index indicating a strong influence not only of the family but also of region and country on the overweight and obesity prevalence. OBJECTIVE: To assess the association between different macro- and micro-level socioeconomic factors and childhood overweight. METHODS: Data from the IDEFICS baseline survey is used to investigate the cross-sectional association between socioeconomic factors, like socioeconomic status (SES), and the prevalence of childhood overweight. Differences and similarities regarding this relationship in eight European regions (located in Belgium, Cyprus, Estonia, Germany, Hungary, Italy, Spain and Sweden) are explored. 11 994 children (50.9% boys, 49.1% girls) and their parents were included in the analyses. RESULTS: In five of the eight investigated regions (in Belgium, Estonia, Germany, Spain and Sweden), the prevalence of childhood overweight followed an inverse SES gradient. In the other three regions (in Cyprus, Hungary and Italy), no association between SES and childhood overweight was found. The SES-overweight association in a region was best explained by the country-specific human development index and the centre-specific mean income. For the investigated association between other socioeconomic factors and overweight, no clear pattern could be found in the different regions. CONCLUSION: The association between socioeconomic factors and childhood overweight was shown to be heterogeneous across different European regions. Further research on nationwide European data is needed to confirm the results and to identify target groups for prevention.

Overweight in singletons compared to children with siblings: the IDEFICS study.

The aim of this study was to compare the prevalence of overweight in only children to those with siblings and to explore potential behavioral mediating factors. This study relies upon cross-sectional data collected at survey centers in eight European countries participating in Identification and prevention of Dietary- and lifestyle-induced health EFfects In Children and infantS (IDEFICS). The present analysis is based on measured anthropometry and parent or guardian-reported socio-demographic characteristics. Subjects include 12 720 children aged 2-9 years for whom number of siblings was known. Singletons were more likely (odds ratio 1.52, 95% confidence interval (CI):1.34-1.72) to be overweight than their peers with siblings when controlling for factors related to childhood overweight, including survey country, parental education, parental weight, maternal age, child's age, birth weight and gender. The three southernmost countries have over threefold risk of overweight, dominated by Italy, compared with the north-central countries, which is not explained by the prevalence of singleton children. The excess risk of overweight among children without siblings was robustly observed even when considering behavioral mediating factors (playtime, screen time per day, dietary propensities for sugar or fat, parental attitudes towards food rewards and television in the child's bedroom). Among singletons aged 6-9 years, the excess risk of overweight was 1.70 (95% CI: 1.44-2.01) compared with 1.32 (95% CI: 1.10-1.60) in younger singletons.

Influence of sample collection and preanalytical sample processing on the analyses of biological markers in the European multicentre study IDEFICS.

OBJECTIVE: To evaluate the influence of a standardised sampling protocol and process quality across the different IDEFICS (Identification and prevention of dietary- and lifestyle-induced health effects in children and infants) centres on the results of the biochemical measurements. DESIGN: Baseline survey within the community-based intervention study. SUBJECTS: A total of 16,224 children, aged 2-8 years, enrolled in the IDEFICS baseline survey in 8 European countries. Venous or capillary blood samples were collected from 12,430 children, urine samples from 13,890 children and saliva samples from 14,019 children. METHODS: A set of quality indicators was recorded for the biological blood, urine and saliva samples collected during the IDEFICS study. Results of blood and urine measurements were analysed and stratified by selected quality indicators. RESULTS: Concentrations of biological markers in blood and urine measured during the IDEFICS baseline survey are associated with several quality indicators assessed in this study. Between-country variations of these biomarkers are described. It was confirmed that fasting has a big influence on the concentration of certain biomarkers. Biomarkers in morning urine samples may be erroneous if the study subjects void during the night or if samples are not taken from the very first morning urine. CONCLUSIONS: The analysed data underline that a standardised sampling protocol is of major importance, especially in multicentre studies, but non-compliance is ever present in spite of well-defined standard operation procedures. Deviations from the protocol should therefore always be documented to avoid error pertaining to the concentration of biological markers.

DNA yield and quality of saliva samples and suitability for large-scale epidemiological studies in children.

OBJECTIVE: To evaluate two saliva collection methods for DNA yield and quality as applied to a large, integrated, multicentre, European project involving the collection of biological material from children. DESIGN: Cross-sectional multicentre comparative study in young children. METHODS: Saliva samples were collected from 14,019 children aged 2-9 years from eight European countries participating in the IDEFICS (Identification and prevention of dietary- and lifestyle-induced health effects in children and infants) study. This involved either the collection of 2 ml of saliva from children who were able to spit, or using a sponge to collect whole saliva and buccal mucosal cells from the inside of the mouth of younger children unable to spit. Samples were assembled centrally in each participating centre and subsequently despatched for DNA extraction and biobanking to the University of Glasgow. A subgroup of 4678 samples (∼33% of sampled individuals) were chosen for DNA extraction before genotyping. RESULTS: The whole-saliva collection method resulted in a higher DNA yield than the sponge collection method (mean±s.d.; saliva: 20.95±2.35 µg, sponge: 9.13±2.25 µg; P<0.001). DNA quality as measured by A (260)/A (280) was similar for the two collection methods. A minimum genotype calling success rate of 95% showed that both methods provide good-quality DNA for genotyping using TaqMan allelic discrimination assays. CONCLUSIONS: Our results showed higher DNA yield from the whole-saliva collection method compared with the assisted sponge collection. However, both collection methods provided DNA of sufficient quantity and quality for large-scale genetic epidemiological studies.

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.