The effects of hypothetical behavioral interventions on the 13-year incidence of overweight/obesity in children and adolescents.

BACKGROUND: In view of the high burden of childhood overweight/obesity (OW/OB), it is important to identify targets for interventions that may have the greatest effects on preventing OW/OB in early life. Using methods of causal inference, we studied the effects of sustained behavioral interventions on the long-term risk of developing OW/OB based on a large European cohort. METHODS: Our sample comprised 10 877 children aged 2 to < 10 years at baseline who participated in the well-phenotyped IDEFICS/I.Family cohort. Children were followed from 2007/08 to 2020/21. Applying the parametric g-formula, the 13-year risk of developing OW/OB was estimated under various sustained hypothetical interventions on physical activity, screen time, dietary intake and sleep duration. Interventions imposing adherence to recommendations (e.g. maximum 2 h/day screen time) as well as interventions 'shifting' the behavior by a specified amount (e.g. decreasing screen time by 30 min/day) were compared to 'no intervention' (i.e. maintaining the usual or so-called natural behavior). Separately, the effectiveness of these interventions in vulnerable groups was assessed. RESULTS: The 13-year risk of developing OW/OB was 30.7% under no intervention and 25.4% when multiple interventions were imposed jointly. Meeting screen time and moderate-to-vigorous physical activity (MVPA) recommendations were found to be most effective, reducing the incidence of OW/OB by -2.2 [-4.4;-0.7] and -2.1 [-3.7;-0.8] percentage points (risk difference [95% confidence interval]), respectively. Meeting sleep recommendations (-0.6 [-1.1;-0.3]) had a similar effect as increasing sleep duration by 30 min/day (-0.6 [-0.9;-0.3]). The most effective intervention in children of parents with low/medium educational level was being member in a sports club; for children of mothers with OW/OB, meeting screen time recommendations and membership in a sports club had the largest effects. CONCLUSIONS: While the effects of single behavioral interventions sustained over 13 years were rather small, a joint intervention on multiple behaviors resulted in a relative reduction of the 13-year OW/OB risk by between 10 to 26%. Individually, meeting MVPA and screen time recommendations were most effective. Nevertheless, even under the joint intervention the absolute OW/OB risk remained at a high level of 25.4% suggesting that further strategies to better prevent OW/OB are required.

Cross-sectional and longitudinal associations between sleep duration, sleep quality, and bone stiffness in European children and adolescents.

In this large perspective cohort among European children and adolescents, we observed that daytime napping was positively associated with bone stiffness, while short or long sleep duration combined with poor sleep quality was associated with less bone stiffness. Our findings are important for obtaining optimal bone stiffness in childhood. INTRODUCTION: To examine the cross-sectional and longitudinal associations between sleep duration, sleep quality, and bone stiffness index (SI) in European children and adolescents. METHODS: Four thousand eight hundred seventy-one children aged 2-11 years from the IDEFICS study and 861 children aged 6-15 years from the subsequent I.Family study were included. Sleep duration (i.e., nocturnal sleep and daytime napping) and sleep quality (i.e., irregularly bedtime routine, have difficulty falling asleep and trouble getting up in the morning) were reported by self-administrated questionnaires. Nocturnal sleep duration was converted into age-specific z-scores, and total sleep duration was classified into short, adequate, and long based on the National Sleep Recommendation. Calcaneal SI of both feet were measured using quantitative ultrasound. Linear mixed-effects models with country as a random effect were used, with adjustments for sex, age, pubertal status, family socioeconomic status, physical activity, screen time, body mass index, and daylight duration. RESULTS: Nocturnal sleep duration z-scores were positively associated with SI percentiles among participants with adequate sleep duration at baseline. Moreover, the positive association between daytime napping and SI percentiles was more pronounced in participants with adequate sleep duration at baseline, while at 4-year follow-up was more pronounced in participants with short sleep duration. In addition, extreme sleep duration at baseline predicted lower SI percentiles after 4 years in participants with poor sleep quality. CONCLUSION: The positive associations between nocturnal sleep, daytime napping and SI depended on total sleep duration. Long-term detrimental effect of extreme sleep duration on SI only existed in individuals with poor sleep quality.

Dietary sources of free sugars in the diet of European children: the IDEFICS Study.

OBJECTIVE: To report dietary free sugars consumption and their different types and food sources in European children. METHODS: The present study is based on the IDEFICS study, a European multicenter cohort study in children (2-9 years old) from eight countries, comprising 8308 children (51.4% males). Dietary intake of the previous 24 h was assessed using a computer-assisted 24-h dietary recalls (24-HDR) and the different types of sugars were assessed using the German food composition database. RESULTS: Mean total energy intake was 1720 (SD 477) kcal/d for boys and 1631 (SD 451) kcal/d for girls. Total sugars intake was 98 (SD 52) g/day for boys and 93 (SD 49) g/day for girls. Free sugars intake was 81 (SD 49) g/day for boys and 77 (SD 47) g/day for girls. Girls had significantly lower intakes of energy, total and free sugars compared with than boys but did not differ in terms of percent of energy from total (23%) or free sugars (18%). There were large variations between countries in average % energy from free sugars (ranging from 13% in Italy to 27% in Germany). Less than 20% of children were within the recommended intake of 10% of energy from free sugars. The food groups that contributed substantially to free sugars intakes were "Fruit juices", "Soft drinks", "Dairy" and "Sweets and candies". CONCLUSIONS: The contribution of free sugars to total energy intake in European children is higher than recommendations. The main food contributors to free sugars intake are sweetened beverages ("Fruit juices" and "Soft drinks"). It is especially important to reduce children's intake of free sugars, focusing in target population on certain foods and food groups.

Dietary calcium intake and adiposity in children and adolescents: Cross-sectional and longitudinal results from IDEFICS/I.Family cohort.

BACKGROUND AND AIMS: Studies in children and adolescents suggest that higher dairy consumption may exert a protective effect on adiposity. However, only few studies examined the association between dietary calcium intake and body mass measures with conflicting results. We evaluated the association between total dietary calcium, calcium from dairy and non-dairy sources and anthropometric indices in a large European cohort of children and adolescents. METHODS AND RESULTS: As many as 6,696 children belonging to the IDEFICS study were eligible for the cross-sectional analysis (Boys = 51%; age 6.0 ± 1.8 years; mean ± SD). Of these, 2,744 were re-examined six years later (Boys = 49.6%; age = 11.7 ± 1.8 years) in the framework of the I.Family study. The exposures were the baseline energy-adjusted total, dairy and non-dairy calcium intakes measured by a validated 24-h dietary recall. Multivariable linear regression was used to determine the association between calcium intake and z-scores of anthropometric indices (body mass index, BMI; waist circumference, WC; sum of skinfolds, SS; fat mass index, FMI) at baseline, and their variation over the 6 years follow-up. The association of dietary calcium with the incidence of overweight/obesity was also assessed. At baseline, an inverse association between total calcium intake and all the adiposity indices was consistently observed in boys, while only SS and FMI were significant in girls. The prevalence of overweight/obesity decreased significantly (P < 0.0001) across tertiles of calcium intake, in both sexes. Over the follow-up, boys with higher baseline calcium intake value showed significantly lower increase in BMI, WC and FMI z-scores, while in girls only a lower increase in WC z-score was observed. Only in boys, the risk to become overweight/obese decreased significantly across tertiles of calcium intake. Similar results were observed by analyzing only dietary calcium from dairy, while no association was observed between non-dairy calcium and adiposity indices. CONCLUSIONS: We showed in a large cohort of European children and adolescents that dietary calcium intake may play a role in the modulation of body fat in developmental age. The association between dietary calcium and adiposity indices was driven by dairy calcium, while no effect was observed for non-dairy calcium intake. The existence of a sex-related difference in the association deserves further investigations.

A within-sibling pair analysis of lifestyle behaviours and BMI z-score in the multi-centre I.Family study.

BACKGROUND AND AIMS: By investigating differences in lifestyle behaviours and BMI in sibling pairs, family-level confounding is minimized and causal inference is improved, compared to cross-sectional studies of unrelated children. Thus, we aimed to investigate within-sibling pair differences in different lifestyle behaviours and differences in BMI z-scores in children and adolescents. METHODS AND RESULTS: We examined three groups of sibling pairs 1) all same-sex sibling pairs with maximum 4 years age difference (n = 1209 pairs from 1072 families in 8 countries, mean age 10.7 years, standard deviation 2.4 years), 2) sibling pairs discordant for overweight (n = 262) and 3) twin pairs (n = 85). Usual dietary intake was estimated by 24-h recalls and time spent in light (LPA) and moderate-to-vigorous physical activity (MVPA) was measured by accelerometers. Screen time, sleep and dieting for weight loss were assessed by questionnaires. Within all 3 groups of sibling pairs, more time in MVPA was associated with lower BMI z-score. Higher energy intake was associated with higher BMI z-score within twin pairs and within all sibling pairs who were not currently dieting for weight loss. Regarding LPA, screen time or sleep duration, no or inconsistent associations were observed for the three groups of sibling pairs. CONCLUSIONS: MVPA and energy intake were associated with BMI differences within sibling and twin pairs growing up in the same home, thus independent of family-level confounding factors. Future studies should explore whether genetic variants regulating appetite or energy expenditure behaviours account for weight differences in sibling pairs.

The association of emotion-driven impulsiveness, cognitive inflexibility and decision-making with weight status in European adolescents.

OBJECTIVE: To explore the association between emotion-driven impulsiveness, cognitive inflexibility, decision-making and weight status as reflected in body mass index (BMI) z-score (zBMI) in European adolescents. METHODS: In total, 3354 adolescents aged between 12 and 18 years from the I.Family cohort completed the questionnaire-based negative urgency subscale from the UPPS-P Impulsive Behavior Scale to measure emotion-driven impulsiveness in 2013/2014. Furthermore, 1584 adolescents completed the computer-based Bergs Card Sorting Test to measure cognitive inflexibility, and 1780 adolescents completed the Hungry Donkey Test to assess decision-making ability. Anthropometric variables were measured objectively; confounding variables (age, sex, socioeconomic status and country) were assessed using a questionnaire. Mixed-effect regression analyses were conducted for each outcome of the test or questionnaire as a predictor with standardised BMI (zBMI) as the dependent variable in order to investigate association between markers of cognitive functioning and zBMI. RESULTS: After controlling for confounders, results showed that emotion-driven impulsiveness (ß=0.18, 95% confidence interval (CI): 0.13 to 0.24, P<0.001) and cognitive inflexibility (ß=0.01, 95% CI: 0.002 to 0.02, P=0.016) were positively associated with zBMI. However, decision-making ability was not significantly related to zBMI (ß=0.001, 95% CI: -0.001 to 0.003, P=0.47). CONCLUSIONS: More emotion-driven impulsiveness and reduced cognitive flexibility were associated with a higher zBMI in adolescents across Europe. These results may indicate that being impulsive in negative situations and having difficulties changing mental sets increase the susceptibility for unhealthy weight development. Reducing impulsivity and training cognitive flexibility seem promising targets for the prevention and intervention programmes of obesity.

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.

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.

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.

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.

Dietary energy density in young children across Europe.

OBJECTIVES: To describe energy density (ED; kcal g(-1)) of dietary intake of European children. METHODS: From 16, 228 children who participated in the IDEFICS (Identification and prevention of Dietary- and lifestyle-induced health EFfects In Children and infantS) baseline examination, 8551 children with 24-h dietary recalls (24-HDR), with plausible reported energy intakes and complete covariate information were included in the present analysis. ED was calculated using two methods: (1) ED including solid foods (EDF) and (2) ED including solid foods and energy-containing beverages (EDF&B). Beverage energy was calculated in kcal per day. Dietary characteristics and body mass index (BMI) z-score of children aged 2 to <6 years and 6 to <10 years were compared between children with an overall EDF below the <25th percentile, between the 25th and 75th percentile as well as above the >75th percentile. Standardised regression coefficients were estimated to assess the association between dietary characteristics, BMI z-score and ED of the diet. RESULTS: Children with low EDF and EDF&B diets consumed less energy but higher quantity of food and beverages than children with high EDF and EDF&B diets. Consumption of caloric beverages decreased with increasing EDF&B of the diet owing to the relatively low ED of the beverages, in relation to solid foods. Generally, children with low EDF and EDF&B diets showed healthier food choices than peers with higher EDF and EDF&B diets. In this sample, EDF and EDF&B were not associated with BMI z-score. CONCLUSION: Health promotion strategies should proclaim lower ED diets by means of foods with high water and low fat content and mainly fruit and vegetable components. Excluding caloric beverages from EDF calculation is a useful method to avoid misinterpretation of true exposure to a high energy dense diet. We recommend excluding caloric beverages from EDF calculation when investigating the effect of ED on a certain (health) outcome.

Reference values of bone stiffness index and C-terminal telopeptide in healthy European children.

BACKGROUND/OBJECTIVE: Quantitative ultrasound measurements and bone metabolic markers can help to monitor bone health and to detect impaired skeletal development. Population-based reference values for children may serve as a basis for preventive measures to reduce the risk of osteoporosis and osteoporotic fractures in later life. This is the first paper providing age-, sex- and height-specific reference values for bone stiffness index (SI) and serum carboxy-terminal cross-linking telopeptide of type I collagen (CTX) in healthy, apparently prepubertal children. SUBJECTS/METHODS: In the population-based IDEFICS baseline survey (2007-2008) and follow-up (2009-2010), 18,745 children from eight European countries were newly recruited. A total of 10,791 2-10.9-year-old and 1646 3-8.9-year-old healthy children provided data on SI of the right and left calcaneus and serum CTX, respectively. Furthermore, height and weight were measured. Percentile curves were calculated using the General Additive Model for Location Scale and Shape (GAMLSS) to model the distribution of SI and CTX depending on multiple covariates while accounting for dispersion, skewness, and the kurtosis of this distribution. RESULTS: SI was negatively associated with age and height in children aged 2-5 years, whereas a positive association was observed in children aged 6-10 years. The dip in SI occurred at older age for higher SI percentiles and was observed earlier in taller children than in smaller children. The CTX reference curves showed a linear-positive association with age and height. No major sex differences were observed for the SI and CTX reference values. CONCLUSION: These reference data lay the ground to evaluate bone growth and metabolism in prepubertal children in epidemiological and clinical settings. They may also inform clinical practice to monitor skeletal development and to assess adverse drug reactions during medical treatments.

Prevalence of overweight and obesity in European children below the age of 10.

BACKGROUND: There is a lack of common surveillance systems providing comparable figures and temporal trends of the prevalence of overweight (OW), obesity and related risk factors among European preschool and school children. Comparability of available data is limited in terms of sampling design, methodological approaches and quality assurance. The IDEFICS (Identification and prevention of Dietary- and lifestyle-induced health Effects in Children and infantS) study provides one of the largest European data sets of young children based on state-of-the-art methodology. OBJECTIVE: To assess the European distribution of weight status according to different classification systems based on body mass index (BMI) in children (2.0-9.9 years). To describe the prevalence of weight categories by region, sex, age and socioeconomic position. DESIGN: Between 2007 and 2010, 18,745 children from eight European countries participated in an extensive, highly standardised protocol including, among other measures, anthropometric examinations and parental reports on socio-demographic characteristics. RESULTS: The combined prevalence of OW/obesity ranges from more than 40% in southern Europe to less than 10% in northern Europe. Overall, the prevalence of OW was higher in girls (21.1%) as compared with boys (18.6%). The prevalence of OW shows a negative gradient with social position, with some variation of the strength and consistency of this association across Europe. Overall, population groups with low income and/or lower education levels show the highest prevalence of obesity. The use of different reference systems to classify OW results in substantial differences in prevalence estimates and can even reverse the reported difference between boys and girls. CONCLUSIONS: There is a higher prevalence of obesity in populations from southern Europe and in population groups with lower education and income levels. Our data confirm the need to develop and reinforce European public health policies to prevent early obesity and to reduce these health inequalities and regional disparities.

Reference values for leptin and adiponectin in children below the age of 10 based on the IDEFICS cohort.

OBJECTIVE: To establish age- and sex-specific reference values for serum leptin and adiponectin in normal-weight 3.0-8.9-year old European children. SUBJECTS AND METHODS: Blood samples for hormone analysis were taken from 1338 children of the IDEFICS (Identification and prevention of Dietary- and lifestyle-induced health Effects in Children and infantS) study cohort. Only normal-weight children aged 3.0-8.9 years were included (n=539) in our analysis. Using the General Additive Model for Location Scale and Shape, age- and sex-specific percentiles were derived. The influence of under/overweight and obesity on the proposed reference curves based on normal-weight children was investigated in several sensitivity analyses using the sample without obese children (n=1015) and the whole study sample (n=1338). RESULTS: There was a negative age trend of adiponectin blood levels and a positive trend of leptin levels in boys and girls. Percentiles derived for girls were generally higher than those obtained for boys. The corresponding age-specific differences of the 97th percentile ranged from -2.2 to 4.6 µg ml(-1) and from 2.2 to 4.8 ng ml(-1) for adiponectin and leptin, respectively. CONCLUSIONS: According to our knowledge, these are the first reference values of leptin and adiponectin in prepubertal, normal-weight children. The presented adiponectin and leptin reference curves may allow for a more differentiated interpretation of children's hormone levels in epidemiological and clinical studies.

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.

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.

C-reactive protein reference percentiles among pre-adolescent children in Europe based on the IDEFICS study population.

OBJECTIVES: C-reactive protein (CRP) is involved in a wide range of diseases. It is a powerful marker for inflammatory processes used for diagnostic and monitoring purposes. We aimed to establish reference values as data on the distribution of serum CRP levels in young European children are scarce. SUBJECTS: Reference values of high-sensitivity CRP concentrations were calculated for 9855 children aged 2.0-10.9 years, stratified by age and sex. The children were recruited during the population-based European IDEFICS study (Identification and prevention of Dietary- and lifestyle-induced health Effects in Children and infantS) with 18 745 participants recruited from 2007 to 2010. RESULTS: In 44.1% of the children, CRP values were below or equal the detection limit of 0.2 mg/l. Median CRP concentrations showed a slight negative age trend in boys and girls, whereas serum CRP values were slightly higher in girls than in boys across all age groups. CONCLUSIONS: Our population-based reference values of CRP may guide paediatric practice as elevated values may require further investigation or treatment. Therefore, the presented reference values represent a basis for clinical evaluation and for future research on risk assessment of diseases associated with increased CRP levels among children.

Percentiles of fasting serum insulin, glucose, HbA1c and HOMA-IR in pre-pubertal normal weight European children from the IDEFICS cohort.

OBJECTIVES: The aim of this study is to present age- and sex-specific reference values of insulin, glucose, glycosylated haemoglobin (HbA1c) and the homeostasis model assessment to quantify insulin resistance (HOMA-IR) for pre-pubertal children. METHODS: The reference population consists of 7074 normal weight 3- to 10.9-year-old pre-pubertal children from eight European countries who participated in at least one wave of the IDEFICS ('identification and prevention of dietary- and lifestyle-induced health effects in children and infants') surveys (2007-2010) and for whom standardised laboratory measurements were obtained. Percentile curves of insulin (measured by an electrochemiluminescence immunoassay), glucose, HbA1c and HOMA-IR were calculated as a function of age stratified by sex using the general additive model for location scale and shape (GAMLSS) method. RESULTS: Levels of insulin, fasting glucose and HOMA-IR continuously show an increasing trend with age, whereas HbA1c shows an upward trend only beyond the age of 8 years. Insulin and HOMA-IR values are higher in girls of all age groups, whereas glucose values are slightly higher in boys. Median serum levels of insulin range from 17.4 and 13.2 pmol l(-1) in 3-<3.5-year-old girls and boys, respectively, to 53.5 and 43.0 pmol l(-1) in 10.5-<11-year-old girls and boys. Median values of glucose are 4.3 and 4.5 mmol l(-1) in the youngest age group and 49.3 and 50.6 mmol l(-1) in the oldest girls and boys. For HOMA-IR, median values range from 0.5 and 0.4 in 3-<3.5-year-old girls and boys to 1.7 and 1.4 in 10.5-<11-year-old girls and boys, respectively. CONCLUSIONS: Our study provides the first standardised reference values for an international European children's population and provides the, up to now, largest data set of healthy pre-pubertal children to model reference percentiles for markers of insulin resistance. Our cohort shows higher values of Hb1Ac as compared with a single Swedish study while our percentiles for the other glucose metabolic markers are in good accordance with previous studies.

Metabolic syndrome in young children: definitions and results of the IDEFICS study.

OBJECTIVE: To estimate the prevalence of the metabolic syndrome (MetS) using reference standards obtained in European children and to develop a quantitative MetS score and describe its distribution in children. DESIGN AND METHODS: Population-based survey in eight European countries, including 18745 children 2.0 to 10.9 years, recruited during a second survey. Anthropometry (weight, height and waist circumference), blood pressure and serum-fasting triglycerides, HDL cholesterol, glucose and insulin were measured. We applied three widely accepted definitions of the pediatric MetS and we suggest a new definition, to guide pediatricians in decisions about close monitoring or even intervention (values of at least three of the MetS components exceeding the 90th or 95th percentile, respectively). We used a z-score standardisation to calculate a continuous score combining the MetS components. RESULTS: Among the various definitions of MetS, the highest prevalence (5.5%) was obtained with our new definition requiring close observation (monitoring level). Our more conservative definition, requiring pediatric intervention gives a prevalence of 1.8%. In general, prevalences were higher in girls than in boys. The prevalence of metabolic syndrome is highest among obese children. All definitions classify a small percentage of thin or normal weight children as being affected. The metabolic syndrome score shows a positive trend with age, particularly regarding the upper percentiles of the score. CONCLUSIONS: According to different definitions of pediatric MetS, a non-negligible proportion of mostly prepubertal children are classified as affected. We propose a new definition of MetS that should improve clinical guidance. The continuous score developed may also serve as a useful tool in pediatric obesity research. It has to be noted, however, that the proposed cutoffs are based on a statistical definition that does not yet allow to quantify the risk of subsequent disease.

Adherence to a Mediterranean-like dietary pattern in children from eight European countries. The IDEFICS study.

BACKGROUND: Despite documented benefits of a Mediterranean-like dietary pattern, there is a lack of knowledge about how children from different European countries compare with each other in relation to the adherence to this pattern. In response to this need, we calculated the Mediterranean diet score (MDS) in 2-9-year-old children from the Identification and prevention of dietary- and lifestyle-induced health effects in children and infants (IDEFICS) eight-country study. SUBJECTS AND METHODS: Using 24 h dietary recall data obtained during the IDEFICS study (n=7940), an MDS score was calculated based on the age- and sex-specific population median intakes of six food groups (vegetables and legumes, fruit and nuts, cereal grains and potatoes, meat products and dairy products) and the ratio of unsaturated to saturated fats. For fish and seafood, which was consumed by 10% of the population, one point was given to consumers. The percentages of children with high MDS levels (>3) were calculated and stratified by sex, age and by having at least one migrant parent or both native parents. Demographic (sex and age) and socioeconomic characteristics (parental education and income) of children showing high (>3) vs low (⩽3) MDS levels were examined. RESULTS: The highest prevalence of children with MDS>3 was found among the Italian pre-school boys (55.9%) and the lowest among the Spanish school-aged girls (26.0%). Higher adherence to a Mediterranean-like dietary pattern was not associated with living in a Mediterranean country or in a highly educated or high-income family, although with some exceptions. Differences in adherence between boys and girls or age groups varied between countries without any general pattern. CONCLUSIONS: With the exception of Italian pre-schoolers, similar adherence levels to a Mediterranean-like dietary pattern have been observed among European children.