Every school on this planet should aim to become a healthy school. This is the motto of the WHO/UNICEF health promoting school strategic agenda (HPS). To address gaps and needs of children’s health and educational inequalities in schools, a qualitative study was set up to synthesize experts’ views and insights on school health programs and the HPS strategy in Europe. This multi-stakeholder consultation took place during an international children’s health workshop in Cyprus (October 2024). Data was collected through focus group interviews with 30 experts engaged in a multistakeholder consultation between academics, governmental officials, teacher liaisons, and health professionals, including WHO experts and NGOs. The consultation identified the following themes: systemic limitations in funding and sustainability of health education/promotion programs, enhanced curriculum needs for health literacy, limitations in school physical environment, rise in behavioral risk factors among children and adolescents, and growing mental health needs. A consensus was reached regarding the prerequisites and recommendations towards improving both health and educational outcomes for children; the implementation of holistic methodological frameworks, such as that of the human exposome and its exposomics tools were collectively proposed to better deploy the HPS recommendations in the school community. Conclusion: By adopting a holistic, multi-sectoral approach for schools and their communities (parents, teachers, authorities, the public) that embeds the exposomics tools and methodologies, future societies would ensure that educational institutions not only serve as centers for academic learning, but also as environments that nurture the physical, mental, and social wellbeing of students.

OBJECTIVE:To examine the associations between BMI trajectories and changes in fat-free mass index (FFMI) and fat mass index (FMI), assessed via bioelectrical impedance analysis (BIA) and skinfold thickness (ST). METHODS:The study included 4708 European children with BIA data and 3627 with ST data, aged 2-9.9 years at baseline, participating in two waves of the IDEFICS (IDEFICS (Identification and Prevention of Dietary- and Lifestyle-Induced Health Effects in Children and Infants))/I.Family (I. Family (Determinants of eating behavior in European children, adolescents, and their parents)) studies (w0: 2007/08; w2: 2013/14). Children were classified into three BMI trajectory groups: retained normal weight (RNW), remained overweight/obese (ROO), and excessive weight gain (EWG). Analyses of covariance evaluated differences in BMI z-score changes, FFMI, and FMI across groups. Mixed-effects linear regression assessed associations between BMI z-score changes and FFMI/FMI over time. RESULTS:BMI z-score changes were more strongly associated with FMI (β = 1.16-1.70 in boys; 1.17-1.62 in girls, p < 0.05) than with FFMI, for both BIA and ST. In ROO and EWG groups, associations with FMI were consistently stronger, except among girls <6 years in the ROO group (BIA). In the RNW group, boys >6 years showed stronger associations with FFMI. CONCLUSIONS:Associations between BMI changes and FFMI/FMI vary by BMI trajectory and body composition method. BIA showed closer alignment with BMI changes than ST. These findings suggest that BMI alone may not adequately capture changes in specific body compartments. While convenient, BMI should be interpreted with caution, especially when fat or fat-free mass plays a differential role in disease risk or health outcomes.

External factors, including digital media (DM), promote body ideals that can shape adolescents’ body image, but studies across European countries are scarce. Therefore, the aim of the study was to examine the relationship between daily DM duration and body image dissatisfaction (BID) in adolescents from nine European countries. Participants from the I.Family study self-reported daily DM duration and BID in 2013/2014 (n = 3,608; 51

This aimed to investigate associations between the vitamin D status and handgrip strength in children and adolescents considering weight status. Participants aged 7 to < 16 years from the European IDEFICS/I.Family cohort were included. Serum 25-hydroxyvitamin D [25(OH)D] and handgrip strength were measured in 2013/2014. In multivariable logistic regression models, we investigated the association of vitamin D status with handgrip strength adjusted for demographic variables, BMI z-score, sports club membership, screen time and UV intensity. Vitamin D-sufficient children had higher odds for a high handgrip strength (OR = 1.92, 95 https://doi.org/10.1186/ISRCTN62310987 .

IntroductionPlant-based dietary patterns may reduce the risk of chronic diseases, but their benefits and risks in younger populations remain unclear due to variations in diet quality and nutrient adequacy. Robust tools to assess adherence to these patterns are essential. The aim of this study was to develop and validate three plant-based diet propensity (PBDP) scores - overall, healthy and unhealthy - to capture plant-based dietary patterns and assess their associations with nutrient intakes and health indicators in children, adolescents and adults.MethodsThis cross-sectional study of children, adolescents and adults used data from the I.Family study (n = 15,780 participants) from eight European countries. Dietary intake was assessed using a food frequency questionnaire. The overall PBDP score was constructed by categorising all plant-based food groups as positive and animal-based food groups as negative. The healthy PBDP emphasised healthy plant-based food groups, whereas the unhealthy PBDP emphasised less healthy plant-based food groups. Validity was assessed through correlations with nutrient intakes and comparison across demographic groups. Associations with health indicators were also analysed.ResultsPBDP scores showed expected associations with nutrient intakes. Higher overall and healthy PBDP scores were observed in females, adults, individuals with higher parental educational levels and those from Belgium and Spain. The healthy PBDP score was associated with higher HDL cholesterol, improved bone stiffness and lower triglycerides. The unhealthy PBDP score was associated with lower HDL cholesterol in adults, but not in children or adolescents.ConclusionPBDP scores describe plant-based dietary patterns across demographic groups and are valid and reliable in adults. The findings highlight challenges in assessing dietary patterns in children and adolescents. Future research should address these challenges to enhance the validity of PBDP scores in younger populations and further explore their potential in guiding dietary recommendations across all age groups.

PURPOSE:Understanding factors influencing clinical biomarkers is important for the prevention of chronic disease. This study aimed to estimate transitions of biomarker status from childhood to adolescence and to identify determinants of biomarker status in early life in a prospective children cohort. SUBJECTS AND METHODS:Our sample comprised 1295 children participating in the baseline (2007/08) and second follow-up examination (2013/14) of the multi-center IDEFICS (Identification and prevention of Dietary- and lifestyle-induced health EFfects In Children and infantS)/I.Family study. Clinical blood biomarkers including glycated hemoglobin A1c (HbA1c), high-density lipoprotein cholesterol (HDL-cholesterol), triglycerides, C-reactive protein (CRP), interleukin 6, ferritin, leptin and insulin-like growth factor 1 (IGF-1) were repeatedly measured in 2007/2008 (age range: 3.0 to <10.0 years) and in 2013/2014. Latent transition analysis was used to estimate biomarker statuses and transition probabilities; determinants of biomarker status were estimated using mixed-effects models. RESULTS:Four distinct biomarker statuses were identified: (1) "normal" (all biomarkers low/medium; except HDL-cholesterol; reference), (2) "low leptin/IGF-1/HbA1c", (3) "dyslipidemia/high leptin" and (4) "inflammation". Children classified as "low leptin/IGF-1/HbA1c" at baseline were most likely to stay in this status (89.8%) or to change to the "normal" status (10%) during follow-up. Compared to "normal" children, children classified as "low leptin/IGF-1/HbA1c" were less likely to have a family history of diabetes (0.26 [0.08;0.86]; odds ratio (OR) and 95% confidence interval) or hypertension (0.53 [0.29;0.99]) and the children (0.32 [0.27;0.38]) as well as their mothers (0.93 [0.88;0.98]) had a lower BMI. Children from families with low/medium education had a 55% [9%-119%] higher risk of being in the "dyslipidemia/high leptin" and 49% [1%-121%] higher risk of being in the "inflammation" status as compared to children in the "normal" status. Membership in a sports club reduced the latter risks by 28% [2%-47%] and 40% [17%-56%], respectively. CONCLUSIONS:European children showed distinct phenotypes for the investigated biomarkers. Especially parental characteristics like a family history of diabetes or hypertension, a high maternal BMI, or low/medium education were associated with unfavorable biomarker status in children.

It remains unclear how serum 25-hydroxyvitamin D (25(OH)D) concentrations relate to childhood bone health. We hypothesized that 25(OH)D was inversely associated with bone turnover biomarkers and positively associated with bone stiffness. Cross-sectional analyses were performed using data from participants (2-15-year-old, 51% boys) from the Identification and Prevention of Dietary- and Lifestyle-induced Health Effects in Children and Infants Study (IDEFICS)/I.Family cohort, comprising 3,638 serum 25(OH)D measurements collected in 2007-2008 and 2012-2013 across eight European countries. A biomarker of bone forma- tion (serum osteocalcin), a biomarker of bone resorption (serum C-terminal telopeptides of type I collagen [CTx]), and stiffness index measured using calcaneal quantitative ultra- sound were considered outcomes. Linear mixed-effects models were used to adjust for con- founders (i.e., age, sex, parental education, time spent in sports club, dairy products con- sumption, sedentary behavior, height and weight z-scores), the cluster effect of country and repeated measurements. Interactions of calcium intake, moderate-to-vigorous physical ac- tivity (MVPA) and weight status with 25(OH)D on outcomes were tested. Only 1 in 3 partic- ipants reached the sufficient 25(OH) D concentration of 20 ng/mL. Sufficient 25(OH)D was associated with higher stiffness index if participants had MVPA >= 60 min/day (beta= 12.14, P < .05). Moreover, 25(OH)D was inversely associated with CTx (beta= -7.09, P < .05); this associa- tion was positive but not statistically significant among primary school children living with overweight/obesity. No interaction was observed for calcium intake. In conclusion, serum 25(OH)D and CTx were inversely associated. MVPA interacted with the positive association between 25(OH)D and bone stiffness, highlighting the importance of promoting MVPA guide- lines in future vitamin D and bone health interventions. (c) 2024 The Author(s). Published by Elsevier Inc. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)

Academic performance in children is associated with a range of health-related factors, including physical fitness, mental well-being, sleep, and behavioral patterns. While previous studies have examined these factors individually, fewer have assessed their independent associations with academic achievement while accounting for other relevant health indicators. This study uses data from the I.Family study to explore how physical, mental, sleep-related, and behavioral health indicators relate to academic achievement among European adolescents, considering each factor’s contribution while adjusting for the others. We used data from the 2013–2014 wave of the I.Family study to investigate eight health indicators: health related quality of life (HRQoL), body mass index (BMI), diet, media use, physical activity, sleep duration and quality, and stressful life events. Their associations with self-reported academic performance in mathematics and language were analyzed using binary logistic regression models, adjusting for confounders such as parents’ education, income, survey country and child’s age. We conducted separate analyses for girls and boys to capture associations that are specific to academic subject and sex. A number of significant associations were found between several health indicators and academic performance. Higher HRQoL scores, reduced media time, and increased physical activity were linked to better academic performance in both mathematics and language for both boys and girls. Variation by sex and academic subjects were observed, with lower BMI, higher healthy diet scores and better sleep quality associated with better academic performance in language among girls. For mathematics, emotional, self-esteem, and family-related HRQoL were all significantly associated with higher performance for both boys and girls. In contrast, for language achievement, only family-related HRQoL was significant for both sexes. Our study underscores the need to consider both the importance of accounting for heterogeneity in sex and the differences between math and language academic subjects when investigating determinants of academic performance, setting the stage for further research on this topic to explore potential competing, synergistic, or time-dependent effects among these different health dimensions.

BACKGROUND:Socioeconomic disparities in dietary behaviors are well-known, but underlying mechanisms are not fully understood. We investigated whether consumer attitudes toward dietary behaviors mediate the relationship between socioeconomic factors and diet quality. METHODS:This analysis included 4051 adult participants from eight European countries of the I.Family study (2013/2014). Dietary intake was assessed using a food frequency questionnaire, and diet quality was measured by adherence to dietary recommendations using the Healthy Dietary Adherence Score. Socioeconomic factors included education, income, and social vulnerabilities (migrant background, experiencing unemployment in the household, single parenthood). Structural equation modeling was used to model pathways between predictors, outcome, and mediators, which also allowed for accounting of the clustered study design, incorporating random intercepts for country. RESULTS:Education and income were positively, and unemployment was negatively associated with diet quality. Attitudes reflecting favorable dietary behaviors were positively associated with diet quality, while unfavorable attitudes were inversely associated. Analysis of the path between socioeconomic factors and attitudes revealed a heterogeneous association pattern. Trusting food advertisements and frequently using ready-to-eat foods partially mediated the association between education, income, and diet quality. The association between single parenthood and diet quality was fully mediated by comparing food labels, valuing organic products, and using ready-to-eat foods. CONCLUSION:Our findings suggest a mediating role of consumer attitudes in the association between socioeconomic factors and diet quality, but results were not consistent across socioeconomic factors. Our findings may inform the development of interventions and regulations promoting healthy diet, such as restricting food advertisments.

BACKGROUND AND OBJECTIVES:To examine whether changes in the Mediterranean Diet (MD) or any of its MD food groups modulate the genetic susceptibility to obesity in European youth, both in cross-sectional and longitudinal analyses. METHODS:For cross-sectional analysis, 1982 participants at baseline, 1649 in follow-up 1 (FU1) and 1907 in follow-up 2 (FU2), aged 2-16 years of the IDEFICS/I.Family studies were considered. For the longitudinal design, 1254 participants were included. Adherence to MD was assessed using the Mediterranean Diet Score (MDS), and genetic susceptibility to high BMI was assessed with a polygenic risk score (BMI-PRS). Multiple linear regression models were fitted to estimate gene × MD effects on markers of obesity. RESULTS:In cross-sectional analyses, at baseline, higher MDS was associated with higher BMI in children with high genetic susceptibility (β = 0.12; 95% CI = [0.01, 0.24]). However, 6 years later, at FU2, higher MDS was associated with lower BMI (β = -0.19; 95% CI = [-0.38, -0.01]) in children with high genetic susceptibility, showing an attenuating MDS effect. Also in FU2, vegetables and legumes (V&L) showed inverse associations with BMI (β = -0.01; CI = [-0.02, -0.00]) and WC (β = -0.02; CI = [-0.03, -0.00]) regardless of the obesity genetic risk, although the effect sizes were small. In the longitudinal analyses, no MDS-obesity associations or gene × diet interaction effects were observed. CONCLUSIONS:In cross-sectional analysis (baseline and FU2), the MD modulated the association between obesity susceptibility and adiposity indicators in European youth, having an exacerbating effect in children measured during infancy years and an attenuating effect in early adolescent years.

Background It is unclear whether a hypothetical intervention targeting either psychosocial well-being or emotion-driven impulsiveness is more effective in reducing unhealthy food choices. Therefore, we aimed to compare the (separate) causal effects of psychosocial well-being and emotion-driven impulsiveness on European adolescents’ sweet and fat propensity. Methods We included 2,065 participants of the IDEFICS/I.Family cohort (mean age: 13.4) providing self-reported data on sweet propensity (score range: 0 to 68.4), fat propensity (range: 0 to 72.6), emotion-driven impulsiveness using the UPPS-P negative urgency subscale, and psychosocial well-being using the KINDL R Questionnaire. We estimated, separately, the average causal effects of psychosocial well-being and emotion-driven impulsiveness on sweet and fat propensity applying a semi-parametric doubly robust method (targeted maximum likelihood estimation). Further, we investigated a potential indirect effect of psychosocial well-being on sweet and fat propensity mediated via emotion-driven impulsiveness using a causal mediation analysis. Results If all adolescents, hypothetically, had high levels of psychosocial well-being, compared to low levels, we estimated a decrease in average sweet propensity by 1.43 [95%-confidence interval: 0.25 to 2.61]. A smaller effect was estimated for fat propensity. Similarly, if all adolescents had high levels of emotion-driven impulsiveness, compared to low levels, average sweet propensity would be decreased by 2.07 [0.87 to 3.26] and average fat propensity by 1.85 [0.81 to 2.88]. The indirect effect of psychosocial well-being via emotion-driven impulsiveness was 0.61 [0.24 to 1.09] for average sweet propensity and 0.55 [0.13 to 0.86] for average fat propensity. Conclusions An intervention targeting emotion-driven impulsiveness, compared to psychosocial well-being, would be marginally more effective in reducing sweet and fat propensity in adolescents.

Meal timing has been associated with metabolic markers in adults, but not in children or adolescents. The aim of this study was to investigate associations of meal timing patterns (MTPs) with insulin resistance (IR) and triglyceride levels in children and adolescents. In this cross-sectional study, we included 2,195 participants aged 8–15 years from the European I.Family study (2013/14). Habitual diet exposures were derived using 24-hr dietary recalls and HOMA-IR, HbA1c, and triglycerides were used as metabolic outcome variables. We applied k-means cluster analysis on five dietary exposures (energy proportion in the morning and evening, eating window, pre-sleep fasting and eating frequency), which revealed the following three MTPs: “early-often”, “late-long” and “late-infrequent-short”. We used linear mixed models to estimate the associations between MTPs and the z-scores of the metabolic outcome variables. The association analysis revealed differences between MTPs in HOMA-IR but not in HbA1c or triglyceride z-scores. The “late-infrequent-short” pattern was associated with a 0.19 (95%-CI: (0.01, 0.36)) higher HOMA-IR z-score compared to the “early-often” pattern in the model adjusted for age, BMI z-score, education, sex, country, and family membership. These findings suggest that the timing of meals may influence IR already in childhood and adolescence. Therefore, the time of meals should be considered in future nutrition research and dietary advice for children and adolescents.

Childhood obesity is a complex disorder that appears to be influenced by an interacting system of many factors. Taking this complexity into account, we aim to investigate the causal structure underlying childhood obesity. Our focus is on identifying potential early, direct or indirect, causes of obesity which may be promising targets for prevention strategies. Using a causal discovery algorithm, we estimate a cohort causal graph (CCG) over the life course from childhood to adolescence. We adapt a popular method, the so-called PC-algorithm, to deal with missing values by multiple imputation, with mixed discrete and continuous variables, and that takes background knowledge such as the time-structure of cohort data into account. The algorithm is then applied to learn the causal structure among 51 variables including obesity, early life factors, diet, lifestyle, insulin resistance, puberty stage and cultural background of 5112 children from the European IDEFICS/I.Family cohort across three waves (2007–2014). The robustness of the learned causal structure is addressed in a series of alternative and sensitivity analyses; in particular, we use bootstrap resamples to assess the stability of aspects of the learned CCG. Our results suggest some but only indirect possible causal paths from early modifiable risk factors, such as audio-visual media consumption and physical activity, to obesity (measured by age- and sex-adjusted BMI z-scores) 6 years later.

Physical activity measured by accelerometry (PA-accelerometry) is used as an indicator of physical capacity in chronic diseases. Currently, only fragmented age ranges of reference percentile curves are available for European children and adolescents. This study aimed to provide age- and sex-specific percentiles for physical activity measured by hip-worn accelerometry derived throughout the full age range of European children and adolescents. Individual-level population-based PA data measured by accelerometry from HELENA and IDEFICS/I.Family studies were pooled and harmonized. Together these studies involved children and adolescents aged 2–18 years from 12 European countries. Primary outcomes included averaged counts per minute (CPM), sedentary time (SED), light PA (LPA) and moderate-to-vigorous PA (MVPA). Generalized Additive Models for Location, Scale and Shape were used to derive age- and sex-specific reference percentile curves for these outcomes. The combined cohort consisted of 11,645 children and adolescents aged 2 to 18 years who contributed 14,610 valid accelerometry recordings, with a median accelerometer wear time of 6 days. This dataset allowed for the construction of age- and sex-specific reference percentile curves for CPM, SED, LPA, and MVPA. The curves demonstrated varying trends and variability across age groups. Conclusions: This study provides age- and sex-specific percentile curves for PA-accelerometry in European children and adolescents, addressing a current gap in the availability of full-age range reference data. These curves based on healthy children and adolescents can be used by clinicians, researchers, and policymakers to interpret PA-accelerometry measurements, track physical activity trends, and evaluate treatment responses and health interventions.

PurposeIt is assumed that sensory taste perception shapes food choices and impacts dietary intake. However, this has rarely been studied in free living subjects of different age-groups with standardised methods. The present study investigated the association of the ability to rank sweet and fat taste intensities with consumption frequency of sweet and fatty foods in children, adolescents and adults from eight European countries.MethodsIn total, 461 children, 421 adolescents and 612 adults from the IDEFICS/I.Family cohort participated in sensory sweet and fat intensity rating tests. Sweet and fatty food consumption frequencies were assessed using a food frequency questionnaire. The association between the ability to rank sweet and fat intensity with sweet and fatty food consumption frequencies was estimated using linear mixed regression models adjusting for weight status, country, sex, age and family affiliation.ResultsAcross all age groups, the largest proportion of participants had medium sweet and fat taste intensity ranking abilities. The next largest proportion had low sweet and fat taste intensity rating abilities, while the smallest proportion had high intensity rating abilities to sweet and fat taste. A negative association of sweet and fat taste intensity ranking ability with sweet and fatty food consumption frequencies was found for children. In adolescents, the association was positive. In adults, there was no association.ConclusionIt seems that the association of taste intensity ratings with food consumption frequencies during adolescence differs from the associations in children and adults. This could be due to hormonal changes during puberty, growth and maturation. Thus, further research focussing on maturation processes in association with taste perception during adolescence may be required.

To investigate the reliability of parental recall of birth weight, birth length and gestational age several years after birth. Parentally recalled birth parameters were obtained from the European multicentric cohort study IDEFICS (Identification and prevention of dietary- and lifestyle-induced health effects in children and infants) and compared to the corresponding data externally recorded in the child’s medical check-up booklet. The agreement between the two sources was examined using Bland–Altman plots, intraclass correlation coefficients and Cohen’s kappa for clinically relevant categories. Additionally, logistic regression models were used to identify factors related to parental recall accuracy. A total of 4930 children aged 2 to 11 years were included. Accuracy of birth weight within 100 g was 88

Introduction: The Mediterranean Diet (MD) has been associated with a better adiposity profile in different cohorts of European children. However, these beneficial effects might be influenced by genetic variations, which could potentially modulate the MD–adiposity association. Objectives: To investigate if higher adherence to the MD, or any of the MD food groups, is associated with lower adiposity during youth. Also, to observe the degree by which the adherence to the MD or any of the MD food groups could modulate the genetic susceptibility to obesity, in relation to adiposity. Methods: Design: Cohort study with three measurement surveys: baseline (T0), follow-up 1 (T1), and follow-up 2 (T3), between 2007 and 2014. Setting: The pan-European IDEFICS/I.Family cohort. Participants: 3098 children aged 2–16 years were genotyped. A total of 1907 participants at time measurement 3 (T3) were included, with complete information in all parameters of interest. Outcome measures: body mass index (BMI) and waist circumference (WC). A 7-item Mediterranean Diet Score (MDS) to assess the degree of MD adherence, and a genome-wide polygenic risk score (PRS) for BMI previously built within the IDEFICS/I.Family consortium, from a previous GWAS to capture obesity risk. Statistical analysis: In T3, multiple linear regressions to test MD–adiposity and MD-food-groups–adiposity associations, adjusted by age, sex, parental education, genetic susceptibility to obesity, population stratification, region of residence, screen sedentary time (SST), and physical activity. Then, the same models were used to estimate gene x diet effects, based on the PRS x MD adherence. Results: No associations were found between MDS and BMI or WC adiposity markers (p-value 0.26, B 0.10). In terms of food groups, higher vegetable consumption was inversely associated to BMI (p-value < 0.01, B −0.01) and WC (p-value 0.01, B −0.02), although no gene x vegetables interaction effects were found (BMI p-value 0.43, B < 0.01; WC p-value 0.49, B 0.01). Age and SST were also significantly associated to BMI (p-value 0.01, B −0.12; p-value < 0.01, B 0.02), and only SST to WC (p-value 0.03, B 0.05), respectively. Conclusions: Higher consumption of vegetables might be associated with lower obesity, irrespective of their obesity genetic risk.

To investigate longitudinal associations between the vitamin D status and inflammatory markers in children and adolescents. Children from eight European countries from the IDEFICS/I.Family cohort with repeated measurements were included in this study. A linear mixed-effect model was used to model the association of serum 25(OH)D as independent variable and z-scores of inflammatory markers [CRP, cytokines, adipokines, combined inflammation score] as dependent variables, where one level accounts for differences between individuals and the other for changes over age within individuals. A total of 1,582 children were included in the study. In the adjusted model, 25(OH)D levels were positively associated with adiponectin (β = 0.11 [95

Summary Objective To investigate population trajectories of behavioural risk factors of obesity from childhood to adolescence and their associations with body mass index (BMI) in children across European regions. Methods Data were harmonised between the European multi‐centre IDEFICS/I.Family and the Amsterdam Born Children and their Development Cohort. Participants were aged 2.0–9.9 and 5.0–7.5 years at baseline, respectively, and were followed until age 18 years. Behavioural risk factors of interest included diet, physical activity, media use and sleep. Mixed effects models were used for statistical analyses to account for repeated measurements taken from the same child. Results The study included a total of 14 328 individuals: 4114, 4582, 3220 and 2412 participants from Northern, Southern, Eastern Europe and Amsterdam, respectively. Risk factor means and prevalences changed with age, but the trajectories were mostly similar across regions. Almost no associations between behavioural factors and BMI were found at the age of 6 years. At 11 years, daily sugar‐sweetened foods consumption, use of active transport, sports club membership and longer nocturnal sleep duration were negatively associated with BMI in most regions; positive associations were found with media use. Most associations at 11 years of age persisted to 15 years. Conclusions Whilst population trajectories of media use and nocturnal sleep duration are similar across European regions, those of other behavioural risk factors like active transport and daily vegetable consumption differ. Also, associations between behavioural risk factors and BMI become stronger with age and show similar patterns across regions.