Urban Moveability and physical activity in children:longitudinal results from the IDEFICS and I.Family cohort

Background: Physical activity (PA) is one of the major protective behaviours to prevent non-communicable diseases. Positive effects of the built environment on PA are well investigated, although evidence of this association is mostly based on cross-sectional studies. The present study aims to investigate the longitudinal effects of built environment characteristics in terms of a moveability index on PA of children in their transition phase to adolescence using data of the IDEFICS/I.Family cohort. Methods: We used data on 3394 accelerometer measurements of 2488 children and adolescents aged 3 to 15 years old from survey centres of three countries, Germany, Italy, and Sweden, who participated in up to three surveys over 6 years. In network-dependent home neighbourhoods, a moveability index was calculated based on residential density, land use mix, street connectivity, availability of public transport and public open spaces such as green spaces and public playgrounds in order to quantify opportunities for PA of children and adolescents. Linear trajectories of light PA (LPA) and moderate-to-vigorous PA (MVPA) were estimated using linear mixed models accounting for repeated measurements nested within individuals. Least squares means were estimated to quantify differences in trajectories over age. Results: LPA and MVPA declined annually with age by approximately 20 min/day and 2 min/day respectively. In girls, the moveability index showed a consistent significantly positive effect on MVPA (β $\hat{\beta}$ = 2.14, 95% CI: (0.11; 4.16)) for all ages, while in boys the index significantly lessened the decline in LPA with age for each year. (β $\hat{\beta}$ = 2.68, 95% CI: (0.46; 4.90)). Availability of public open spaces was more relevant for MVPA in girls and LPA in boys during childhood, whereas in adolescence, residential density and intersection density became more important. Conclusion: Built environment characteristics are important determinants of PA and were found to have a supportive effect that ameliorates the decline in PA during the transition phase from childhood to adolescence. In childhood environmental support for leisure time PA through public open spaces was found to be the most protective factor whereas in adolescence the positive influence of street connectivity and residential density was most supportive of physical activity. © 2019 The Author(s).Export Date: 30 December 2019; Article; Correspondence Address: Buck, C.; Leibniz Institute for Prevention Research and Epidemiology, BIPS, Achterstraße 30, Germany; email: [email protected]; Funding details: Deutsche Forschungsgemeinschaft, DFG, PI 345/7–1; Funding details: Sixth Framework Programme, FP6, 016181; Funding details: 266044, KBBE 2010–14; Funding details: European Commission, EU; Funding details: German-Israeli Foundation for Scientific Research and Development, GIF; Funding text 1: The work of the first author was funded by the German Research Foundation (DFG) under grant PI 345/7–1. Baseline data collection and the first follow-up work as part of the IDEFICS Study [www.idefics.eu] were financially supported by the European Commission within the Sixth RTD Framework Programme Contract No. 016181 (FOOD). The most recent follow-up was conducted in the framework of the I.Family study [www.ifamilystudy.eu] which was funded by the European Commission within the Seventh RTD Framework Programme Contract No. 266044 (KBBE 2010–14). The research presented here incorporates data from both projects.</p

Impact of physical activity, sedentary behaviour and muscle strength on bone stiffness in 2-10-year-old children-cross-sectional results from the IDEFICS study

Background: Physical activity (PA), weight-bearing exercises (WBE) and muscle strength contribute to skeletal development, while sedentary behaviour (SB) adversely affects bone health. Previous studies examined the isolated effect of PA, SB or muscle strength on bone health, which was usually assessed by x-ray methods, in children. Little is known about the combined effects of these factors on bone stiffness (SI) assessed by quantitative ultrasound. We investigated the joint association of PA, SB and muscle strength on SI in children. Methods: In 1512 preschool (2- < 6 years) and 2953 school children (6-10 years), data on calcaneal SI as well as on accelerometer-based sedentary time (SED), light (LPA), moderate (MPA) and vigorous PA (VPA) were available. Parents reported sports (WBE versus no WBE), leisure time PA and screen time of their children. Jumping distance and handgrip strength served as indicators for muscle strength. The association of PA, SB and muscle strength with SI was estimated by multivariate linear regression, stratified by age group. Models were adjusted for age, sex, country, fat-free mass, daylight duration, consumption of dairy products and PA, or respectively SB. Results: Mean SI was similar in preschool (79.5 +/- 15.0) and school children (81.3 +/- 12.1). In both age groups, an additional 10 min/day in MPA or VPA increased the SI on average by 1 or 2 %, respectively (p = .05). The negative association of SED with SI decreased after controlling for MVPA. LPA was not associated with SI. Furthermore, participation in WBE led to a 3 and 2 % higher SI in preschool (p = 0.003) and school children (p < .001), respectively. Although muscle strength significantly contributed to SI, it did not affect the associations of PA with SI. In contrast to objectively assessed PA, reported leisure time PA and screen time showed no remarkable association with SI. Conclusion: This study suggests that already an additional 10 min/day of MPA or VPA or the participation in WBE may result in a relevant increase in SI in children, taking muscle strength and SB into account. Our results support the importance of assessing accelerometer-based PA in large-scale studies. This may be important when deriving dose-response relationships between PA and bone health in children

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 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

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

Associations between sleep duration and insulin resistance in European children and adolescents considering the mediating role of abdominal obesity

Background Short sleep duration has been suggested to lead to insulin resistance both directly by altering glucose metabolism and indirectly through obesity. This study aims to investigate associations between nocturnal sleep duration and insulin resistance considering abdominal obesity as a mediator. Methods We analysed data of 3 900 children aged 2-15 years participating in the second (2009/10) and third (2013/14) examination wave of the European IDEFICS/I.Family study (hereafter referred to as baseline and follow-up). Information on nocturnal sleep duration was collected by questionnaires and age-standardised (SLEEP z-score). The homeostasis model assessment (HOMA) was calculated from fasting insulin and fasting glucose obtained from blood samples; waist circumference (WAIST) was measured with an inelastic tape. HOMA and WAIST were used as indicators for insulin resistance and abdominal obesity, respectively, and transformed to age- and sex-specific z-scores. Cross-sectional and longitudinal associations between SLEEP z-score and HOMA z-score were investigated based on a path model considering WAIST z-score as a mediator adjusting for relevant confounders. Results Cross-sectionally, baseline SLEEP z-score was negatively associated with baseline WAIST z-score (unstandardised effect estimate -0.120, 95% confidence interval [-0.167; -0.073]). We observed no direct effect of baseline SLEEP z-score on baseline HOMA z-score but a negative indirect effect through baseline WAIST z-score (-0.042 [-0.058; -0.025]). Longitudinally, there was no direct effect of baseline SLEEP z-score on HOMA z-score at follow-up but a negative indirect effect through both baseline WAIST z-score and WAIST z-score at follow-up (-0.028 [-0.040; -0.016]). Conclusions Our results do not support the hypothesis of an association between short sleep duration and insulin resistance independent of abdominal obesity. However, longer sleep duration may exert short and long term beneficial effects on insulin resistance through its beneficial effects on abdominal obesity

Weight Status and BMI-related traits in adolescent friendship groups and role of sociodemographic factors : the European IDEFICS/I.Family Cohort

Background: During adolescence, health behaviors and weight status are increasingly influenced by friendship and peer networks. This paper examines resemblances in weight-related characteristics and how they differ by sociodemographic factors. Methods: Over 3,000 friendships were reported by 1,603 adolescents, aged 11-16 years, who participated in the school-based I.Family study in 6 European countries. Each "source child" named 1-10 friends for whom standardized weight-related traits were available in the same survey. The mean value of the friends' traits weighted by time spent together was calculated, and related to the source child's trait. Country, age and sex of the source child, parental education, and immigrant background were considered for confounding and moderation. Results: Source children's z-scores of body fat percent and BMI were positively associated with their friends' characteristics, in particular if they had highly educated parents. Positive associations were also found regarding the frequency of fast-food consumption, impulsivity, screen time, preference for sugar-sweetened foods, and hours spent in sports clubs, in increasing order of effect size. Additionally, correlations were observed between friends' cognitive and school functioning and being bullied. No associations were seen for a preference for high-fat foods, weight concerns, and health-related quality of life. Finally, parental education and immigrant background were associated between friends in all countries except Sweden, where no associations were observed. Conclusion: Adolescent friends shared a number of weight-related characteristics. For weight measures per se, positive associations with friends' characteristics were only observed in adolescents with high parental education. Associations regarding energy-balance behaviors and indicators of school-related well-being did not differ by parental education. Parental education and immigrant background correlated positively in friends in most countries showing that social aggregation is already occurring in adolescence. The wide spectrum of friendship associations in weight-related traits and behaviors suggests that health promotion initiatives in adolescents should be directed towards peer groups in both school-related and leisure-time environments. ISRCTN Registry: Pan-European IDEFICS/I.Family children cohort (ID ISRCTN62310987; https://doi.org/10.1186/ISRCTN62310987)

Cross-sectional and longitudinal associations between psychosocial well-being and sleep in European children and adolescents

Research on associations of positive mental health, in contrast to mental ill-health, with sleep duration and sleep disturbances in young populations is scarce. In particular, longitudinal studies focussing on the influence of positive mental health on sleep characteristics are lacking. Therefore, we investigated cross-sectional and longitudinal associations of psychosocial well-being with sleep duration and sleep disturbances. For the cross-sectional analysis, we used data of 3-15-year-old children and adolescents participating in the 2013/14 examination of the European IDEFICS/I.Family cohort study (N = 6,336). The longitudinal analysis was restricted to children who also participated in the 2009/10 examination (N = 3,379). Associations between a psychosocial well-being score created from 16 items of the KINDLR Health-Related Quality of Life Questionnaire covering emotional well-being, self-esteem and social relationships, an age-standardized nocturnal sleep duration z-score and two sleep disturbance indicators ("trouble getting up in the morning", "difficulties falling asleep") were estimated using linear and logistic mixed-effects models. Cross-sectionally, a higher well-being score was associated with longer sleep duration and lower odds of sleep disturbances. A positive change in the well-being score over the 4-year period was associated with longer sleep duration and lower odds of sleep disturbances at follow-up. However, there was only weak evidence that higher psychosocial well-being at baseline was associated with better sleep 4 years later. Thus, our results suggest that increases in well-being are associated with improvements in both sleep duration and sleep disturbances, but that well-being measured at one point in time does not predict sleep characteristics several years later.Peer reviewe

Early life course risk factors for childhood obesity : the IDEFICS case-control study

Background: The early life course is assumed to be a critical phase for childhood obesity; however the significance of single factors and their interplay is not well studied in childhood populations. Objectives: The investigation of pre-, peri- and postpartum risk factors on the risk of obesity at age 2 to 9. Methods: A case-control study with 1,024 1: 1-matched case-control pairs was nested in the baseline survey (09/2007-05/2008) of the IDEFICS study, a population-based intervention study on childhood obesity carried out in 8 European countries in pre- and primary school settings. Conditional logistic regression was used for identification of risk factors. Results: For many of the investigated risk factors, we found a raw effect in our study. In multivariate models, we could establish an effect for gestational weight gain (adjusted OR = 1.02; 95% CI 1.00-1.04), smoking during pregnancy (adjusted OR = 1.48; 95% CI 1.08-2.01), Caesarian section (adjusted OR = 1.38; 95% CI 1.10-1.74), and breastfeeding 4 to 11 months (adjusted OR = 0.77; 95% CI 0.62-0.96). Birth weight was related to lean mass rather than to fat mass, the effect of smoking was found only in boys, but not in girls. After additional adjustment for parental BMI and parental educational status, only gestational weight gain remained statistically significant. Both, maternal as well as paternal BMI were the strongest risk factors in our study, and they confounded several of the investigated associations. Conclusions: Key risk factors of childhood obesity in our study are parental BMI and gestational weight gain; consequently prevention approaches should target not only children but also adults. The monitoring of gestational weight seems to be of particular importance for early prevention of childhood obesity

Bidirectional associations between psychosocial well-being and body mass index in European children : longitudinal findings from the IDEFICS study

Background: The negative impact of childhood overweight on psychosocial well-being has been demonstrated in a number of studies. There is also evidence that psychosocial well-being may influence future overweight. We examined the bidirectional association between childhood overweight and psychosocial well-being in children from a large European cohort. The dual aim was to investigate the chronology of associations between overweight and psychosocial health indicators and the extent to which these associations may be explained by parental education. Methods: Participants from the IDEFICS study were recruited from eight countries between September 2007 and June 2008 when the children were aged 2 to 9.9 years old. Children and families provided data on lifestyle, psychosocial well-being, and measured anthropometry at baseline and at follow-up 2 years later. This study includes children with weight, height, and psychosocial well-being measurements at both time points (n = 7,831). Psychosocial well-being was measured by the KINDL (R) and Strengths and Difficulties Questionnaire respectively. The first instrument measures health-related quality of life including emotional well-being, self-esteem, parent relations and social relations while the second measures well-being based on emotional symptoms, conduct problems and peer-related problems. Logistic regression was used for modeling longitudinal associations. Results: Children who were overweight at baseline had increased risk of poor health-related quality of life (odds ratio (OR) = 1.23; 95 % confidence interval (CI): 1.03-1.48) measured 2 years later; this association was unidirectional. In contrast to health-related quality of life, poor well-being at baseline was associated with increased risk of overweight (OR = 1.39; 95 % CI: 1.03-1.86) at 2 year follow-up; this association was also only observed in one direction. Adjustment for parental education did not change our findings. Conclusion: Our findings indicate that the association between overweight and psychosocial well-being may be bidirectional but varies by assessment measures. Future research should further investigate which aspects of psychosocial well-being are most likely to precede overweight and which are more likely to be consequences of overweight

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 mu g 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