Association between individual fat depots and cardio-metabolic traits in normal- and overweight children, adolescents and adults.

OBJECTIVES: To determine age-related associations between fat mass (FM), regional fat depots and cardiometabolic traits in normal- and overweight children, adolescents and adults. METHODS: Detailed body composition (regional subcutaneous and visceral adipose tissue; SAT, VAT) by whole-body magnetic resonance imaging (MRI), FM and fat-free mass by air-displacement plethysmography, systolic and diastolic blood pressure (SBP, DBP), triglycerides (TG), high-density lipoprotein cholesterol (HDL), plasma glucose and plasma insulin were measured in 433 subjects (BMI: 23.6 (21.0-27.7); 151 children and adolescents, aged 6-18 years, 150 young adults, aged 18-30 years and 132 adults, aged 30-60 years). Data were derived from pooled data of the 'Reference Center for Body Composition' in Kiel, Germany. Insulin resistance was determined by the homeostatic model assessment of insulin resistance (HOMA-IR). Partial correlations and multivariate linear regression analyses were used to evaluate the associations between body composition and cardiometabolic traits. A descriptive approach was used to demonstrate age-dependent differences in associations between body fat depots and insulin resistance, independent of BMI. RESULTS: FM, SAT, and VAT increased from childhood to adulthood with low VAT in children and adolescents. When compared to children, TG was higher in adults. HDL and DBP did not differ between age groups. Insulin resistance was highest in male adolescents and female young adults. Associations between body fat depots and cardiometabolic traits were seen after puberty with no associations in pre- and intrapubertal children. When compared to FM, SAT and VAT had the strongest association with insulin resistance in adults. This association was independent of BMI. CONCLUSIONS: Associations between individual body fat depots and most cardiometabolic traits became evident after puberty only. The strongest associations were observed between insulin resistance and abdominal fat in adults. The impact of VAT was independent of BMI.

[Required Effekt Sizes of Preventive Measures for Overweight in Children and Adolescents]. / Wie groß muss die Wirkung von Prävention auf das Übergewicht von Kindern und Jugendlichen sein?

BACKGROUND AND AIM OF THE STUDY: Successful preventive measures can stop a further increase in the prevalence of overweight in children and adolescents. However, up to now, the required effect sizes of interventions for reducing childhood overweight remain unclear. The calculation of the energy gap (excess calories consumed over calories expended) offers the possibility to estimate the required effect sizes. In this work 2 approaches to calculate the energy gap will be compared. METHODS: Longitudinal data of 1690 children and adolescents of the Kiel Obesity Prevention Study (KOPS) on measured height, weight, fat mass and fat-free mass (using bioelectrical impedance analysis) at age 6 and 10 years will be used to calculate energy gap with 2 different approaches: (i) using age-independent changes in fat mass and fat-free mass (old approach) and (ii) using a mathematic model of weight dynamic (new approach). RESULTS: Energy gap according to the old approach was 140 kcal/day; by contrast, new modeling resulted in an energy gap between 270 and 370 kcal/day. Both, BMI and fat mass were suitable to calculate energy gap and led to nearly same results. Exceeding the 90(th) percentile of BMI or fat mass (incidence approach) as well as large changes within the normal range (i.e. between the 10(th) and the 90(th) percentile) led to large energy gaps. Thus, all children with large energy gaps have to be characterized as at risk for overweight. CONCLUSION: The new approach seems to be convincing because it considered the additional energy expenditure for building fat-free mass due to increasing age and weight.Calculating energy gap offers a new approach for prevention of overweight. It shows that the required effect sizes of prevention measures have to be in a region of 140 to 400 kcal/day. This differs clearly from energy reduction of diets in the therapy of obesity.

[GeKo KidS--Health Literacy in School Children]. / GeKo KidS--Gesundheitskompetenz bei Kindern in der Schule.

The main goal of this study was the evaluation of an intervention programme for the promotion of health literacy in school-aged children (grade 5-6). The project and the programme were highly accepted, the extension of the annual dental health examination was suitable to collect data within evaluation projects in schools. In spite of positive outcomes, a longer supervision phase would be necessary in order to optimise and to implement other programme components fully.

Adiposity rebound is misclassified by BMI rebound.

BACKGROUND/OBJECTIVES: Adiposity rebound (AR) is defined as the nadir or the inflexion point of body mass index (BMI) percentiles between the age of 3 and 7 years. An early rebound is seen as a risk of obesity and, thus, AR is considered as a suitable time period for prevention. As BMI does not reflect body composition, we aimed to examine the rebounds of fat mass index (FMI) and fat-free mass index (FFMI) together with BMI. SUBJECTS/METHODS: Cross-sectional data of 19 264 children aged 3-11 years were pooled from three German studies (Kiel Obesity Prevention Study, the project 'Better diet. More exercise. KINDERLEICHT-REGIONS' and regular examinations of Jena children). Height and weight were measured. Fat mass (FM) and fat-free mass (FFM) were obtained from bioelectrical impedance analysis and analysed using a population-specific algorithm. Percentiles of BMI, FMI and FFMI were constructed by the LMS method. RESULTS: Both BMI and FMI percentiles showed a rebound, whereas FFMI percentiles steadily increased with age. On P90, FMI rebound was about 1.6-1.8 years later compared with that of BMI, that is, at ages 4.2 years (BMI) and 5.8 years (FMI) in boys and at 4.2 years (BMI) and 6.0 years (FMI) in girls. At AR, the slope of the BMI-P90 was explained by increases in FFMI rather than FMI. By contrast, at FMI rebound, the slope of BMI was strongly related to FMI. CONCLUSIONS: BMI rebound does not equal the rebound of FM. At AR, the slope in BMI is determined by the increase in FFMI. AR should be defined as FMI rebound rather than BMI rebound.

[Longitudinal data of the Kiel Obesity Prevention Study (KOPS)]. / Längsschnittdaten der Kieler Adipositas-Präventionsstudie (KOPS).

The Kiel Obesity Prevention Study (KOPS) has been performed since 1996. Examinations were performed at age 6, 10 and 14 years. In addition, birth weight as well as height and weight at age 2 years were collected retrospectively. For the study 4,997, 1,671 and 748 children were recruited at baseline (at age 6 years) as well as at 4 and 8-year follow-up, respectively. In this paper we will analyze and discuss (i) the important time period for preventive measures, (ii) effect sizes needed for successful interventions and (iii) suitable approaches for preventive measures. The main results were: (i) at age 6 years persistence of overweight was 69% while at younger ages persistence was 21% only. Thus, school entry was shown to be an important period for preventive measures. (ii) Interventions have to reduce energy balance by 140 kcal/day to prevent overweight (e.g. a reduction of energy intake). (iii) Prevention programs should involve the family and focus on increasing physical activity.

Different age-specific incidence and remission rates in pre-school and primary school suggest need for targeted obesity prevention in childhood.

BACKGROUND: School entry marks a tremendous change in the children's life style, which might well be relevant for the emergence of overweight. Previous studies suggested a dramatic increase in the prevalence of overweight during this age. OBJECTIVE: To compare the age-specific balance between the incidence and remission of overweight between pre-school and primary school age children. DESIGN: We combined the data of three studies that had been conducted within the setting of the compulsory school entry health examination in different parts of Germany: one covering retrospective cohort data from age 2 to school entry (n=5045), one prospective data from school entry to fourth grade (n=1235) and one comprising both (n=1194). We assessed the rates of incidence and remission of overweight and obesity from age 2 to school entry and from school entry to fourth grade. RESULTS: In pre-school age, the pooled incidence for overweight was 8.2% (95% confidence interval: 7.5, 8.9) compared with a remission rate of 62.6% (58.4, 66.7), yielding a prevalence at school entry of 10.7% (9.9, 11.5). In primary school age, the pooled incidence for overweight increased to 14.6% (13.1, 16.1), whereas the remission rate was reduced to 17.7% (13.8, 22.3), yielding a prevalence of 23.7% (22.0, 25.4) in fourth grade. A similar pattern was observed for obesity. CONCLUSIONS: While high remission rates balance incident overweight in pre-school years, the dramatic increase in the prevalence of overweight and obesity in primary school years reflects a higher incidence and even more a lower remission rate. Obesity prevention programs in primary school age are mandatory and need to address primary and secondary prevention elements.

Associations between neighbourhood characteristics, body mass index and health-related behaviours of adolescents in the Kiel Obesity Prevention Study: a multilevel analysis.

BACKGROUND/OBJECTIVES: To understand determinants of overweight, several studies addressed the association between neighbourhood characteristics and adult obesity. However, little is known about the association of such characteristics with adolescents' overweight. This study aims at the influence of neighbourhood characteristics on adolescent body mass index (BMI) and lifestyle and to what extent BMI and lifestyle variation between neighbourhoods can be explained by neighbourhood characteristics. SUBJECTS/METHODS: We used cross-sectional data from the Kiel Obesity Prevention Study collected between 2004 and 2008 in 28 different residential districts of the city of Kiel (North Germany). Anthropometric data were available for 1675 boys and 1765 girls (n=3440) aged 13-15 years, and individual lifestyle factors and sociodemographic data were included in the analysis. At the macro level, six different neighbourhood characteristics were used: unemployment rate, population density, traffic density, prevalence of energy-dense food supply, number of sports fields and parks, and crime rate. To test our main hypothesis, linear and logistic multilevel regression analyses were performed to predict BMI and lifestyle factors in individuals nested in neighbourhoods. RESULTS: Findings of multilevel analysis show little between-neighbourhood variations in BMI and health-related behaviours. In all, 2% of BMI variation, 4% of media time variation and 3% of variation in snacking behaviour could be attributed to differences in neighbourhoods. CONCLUSIONS: Environmental factors are significantly associated with adolescent BMI and health-related behaviour; however, their total effect is small. Owing to these results, recommendations for structural policy measures as part of prevention of overweight in adolescents must be made cautiously.

[15 years of the Kiel Obesity Prevention Study (KOPS). Results and its importance for obesity prevention in children and adolescents]. / 15 Jahre Kieler Adipositas-Präventionsstudie (KOPS). Ergebnisse sowie deren Einordnung und Bedeutung für die Prävention von Adipositas bei Kindern und Jugendlichen.

The Kiel Obesity Prevention Study (KOPS) has been performed since 1996 and aims to characterize determinants and to prevent overweight. A total of 15,251 children and adolescents aged 5-16 years were recruited, of whom 780 and 92, respectively, underwent school-based and family-based interventions. Long-term evaluation of the school-based intervention was available over 4 and 8 years, while family-based intervention was evaluated over 1 year. The prevalence of overweight was 18.8% for the whole KOPS cohort. Determinants of overweight were parental overweight and obesity, low socioeconomic status (SES), early life factors, and lifestyle factors. School-based intervention ameliorated the weight status of children of high SES and of normal weight mothers over the long-term. The intervention effect was small but within the expectable range as calculated from analysis of determinants. Alternative outcome variables (e.g., fat mass) and new evaluation approaches (e.g., excess gain in fat mass) gave no detailed information of the intervention success. Family-based intervention showed that even with this individual approach children of low SES could not be reached.

[Self-reported and measured height and weight in adolescents]. / Schätz- und Messwerte von Größe und Gewicht bei Jugendlichen.

OBJECTIVES: The aim of this study was to assess the validity of self-reported height and weight and resulting body-mass-index (BMI) in adolescents, to identify influencing factors and to generate appropriate algorithms for the correction of self-reported values. METHODS: In the Kiel Obesity Prevention Study (KOPS) height and weight were assessed in 2,706 12- to 17-year-old adolescents by self-report and by measurements. Differences between self-reported and measured values were calculated. Algorithms for correction of self-reported data were generated in a random sample (n=941) and validated in another random sample (n=946). RESULTS: Overestimation of height and underestimation of weight resulted in a remarkable underestimation of BMI. Girls underestimated BMI more than boys (-0.8±1.0 kg/m² vs. -0.4±1.1 kg/m²; p<0.01), overweight adolescents underestimated more than normal weight adolescents (boys: -1.4±1.4 kg/m² vs. -0.3±0.9 kg/m²; p<0.01; girls:-1.6±1.3 kg/m² vs. -0.7±0.8 kg/m²; p<0.01). Prevalence of overweight and obesity was underestimated by 2.0% and 1.5%, respectively, in boys and by 2.2% and 2.0%, respectively in girls. Differences between self-reported and measured values were influenced by gender and weight status. Correction of self-reported data resulted in approaching the valid overweight prevalence. However, underestimations persisted. CONCLUSIONS: Self-reported height, weight and BMI calculated from these values are discrepant from measured data and cause underestimation of the prevalence of overweight and obesity in adolescents. Correction of self-reported values is possible. However, valid data can only be assessed by measurements of height and weight.

[Social inequality, migration, and healthy environments as determinants of overweight of children and adolescents. Results of the Kiel Obesity Prevention Study (KOPS)]. / Soziale Ungleichheit, Migrationshintergrund, Lebenswelten und Ubergewicht bei Kindern und Jugendlichen. Ergebnisse der Kieler Adipositas-Präventionsstudie (KOPS).

This study aimed at studying the relationships between different social determinants, overweight, migration background, lifestyle factors, and neighborhood characteristics in children and adolescents aged 6-14 years. Data were collected within the Kiel Obesity Prevention Study (KOPS). The lower the social status, the higher the prevalence of overweight (e.g., parental education low/middle/high,%: 18.4/13.6/7.9). Non-German children are twice as often overweight as German children (20.2% versus 11.7%) with a social gradient in overweight (%: 26.0/28.2/17.2). There are social differences in health-related behavior between the social groups and also between German and non-German children of the same social group. The social gradient in overweight is, in part, independent of lifestyle factors. Neighborhood characteristics like high food supply and traffic density add to the development of overweight. To summarize, overweight is a social issue; direct prevention has to address the social determinants of health as well as families with migration background. In addition, the development of "healthy" neighborhoods may support the prevention of overweight.

Long-term effects of rapid weight gain in children, adolescents and young adults with appropriate birth weight for gestational age: the Kiel Obesity Prevention Study.

AIM: This study investigates the effect of rapid weight gain in term children, adolescents and young adults born appropriate for gestational age. METHODS: In all, 173 girls and 178 boys aged 6.1-19.9 (12.5 +/- 3.1)years participated. Rapid weight gain (group 1) was defined as a change in weight-SDS (standard deviation score) from birth till two years >0.67, 'no change' as > or =-0.67 and < or =0.67 (group 2) vs 'slow weight gain' as <-0.67 (group 3). BMI-SDS, waist circumference (WC) z-score, fat mass (FM)/fat free mass (FFM; Air-Displacement-Plethysmography), resting energy expenditure (REE; ventilated hood system), cardio-metabolic risk factors, serum leptin and adiponectin were assessed. >90th age-/sex-specific BMI-percentile was defined as overweight. Parental BMI, socio-economic status and lifestyle were assessed as confounders. RESULTS: A total of 22.8% gained weight rapidly, and 15.7% was overweight. Group 1 compared with group 2 and 3 subjects was taller, heavier and had a higher prevalence of overweight (girls/boys: 26.2%/28.9% vs 11.6%/19.0% vs 2.8%/5.0%; p < 0.01/p < 0.05). Concomitantly, a higher WC, %FM and FFM were observed. Rapid weight gain was positively associated with REE (adjusted for FFM) in boys (r = 0.26; p < 0.01), but not with cardio-metabolic risk factors. CONCLUSION: Rapid weight gain was related to increases in height, weight, a higher prevalence of overweight and central fat distribution. In addition, rapid weight gain was related to a higher REE in boys, but not to cardio-metabolic risk factors.

Determinants and impact of sleep duration in children and adolescents: data of the Kiel Obesity Prevention Study.

BACKGROUND/OBJECTIVES: This study investigates determinants of sleep duration and its impact on nutritional status, resting energy expenditure (REE), cardiometabolic risk factors and hormones in children/adolescents. SUBJECTS/METHODS: In 207 girls and 207 boys (13.0+/-3.4 (6.1-19.9) years) body mass index standard deviation score (BMI SDS), waist circumference (WC) z-score, body composition (air-displacement plethysmography), REE (ventilated hood system; n=312) and cardiometabolic risk factors/hormones (n=250) were assessed. Greater than 90th percentile of BMI/WC references was defined as overweight/overwaist. Sleep duration, media consumption (TV watching/computer use), physical activity, dietary habits, parental BMI, socio-economic status and early infancy were assessed by questionnaire. Short sleep was defined as <10 h per day for children <10 years and otherwise <9 h per day. RESULTS: Total 15.9% participants were overweight, mean sleep duration was 8.9+/-1.3 h per day. Age explained most variance in sleep (girls: 57.0%; boys: 41.2%) besides a high nutrition quality score (girls: 0.9%) and a low media consumption (boys: 1.3%). Sleep was inversely associated with BMI SDS/WC z-score (girls: r=-0.17/-0.19, P<0.05; boys: r=-0.21/-0.20, P<0.01), which was strengthened after adjusting for confounders. Short vs long sleep was associated with 5.5-/2.3-fold higher risks for obesity/overwaist (girls). After adjusting for age, REE (adjusted for fat-free mass) was positively associated with sleep in boys (r=0.16, P<0.05). Independently of age and WC z-score, short sleep was associated with lower adiponectin levels in boys (11.7 vs 14.4 microg/ml, P<0.05); leptin levels were inversely related to sleep in girls (r=-0.23, P<0.05). Homoeostasis model assessment-insulin resistance (r=-0.20, P<0.05) and insulin levels (r=-0.20, P<0.05) were associated with sleep (girls), which depended on WC z-score. CONCLUSIONS: Age mostly determined sleep. Short sleep was related to a higher BMI SDS/WC z-score (girls/boys), a lower REE (boys), higher leptin (girls) and lower adiponectin levels (boys).

Associations between active commuting to school, fat mass and lifestyle factors in adolescents: the Kiel Obesity Prevention Study (KOPS).

OBJECTIVE: To examine possible associations between active commuting (walking or cycling) to school, parameters of adiposity and lifestyle factors in 14-year-old adolescents of the Kiel Obesity Prevention Study. SUBJECTS: A total of 626 14-year-old adolescents. METHODS: Measured body mass index (BMI), fat mass (FM), distance to school as well as self-reported modes and duration of commuting to school, time spent in structured and unstructured physical activities (PAs), media use, nutrition, alcohol consumption and smoking. RESULTS: Parameters of adiposity did not differ between different commuting modes after stratifying by gender. Active commuters reported higher overall PA, which was caused by commuting activity and time spent in unstructured PA in girls and just by commuting activity in boys. In active commuters, 28.4% of overall PA was explained by commuting activity. Additionally, TV viewing was lower in active commuters. Compared to their inactively commuting counterparts, actively commuting boys were less likely to smoke. After controlling for potential confounders the interaction term 'active commuting by distance to school' and 'time spent in structured PA' were independent predictors of FM, whereas active commuting by itself showed no effect. CONCLUSION: The present data suggest that active commuting to school per se does not affect FM or BMI until considering distance to school. Increasing walking or cycling distance results in decreasing FM. However, the everyday need to get to and from school may enhance adolescents' overall PA.

Interventions to prevent overweight in children.

There are only few controlled studies on prevention of overweight in children and adolescence. These studies differ with respect to strategy, setting, duration, focus, variables of outcome and statistical power. Universal and school-based interventions show some improvement of health knowledge and health-related behaviours but they have only minor or no effects on nutritional status. However they reduce the incidence of overweight. The effects seem to be more pronounced in girls than in boys. Children of middle and high class as well as children with intact families benefit better from intervention than children with low socioeconomic status. Selected prevention in overweight children was most successful when children were treated together with their parents. However there are social barriers limiting the success. Simple interventions in a single area are unlikely to work on their own. The development of effective preventive interventions likely require strategies that affect multiple settings simultaneously. At present there is no concerted action but many strategies are followed in isolation. There is need for national campaigns and action plans on childhood overweight and obesity. It is tempting to speculate that this will also increase the effects of isolated approaches.

First lessons from the Kiel Obesity Prevention Study (KOPS).

AIMS: Prevention of obesity is a public health agenda. There are only few longitudinal studies on prevention of overweight in children. The Kiel Obesity Prevention Study (KOPS) intends to characterise the determinants of childhood overweight and the effect of preventive measures within schools as well as within families. METHODS: Between 1996 and 2005, KOPS investigated 4997 German 5-7 and 4487 9-11-y-old children or 41 and 37% of the total population of all first and fourth graders in 32 primary schools in Kiel (248 000 inhabitants), northwest Germany. Main outcome measures were nutritional status, health habits and risk factors of disease. In addition, health promotion was performed each year in three schools for all first graders and their teachers (nutrition education and active school breaks) together with a family-oriented approach in families with obese and preobese children. Up to now, the children were followed for 4y and were reinvestigated at age 10 y. RESULTS: The KOPS population was representative for all 5-7 and 9-11-y-old children in Kiel. The prevalence of overweight/ obesity (> or = 90th/97th BMI reference percentile) was 7.0/5.8 and 11.3/6.3% in 5-7 and 9-11-y-old children, respectively. Parental overweight, a low socio-economic status and a high birth weight were identified as main risk factors for overweight in prepubertal children. The first results of the interventions show that obesity prevention was possible, but there were limited success rates in boys and children from low social class. CONCLUSION: Faced with the environmental contributors to the obesity problem societal rather than individual responsibilities are evident. This idea suggests that dissecting and tackling the obesogenic environment is necessary to complement school- and family-based interventions.

Parental overweight, socioeconomic status and high birth weight are the major determinants of overweight and obesity in 5-7 y-old children: baseline data of the Kiel Obesity Prevention Study (KOPS).

OBJECTIVES: To identify the major risk factors of overweight and obesity in prepubertal children. DESIGN: Cross-sectional study. SETTING: In all, 32 primary schools in Kiel (248 000 inhabitants), northwest Germany. SUBJECTS: A total of 2631 5-7-y-old German children and their parents. MAIN OUTCOME MEASURES: Weight status, socio-economic status (SES), parental overweight, dietary intake, activity, inactivity and further determinants (birth weight, breast feeding, nutritional status of siblings) of the children. RESULTS: The prevalence of overweight (>/=90th BMI percentile of reference) was 9.2% in boys and 11.2% in girls, respectively. Considered univariately, family-, environment- and development-related determinants showed some relations to overweight and obesity. In multivariate analyses parental overweight, a low SES as well as a high birth weight were the strongest independent risk factors of overweight and obesity in children. Additionally, there were sex-specific risk factors: parental smoking and single households were risk factors in boys, whereas a low activity was associated with obesity in girls. Birth weight was associated with obesity, but not with overweight. The prevalence of obesity reached 29.2% in boys and 33.4% in girls with all the three main risk factors. CONCLUSIONS: Overweight families of low SES have the highest risk of overweight and obese children. Future prevention programmes must also take into account sex-specific risk factors.

[Prevention and nutrition related illnesses. Obesity, diabetes mellitus]. / Prävention ernährungsabhängiger Erkrankungen. Adipositas, Diabetes mellitus.

Faced with the obesity epidemic there is need for therapy as well as public health strategies for health promotion and obesity prevention. Both strategies add to each other, none should be done in isolation. Obesity is not only an individual problem. It is also a problem of our society. We are now an overweight society, which is on the way to a fat society. There is urgent need for a national public health strategy for population wide prevention of overweight and obesity. Health authorities as well as politicians are asked to support public health strategies creating a supportive environment for making healthy choices the easier choices.

[Problems in defining obesity in prepubescent children: consequences for assessing the requirements for medical rehabilitation]. / Probleme der Definition der Adipositas bei Kindern vor der Pubertät: Konsequenzen für die Ermittlung ihres Rehabilitationsbedarfs.

INTRODUCTION: Prevalence of obesity has been on the increase in recent years. In contrast to obesity in adulthood, childhood obesity is still not uniformly defined. This results in problems to determine the need for medical rehabilitation. METHODS: The Kiel Obesity Prevention Study (KOPS) is a cross-sectional study assessing the nutritional status of 5-7 year-old German children. Three different definitions of overweight and obesity (German reference data for triceps skinfold thickness [90(th) percentile] and BMI [90(th)/97(th) percentile] as well as an international standard for BMI [extrapolated to levels of adults]) were applied to 1,643 children of KOPS enrolled between 1996 and 2000 (19 % of all first-graders in Kiel in this period). RESULTS: The prevalence of overweight varies from 9 to 21 % depending on the applied definition. With the definitions of overweight and obesity based on newer BMI percentiles a part of overweight children are not classified as such. The present state of art is that there is only a need for obese children for medical rehabilitation: these are 3.3 and 3.5 % of 5-7 year-old children in Kiel, respectively. CONCLUSIONS: Experts should work out an agreement concerning a uniform definition of childhood obesity. Currently, medical rehabilitation services are offered only to extremely obese children. There is a need for more and earlier preventive measures.