[Longitudinal data of the Kiel Obesity Prevention Study (KOPS)]

Body Composition Characteristics of a Load-Capacity Model: Age-Dependent and Sex-Specific Percentiles in 5- to 17-Year-Old Children

INTRODUCTION

Body composition assessment is superior to the use of body mass index (BMI) to characterize the nutritional status in pediatric populations. For data interpretation, suitable reference data are needed; hence, we aimed to generate age-dependent and sex-specific body composition reference data in a larger population of children and adolescents in Germany.

METHODS

This is a cross-sectional study on a representative group of 15,392 5- to 17-year-old children and adolescents. Body composition was assessed by bioelectrical impedance analysis using a population-specific algorithm validated against air displacement plethysmography. Age- and sex-specific percentiles for BMI, fat mass index (FMI), fat-free mass index (FFMI), and a "load-capacity model" (characterized by the ratios of fat mass [FM]/ fatt-free mass [FFM] and FM/FFM2) were modeled using the LMS method.

RESULTS

BMI, FMI, FFMI, FM/FFM, and FM/FFM2 curves showed similar shapes between boys and girls with steady increases in BMI, FMI, and FFMI, while FM/FFM2-centiles decreased during early childhood and adolescence. Sex differences were observed in FMI and FM/FFM percentiles with increases in FMI up to age 9 years followed by a steady decrease in FM/FFM during and after puberty with a fast-growing FFMI up to age 17 in boys. The prevalence of low FFM relative to FM reached more than 60% in overweight children and adolescents.

CONCLUSION

These pediatric body composition reference data enable physicians and public health scientists to monitor body composition during growth and development and to interpret individual data. The data point out to an early risk of sarcopenia in overweight children and adolescents.

Physical Activity and Social Network Use of Adolescents in Overweight and Obesity Treatment

Tackling obesity among adolescents requires the optimization of existing obesity treatment strategies. For this purpose, social and personal circumstances, individual needs and behavior of therapy participants need to be analyzed to tailor aims, content and methods of therapy interventions to the target groups. A total of 432 obesity therapy participants between 11 and 17 years completed a written survey in a national multi-center study conducted in 2015. The data collection on behavior, in terms of physical activity, media use and sociodemographic variables, was based on questionnaires from the KiGGS, HBSC and JIM studies. The results show that participants were found to be physically active together with friends (75.5%), alone (41.4%) and in sports clubs (34.9%). Girls (OR 1.55) were less likely to participate in sports clubs. Social networks, especially YouTube, WhatsApp, Instagram and Facebook, were widely used. However, differences emerged among sociodemographic groups (e.g., boys vs. girls) regarding the use of social network features. A third of participants reported that smartphone apps regularly encouraged them to exercise. The findings imply that obesity therapy approaches need to be adapted and more differentiated according to the specific needs of the target groups.

Family and Lifestyle Factors Mediate the Relationship between Socioeconomic Status and Fat Mass in Children and Adolescents

Socioeconomic status (SES) is strongly associated with childhood overweight. The underlying mechanism and the role of family and lifestyle factors as potential mediators of this relationship remain, however, unclear. Cross-sectional data of 4,772 girls and boys aged 5-16 years from the Kiel Obesity Prevention Study were considered in mediation analyses. Fat mass (FM) was assessed by bioelectrical impedance analysis and converted into a percent FM SD score (FM%-SDS). SES was defined by the parental educational level, classified as low, middle, or high. Characteristics of family and lifestyle factors were obtained via validated questionnaires and considered as mediators. In 3 different age groups, the product-of-coefficients method was used to examine age-specific mediator effects on the relationship between SES and FM%-SDS (c = total effects) and their ratio to total effects, adjusted for age, sex, puberty, and nationality. The prevalence of overweight was 6.9%. In all age groups, SES was inversely associated with FM%-SDS as follows: 5-7 years, c1 = -0.11 (95% CI -0.19 to -0.03); 9-11 years, c2 = -0.21 (95% CI -0.27 to -0.14); and 13-16 years, c3 = -0.23 (95% CI -0.28 to -0.17). The relationship between SES and FM%-SDS was fully (5-7 and 9-11 years) and partly (13-16 years) mediated by similar and age-specific mediators, including parental BMI, parental smoking habits, media consumption, physical activity, and shared meals. Overall, these variables resulted in a total mediating effect of 77.8% (5-7 years), 82.4% (9-11 years), and 70.6% (13-16 years). Consistent for both sexes, the relationship between SES and FM%-SDS was therefore mediated by parental weight status, risk-related behavior within families, and children's and adolescents' lifestyle factors. Strategies for obesity prevention, which are predominantly targeted at socially disadvantaged groups, should therefore address the family environment and lifestyle factors.

A 6-month randomized, double-blind, placebo-controlled trial of weekly exenatide in adolescents with obesity

BACKGROUND

Pharmacological treatment options for adolescents with obesity are very limited. Glucagon-like-peptide-1 (GLP-1) receptor agonist could be a treatment option for adolescent obesity.

OBJECTIVE

To investigate the effect of exenatide extended release on body mass index (BMI)-SDS as primary outcome, and glucose metabolism, cardiometabolic risk factors, liver steatosis, and other BMI metrics as secondary outcomes, and its safety and tolerability in adolescents with obesity.

METHODS

Six-month, randomized, double-blinded, parallel, placebo-controlled clinical trial in patients (n = 44, 10-18 years, females n = 22) with BMI-SDS > 2.0 or age-adapted-BMI > 30 kg/m² according to WHO were included. Patients received lifestyle intervention and were randomized to exenatide extended release 2 mg (n = 22) or placebo (n = 22) subcutaneous injections given once weekly. Oral glucose tolerance tests (OGTT) were conducted at the beginning and end of the intervention.

RESULTS

Exenatide reduced (P < .05) BMI-SDS (-0.09; -0.18, 0.00), % BMI 95th percentile (-2.9%; -5.4, -0.3), weight (-3 kg; -5.8, -0.1), waist circumference (-3.2 cm; -5.8, -0.7), subcutaneous adipose tissue (-552 cm³ ; -989, -114), 2-hour-glucose during OGTT (-15.3 mg/dL; -27.5, -3.1), total cholesterol (11.6 mg/dL; -21.7, -1.5), and BMI (-0.83 kg/m² ; -1.68, 0.01) without significant change in liver fat content (-1.36; -3.12, 0.4; P = .06) in comparison to placebo. Safety and tolerability profiles were comparable to placebo with the exception of mild adverse events being more frequent in exenatide-treated patients.

CONCLUSIONS

Treatment of adolescents with severe obesity with extended-release exenatide is generally well tolerated and leads to a modest reduction in BMI metrics and improvement in glucose tolerance and cholesterol. The study indicates that the treatment provides additional beneficial effects beyond BMI reduction for the patient group.

Dietary Patterns in Primary School are of Prospective Relevance for the Development of Body Composition in Two German Pediatric Populations

This study performed comparative analyses in two pediatric cohorts to identify dietary patterns during primary school years and examined their relevance to body composition development. Nutritional and anthropometric data at the beginning of primary school and two or four years later were available from 298 and 372 participants of IDEFICS-Germany (Identification and prevention of Dietary-induced and lifestyle-induced health Effects In Children and infants Study) and the KOPS (Kiel Obesity Prevention Study) cohort, respectively. Principal component analyses (PCA) and reduced rank regression (RRR) were used to identify dietary patterns at baseline and patterns of change in food group intake during primary school years. RRR extracted patterns explaining variations in changes in body mass index (BMI), fat mass index (FMI), and waist-to-height-ratio (WtHR). Associations between pattern adherence and excess gain in BMI, FMI, or WtHR (>75th percentile) during primary school years were examined using logistic regression. Among PCA patterns, only a change towards a more Mediterranean food choice during primary school years were associated with a favorable body composition development in IDEFICS-Germany (p < 0.05). In KOPS, RRR patterns characterized by a frequent consumption of fast foods or starchy carbohydrate foods were consistently associated with an excess gain in BMI and WtHR (all p < 0.005). In IDEFICS-Germany, excess gain in BMI, FMI, and WtHR were predicted by a frequent consumption of nuts, meat, and pizza at baseline and a decrease in the consumption frequency of protein sources and snack carbohydrates during primary school years (all p < 0.01). The study confirms an adverse impact of fast food consumption on body composition during primary school years. Combinations of protein and carbohydrate sources deserve further investigation.

Migration background and childhood overweight in the Hannover Region in 2010-2014: a population-based secondary data analysis of school entry examinations

Overweight and obesity constitute a global epidemic with rates that are increasing rapidly in children. The aim of the present study was to examine ethnic differences in the prevalence of overweight in pre-school children in a multicultural context. Data were collected from a compulsory school entry examination in the Hannover Region, Germany (n = 50,716) from 2010 to 2014. The prevalence of overweight (including pre-obesity and obesity status) and obesity was estimated using a German national reference. The migration status of the children was based on the parent's migration history. Multivariable logistic and hierarchical multinomial regression analyses were performed to identify factors associated with the overweight, pre-obesity, and obesity status. The prevalence of overweight was significantly higher among migrant children (12.7%) than among the non-migrant children (6.9%). After adjusting for socioeconomic and child development variables, migration background was strongly associated with weight status. The Turkish migrant children showed the highest odds of being pre-obesity (OR 2.05, 95%CI 1.7-2.56) and obesity (OR 2.09, 95%CI 1.67-2.77) compared to non-migrant children.

CONCLUSION

Ethnic and social inequalities exist in childhood overweight among pre-school children in the Hannover Region. Thus, appropriate interventions targeting high-risk migrant groups are needed. What is Known: • The current trend of prevalence rates in Germany for overweight and obesity of pre-school children is becoming stable. • Prevalence of overweight and obesity is clearly higher among migrant children than among non-migrant children. What is New: • This article reveals ethnic variance among different migrant groups. • Turkish migrant children have a higher rate of prevalence even compared to other migrant groups. • Length of child day care attendance fails to exert a strong influence on overweight after adjusting for socio-economic and child development variables.

Media Use and Physical Activity Behaviour of Adolescent Participants in Obesity Therapy: Impact Analysis of Selected Socio-Demographic Factors

BACKGROUND

To address the challenge of juvenile obesity, effective therapeutic concepts focusing on lifestyle changes are necessary. A relevant aspect is the media use, which is associated with nutrition and physical activity patterns and is influenced by socio-demographic factors. To optimise obesity therapy, the use of media depending on these socio-demographic factors needs to be analysed to adjust the aims, content and methods of interventions as well as to harness the potential of media use in obesity therapy. The question considered in this research is: What media and physical activity patterns show 11- to 17-year-old obesity therapy participants in dependence on socio-demographic factors?

METHODS

A national multicentre study was conducted in 2015. A questionnaire was used to survey 432 participants' aged 13.75 ± 1.4 years. Standardised instruments were used to assess the variables: physical activity, media use and socio-demographic factors.

RESULTS

The participants were 1-hour physically active for 3.9 ± 1.9 days/week, 14.1% daily. Televisions, mobile phones and computers were available in all socio-demographic groups and used for 2 h/day. Socio-demographic differences emerged in the duration of media use (h/day). Girls were found to use mobile phones for longer (2.49 vs. 1.90; p < 0.01) and spend less time on game consoles than boys (0.55 vs. 1.65; p < 0.01).

CONCLUSION

Compared to current recommendations, the sample shows reduced physical activity and increased media use, which vary between the groups. Hence, differentiated therapy approaches appear recommendable. Future research needs to evaluate, how media (despite its risks) can facilitate therapy, training and aftercare concepts.

[Media use and physical activity patterns of adolescent participants in obesity therapy: Analysis of the impact of selected sociodemographic factors]

To meet the challenge of obesity, effective therapeutic concepts for adolescents focusing on lifestyle changes are necessary. Particularly relevant are nutrition and physical activity patterns associated with media use, which can be influenced by sociodemographic factors. For the optimization of obesity therapy approaches, it is essential to analyze these sociodemographic factors to adjust the aims, content, and methods of interventions, and to use the potential of media in treatment concepts. Thus, the research question is: what are the media and physical activity patterns of 11- to 17-year-old participants in obesity therapy, depending on sociodemographic factors? The national multicenter study was conducted from 2012 to 2013. A questionnaire was administered to 564 participants aged 13.4 ± 1.6 (mean ± standard deviation) years. Standardized instruments were used to assess the variables physical activity, media use, and sociodemographic factors. Participants were physically active for 1 h on 3.3 ± 1.8 days per week, 8.5 % daily. Televisions, mobile phones, and computers were available in all sociodemographic groups and were used for 2 h per day. Sociodemographic differences can be seen in the extent of media usage (h/day). These differences can be found between girls and boys concerning their usage of mobile phones (2.49 vs. 1.90; p  < 0.001), between 11- to 13- and 14- to 17-year-old children concerning their usage of game consoles (0.55 vs. 1.65; p  = 0.007), and in the correlation analysis of media usage and physical activity. Compared with existing literature, the survey results reveal reduced activity and increased media use, which vary among the groups. Thus, differentiated therapy approaches appear to be reasonable. Future research needs to evaluate to what extent media, despite the risks, can contribute to the methodological support of therapy, training, and aftercare concepts.

Differences in BMI z-scores between offspring of smoking and nonsmoking mothers: a longitudinal study of German children from birth through 14 years of age

BACKGROUND

Children of mothers who smoked during pregnancy have a lower birth weight but have a higher chance to become overweight during childhood.

OBJECTIVES

We followed children longitudinally to assess the age when higher body mass index (BMI) z-scores became evident in the children of mothers who smoked during pregnancy, and to evaluate the trajectory of changes until adolescence.

METHODS

We pooled data from two German cohort studies that included repeated anthropometric measurements until 14 years of age and information on smoking during pregnancy and other risk factors for overweight. We used longitudinal quantile regression to estimate age- and sex-specific associations between maternal smoking and the 10th, 25th, 50th, 75th, and 90th quantiles of the BMI z-score distribution in study participants from birth through 14 years of age, adjusted for potential confounders. We used additive mixed models to estimate associations with mean BMI z-scores.

RESULTS

Mean and median (50th quantile) BMI z-scores at birth were smaller in the children of mothers who smoked during pregnancy compared with children of nonsmoking mothers, but BMI z-scores were significantly associated with maternal smoking beginning at the age of 4-5 years, and differences increased over time. For example, the difference in the median BMI z-score between the daughters of smokers versus nonsmokers was 0.12 (95% CI: 0.01, 0.21) at 5 years, and 0.30 (95% CI: 0.08, 0.39) at 14 years of age. For lower BMI z-score quantiles, the association with smoking was more pronounced in girls, whereas in boys the association was more pronounced for higher BMI z-score quantiles.

CONCLUSIONS

A clear difference in BMI z-score (mean and median) between children of smoking and nonsmoking mothers emerged at 4-5 years of age. The shape and size of age-specific effect estimates for maternal smoking during pregnancy varied by age and sex across the BMI z-score distribution.

Overweight in adolescence can be predicted at age 6 years: a CART analysis in German cohorts

OBJECTIVE

To examine, whether overweight in adolescents can be predicted from the body mass index (BMI) category, at the age of 6, the mother's education level and mother's obesity and to quantify the proportion of overweight at the age of 14 that can be explained by these predictors.

METHOD

Pooled data from three German cohorts providing anthropometric and other relevant data to a total of 1 287 children. We used a classification and regression tree (CART) approach to identify the contribution of BMI category at the age of 6 (obese: BMI > 97th percentile (P97); overweight: P90 < BMI ≤ P97; high normal weight: P75P90) at the age of 14.

RESULTS

While 4.8% [95%CI: 3.2;7.0] of 651 boys and 4.1% [95%CI: 2.6;6.2] of 636 girls with a BMIP97 (similar results for girls). BM I ≥ P75 at the age of 6 explained 63.5% [95%CI: 51.1;74.5]) and 72.0% [95%CI: 60.4;81.8] of overweight/obesity at the age of 14 in boys and girls, respectively.

CONCLUSIONS

Overweight/obesity in adolescence can be predicted by BMI category at the age of 6 allowing for parent counselling or risk guided interventions in children with BMI ≥ P75, who accounted for >2/3 of overweight/obesity in adolescents.