Objective: Current guidelines for prevention of obesity in childhood and adolescence are discussed. Methods: A literature search was performed in Medline via PubMed, and appropriate studies were analyzed. Results: Programs to prevent childhood obesity have so far remained mainly school-based and effects have been limited. Analyses by age group show that prevention programs have the best results in younger children (<12 years). Evidence-based recommendations for pre-school- and early school-aged children indicate the need for interventions that address parents and teachers alike. During adolescence, school-based interventions proved most effective when adolescents were addressed directly. To date, obesity prevention programs have mainly focused on behavior-oriented prevention. Recommendations for community- or environment-based prevention have been suggested by the German Alliance of Noncommunicable Diseases and include a minimum of 1 h of physical activity at school, promotion of healthy food choices by taxing unhealthy foods, mandatory standards for meals at kindergartens and schools as well as a ban on unhealthy food advertisement aimed at children. Conclusion: Behavior-oriented prevention programs showed only limited long-term effects. Certain groups at risk for the development of obesity are not reached effectively by current programs. Although universally valid conclusions cannot be drawn given the heterogeneity of available studies, clearly combining behavior-based programs with community-based prevention to counteract an ‘obesogenic environment' is crucial for sustainable success of future obesity prevention programs.

Objective: Trends of overweight (ov)/obesity (ob) prevalence among German children aged 4–16 years were studied between 1999 and 2008. Subjects: Body mass index (BMI) data (>P90 [ov] and >P97 [ob]) from the national CrescNet database were analysed in three age groups: 4–7.99, 8–11.99, and 12–16 years. Results. Trend analyses. Data from 272 826 children were analyzed. a) Whole study population aged 4–16 years old. A significant upward trend for ov/ob prevalence was found between 1999 and 2003, and a significant downward trend between 2004 and 2008. b) Subgroup analyses. Ov/Ob prevalence increased in most subgroups studied until 2004. Between 2004 and 2008, a downward trend for ov/ob prevalence was found in children, aged 4–7.99 years, whereas it stabilized in most other subgroups studied. Cross-sectional analyses. Data from 93 028 children were analyzed. Ov/ob prevalence was significantly higher in 2004 compared with 2000 in girls aged 12–16 years and in boys aged 8–16 years. Ov/ob obesity prevalence was significantly lower in 2008 compared with 2004 in children aged 4–7.99 years. Conclusion. Ov/ob prevalence increased between 1999 and 2003 in German children. Since 2004, this trend has been stabilizing or turning into a downward trend. Our data confirm the global trend of stabilizing prevalence rates of childhood obesity at a high level and add important information for individual age groups. Intervention programs targeted to prevent childhood obesity may have had beneficial effects, and a new balance between factors favouring obesity and those favouring leanness may have been reached recently. Age- and gender-specific differences found in trends of ov/ob prevalence may help optimise preventive and therapeutic measures.

Objective: Exercise improves weight status and metabolism. Irisin, a novel myokine, may be involved in the regulation of metabolic function. The effect of an exercise and dietary lifestyle intervention for 1‐year on irisin, adipokines (leptin, adiponectin, resistin) and inflammatory markers (C‐reactive protein (CRP), soluble tumor necrosis factor receptor II (sTNFR‐II) was evaluated, and predictors of irisin levels were characterized in obese children.Methods: Parameters were assessed at baseline and at follow‐up for 65 obese children who completed the program (7–18 years, 54%boys). Their relation to weight status and metabolic risk was analyzed.Results: Anthropometric and metabolic parameters improved after completion of the program. Circulating irisin levels at baseline were 111.0 ± 8.0 ng ml⁻¹ and increased after the intervention by 12% [6%, 17%], P = 0.00003. There was no evidence for differences in irisin levels between genders and across age. Moreover, changes in irisin did not correlate with those in BMI‐SDS, adipokines or inflammatory markers. Leptin decreased after the intervention (Δ5.3 ng ml⁻¹, [3.2, 6.3], P = 10⁻⁷). Anthropometric measures were significantly associated with leptin and inflammatory markers.Conclusions: A 1‐year long lifestyle intervention program is associated with improvement in anthropometric and metabolic parameters and leads to an elevation in irisin levels in obese children.

Context: The predictive value of body mass index (BMI), waist circumference (WC), and waist-to-height ratio (WtHR) to define cardiometabolic risk is unclear in childhood obesity. Obective: The associations between BMI, WtHR, or WC and cardiometabolic risk markers were analyzed in a multicenter data collection of obese youth. Design and Subjects: BMI, WtHR, and WC were retrospectively evaluated in 1278 patients (11–18 years, 53% boys) from the German/Austrian/Swiss Adiposity Patients Registry. Main outcome measures: Parameters were correlated with homeostasis model assessment for insulin resistance, fasting insulin, blood pressure, transaminases, lipids and uric acid, applying adjusted regression models, with age group, pubertal stage and gender as covariates. Results: Homeostasis model assessment for insulin resistance and fasting insulin were most strongly correlated with BMI, independent of age group or gender. Lipids, transaminases, and uric acid were most strongly correlated with WC with stronger associations for boys. Correlations between BMI and WC as well as metabolic markers and systolic blood pressure showed only minor differences. The pattern of relationship changed during the course of pubertal development with the strongest associations for pubertal children. None of the parameters showed a dependency on WtHR that was superior to BMI or WC. Conclusions: There is only small additional benefit in using WC measurements for routine pediatric care in addition to BMI for predicting metabolic risk. For all parameters, the relationship is strongest during midpuberty, emphasizing that among obese pubertal adolescents, anthropometric measures (BMI and WC) best predict cardiometabolic comorbidities. WtHR does not seem to be superior to BMI or WC in predicting metabolic or cardiovascular risk related to childhood obesity.

To assess the distribution of autonomic nervous system (ANS) dysfunction in overweight and obese children. Parasympathetic and sympathetic ANS function was assessed in children and adolescents with no evidence of impaired glucose metabolism by analysis of heart rate variability (low frequency power ln(LF), high frequency power, ln(HF); ln(LF/HF) ratio, ratio of longest RR interval during expiration to shortest interval during inspiration (E/I ratio), root mean square of successive differences (RMSSD); sympathetic skin response (SSR); and quantitative pupillography (pupil diameter in darkness, light reflex amplitude, latency, constriction velocity, re-dilation velocity). The relationship of each ANS variable to the standard deviation score of body mass index (BMI-SDS) was assessed in a linear model considering age, gender and pubertal stage as co-variates and employing an F-statistic to compare the fit of nested models. Group comparisons between normal weight and obese children as well as an analysis of dependence on insulin resistance (as indexed by the Homeostasis Model Assessment of Insulin Resistance, HOMA-IR) were performed for parameters shown to correlate with BMI-SDS. Statistical significance was set at 5%. Measurements were performed in 149 individuals (mean age 12.0 y; 90 obese 45 boys; 59 normal weight, 34 boys). E/I ratio (p = 0.003), ln(HF) (p = 0.03), pupil diameter in darkness (p = 0.01) were negatively correlated with BMI-SDS, whereas ln(LF/HF) was positively correlated (p = 0.05). Early re-dilation velocity was in trend negatively correlated to BMI-SDS (p = 0.08). None of the parameters that depended significantly on BMI-SDS was found to be significantly correlated with HOMA-IR. These findings demonstrate extended ANS dysfunction in obese children and adolescents, affecting several organ systems. Both parasympathetic activity and sympathetic activity are reduced. The conspicuous pattern of ANS dysfunction raises the possibility that obesity may give rise to dysfunction of the peripheral autonomic nerves resembling that observed in normal-weight diabetic children and adolescents.