Introducing excess body weight in childhood and adolescence and comparison with body mass index and waist-to-height ratio.

BACKGROUND: Weight status in children and adolescents is commonly defined using age- and gender-corrected standard deviation scores for body mass index (BMI-SDS, also called z-scores). Values are not reliable for the extremely obese however. Moreover, paediatricians and parents may have difficulties understanding z-scores, and while percentiles are easier to gauge, the very obese have values above the 99th percentile, making distinction difficult. The notion of excess body weight (EBW) is increasingly applied in adult patients, mainly in the context of bariatric surgery. However, a clear definition is not available to date for the paediatric population. METHODS: A simple definition of EBW for children and adolescents is introduced, with median weight as a function of height, age and gender (characterized by an asterisk): EBW (%) = 100x(weight-median weight*)/median weight*. EBW is compared with BMI-SDS and waist-to-height ratio (WHtR). Using two data sources (APV registry and German Health Interview and Examination Survey for Children and Adolescents (KiGGS)) including more than 14,000 children, the relationships between these anthropometric and various metabolic parameters are analysed for a group of overweight/obese children who have sought obesity therapy (APV), for the general paediatric population and for the subset of overweight/obese children from the general population (KiGGS). RESULTS: The three anthropometric parameters are strongly correlated, with the linear correlation coefficients exceeding 0.8 in the general population and 0.75 in those seeking obesity therapy. Moreover, their relationship to metabolic parameters is quite similar regarding correlations and area under the curve from receiver operating characteristic analyses. CONCLUSIONS: EBW has similar predictive value for metabolic or cardiovascular comorbidities compared with BMI and WHtR. As it is reliable at the extreme end of the obesity spectrum, easily communicable and simple to use in daily practice, it would make a very useful addition to existing tools for working with obese children and adolescents. Its usefulness in assessing weight change needs to be studied however.

Longitudinal multicenter analysis on the course of glucose metabolism in obese children.

OBJECTIVE: Although there is evidence of increasing prevalence of impaired glucose metabolism in obese children from smaller single cohorts, data are lacking on the progression of glucose metabolism in this patient group.We aimed to assess the prevalence and the longitudinal course of impaired glucose metabolism assessed by oral glucose tolerance test (oGTT) in a large multi-center pediatric obesity registry. SUBJECTS: We performed an observational multicenter (n=84) cross-sectional (n=11 156) and longitudinal analysis (n=1008) on the course of glucose metabolism evaluated by oGTT in obese children documented in the Adiposity Patients Verlaufsbeobachtung (APV) registry. Patients were stratified with impaired fasting glucose (IFG), impaired glucose tolerance (IGT) and Type 2 diabetes (T2D), according to American Diabetes Association criteria. RESULTS: A total of 12.6% of the children presented with abnormal glucose metabolism (5.99% IFG, 5.51% IGT, 1.07% T2D). Body mass index (BMI) correlated modestly with 2-h blood glucose (r=0.04, P<0.001).In the 1008 patients with follow-up oGTT, metabolic parameters improved and the percentage of abnormal glucose metabolism decreased from 18.7 to 14.2%. Of the children with initial IGT, 70.6% converted to normal glucose tolerance. The improvement in oGTT results was associated with, but not dependent on, a reduction of BMI s.d. score. CONCLUSION: In summary, we provide evidence for significant improvement of oGTT parameters in obese children treated in specialized treatment centers, even though reduction in BMI was modest.

Clinical diagnosis of metabolic and cardiovascular risks in overweight children: early development of chronic diseases in the obese child.

Childhood overweight (body mass index (BMI)>90th centile) poses a major public health problem in so far as adult diseases manifest themselves already during childhood. In this review, after examining the prevalence of metabolic and cardiovascular diseases, the issue of whether BMI or other clinical parameters are valid tools to predict co-morbidities in children is discussed. Data of 2001-2008 are reviewed, including several studies conducted on more than 260,000 overweight and obese children in Germany and Switzerland. Apart from non-metabolic co-morbidities, namely musculoskeletal complications and attention deficit/hyperactivity disorders in up to 74% and up to 58% of overweight children, respectively, at least one cardiovascular and metabolic risk factor was seen in 52% of the overweight children, mostly high blood pressure (35%) with increased left ventricular mass or arterial stiffness. Signs of fatty liver disease or dyslipidemia were found in up to 29 and 32% of the children, respectively. Type 2 diabetes was found in less than 0.7% of the children, and an elevated fasting glucose or glucose intolerance in 3%. Irrespective of BMI, the quality of fat and protein intake predicted hypertension or insulin resistance, and fructose predicted lower (and more atherogenic) particle size of low-density lipoprotein-cholesterol. Out of the adiposity markers, waist circumference was closely correlated with insulin resistance and the components of the metabolic syndrome. In conclusion, risk factors are found in more than half of the overweight children, most frequently high blood pressure or dyslipidemia, and were mainly related to waist circumference, but also to BMI and fat mass. Even in the presence of normal BMI, screening for cardiovascular risk factors is advocated in each child with elevated waist circumference, but its cut-off points still remain to be validated. The increased occurrence of orthopedic and psychiatric complaints may detrimentally influence health-related lifestyle and obesity therapy.