Sandra Danielzik

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.

Phase Angle From Bioelectrical Impedance Analysis: Population Reference Values by Age, Sex, and Body Mass Index

BACKGROUND The use of bioelectrical impedance phase angle has been recommended as a prognostic tool in the clinical setting, but published reference data bases are discrepant and incomplete (eg, they do not consider body mass index [BMI], and data are lacking for children). METHODS Phase angle reference values stratified by age, sex, and BMI were generated in a large German data base of 15,605 children and adolescents and 214,732 adults, and the determinants of phase angle values were assessed. The reference values were applied to 3 groups of patients and compared with previously published reference values from the United States and Switzerland. RESULTS Gender and age were the main determinants of phase angle in adults, with men and younger subjects having higher phase angles. In children and adolescents, age and BMI were the main determinants of phase angle. In normal and overweight adults, phase angle increased with increasing BMI, but there was an inverse association at a BMI >40 kg/m2. In cirrhosis, the prevalence of a low phase angle increased with the state of disease, whereas it was not different between patients with the metabolic syndrome and controls. There are considerable differences between phase angle reference values from different populations. These differences are not explained by age or BMI and may be due to differences between impedance analyzers. CONCLUSION The determinants of phase angle differ between adults and children. In adults, the influence of BMI on phase angle depended on the BMI range. The prognostic value of phase angle may differ in different clinical settings. The use of population-specific and probably impedance-analyzer-specific reference values for phase angle is recommended.

School- and family-based interventions to prevent overweight in children

There have been only a few controlled studies on the prevention of overweight and obesity in children and adolescents. These studies differ in relation to strategy, setting, duration, focus, variables of outcome and statistical power, and therefore do not allow general conclusions to be made about the value of preventive measures. All school-based interventions aimed at the prevention of overweight and obesity show some improvement of health knowledge and health-related behaviours. Short-term effects on nutritional state seem to be more pronounced in girls than in boys. School-based interventions can reduce the incidence of overweight. There is evidence that families of intermediate and high socio-economic status as well as intact families benefit more from treatment than families sharing other characteristics. Selected prevention in obese children is most successful when children are treated together with their parents. However, there are social barriers limiting the success of family-based interventions. Although some positive effects have been reported, simple interventions in a single area (e.g. a school health education programme) are unlikely to work on their own. The development of effective preventive interventions probably requires strategies that affect multiple settings simultaneously. At present there is no concerted action, rather many strategies in health promotion that are followed in isolation. Faced with the epidemic of overweight there is a need for national campaigns and action plans on childhood overweight and obesity. It is tempting to speculate that this strategy will also increase the value of isolated approaches (e.g. in schools and families).

Patterns of bioelectrical impedance vector distribution by body mass index and age: implications for body-composition analysis.

BACKGROUND Bioelectrical impedance analysis (BIA) gives resistance (R) and reactance (Xc). R and Xc normalized for body height (H) can be plotted as a bivariate vector (H(2)/Xc versus H(2)/R). Vector BIA is useful for studying the determinants of BIA results. OBJECTIVE We investigated the effect of age on BIA results and its relevance to body-composition analysis in a large database of impedance vector distributions stratified by age, sex, and body mass index (BMI). DESIGN Mean bivariate vector distribution patterns (95% confidence ellipses) were examined in a German population of 15605 children and adolescents and 213294 adults. Children and adolescents were divided into 3 age groups with up to 5 BMI categories. In adults, 5 BMI categories were stratified into 7 age groups. RESULTS Mean impedance vectors were shorter in children than in adults. The vector distribution pattern was influenced by sex, BMI, and age, with shorter vectors in females than in males and longer vectors with increasing BMI. Consistent with a decrease in body cell mass with increasing age, there was a downward slope in the mean vector with age as a result of a decrease in the H(2)/Xc vector component. By contrast, there was no age-dependent increase in the H(2)/R vector component. In women of the same BMI at different ages, H(2)/R and percentage fat mass tended to decrease with age. CONCLUSIONS The lack of an age-dependent increase in the H(2)/R vector component renders conventional BIA unsuitable for an examination of the age-related increase in body fat mass. By contrast, the increase in the H(2)/Xc vector component with advancing age suggests the potential of BIA to depict the age-related decrease in body cell mass.

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 4 y 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 (≥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.

School‐based interventions to prevent overweight and obesity in prepubertal children: process and 4‐years outcome evaluation of the Kiel Obesity Prevention Study (KOPS)

Aim: To evaluate the feasibility and 4‐year outcome of school‐based health promotion on overweight among 6–10‐year‐old children.

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.

Use of height3:waist circumference3 as an index for metabolic risk assessment?

Current anthropometric indices for health risk assessment are indirect measures of total or visceral body fat mass that do not consider the inverse relationship of lean body mass to metabolic risk as well as the non-linear relationship between central obesity and insulin resistance. We examined a new anthropometric index that reflects the relationship of waist circumference (WC) as a risk factor to fat-free mass (FFM) as a protective parameter of body composition. In a population of 335 adults (191 females and 144 males; mean age 53 (SD 13.9) years) with a high prevalence of obesity (27%) and metabolic syndrome (30%) we derived FFM:WC(3) from the best fit of the relationship with metabolic risk factors (plasma triacylglycerol levels and insulin resistance by homeostasis model assessment index). Because FFM is known to be proportional to the cube of height, FFM was subsequently replaced by height(3) yielding height(3):WC(3) as an easily applicable anthropometric index. Significant inverse relationships of height(3):WC(3) to metabolic risk factors were observed for both sexes. They slightly exceeded those of conventional anthropometric indices such as BMI, WC or WC:hip ratio in women but not in men. The exponential character of the denominator WC(3) implies that at a given FFM with gradually increasing WC the increase in metabolic risk is lower than proportional. Further studies are needed to evaluate height(3):WC(3) as an anthropometric index for health risk assessment.