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Background/objectives: Body mass index (BMI) is reportedly gender assortative (mother-daughter, father-son) in contemporary children. We investigated the corresponding transmission of waist circumference (WC) and its implications., Methods: We measured parental WC at baseline and WC, height, weight and para-umbilical skin-fold (USF) annually in their offspring from 5 to 15 years (n = 223 trios). Parents were deemed normal metabolic risk (NR) or high risk (HR) according to World Health Organization (WHO) cut-points for WC (mothers 80 cm, fathers 94 cm). The residual from WC adjusted for BMI (WC|BMI ) was used as a surrogate for excess intra-abdominal fat, and its association with insulin resistance (HOMA2-IR) was sought., Results: WC and USF were both gender assortative, while WC|BMI was not. WC was greater by 1.62 cm (P < 0.05, confidence interval [CI]: 0.09-3.16) and USF by 0.37 cm (P < 0.01, CI: 0.19-0.56) among the daughters (but not the sons) of HR compared with those of NR mothers, and by 1.32 cm (P < 0.05, CI: 0.09-2.55) and 0.18 cm (P < 0.05, CI: 0.04-0.32), respectively in the corresponding father-son (but not father-daughter) pairings. No such differences could be demonstrated for WC|BMI . A standard deviation score 1(SDS) change in WC|BMI , independent of BMI, was associated with a 7.14% change in IR in girls (P < 0.01, CI: 1.76-12.80) and 8.02% in boys (P < 0.001, CI: 2.93-13.36), but there was no relationship between IR and USF., Conclusion: The relationship of offspring WC to metabolic health and to parental size is complex. Subcutaneous abdominal fat is gender assortative but harmless, while intra-abdominal fat (its surrogate in this analysis) is unrelated to parental waist circumference, but metabolically harmful., (© 2013 The Authors. Pediatric Obesity © 2013 International Association for the Study of Obesity.)

Background: The role of the autonomic nervous system in the complex link between insulin resistance and cardiovascular risk remains unclear. Increased sympathetic nervous system activity has been implicated in the pathophysiology of insulin resistance but is confounded by a number of factors., Methods: We have therefore examined the relationship among cardiac autonomic control, insulin resistance, habitual physical activity, resting energy expenditure (REE), and anthropometric variables in a subset (107 boys, 101 girls, age 9 +/- 0.25 yr) of the EarlyBird cohort. Cardiac autonomic activity was assessed using time domain and power spectral density analysis methods of heart rate variability. Insulin resistance was measured using homeostasis model assessment of insulin resistance (HOMA2-IR)., Results: Girls, in comparison to boys, showed significantly higher resting heart rate and lower systolic blood pressure (BP); were more insulin resistant; undertook less physical activity, and had lower fat-free mass and REE. Increasing fasting insulin and increasing insulin resistance were associated with increasing BP., Conclusion: The data suggest early gender differences in predictors of cardiac autonomic control. Pubertal staging was not undertaken in this study, and we plan to evaluate this in future studies to further clarify these associations.

The International Obesity TaskForce has published paediatric cutoffs from the age of 2 years for overweight and obesity, based on adult thresholds. We question their rationale. The adult cutoffs were based on known health risk; the children's were not. Data from the EarlyBird Study show that BMI category for overweight and obesity in young children are poor markers of insulin resistance and, by implication, of metabolic risk and diabetes. Moreover, BMI is known to track poorly from early childhood to adulthood. We know even less about the tracking of insulin resistance and other indices of metabolic risk from the earliest years. Until we understand more about which children acquire such risk factors, any such thresholds for overweight and obesity should be used with caution in the very young, as they may unnecessarily stigmatise the heavier child.

Objective: For a decade or more, poor nutrition during gestation, expressed as low weight at birth, was held to be the factor responsible for insulin resistance later in life. Birth weights, however, are rising and insulin-resistant states, such as diabetes, faster still. Alternative explanations are needed for insulin resistance in contemporary society. This review cites data from the EarlyBird study on the relationships of insulin resistance and metabolic disturbance in early childhood., Design: EarlyBird is a nonintervention prospective cohort study that asks the question 'Which children develop insulin resistance, and why?' It is unique in taking serial blood samples from a young age with which to monitor the behaviour of insulin resistance and its metabolic correlates, and in its comprehensive assessment of factors known or thought to influence insulin resistance, Subjects: In all, 307 randomly selected healthy school children at school entry (mean age 4.9 y) and at 12 and 24 months later., Measurements: In the children: Birth weight and, at each time point height, weight, body mass index (BMI, kg/m(2)), skinfolds at five sites, circumferences, resting energy expenditure, physical activity, body composition, heart rate variability, diet, HOMA-IR and HOMA-ISC, blood pressure, full blood count, haemoglobin and haematocrit, HbA1C, total cholesterol, HDL cholesterol, LDL cholesterol, triglycerides, uric acid, IGF-1, gonadotrophins and SHBG. In their parents: At baseline height, weight, BMI, waist circumference, HOMA-IR and HOMA-ISC, full blood count, haematocrit, HbA1C, total cholesterol, HDL cholesterol, calculated LDL cholesterol, triglycerides, uric acid, gonadotrophins and SHBG., Results: Four observations are reported here: (1) There are clear correlations in contemporary children between insulin resistance and weight at 5 y, but none with birth weight. (2) Females throughout life are intrinsically more insulin resistant than males. (3) The substantial variation of physical activity among young children is attributable to the child, and not to his environment. (4) There is dissociation in young children between fatness and insulin resistance., Conclusion: There is much yet to be learned about the development of obesity and insulin resistance in children. The notions of overnutrition and underactivity alone are too simplistic.

The increasing incidence of type 2 diabetes worldwide is causing concern. Genetic and environmental influences have been put forward to explain the origins of this disease, but perhaps the most convincing contributory factor is high body weight. The authors review the literature on the subject to identify some of the predisposing factors influencing healthcare practitioners' concerns about the issue.

What is already known about this subject Body mass index (BMI) is gender assortative (mother-daughter, father-son) in contemporary families., The impact of obesity on the metabolic health of contemporary children is nevertheless a correlate of their own weight, not that of their parents., Waist circumference ( WC; abdominal fat) is a better predictor of metabolic risk than BMI., Abdominal fat has two components - visceral, which increases metabolic risk, and subcutaneous, which is neutral or even protects., What this study adds WC, like BMI, is gender assortative. Daughters derive their girth from their mother and sons from their father., Subcutaneous fat accounts for the gender-assortative link with parental WC, but not the surrogate we used for visceral fat ( WC| BMI)., Insulin resistance, on the other hand, is a function of WC| BMI but not of subcutaneous fat., Given appropriate standards, WC| BMI may help refine the predictive value of WC for metabolic risk in children., Background/Objectives Body mass index (BMI) is reportedly gender assortative (mother-daughter, father-son) in contemporary children. We investigated the corresponding transmission of waist circumference ( WC) and its implications. Methods We measured parental WC at baseline and WC, height, weight and para-umbilical skin-fold ( USF) annually in their offspring from 5 to 15 years ( n = 223 trios). Parents were deemed normal metabolic risk ( NR) or high risk ( HR) according to World Health Organization ( WHO) cut-points for WC (mothers 80 cm, fathers 94 cm). The residual from WC adjusted for BMI ( WC| BMI) was used as a surrogate for excess intra-abdominal fat, and its association with insulin resistance ( HOMA2- IR) was sought. Results WC and USF were both gender assortative, while WC| BMI was not. WC was greater by 1.62 cm ( P < 0.05, confidence interval [ CI]: 0.09-3.16) and USF by 0.37 cm ( P < 0.01, CI: 0.19-0.56) among the daughters (but not the sons) of HR compared with those of NR mothers, and by 1.32 cm ( P < 0.05, CI: 0.09-2.55) and 0.18 cm ( P < 0.05, CI: 0.04-0.32), respectively in the corresponding father-son (but not father-daughter) pairings. No such differences could be demonstrated for WC| BMI. A standard deviation score 1(SDS) change in WC| BMI, independent of BMI, was associated with a 7.14% change in IR in girls ( P < 0.01, CI: 1.76-12.80) and 8.02% in boys ( P < 0.001, CI: 2.93-13.36), but there was no relationship between IR and USF. Conclusion The relationship of offspring WC to metabolic health and to parental size is complex. Subcutaneous abdominal fat is gender assortative but harmless, while intra-abdominal fat (its surrogate in this analysis) is unrelated to parental waist circumference, but metabolically harmful. [ABSTRACT FROM AUTHOR]

Objective:Several studies suggest that taller children may be wrongly labelled as 'overweight' because body mass index (BMI) is not independent of height (Ht) in childhood, and recommend adjustment to render the index Ht independent. We used objective measures of %body fat and hormonal/metabolic markers of fatness to investigate whether BMI and the corresponding fat mass index (FMI) mislead in childhood, or whether taller children really are fatter.Design:Longitudinal observational study measuring children annually from age 7 to 12 years.Subjects:Two hundred and eighty healthy children (56% boys) from the EarlyBird study.Measurements:BMI (body mass (BM)/Ht2), FMI (fat mass (FM)/Ht2), %body fat ((FM/BM) × 100, where FM was measured by dual-energy X-ray absorptiometry), fasting leptin (a hormonal measure of body fatness) and insulin resistance (a metabolic marker derived from the validated homeostasis model assessment program for insulin resistance - HOMA2-IR) were all analysed in relation to Ht. Alternative Ht-independent indices of BM and FM were compared with BMI and FMI as indicators of true fatness and related health risk.Results:BMI and FMI correlated with Ht at each annual time point (r∼0.47 and 0.46, respectively), yet these correlations were similar in strength to those between Ht and %fat (r∼0.47), leptin (r∼0.41) and insulin resistance (r∼0.40). Also, children who grew the most between 7 and 12 years showed greater increases in BMI, FMI, leptin and insulin resistance (tertile 1 vs 3, all p<0.05). BMI and FMI explained ∼20% more of the variation in %fat, ∼15% more in leptin and ∼10% more in insulin resistance than the respective Ht-independent reformulations (BM/Ht3.5 and FM/Ht7, both p<0.001).Conclusion:Taller children really are fatter than their shorter peers, have higher leptin levels and are more insulin resistant. Attempts to render indices of BM or FM independent of Ht in children seem inappropriate if the object of the index is to convey health risk. [ABSTRACT FROM AUTHOR]

Background: In the UK and USA, government guidelines for childhood physical activity have been set (⩾60 min/day at ⩾3 metabolic equivalents of thermogenesis (METs)), and body mass index (BMI) chosen as the outcome measure. Aim: To determine the extent to which physical activity at the government-recommended intensity is associated with change in body mass/fat and metabolic health in prepubertal children. Methods: Non-intervention longitudinal study of 113 boys and 99 girls (born 1995196) recruited from 54 schools. Physical activity (Actigraph accelerometers), changes in body mass (raw and age/gender-standardised BMI), fatness (skin-fold thickness and waist circumference) and metabolic status (insulin resistance, triglycerides, cholesterol/HDL ratio and. blood pressure — separately and as a composite metabolic z score) were measured on four annual occasions (5, 6, 7 and 8 years). Results: Mean physical activity did not change over time in either sex. Averaging the 7-day recordings from four time points rather than one increased the reliability of characterising a child's activity from 71% to 90%. Some 42% of boys and 11% of girls met the guideline. There were no associations between physical activity and changes in any measurement of body mass or fatness over time in either sex (eg, BMI standard deviation scores: r = -0.02, p = 0.76). However, there was a small to moderate inverse association between physical activity and change in composite metabolic score (r = -0.19, p<0.01). Mixed effects modelling showed that the improvement in metabolic score among the more active compared to the less active children was linear with time (-0.08 z scores/year, p = 0.001). Conclusions: In children, physical activity above the government-recommended intensity of 3 METs is associated with a progressive improvement in metabolic health but not with a change in BMI or fatness. Girls habitually undertake less physical activity than boys, questioning whether girls in particular should be encouraged to do more, or the recommendations adjusted for girls. [ABSTRACT FROM AUTHOR]