Waist circumference is an independent predictor of insulin resistance in black and white youths

OBJECTIVES: We examined how well waist circumference (WC) reflects total and abdominal fat and whether WC predicts insulin resistance independent of body mass index (BMI) percentile in youths. STUDY DESIGN: Body composition was measured by dual-energy x-ray absorptiometry and abdominal adiposity by computed tomography. Insulin sensitivity was measured by the hyperinsulinemic-euglycemic clamp. RESULTS: Both BMI percentile and WC were significantly associated (P < .01) with total and abdominal fat and insulin sensitivity. WC remained a significant (P < .01) correlate of total and abdominal fat and insulin sensitivity after controlling for BMI percentile. By contrast, BMI percentile did not remain a significant correlate of visceral fat and markers of insulin resistance after controlling for WC. Without exception, WC explained a greater variance in abdominal fat and metabolic profiles than did BMI percentile. CONCLUSIONS: Our findings suggest that the prediction of health risks associated with obesity in youths is improved by the additional inclusion of WC measure to the BMI percentile. Such observations would reinforce the importance of including WC in the assessment of childhood obesity to identify those at increased metabolic risk due to excess abdominal fat.     

Insulin and insulin resistance index are not independent determinants for the variation in leptin in obese children and adolescents

Recent findings have questioned the independent influence of insulin on leptin. We studied whether insulin contributes to leptin in obese children, independent of confounding parameters, such as total adiposity, fasting insulin resistance index, and fat free mass. In 100 obese boys and 103 obese girls, blood levels of leptin, insulin, glucose, and triglycerides were determined. The fasting insulin resistance index (FIRI) was calculated, and body composition was assessed by means of impedance. Leptin and glucose were higher in girls, and all estimates of adiposity were significantly associated with leptin. However, when adjusted for adiposity, the relationship between insulin and leptin, and also between FIRI and leptin, remained significant in boys and girls (p<0.05). Although several regression models were tested, neither insulin nor FIRI were found to contribute significantly and independently to leptin. BMI together with triglycerides and FFM were the main determinants for the variation in leptin in boys (adj. R2=0.46, p<0.0001). In girls, BMI explained a great magnitude of the variation in leptin (adj. R2=0.60, p<0.0001). These findings indicate that in the state of childhood and adolescent obesity, total adiposity but not insulin or insulin resistance index is the main determinant for leptin. In contrast to obese girls, the fat free mass and triglycerides contribute significantly to the variation in leptin in obese boys. The biological significance for these findings should be elucidated in longitudinal studies.     

The relationship between different subcutaneous adipose tissue layers, fat mass and leptin in obese children and adolescents

We studied the relationships of subcutaneous adipose tissue layers (SAT-layers), body fat mass (FM) and waist-to-hip ratio (WHR) with leptin in obese children and adolescents. Twenty-nine obese children and adolescents (12 boys: age: 11.3 +/- 3.7 yr; body mass index [BMI]: 28.5 +/- 4) and 17 girls (age: 12.2 +/- 2.2 yr; BMI: 29.8 +/- 4.7) (mean +/- SD) were studied. FM was estimated by bioelectrical impedance. SAT-layers were determined at 15 different body sites from 1-neck to 15-calf by the Lipometer optical device. Leptin and insulin were determined by RIA. Maturity was associated with a greater thickness of certain SAT-layers from the upper body and with a lower thickness of SAT-layers from the abdominal region and lower extremities. Significant correlations were found for all estimates of adiposity and leptin (all p<0.001). Waist and hip circumferences were not correlated to leptin after adjustment for FM. SAT-layers from the upper body were significantly and positively correlated to leptin. Multiple regression analysis revealed FM as a main contributor to the variation in leptin (R2=0.53, p<0.0001). FM together with SAT-layers 5-front chest and 13-rear thigh explained 72% of the variation in leptin (p<0.0001). In a body fat distribution model, hip circumference together with SAT-layers 4-upper back and 2-triceps explained 75% of the variation in leptin (p< 0.0001). The results suggest that SAT-layers and their topography are main determinants for leptin in obese children and adolescents. Maturity in obese children is associated with higher values of upper body SAT-layers and lower values of abdominal and lower extremities SAT-layers. Whether leptin is under the control of certain subcutaneous adipose tissue depots from the upper body remains to be elucidated by longitudinal studies.     

Metformin therapy to reduce weight gain and visceral adiposity in children and adolescents with neurogenic or myogenic motor deficit

Casteels K, Fieuws S, van Helvoirt M, Verpoorten C, Goemans N, Coudyzer W, Loeckx D, de Zegher F. Metformin therapy to reduce weight gain and visceral adiposity in children and adolescents with neurogenic or myogenic motor deficit.
The aim of this randomized, placebo-controlled study was to explore the effect of metformin in children with a neurogenic or myogenic motor deficit, who are therefore prone to develop overweight, adiposity, and insulin resistance.
Study participants (n = 42) had a mean age of 15.5 yr, a short stature (height −2.4 SD), a relatively high BMI (+1.7 SD), and a high body fat fraction (41.9% or +2.8 SD). Abdominal CT confirmed the high fat mass and disclosed a high fraction of visceral fat. As expected, insulin resistance was increased.
As compared to placebo, metformin intake for 6 months exerted an insulin sensitizing effect and lowered weight (mean difference of 2 kg within 6 months, p = 0.007) and BMI (p = 0.016). Weight loss appeared to be primarily due to loss of visceral fat (∼20% vs. placebo; p < 0.0001). Results were similar across diagnostic subgroups.
In conclusion, metformin treatment for 6 months was associated with a rise in insulin sensitivity and with a reduction of visceral adiposity in children and adolescents with a primary muscle disorder or with a neural tube defect. These findings suggest that insulin resistance underpins, at least partly, the overweight and visceral adiposity of these patients, who are not necessarily obese.     

Moderate–vigorous physical activity and body fatness in Chinese urban school children

Background: The exact relation between moderate-vigorous physical activity (MVPA) and body fatness in children has yet to be fully defined. This study examined the relationship between MVPA and body fatness in Chinese urban school children aged 9-11 years, in an 8 month longitudinal study. Methods: Two hundred and ten children (aged 9-11 years; 97 boys and 113 girls) were recruited from two public primary schools in the Beijing urban area. The baseline and the 8 month follow-up percent body fat (fat%), fat mass (FM), body mass index (BMI), waist size, hip size and the waist : hip ratio were investigated as measures of body fatness. Habitual MVPA level (activity-related energy expenditure, AEE) was measured using a validated self-report questionnaire recall. Results: Nine-year-old girls who were in the top quartile for MVPA had significantly lower fat% than other girls at the same age (P < 0.05); 10-11-years girls who were in the top quartile for MVPA had significantly less increase in all of the indices of body fatness (P < 0.05). There was no difference in fat% between the highly physically active (top quartile for MVPA) and less active 9-11 year boys in both cross-sectional and longitudinal statistical analyses. Conclusions: Highly physically active girls had lower fat% and less increase in body fatness. In light of world trends showing increasing childhood obesity, this study supports the hypothesis that MVPA might be effective in fighting excess body fat gain in Chinese school-age girls.     

The influence of weight loss on fibrinolytic and metabolic parameters in obese children and adolescents

We studied i) whether short-term weight loss alters plasminogen activator inhibitor-1 antigen (PAI-1-Ag) and tissue-type plasminogen activator antigen (tPA-Ag) in obese children, and ii) whether changes in body composition and/or abdominal adiposity are responsible for changes in PAI-1 and tPA-Ag. 20 obese boys (mean age 11.9 yr) and 40 obese girls (mean age 12 yr) were studied before and after three weeks of low-caloric diet and physical activity. Body composition was assessed by means of bioelectrical impedance, and the waist-to-hip ratio (WHR) was measured. Blood samples were determined for insulin, glucose, triglycerides, PAI-1-Ag, tPA-Ag, and the fasting insulin resistance index (FIRI) was calculated. Boys had a greater WHR, higher levels of glucose, and a slightly greater FIRI than girls. Estimates of adiposity, insulin, and triglycerides were correlated with PAI-1 and tPA-Ag. WHR was significantly correlated with fibrinolytic parameters only in girls. Insulin and tPA-Ag contributed to PAI-1 (adj. R2 = 0.36, p <0.0001), whereas percentage fat mass and triglycerides contributed to tPA-Ag (adj. R2 = 0.469, p <0.0001). The weight loss program significantly reduced adiposity, abdominal adiposity, and lowered fibrinolytic and metabolic parameters. Initial levels of PAI-1 and changes in body mass contributed to the fall in PAI-1 (adj. R2 = 0.18, p = 0.0016) and initial levels of tPA-Ag contributed significantly to changes in tPA-Ag (adj. R2 = 0.57, p <0.0001). The results suggest that changes in fibrinolytic parameters are associated with the loss in body mass but can occur independently of a concomitant reduction in fatness. Although initial PAI-1 and tPA-Ag predict the changes of these fibrinolytic parameters, the results do not exclude the possibility that the improvement in metabolic state and changes in unmeasured parameters related to physical activity and low-caloric diet could have influenced our findings.     

Use of markers of dyslipidemia to identify overweight youth with insulin resistance

CONTEXT: Markers to identify overweight youth with insulin resistance are of clinical importance. OBJECTIVE: To determine if markers of dyslipidemia could identify overweight adolescents with insulin resistance. SETTING, PARTICIPANTS, AND STUDY DESIGN: We retrospectively examined the association between markers of dyslipidemia and insulin resistance in 35 overweight [body mass index (BMI) of > or =95th percentile], white adolescents [mean age 13.5 +/- (SD) 1.6 yr] who had participated in hyperinsulinemic-euglycemic clamp studies to evaluate insulin action. Total body fat was measured by dual-energy X-ray absorptiometry and abdominal fat with computed tomography. Using receiver-operating curves, cut-points for triglyceride (TG)/high-density lipoprotein (HDL) and TG level to identify overweight individuals in the lowest tertile for insulin sensitivity were determined. MAIN OUTCOME MEASURE: Difference in the values for insulin sensitivity among the groups. RESULTS: Of the markers examined (TG, TG/HDL, adiponectin, measures of adiposity and fasting insulin), fasting insulin was the strongest correlate of insulin sensitivity (r = 0.87, p < 0.001). Youth with TG/HDL level > or =3 had lower insulin sensitivity (50% lower median values, p < 0.01) and higher visceral fat (p < 0.05) despite BMI comparable to that of youth with TG/HDL level <3. Youth with TG/HDL > or =3 had a sensitivity of 61% and specificity of 82% for identifying participants with the greatest degree of insulin resistance. CONCLUSIONS: TG and TG/HDL are easily obtained markers associated with insulin resistance. Further research is needed to determine if a constellation of clinical findings, such as components of the metabolic syndrome along with other metabolic markers including adiponectin, better predicts insulin resistance in overweight youth.     

Serum levels of soluble tumor necrosis factor-alpha receptor 2 are linked to insulin resistance and glucose intolerance in children

BACKGROUND: Obesity and insulin resistance are increasingly common problems in children. Tumor necrosis factor-alpha (TNF-alpha) has important effects on lipid and glucose metabolism. This effect may be mediated through soluble TNF-alpha receptor 2 (sTNFR2). OBJECTIVE: To investigate the relationship between insulin resistance and the TNF-alpha system in childhood obesity. CHILDREN AND METHODS: Twenty-one obese and six non-obese children were studied. Body mass index (BMI) z-scores, percent body fat (PBF) and waist to hip ratio (WHR) were determined. Fasting serum levels of total cholesterol, HDL-cholesterol, LDL-cholesterol, TNF-alpha and sTNFR2 were measured. A standard 2-hour oral glucose tolerance test (dose of glucose: 1.75 g/kg, max. 75 g) was done. Insulin resistance (IR) was estimated by fasting plasma insulin, plasma insulin at 120 min, homeostasis model assessment (HOMA) and insulin area under the curve (AUC) from OGTT. Insulin sensitivity was estimated by oral glucose insulin sensitivity (OGIS120). RESULTS: Among the obese participants, one child (5.2%) was found to have diabetes mellitus and four others (21.1%) impaired glucose tolerance (IGT). Obese children had significantly elevated sTNFR2 levels. Furthermore, the group of obese children with IGT and the patient with newly diagnosed diabetes mellitus together (n = 5) had significantly higher levels of serum sTNFR2 (2,865+/-320 pg/ml) than the rest of the obese (2,460+/-352 pg/ml; p = 0.016) or lean (1,969+/-362 pg/ml; p = 0.014) children. Serum sTNFR2 levels correlated positively with insulin AUC, HOMA IR, fasting plasma insulin, plasma insulin at 120 min, total cholesterol and LDL/ HDL ratio, and negatively with OGIS120. Multiple regression analysis revealed that age, WHR, sTNFR2 and LDL predicted 81% of the variability in glucose at 120 min. CONCLUSION: sTNFR2 is a candidate marker of insulin resistance and glucose intolerance.     

Bioelectrical impedance analysis of body fatness in childhood congenital adrenal hyperplasia and its metabolic correlates

There is a tendency to adiposity in patients with congenital adrenal hyperplasia (CAH) despite physiological corticosteroid doses. This study investigated body fatness in children with CAH under corticosteroid replacement therapy. Seventeen children with CAH (female:male, 9:8; age range 1.6–10.5 years) and 18 controls (female:male, 9:9; age range 1.4–10.2 years) were studied. Serum lipids, leptin, insulin, anthropometry, body circumferences, skinfold thickness, and body fat ratio as measured with bioelectrical impedance analysis (BIA) were the study parameters. Weight standard deviation scores (SDS), body mass index (BMI), BMI–SDS, body circumferences, skinfold thickness, and body fat ratio were higher and leptin was positively correlated with all of the body circumference and skinfold thickness parameters as well as body fat ratio in the study group. Waist/hip ratio was lower in the study group. Body fatness is a serious problem starting in early childhood in CAH patients and further refinement of the glucocorticoid replacement regimens as well as lifestyle measures are needed.     

Clinical measures of adiposity and percentage fat loss: which measure most accurately reflects fat loss and what should we aim for?

OBJECTIVE: To determine which clinical measure of childhood obesity should be monitored to best reflect change in adiposity in a weight management programme and estimate the degree of change needed to be relatively certain of fat reduction. SUBJECTS: 92 obese children with a mean (range) age of 12.8 (6.9-18.9) years and a mean body mass index standard deviation score (BMI SDS) of +3.38 (+2.27 to +4.47) attending a hospital-based clinic on a regular, 3 monthly basis. Measurements: Pairs of weight and height measured up to 2.41 years apart used to derive BMI as kg/m2, and adjusted for age and gender to give weight and BMI SDS (BMI-z score) using British 1990 Growth Reference Data. Contemporaneous adiposity estimated by fatness measured by a bioimpedance segmental body composition analyser. RESULTS: Changes in BMI-z scores, compared to BMI, weight and weight SDS, most accurately reflected loss of fat. Reductions of 0.25, 0.5, 0.75, and 1 BMI SDS equate to expected mean falls in total body fat percentage of 2.9%, 5.8%, 8.7% and 11.6%. Approximate 95% prediction intervals indicated that a fall in BMI SDS of at least 0.6 over 6-12 months (or 0.5 over 0-6 months) is consistent with actual fat loss. CONCLUSION: Change in BMI-z score best reflects percentage fat loss compared to BMI, weight and weight SDS. The wide variation in likely percentage fat loss for a given BMI SDS reduction means a loss of 0.5-0.6 is required to be relatively certain of definite percentage fat reduction.     

Can waist circumference identify children with the metabolic syndrome?

OBJECTIVE: To determine in children the association between waist circumference (WC) and insulin resistance determined by homeostasis modeling (HOMA-IR) and proinsulinemia and components of the metabolic syndrome, including lipid profile and blood pressure (BP). METHODS: Eighty-four students (40 boys) aged 6 to 13 years and matched for sex and age underwent anthropometric measurements; 40 were obese; 28, overweight; and 16, nonobese. Body mass index (BMI), WC, BP, and Tanner stage were determined. An oral glucose tolerance test, lipid profile, and insulin and proinsulin assays were performed. Children were classified as nonobese (BMI < 85th percentile), overweight (BMI, 85th-94th percentile), and obese (BMI > or = 95th percentile). RESULTS: There was univariate association (P < .01) between WC and height (r = 0.73), BMI (r = 0.96), Tanner stage (r = 0.67), age (r = 0.56), systolic BP (r = 0.64), diastolic BP (r = 0.61), high-density lipoprotein cholesterol level (r = 0.45), triglyceride level (r = 0.28), proinsulin level (r = 0.59), and HOMA-IR (r = 0.59). Multiple linear regression analysis using HOMA-IR as the dependent variable showed that WC (beta coefficient = 0.050 [95% confidence interval, 0.028 to 0.073]; P = .001) and systolic BP (beta coefficient = 0.033 [95% confidence interval, 0.004 to 0.062]; P = .004) were significant independent predictors for insulin resistance adjusted for diastolic BP, height, BMI, acanthosis nigricans, and high-density lipoprotein cholesterol level. CONCLUSION: Waist circumference is a predictor of insulin resistance syndrome in children and adolescents and could be included in clinical practice as a simple tool to help identify children at risk.     

Relation of subepicardial adipose tissue thickness and clinical and metabolic parameters in obese prepubertal children

HızlıŞ, Özdemir O, Abacı A, Razi CH and Kabakuş N. Relation of subepicardial adipose tissue thickness and clinical and metabolic parameters in obese prepubertal children. Background: The measurement of subepicardial adipose tissue thickness (SATT) has been found to be related to insulin resistance (IR) in adults. Until now, the association between SATT and IR has not been evaluated in obese prepubertal children. We aimed to determine the relation of SATT with clinical anthropometric and metabolic parameters and to provide cutoff value of SATT associated with IR in obese prepubertal children. Methods: Fifty‐two obese (mean age: 9.5 ± 1.6 years, 29 female) and 31 lean prepubertal age‐ and gender‐matched subjects (mean age: 9.2 ± 1.4 years, 12 female) were evaluated by echocardiography. SATT was measured by transthoracic echocardiography. Results: SATT (6.54 ± 1.38 mm) and homeostatic model assessment‐insulin resistance (HOMA‐IR) (3.2 ± 2) values of obese prepubertal subjects were significantly higher than those of the lean subjects (3.72 ± 0.57 mm and 1.6 ± 1) in the control group (both p < 0.001). Bivariate correlation analysis showed significant correlation between SATT, age, body mass index (BMI), waist circumference (WC), hip circumference (HC), waist‐to‐hip ratio (WHR), mid‐arm circumference (MAC), triceps skin fold (TSF) thickness, insulin, and HOMA‐IR (r = 0.547, r = 0.524, r = 0.543, r = 0.431, r = 0.289, r = 0.402, r = 0.400, r = 0.328, r = 0.289, p < 0.05, respectively). As an optimal cutoff point, an SATT of 4.33 mm determined IR with 93.3% sensitivity and 51% specificity. Conclusions: Our study on obese prepubertal children showed that SATT was significantly correlated with age, BMI, WC, HC, MAC, TSF, insulin, and HOMA‐IR.     

Body fat ratios in urban Chinese children

OBJECTIVE: As obesity has been increasing in China, the present study examined the body composition of children to assess their fatness. STUDY DESIGN: A total of 532 healthy schoolchildren who lived in central Beijing were examined. Skinfold thicknesses, hip and waist circumferences, and body fat percentage were measured, as well as height and weight. RESULTS: The prevalence of overweight (Body Mass Index (BMI) >or= 95% for age and sex of Chinese children) was 27.7% in boys and 14.2% in girls (chi-squared; P = 0.0001). The percentages of body fat (BF%), waist/hip ratios and skinfold thicknesses ratios (subscapular/triceps) in overweight children were significantly higher than those in non-overweight children (Mann-Whitney U-test). The BF% of non-overweight boys was significantly higher than that of non-overweight girls. CONCLUSION: Urban Chinese overweight children have high BF% with adverse fat distribution. They may have high risk of atherogeniety. Boys in the non-overweight category may have higher fat accumulation than predicted by BMI. The establishment of an intervention program for childhood obesity is strongly recommended.     

Correlates of adiponectin and the leptin/adiponectin ratio in obese and non-obese children

Adiponectin is an adipocyte secreted protein that has been reported to increase fatty acid oxidation and improve insulin sensitivity. Our aim was to study the relationship between adiponectin and leptin, body fat, insulin and lipoproteins in obese compared to non-obese children matched for age and gender. Adiponectin serum concentrations were significantly lower in the obese compared to the non-obese children (9.1+/-3.7 vs 17.1+/-12.3 microg/ml, p <0.05), in contrast to serum leptin concentrations which were greater in the obese compared to the non-obese subjects (31.8+/-11.1 vs 8.2+/-5.7 ng/ml, p <0.001). When considered as a single group to assess adiponectin concentrations over a spectrum of body size, adiponectin values correlated inversely with body weight (r = -0.33, p <0.05) and BMI (r = -0.35, p <0.05). Adiponectin values correlated directly with HDL-C (r = 0.47, p <0.005), but not with total cholesterol, IGF-I, or leptin binding activity. Since leptin and adiponectin change inversely in relation to BMI, the leptin/adiponectin (L/A) ratio was determined as a potential index relating adiposity to the development of complications of obesity. The L/A ratio was eight-fold greater in the obese compared to the non-obese children, and correlated more strongly with BMI (r = 0.779, p <0.0001) and with HDL-C (r = -0.53, p <0.001), than did adiponectin alone. The L/A ratio also correlated significantly with triceps skinfold thickness (TSF) (r = 0.77, p <0.001) and percent body fat (r = 0.79, p <0.0001) in non-obese children. These data suggest that adiponectin concentrations are already differentially regulated in childhood obesity. The index of increased leptin concentration corrected by reduced adiponectin values (L/A ratio) merits investigation as a marker for morbidities associated with childhood obesity.     

Abdominal obesity is an independent risk factor for increased carotid intima- media thickness in obese children

We aimed in this study to investigate carotid intima-media thickness (IMT) in obese children and evaluate the relationship of IMT to various cardiovascular risk factors. One-hundred four obese children (9.3 +/- 2.5 years) and 30 healthy age-matched control subjects were enrolled in the study. All children were assessed for fasting levels of glucose, insulin, lipid profile, skinfold thickness (SFT), waist circumference (WC), and blood pressure (BP). Insulin resistance was estimated by the homeostasis model assessment (HOMA) index. Carotid IMT measurements and non-alcoholic fatty liver disease (NAFLD) were diagnosed with ultrasonographic findings. IMT was significantly higher in obese children compared to controls (0.49 +/- 0.05 vs. 0.40 +/- 0.02 mm, p < 0.001). Significant positive correlations were found between increased carotid IMT and body fat percentage (BFP), body mass index (BMI), age, height, systolic BP, WC, SFT, triglyceride and insulin levels, and insulin resistance index. In a linear logistic regression analysis, the only parameter affecting the increase in carotid IMT was WC (beta: 0.589, p < 0.001). Furthermore, IMT was increased significantly in obese children with NAFLD when compared to obese children without NAFLD (0.54 +/- 0.04 vs. 0.48 +/- 0.05 mm, p < 0.001). Children with abdominal obesity are at increased risk for atherosclerosis, and WC can be used to determine the atherosclerosis risk in obese children.     

Non-alcoholic fatty liver disease in obese children evaluated by magnetic resonance imaging

AIM: To investigate the prevalence of non-alcoholic fatty liver disease (NAFLD) in a group of obese children (BMI > 97th %) and to establish correlations between the severity of hepatic fatty infiltration, auxological findings and parameters of insulin resistance. METHODS: 44 obese children, aged 6-16 years, with a BMI above the 97th centile were selected for analysis. Hepatic fat content was assessed by phase contrast MRI. Demographic data included weight, height, body mass index, body fat mass and waist circumference. Blood tests included fasting blood glucose, fasting insulin and lipid profile. Insulin sensitivity was evaluated with QUICKI. RESULTS: Elevated hepatic fat fraction (FF) was identified in 14 subjects (31.8%; 0.07 SEM). Children with fatty liver (FF > 9%) had higher ALT (P<0.0001), AST (P=0.002) and triglycerides (P=0.008) values compared to the children without NAFLD. All the children showed a decreased insulin sensitivity (P<0.0001), but no difference was found between children with or without NAFLD. The degree of liver fatty infiltration was positively correlated with ALT (P<0.0001), AST (P<0.002) and gammaGT (P<0.0001), with height (P<0.006) and BMI (P<0.05) but not with estimates of body fat mass or fat distribution. CONCLUSION: Obese children are frequently affected by NAFLD, which cannot be predicted by clinical and/or anthropometrical findings. There is however a strict correlation between the degree of liver fatty infiltration and elevation of liver enzymes.     

Low-density lipoprotein subclasses in children under 10 years of age

OBJECTIVE: To examine the prevalence of small dense low density lipoprotein (LDL) in a cohort of children under 10 years of age and to investigate the relationship to other biochemical variables and to measures of fatness. A preponderance of small dense LDL (pattern B), is associated with obesity, abdominal fat accumulation, insulin resistance and risk of heart disease in adults. METHODOLOGY: LDL peak particle diameter (PPD) was determined by gel electrophoresis in 53 children under 10 years of age and in 65 of their parents: apoproteins A1 and B were determined by turbidimetry. Anthropometric variables, basic lipid profiles, insulin and leptin had been determined previously. Differences between patterns A (large light particles > 25.5 nm diameter) and B were examined by t-test, Chi-square, or Mann-Whitney test. Relationships between the variables were reported as Pearson correlation coefficients. RESULTS: Pattern B (PPD of < or = 25.5 nm) prevalence was 7.5% in children and 11% in parents (17% in men and 5% in women). Most of the children (86%) who had PPD < or = 26.0 nm also had parents with PPD in this range. A strong association was found between children's and mother's PPD (r=0.60, P < 0.001), but this was somewhat less with fathers (r=0.40, P=0.02). Children in the lowest tertile of PPD had a tendency towards a higher body mass index, waist, fat mass and insulin. CONCLUSIONS: The prevalence of small dense LDL is lower in children under 10 years of age than in their parents; fathers had a higher prevalence of pattern B than mothers and there is some evidence of a familial effect in the inheritance of pattern B.     

肥胖儿童伴良性黑棘皮病与胰岛素抵抗19例分析

目的　探讨肥胖儿童伴良性黑棘皮病与胰岛素抵抗及 2型糖尿病的关系。方法2 0 0 3年 6月～ 2 0 0 3年 9月 ,在我院内分泌门诊及病房就诊的体重指数 (BMI)≥ 2 5的肥胖儿童共 76例 ,对其中伴黑棘皮病皮肤改变的 19例 ( 2 5 % )均行皮肤病理活检以明确诊断 ,同时对这些患儿行空腹血糖、空腹血胰岛素水平、空腹血糖 /胰岛素比值 (FGIR)及人体测量学参数 [腰围 /臀围比值(WHR) ,全身体脂含量 (FM)、体脂百分数 (BF % )、体重指数 (BMI) ]等的检测 ,并行葡萄糖耐量试验(OGTT试验 ) ,以探讨肥胖儿童伴良性黑棘皮病与胰岛素抵抗及 2型糖尿病的关系。结果　 19例良性黑棘皮病患儿人体测量学参数包括腰围 /臀围比值 ,全身体脂含量 (FM)、体脂百分数 (BF % )、体重指数 (BMI)及空腹血胰岛素水平明显高于正常对照组 (P <0 0 1) ,空腹血糖 /胰岛素比值 (FGIR) ( 4 2 7± 0 5 3)小于 7,存在明显的胰岛素抵抗 ,其中 1例诊断为 2型糖尿病 ,10例有糖耐量异常。结论　儿童良性黑棘皮病与肥胖、高胰岛素血症 ,胰岛素抵抗及 2型糖尿病密切相关 ,是临床胰岛素抵抗的皮肤标志     

Does short sleep duration favor abdominal adiposity in children?

The main aim of this cross-sectional study was to determine whether the increased body mass index (BMI) characterizing short-duration sleeping children is related to an increased predisposition to abdominal adiposity. A total of 422 children (211 boys and 211 girls) involved in the "Québec en Forme" Project were tested for body weight, height, waist circumference, and sleep duration. As there was no gender interaction with the other factors, a partial regression of waist circumference on hours of sleep was performed for both genders combined, adjusting for age, sex, BMI, parental obesity, parental education, total annual family income, frequency of taking breakfast, watching television, playing videogames, computer use, and frequency of practicing sports activities outside of school. Sleep duration had an independent effect on waist circumference, with the correlation between these variables remaining significant after adjustment for BMI and the several other covariates (r=- 0.17, p<0.001). In conclusion, these results suggest that short sleep duration favors abdominal adiposity in children. This finding is of particular concern since abdominal obesity is an important feature of the metabolic syndrome.     

Preschool children born moderately preterm have increased waist circumference at two years of age despite low body mass index

Aim: To investigate the development of waist circumference (WC) in preschool children born preterm compared with a population‐based reference. Background: Children born preterm are reported to be insulin resistant, despite being lean during early childhood. We hypothesize that the mechanism is through increased visceral adiposity. Methods: Data from 4446 preschool children (2169 girls/2277 boys) born in 2001–2006 from a population‐based study were compared with longitudinal measurements of body mass index (BMI) and WC from a cohort of 152 children (64 girls/88 boys) born moderately preterm in 2002–2004 (gestational age, 32–37 weeks). Results: In the preterm children, the mean WC was 2.8 cm larger compared with the reference group (p < 0.001) at 2 years of age but not at 5 years of age. There was no significant difference in the mean BMI at 2 years of age. The preterm group was significantly leaner at 5 years of age, with a mean BMI of 15.13 compared with 15.98 in the reference group (p < 0.001). Conclusion: Children born moderately preterm present as lean during early childhood but have an increased waist circumference in infancy, pointing towards a change in fat distribution with more abdominal fat. This may have implications for their metabolic status.