Waist circumference, blood pressure, and lipid components of the metabolic syndrome

OBJECTIVES: To examine whether waist circumference (WC) predicts blood pressure (BP) and lipid components of the metabolic syndrome independent of body mass index (BMI) percentile in youths. STUDY DESIGN: The study group comprised 70 African-American youths and 97 Caucasian youths. Outcome measures included BP, lipid profile, and abdominal adipose tissue (AT). RESULTS: Both BMI percentile and WC were significantly (P < .05) associated with daytime and nighttime systolic and diastolic BP, triglycerides (TG), high-density lipoprotein (HDL), and TG/HDL ratio independent of race. In African-Americans and Caucasians, WC remained a significant (P < .05) correlate of daytime (r = .50 and .59, respectively) and nighttime (r = .49 and .62, respectively) systolic BP, and in Caucasians, TG, HDL, TG/HDL, and very-low-density lipoprotein after controlling for BMI percentile. After accounting for age, sex, and race, the addition of WC to BMI percentile increased the variance (R(2)) in systolic BP by 15% (P < .05). The inclusion of WC with BMI percentile explained an additional 3% and 7% of the variance in TG and HDL, respectively (P < .05). CONCLUSIONS: The prediction of childhood obesity-related health risks is significantly improved by the inclusion of WC in addition to BMI percentile. This observation supports the notion that WC should be included in the evaluation of childhood obesity along with BMI percentile to identify those at increased health risks due to excess abdominal fat.     

Definition of metabolic syndrome in preadolescent girls

OBJECTIVE: To compare and contrast proposed definitions of metabolic syndrome in pediatrics, and to determine prevalence of metabolic syndrome in preadolescent females when applying different criteria. STUDY DESIGN: A literature review on definitions of metabolic syndrome and cardiovascular "risk factor clustering" in children and adolescents published in the past decade. Pediatric definitions of metabolic syndrome were then applied to a community-based study of 261 black preadolescent females (Girls Health Enrichment MultiSite studies [GEMS]) and a school-based, cross-sectional study of 240 ethnically-diverse preadolescent females (Girls Activity, Movement and Environmental Strategy [GAMES]) who had a baseline physical examination and fasting morning blood sample. RESULTS: Agreement among pediatric definitions of metabolic syndrome was poor. The prevalence of MS and cardiovascular risk factor clustering ranged from 0.4% to 23.0% for GEMS and 2.0% to 24.6% for GAMES with definitions adapted from the National Cholesterol Education Program Adult Treatment Panel III, and 0% to 15.3% for GEMS and 0.4% to 15.8% for GAMES using modified criteria from the World Health Organization. CONCLUSIONS: The prevalence of metabolic syndrome in preadolescent girls varies widely because of disagreement among proposed definitions of metabolic syndrome in pediatrics. Further investigation is needed to determine which metabolic factors and their respective cut points should be used to identify children at risk for development of clinical disease.     

Nontraditional cardiovascular risk factors in pediatric metabolic syndrome

OBJECTIVE: To study the relationships between nontraditional cardiovascular (CV) risk factors and components of the metabolic syndrome in Native Canadian children, a population at risk of future CV disease. STUDY DESIGN: CV risk factors were evaluated in a population-based study of a Canadian Oji-Cree community, involving 236 children aged 10 to 19 years. RESULTS: Using an age- and sex-specific case definition, 18.6% of the children met criteria for pediatric metabolic syndrome. As the number of metabolic syndrome component criteria increased, C-reactive protein, leptin, and ratio of apolipoprotein B to apolipoprotein A1 levels rose (all P < .0001) and adiponectin concentration decreased (P = .0006). Principal factor analysis using both traditional and nontraditional CV risk factors revealed 5 underlying core traits, defined as follows: adiposity, lipids/adiponectin, inflammation, blood pressure, and glucose. CONCLUSIONS: Nontraditional CV risk factors accompany the accrual of traditional risk factors early in the progression to pediatric metabolic syndrome. Furthermore, inclusion of these factors in factor analysis suggests that 5 core traits underlie the early development of an enhanced CV risk factor profile in Native children.     

Obesity, metabolic syndrome, and cardiovascular disease

Early childhood overweight and obesity have alarmingly increased over the years. Adulthood obesity is a well demonstrated significant independent predictor of cardiovascular risk (CVR) and/or mortality, which predisposes to the major components of metabolic syndrome (MS). Evidence of MS in obese children has been also reported associated with biochemical and inflammatory factors that affect vascular physiologic function. Assessment of vascular function can be measured noninvasively in children allowing early detection of endothelial dysfunction and severe increase of arterial stiffness before clinical manifestations of atherosclerosis. Impairment of endothelial function related to the severity of obesity and to the degree of insulin resistance is considered as a condition that confers a premature atherogenicity status and is linked to adult conventional cardiovascular risk factors. Adipose tissue factors that interfere with insulin action and endothelial cell function have also been identified as major precursors of CVR factors. The metabolic and cardiovascular consequences of childhood obesity are well demonstrated and have a major impact on the development of atherosclerosis and lifetime CVR. The development of programs involving both diet and exercise for children with overt overweight/obesity appears to be essential to improve vascular function and metabolic disorders. Such interventions should be complemented by a primary prevention against childhood obesity.     

Obesity, inflammation and metabolic syndrome in Danish adolescents

Aim: To describe biomarkers of inflammation and markers related to the metabolic syndrome (MS) in healthy obese Danish adolescent and compare to a normal‐weight group. Methods: Fifty‐one obese and 30 normal‐weight adolescents (12–15 years) were included. Anthropometry and blood pressure were measured, and blood was sampled. Results: Obese adolescents had significantly higher blood pressure, insulin, homeostasis model assessment of insulin resistance, C‐peptide, total cholesterol, low‐density lipoprotein cholesterol (LDL), triglyceride, C‐reactive protein (CRP), interleukin‐6 and tumour necrosis factor alpha and lower high‐density lipoprotein cholesterol values, compared with normal‐weight adolescents, whereas there were no differences between the groups for glucose, free fatty acids or faecal calprotectin. Within the obese group insulin, low‐density lipoprotein cholesterol, and CRP were positively associated with body mass index (BMI) Z‐scores. The MS was present in 14% of obese adolescents. CRP was positively associated with most anthropometric measures within the obese group, and in multiple linear regression analysis both BMI Z‐score and the sum of skin folds explained a considerable part (R² = 0.421) of the variation in CRP. Conclusion: Otherwise healthy Danish obese adolescents had marked low‐grade inflammation, elevated biomarkers of the MS and high prevalence of the MS.     

肝X受体与代谢综合征代谢紊乱

肝X受体是与代谢综合征相关的核受体之一,对体内胆固醇的平衡和脂代谢的调控起重要作用.肝X受体能增加组织对葡萄糖的利用,延缓胰岛素抵抗,同时对胰岛β细胞有不利的作用.肝X受体影响脂肪细胞分化和下调肥胖基因的表达而引发肥胖,参与非酒精性脂肪肝的发生发展,同时具有控制动脉粥样硬化的作用,并参与巨噬细胞和淋巴细胞的炎症反应.作为代谢通路与炎症反应信号通路的结合点,肝X受体有望作为治疗代谢综合征的新靶点.