Predictive value of body mass index and waist circumference for metabolic syndrome in 6-12-year-olds

Aim: To determine the predictive value of body mass index (BMI) and waist circumference (WC) and their optimal cut‐off points for metabolic syndrome (MetS), and also the incidence of MetS. Methods: This study included 888 children, aged 6–12 years, who were followed for a mean of 6.6 years. BMI, WC and their optimal cut‐off points to predict MetS were investigated. Results: The cumulative incidence of MetS was 10.7%. The adjusted ORs for age, sex and family history to predict MetS for BMI and WC z‐scores were 2.6 (95% CI, 2.0–3.5) and 2.6 (95% CI, 1.9–3.5), respectively. In their correspondent models, area under the receiver operating characteristic (ROC) curve was 0.73 (95% CI, 0.68–0.79) for BMI z‐scores and 0.72 (95% CI, 0.67–0.78) for WC z‐scores with no statistically significant difference. The optimal cut‐off values for BMI were 16.5 kg/m² for boys and 16.3 kg/m² for girls and those for WC were 57.5 cm for boys and 56.5 cm for girls. Conclusions: Our findings suggest that both BMI and WC have the same power to predict MetS and also children with higher BMI or WC are more susceptible to MetS. Moreover, a high incidence of MetS in children highlights the importance of interventional strategies during early childhood.     

Waist circumference percentiles for 7- to 17-year-old Turkish children and adolescents

Abdominal obesity is associated with risk of cardiovascular disease and type 2 diabetes mellitus. Waist circumference as a measure of obesity may be clinically useful as a predictor of metabolic syndrome in children. To develop age- and sex-specific reference values for waist circumference we evaluated the data obtained from Turkish children and adolescents. Waist circumference measurements from 4,770 healthy schoolchildren were obtained. Smoothed percentile curves were produced by the LMS method. The median curves of Turkish children were compared with four other countries: Australia, the UK, USA (Bogalusa) and Japan. Smoothed percentile curves and values for the 3rd, 5th, 10th, 25th, 50th, 75th, 85th, 90th, 95th and 97th percentiles were calculated for boys and girls. We found that waist circumference increased with age both in boys and girls. The 50th percentile waist circumference curve of Turkish children was over the British and Japanese but lower than the Bogalusa children and adolescents. This study presents data and smoothed percentile curves for waist circumference of healthy Turkish children aged 7–17 years. The differences in waist circumference of different countries can be explained by lifestyles and cultural characteristics. These data can be added to the existing international reference values for waist circumference of children and adolescents.     

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.     

Waist circumference in relation to body perception reported by Finnish adolescent girls and their mothers

Aim: To study how waist circumference (WC) relates to body perception in adolescent girls and to maternal perception of the girl's body size.
Methods: Three hundred and four girls, 11–18 years, were measured for height, weight and WC. 294 girls provided self-report data on weight, height and body image before anthropometric measurements. Paired data from 237 girls and mothers on perception of the girls' body size were collected.
Results: In girls, self-reported weight indicated awareness of actual body size. The girls' body perception showed an overestimation of body size relative to international reference values for body mass index (BMI) (p < 0.05), but not for WC. Girls' body perception exceeded that of their mothers (p < 0.05). Maternal perception agreed better than the girls' perception with international reference values for BMI (p < 0.05). No significant difference between mothers and girls were found concerning agreement of body perception with international reference values for WC.
Conclusion: WC rather than BMI agrees with perception of body size, possibly due to its relation to abdominal fat at different ages. For effective prevention and treatment programmes for weight-related health problems among adolescent girls, we recommend measuring WC to diminish the discrepancy between measured and perceived body size.     

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.     

The metabolic syndrome in children and adolescents

The metabolic syndrome is a constellation of metabolic abnormalities that result in an increased risk for type 2 diabetes mellitus and cardiovascular disease in adults. It emerges when a person’s predisposition for insulin resistance is worsened by increasing central obesity and is largely confined to the overweight population. The United States National Cholesterol Education Program’s Adult Treatment Panel III report proposed a set of criteria for the clinical diagnosis of metabolic syndrome in the adult population. A uniform definition for the paediatric population is lacking. Despite this, several studies have demonstrated that features of the syndrome develop in childhood and that the syndrome is present in up to 30% of obese children (body mass index at or above the 95th percentile). Ninety per cent of obese children meet at least one of the five criteria. The degree of abnormality is related to the body mass index, waist circumference and fasting insulin levels. There appears to be a genetic predisposition to the development of the syndrome and certain ethnic groups are at increased risk. The intrauterine environment also appears to play a role. Insulin resistance should be targeted for treatment through exercise and dietary intervention. The role of pharmacotherapeutic agents remains unclear. A uniform definition of the metabolic syndrome for paediatric patients needs to be created. Early intervention should be instituted because many of the features of the syndrome track from childhood into adulthood.     

Relationship of body mass index with serum lipids in elementary school students

Objective  To determine the relationship of body mass index with serum lipids in elementary students. Methods  This prospective analytic study was conducted among 954 elementary school students (9–11years), selected by multi stage random systematic method from 6 cities and their rural areas from The South Khorasan province (eastern Iran) from September to December 2006. Height and weight was measured and Body mass index was calculated. Total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C) were determined. Results  954 students 9–11 years old were studied. 45.4% were boys. 76.5% were living in the city. 1.8% of students were obese and 3.4% were over weight. There was no significant relation between obesity and overweight with sex, age and the area of residence. There was significant relation between BMI with TC (P= 0.003), TG (P< 0.001) and LDL-C (P= 0.04). TG was significantly higher in obese and overweight students than in normal weight students (P< 0.001). TC (0.002) and LDL-C (0.01) were significantly higher in obese students than normal weight students. The prevalence of high TG was significantly higher in obese and overweight students than normal weight students (0.003). There was no significant difference between different kinds of dyslipidemia with area of residence. Conclusion  it is necessary to measure serum lipid profile in obese and overweight children.     

肥胖儿童非酒精性脂肪肝病及代谢综合征发病情况分析

目的 研究肥胖儿童中非酒精性脂肪肝病(NAFLD)与代谢综合征(MS)的发生情况,并探索两者之间的关系.方法 对308例在本院内分泌科住院的9～14岁肥胖儿童进行腰围、体块指数、血脂、肝功能、肝脏B超、糖耐量试验及胰岛素释放试验等各项检查,根据诊断标准分别计算发生NAFLD[包括单纯性非酒精性脂肪肝(SNAFL)、非酒精性脂肪肝炎(NASH)]和MS的患病率,并将308例肥胖患儿分为无肝脏损害的肥胖儿童组(OCWLD组),SNAFL组和NASH组,比较各组胰岛素、胰岛素抵抗(IR)指标及MS的发病率和MS组成成分的发病率.结果 (1)308例中发生NAFLD的达到203例(65.9%),其中发生SNAFL者140例(45.5%),发生NASH者63例(20.5%).(2)308例中发生MS 76例(24.7%),这76例中合并有NAFLD的64例(84.2%).NAFLD组中MS 64例(31.5%),高于OCWLD组的12例(11.4%),差异有统计学意义,但SNAFL组中MS 41例(29.3%),与NASH组的23例(36.5%)比较差异无统计学意义.(3)就单个MS的组成成分来说,OCWLD组与SNALF组比较仅在高血压的发病率上差异有统计学意义,而OCWLD组与NASH组比较在高血压、高血脂、高血糖的发病率上差异均有统计学意义;SNALF组与NASH组比较在高血脂的发病率上差异有统计学意义.随OCWLD向SNAFL和NASH发展,空腹胰岛素水平逐渐上升,IR也越加明显.但NAFLD患儿与MS患儿比较各IR指标差异无统计学意义.结论 肥胖儿童中NAFLD和MS的发生率均已相当高,MS患儿合并NAFLD的比例很高,IR是NAFLD和MS共同的发病基础,且随着NAFLD患儿病情的进展,MS成分指标越来越严重,IR也越来越严重.     

Population-based waist circumference and waist-to-height ratio reference values in preschool children

Aim:  To establish new reference values for measurements of waist circumference and waist-to-height ratio in preschool children.
Methods:  A population-based, cross-sectional study of 4502 children aged 0–5 years derived from child health care in a Swedish county. Measurements of weight, height and waist circumference were recorded using a standardized procedure.
Results:  New reference values for waist circumference and waist-to-height ratio for preschool children are presented. Reference charts were constructed and are presented. Waist circumference increased with age (r = 0.80, p < 0.001). After adjustment to the individual height, expressed as waist-to-height ratio, there was an inverse correlation to age during the first 5 years of age (r = −0.87, p < 0.001).
Conclusion:  The new reference values for waist circumference and waist-to-height ratio for Swedish preschool children enable future identification of new risk populations for childhood obesity. For clinicians, new reference charts for these two variables are provided for practical use.     

中国六城市学龄儿童代谢综合征流行现状研究

目的 分析中国汉族学龄儿童代谢综合征(MS)流行现状,比较两种儿童青少年MS定义(中国:简称MS-CHN2012,国际糖尿病联盟:简称MS-IDF2007)在人群中的诊断效率.方法 对我国北部地区(北京、天津)、东部(杭州、上海)、中西部(重庆和南宁)六城市2010年22 071名(男性11 638名,女性10 433名)7 ～16岁中小学生的流行病学调查资料进行分析;分别采用上述两种定义诊断MS并比较两者诊断的一致性.结果 (1)7～16岁学龄儿童中,19.9％为超重及肥胖,肥胖占8.9％,男性10.9％,女性6.6％ (P＜0.001).(2)肥胖患病率依次为:北部16.9％、中西部5.9％、东部4.9％,差异有统计学意义(x2=1.007×103,P ＜0.001).(3)两种定义界定的MS,在7～ 16岁学龄儿童中分别为2.4％和1.4％,在肥胖人群中分别为28.8％和16.8％;不同定义所得的患病率差异有统计学意义(P ＜0.001).(4)两种定义诊断一致率达98.9％(Kappa值为0.711,P＜0.001).结论 7 ～16岁学龄儿童超重及肥胖已达19.9％,需引起高度重视;MS-CHN2012和MS-IDF2007两种定义在儿童青少年MS诊断上具有较好的一致性,而MS-CHN2012定义能较早检出MS高风险儿童青少年,有利于早期实行防治措施并降低成年期MS的发生风险.     

Waist circumference and waist-to-height ratio in Norwegian children 4-18 years of age: reference values and cut-off levels

Aim: To establish reference values for waist circumference and waist‐to‐height ratio of Norwegian children. Material: Data were collected in 2003–2006 as part of a cross‐sectional study, including 5725 children 4–18 years of age. Reference curves were fitted with the LMS method; appropriate cut‐offs were selected using receiver operating characteristic analysis. Results: Reference values for waist circumference and waist‐to‐height ratio are presented. Mean waist circumference increased with age for both genders. Boys had a higher waist circumference at almost all ages. Mean waist‐to‐height ratio decreased until early adolescence and thereafter increased slightly towards adult age. There was a strong positive correlation between waist circumference and BMI (r = 0.907, p < 0.01) and a moderate positive correlation between waist‐to‐height ratio and BMI (r = 0.397 p < 0.01). A waist circumference cut‐off value of 1.0 SDS (85th percentile) gave a sensitivity of 79% and a specificity of 94% to detect overweight. A cut‐off value of 1.6 SDS (95th percentile) gave a sensitivity of 94% and a specificity of 96% to detect obesity. Conclusion: This study presents the first reference values of waist circumference and waist‐to‐height ratio for Norwegian children 4–18 years, which also represent the first reference in Scandinavian schoolchildren. The 85th and 95th percentiles of waist circumference are proposed as appropriate cut‐offs for central overweight and obesity.     

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.     

Body mass index, triceps skinfold and waist circumference in screening for adiposity in male children and adolescents

Simple anthropometric measurements and indices are the most commonly used tools for assessing body composition. Only a few papers have examined the sensitivity and specificity of the body mass index (BMI) against total body fat percentage (TBF%) from underwater weighing in children and adolescents. The objective of the study was to evaluate the screening performance of BMI, triceps skinfold thickness and waist circumference for excess TBF%. A total of 175 healthy volunteer males, aged 7.0-16.9 y, participated in the study. TBF% was measured using underwater weighing as the reference method. Receiver operating characteristic (ROC) curves were constructed to assess the value of the three anthropometric measurements as a screening measure for total adiposity. Sensitivity and specificity were calculated at several percentile cut-offs for BMI, triceps skinfold and waist circumference. The areas under the ROC curves were also calculated, and were 0.86 for BMI, 0.90 for triceps skinfold and 0.88 for waist circumference. The point on the ROC curve closest to 1 corresponded to the 70th percentile for BMI, to the 75th percentile for triceps skinfold, and to the 70th percentile for waist circumference. Conclusion: BMI, triceps skinfold and waist circumference predicted total fat content well in male children and adolescents.     

腰围预测肥胖儿童非酒精性脂肪性肝病的价值

目的探讨腰围预测肥胖儿童发生非酒精性脂肪性肝病(NAFLD)的价值。方法2003-06—2006-09对浙江大学医学院附属儿童医院儿科197例9~14岁肥胖儿童进行腰围、体质指数(BMI)测定,作肝脏B超检查、血清肝酶测定,并与正常对照组比较。同时对肥胖儿童进行腰围、BMI与脂肪肝严重程度、血清ALT水平的相关性分析,以及腰围、BMI诊断肥胖儿童发生NAFLD曲线下面积的ROC分析。结果肥胖组腰围[(91.99±11.03)cm]显著大于正常对照组[(66.27±4.76)cm],BMI、肝酶水平也显著高于正常对照组。197例9~14岁肥胖患儿中诊断为NAFLD者147例,占74.62%;肥胖组NAFLD患儿腰围、BMI均大于非NAFLD患儿。肥胖患儿腰围、BMI与脂肪肝严重程度、血清ALT水平均呈正相关(r=0.478、0.356、0.302、0.205,均P<0.01);腰围和BMI诊断NAFLD的ROC曲线下面积分别为0.767、0.717(均P<0.01)。结论9~14岁肥胖儿童NAFLD发生与腰围密切相关,腰围、BMI对肥胖儿童发生NAFLD有一定的预测价值。     

Ethnic differences in metabolic syndrome among overweight and obese children and adolescents: the Oslo Adiposity Intervention Study

Aim: Are there differences in the prevalence of metabolic syndrome between obese and overweight Norwegian and immigrant children and adolescents? Methods: Two hundred and three overweight and obese Norwegian, Pakistani, Tamil and Turkish patients aged 6–17 years living in Norway were included. Metabolic syndrome was defined as the presence of at least three abnormal values of waist circumference, blood pressure, fasting triglycerides, fasting glucose and HDL cholesterol. Results: The prevalence of metabolic syndrome was significantly higher among the immigrant compared to Norwegian subjects when adjusted for age, gender and BMI‐Z‐score (20.8 vs. 30.6%; OR = 2.2, 95% CI = 1.05–4.77). The prevalence of metabolic syndrome increased with increasing severity of obesity and reached 50% in severely obese immigrants and 30% in severely obese Norwegians. Among the overweight subjects metabolic syndrome prevalence was 23.5% among immigrants and 19.4% among Norwegians. Conclusion: Metabolic syndrome was found more frequently among children and adolescents with Middle Eastern and South Asian origins than Norwegians. Differences were found even after adjustment for age, sex and degree of obesity. This suggests that ethnic minorities may have an increased sensitivity to adiposity and need more aggressive prevention and treatment than their Norwegian counterparts.     

肥胖儿童黑色棘皮病与脂肪因子和代谢综合征的关系

目的 了解肥胖伴黑色棘皮病(AN)患儿代谢特点及血清脂肪因子水平,探讨AN 对代谢综合征的预测价值。方法 将2012 年2 月至2013 年6 月收治的109 名肥胖儿童分为伴AN 组(n=44)和无AN 组(n=65),同期选取年龄、性别相匹配的健康儿童做为对照组(n=47)。采用ELISA 法检测血脂联素、瘦素、肿瘤坏死因子α 和视黄醇结合蛋白4 的水平,并对代谢综合征的危险因素进行多元logistic 回归分析。结果 肥胖伴AN 组腰臀比、收缩压、血甘油三酯、空腹胰岛素、胰岛素抵抗指数均较肥胖无AN 组和对照组升高(P<0.05)。肥胖伴AN 组和肥胖无AN 组脂联素水平均较对照组降低,肥胖伴AN 组瘦素水平较肥胖无AN 组和对照组明显升高(P<0.05)。Logistic 回归提示伴发AN(OR=3.469,95%CI:1.518~7.929)和高BMI(OR=7.108,95%CI:2.359~21.416)是代谢综合征的独立危险因素(P<0.05)。结论 AN 是胰岛素抵抗的皮肤标志,与脂肪因子分泌异常密切相关,降低AN 发生率和BMI 将减少代谢综合征的发生。     

血浆促酰化蛋白水平与儿童青少年肥胖和代谢综合征的关联性分析

目的探讨儿童青少年血浆促酰化蛋白（ASP）水平与肥胖及代谢综合征（MS）的关系。方法以2004年北京市儿童青少年代谢综合征（BCAMS）调查总样本中1 603名6~18岁儿童青少年为研究对象。采用中国肥胖问题工作组推荐的标准诊断超重和肥胖。符合下述5项指标中的3项及以上者诊断为MS：①腹型肥胖（腰围≥P90）;②高血压（≥P90）;③高密度脂蛋白胆固醇≤1.03 mmol·L-1;④三酰甘油≥1.24 mmol·L-1;⑤高空腹血糖（≥5.60 mmol·L-1)。采用ELISA法检测血浆ASP水平,免疫透射比浊法检测补体3（C3）水平。采用方差分析比较超重、肥胖及MS儿童青少年的血浆ASP水平,多因素Logistic回归分析血浆ASP水平与超重、肥胖及MS的关系。结果1 603名研究对象中男性873名（54.5%）、女性730名（45.5％）;超重和肥胖者分别为291名（18.2%）和709名（44.2%）;MS为376名（23.4%）。正常体重、超重和肥胖组MS检出率分别为2.2%(13/603名)、15.5%(45/291名)和44.9%(318/709名)。正常体重组血浆ASP水平男性低于女性,差异有统计学意义（t=2.527,P<0.05）。正常体重、超重和肥胖组血浆ASP的几何均值（P25~P75）,男性分别为37.52(22.36~64.58)、57.88(34.10~95.11)和60.63(35.30~109.72) nmol·L-1;女性分别为44.16(27.27~74.72)、60.25(35.68~113.15)和66.68(44.56~113.97) nmol·L-1,均呈逐渐升高趋势（男性：F=34.329,P<0.001;女性：F=22.246,P<0.001）。C3水平仅在肥胖女性中升高（P<0.01）。血浆ASP水平随MS组分聚集的数目增加而升高（男性：F=16.422,P<0.001;女性：F=9.661,P<0.001）,与高血压、腹型肥胖和高空腹血糖的关系尤为密切。血浆ASP水平升高与儿童青少年超重、肥胖和MS的患病风险密切相关,相对于最低5分位值,位于最高5分位值的ASP水平与超重、肥胖和MS关系的OR值(95%CI)分别为3.90(2.38~6.39)、6.05(4.06~9.01)和2.89(1.93~4.33)。结论超重、肥胖和MS儿童青少年血浆ASP水平明显升高,血浆ASP水平可能对儿童青少年超重、肥胖和MS的发生具有较好的预测价值。