A proposed simplified definition of metabolic syndrome in children and adolescents: a global perspective.

Metabolic syndrome (MetS) is becoming prevalent in the pediatric population. The existing pediatric MetS definitions (e.g., the International Diabetes Federation (IDF) definition and the modified National Cholesterol Education Program (NCEP) definition) involve complex cut-offs, precluding fast risk assessment in clinical practice.We proposed a simplified definition for assessing MetS risk in youths aged 6-17 years, and compared its performance with two existing widely used pediatric definitions (the IDF definition, and the NCEP definition) in 10 pediatric populations from 9 countries globally (n = 19,426) using the receiver operating characteristic (ROC) curve analyses. In general, the total MetS prevalence of 6.2% based on the simplified definition was roughly halfway between that of 4.2% and 7.7% estimated from the IDF and NCEP definitions, respectively. The ROC curve analyses showed a good agreement between the simplified definition and two existing definitions: the total area under the curve (95% confidence interval) of the proposed simplified definition for identifying MetS risk achieved 0.91 (0.89-0.92) and 0.79 (0.78-0.81) when using the IDF or NCEP definition as the gold standard, respectively.The proposed simplified definition may be useful for pediatricians to quickly identify MetS risk and cardiometabolic risk factors (CMRFs) clustering in clinical practice, and allow direct comparison of pediatric MetS prevalence across different populations, facilitating consistent pediatric MetS risk monitoring and the development of evidence-based pediatric MetS prevention strategies globally.

Establishing international optimal cut-offs of waist-to-height ratio for predicting cardiometabolic risk in children and adolescents aged 6-18 years.

BACKGROUND: Waist-to-height ratio (WHtR) has been proposed as a simple and effective screening tool for assessing central obesity and cardiometabolic risk in both adult and pediatric populations. However, evidence suggests that the use of a uniform WHtR cut-off of 0.50 may not be universally optimal for pediatric populations globally. We aimed to determine the optimal cut-offs of WHtR in children and adolescents with increased cardiometabolic risk across different countries worldwide. METHODS: We used ten population-based cross-sectional data on 24,605 children and adolescents aged 6-18 years from Brazil, China, Greece, Iran, Italy, Korea, South Africa, Spain, the UK, and the USA for establishing optimal WHtR cut-offs. We performed an external independent test (9,619 children and adolescents aged 6-18 years who came from other six countries) to validate the optimal WHtR cut-offs based on the predicting performance for at least two or three cardiometabolic risk factors. RESULTS: Based on receiver operator characteristic curve analyses of various WHtR cut-offs to discriminate those with ≥ 2 cardiometabolic risk factors, the relatively optimal percentile cut-offs of WHtR in the normal weight subsample population in each country did not always coincide with a single fixed percentile, but varied from the 75th to 95th percentiles across the ten countries. However, these relatively optimal percentile values tended to cluster irrespective of sex, metabolic syndrome (MetS) criteria used, and WC measurement position. In general, using ≥ 2 cardiometabolic risk factors as the predictive outcome, the relatively optimal WHtR cut-off was around 0.50 in European and the US youths but was lower, around 0.46, in Asian, African, and South American youths. Secondary analyses that directly tested WHtR values ranging from 0.42 to 0.56 at 0.01 increments largely confirmed the results of the main analyses. In addition, the proposed cut-offs of 0.50 and 0.46 for two specific pediatric populations, respectively, showed a good performance in predicting ≥ 2 or ≥ 3 cardiometabolic risk factors in external independent test populations from six countries (Brazil, China, Germany, Italy, Korea, and the USA). CONCLUSIONS: The proposed international WHtR cut-offs are easy and useful to identify central obesity and cardiometabolic risk in children and adolescents globally, thus allowing international comparison across populations.

Family Based Prevention of Cardiovascular Disease Risk Factors in Children by Lifestyle Change: The PEP Family Heart Study.

AIM: The 14 years' Prevention Education Program PEP was started 1994 among first graders, their siblings and parents living in the half million city Nuremberg (Germany). The aim of prospective family-based observational study was early detection and lifestyle intervention of traditional cardiovascular risk factors. SUBJECTS AND METHODS: Out of 3370 families 24,927 adults and 23,740 children participated in the PEP Family Heart study. Anthropometric parameters including blood pressure and fasting lipids were measured. Because these variables change specifically because of natural growth and development in 3-18 years old children we had to calculate age-and gender-specific growth curves using the LMS method. Non-overweight (normal weight) is defined as BMI < 85th percentile (pctl), overweight as BMI 85th to <95th percentile, obesity as BMI ≥ 95th percentile and severe obesity as ≥ 120% of the 95th pctl. Prehypertension is categorized as the ≥90th to <95th pctl or ≥120/80 mm Hg and hypertension as ≥95th pctl on ≥3 occasions. MAIN RESULTS: 1. Cardiovascular risk (CVD) factor screening in school children predicted CVD risk in parents. 2. The growths curves for auscultatory systolic (SBP) and diastolic (DBP) blood pressure of non-overweight 8713 boys and 8138 girls nearly identical with the percentile curves of all 11,328 boys and 10,723 girls. 3. The shapes of the 10 lipid percentile curves between the 3rd and 97th pctl differ considerably by age and gender. 4. The wais-to-height ratio (WHtR) percentiles as a measure for abdominal adiposity vary substantially by age and gender 5. Among overweight and obese ≥85th pctl the percentile curves of body fat increase steeply until age 10 years and then decrease slowly in boys whereas the BF% percentile curves in girls increase continuously until age 18 years 6. The prevalence of hypertension increased strongly in severe obesity at the 99th pctl, more steeply beyond 120% of the 95th pctl to 59.1% in boys and 56% in girls. 7. The association between hypertension and normal weight, overweight and obesity increased in boys from 0,5, via 2,7 to 4,3 and in girls from 0,4 via 2,1 to 5,9. 8. Between 2000 and 2007 mean blood pressure decreased from 138.3 ± 18.5 mm Hg to 124.0 ± 13.8 mm Hg in fathers and from 119.1 ± 2.8 mm Hg to 110.4 ± 11.2 mm Hg in mothers. 9. After 1 year weighed dietary protocols demonstrate in 166 fathers a decrease of all six nutrional components like daily energy consumption from 2423 to 2307 Kcal, from 98 g to 91 g fat, from 260 g to 252 g carbohydrates, from 88 g to 84 g protein, cholesterol from 362 mg to 339 mg and alcohol from 19 g to 17 g per day and in 237 mothers from 1915 Kcal to 1830 Kcal, from 79 g to 73 g total fat, from 216 g to 212 g carbohydrates, from 66 g to 64 g protein, from 299 g to 244 mg cholesterol. 10. Sustained intensive individual and family-based lifestyle counseling in daily life in terms of healthy diet, less sedentary behavior and more leisure time physical activity slightly improved the CVD risk factor profiles in parents and their children already after 1 year.

What do we Learn from the Prevention Education Program Family Heart Study about Lifestyle change, Blood Pressure, and Lipids in Children and Parents?

OBJECTIVES: The PEP Family Heart Study is a perspective community-based long-term project for the whole family to improve cardiovascular health aiming to assess and to amend risk factors in children and their parents by lifestyle change. METHODS: A total of 48,667 subjects (24,927 adults and 23,740 children) from 3,370 families living in 94% of the elementary school districts of Nuremberg (Germany) participated in this observational study from 1993/1994 -2007/2008. The yearly surveys consisting of personal and family histories, structured interviews on leisure time physical activity and tobacco smoke exposition, physical examinations and nutritional intake as documented by seven days weighed dietary protocols and sustained healthy lifestyle counselling were mainly performed at home. Fasting blood collections for biochemical analyses in the study laboratories, cooking courses and seminars on healthy lifestyle were performed on weekends in central school buildings. RESULTS: Here we report some of the main results demonstrating e.g., that at least one CVD risk factor in a child conferred a 2-4 fold higher risk among their parents, that obese children and adolescents had a nearly five times higher prevalence of hypertension than non-overweight youths. CONCLUSIONS: Sustained healthy lifestyle behavior can be implemented in daily life of family members which results in amended nutritional intake and improved cardiometabolic risk factors.

Establishing International Blood Pressure References Among Nonoverweight Children and Adolescents Aged 6 to 17 Years.

BACKGROUND: Several distributions of country-specific blood pressure (BP) percentiles by sex, age, and height for children and adolescents have been established worldwide. However, there are no globally unified BP references for defining elevated BP in children and adolescents, which limits international comparisons of the prevalence of pediatric elevated BP. We aimed to establish international BP references for children and adolescents by using 7 nationally representative data sets (China, India, Iran, Korea, Poland, Tunisia, and the United States). METHODS AND RESULTS: Data on BP for 52 636 nonoverweight children and adolescents aged 6 to 19 years were obtained from 7 large nationally representative cross-sectional surveys in China, India, Iran, Korea, Poland, Tunisia, and the United States. BP values were obtained with certified mercury sphygmomanometers in all 7 countries by using standard procedures for BP measurement. Smoothed BP percentiles (50th, 90th, 95th, and 99th) by age and height were estimated by using the Generalized Additive Model for Location Scale and Shape model. BP values were similar between males and females until the age of 13 years and were higher in males than females thereafter. In comparison with the BP levels of the 90th and 95th percentiles of the US Fourth Report at median height, systolic BP of the corresponding percentiles of these international references was lower, whereas diastolic BP was similar. CONCLUSIONS: These international BP references will be a useful tool for international comparison of the prevalence of elevated BP in children and adolescents and may help to identify hypertensive youths in diverse populations.

Blood pressure percentiles in 22,051 German children and adolescents: The PEP Family Heart Study.

BACKGROUND: Strong associations between blood pressure (BP) and overweight raise the question whether overweight children (body mass index (BMI) ≥85th percentile) should be included in the normative database. METHODS: Using the LMS (Lamda-Mu-Sigma) method, we developed age-, gender-, and height-adjusted percentile curves for systolic blood pressure (SBP) and diastolic blood pressure (DBP) at the 50th, 85th, 90th, 95th, and 97th percentiles in 22,051 German youths (18,917 normal-weight, 1,938 overweight, and 1,196 obese) aged 3-18 years from yearly cross-sectional surveys of the PEP Family Heart Study Nuremberg. RESULTS: Among children, we found no gender differences for BP and BMI. Male adolescents are taller and heavier. The mean prevalence of hypertension and obesity is 7.3% and 5.2% among children and 7.2% and 5.8% among adolescents, respectively. The prevalence of elevated BP increased substantially by weight groups achieving 24.4% in obese females and 21.9% in obese males with odds ratios of 5.9 (95% confidence interval (CI): 5.1-7.5) and 4.3 (95% CI: 3.5-5.2), respectively. The shapes of the 10 LMS-smoothed SBP and DBP percentile curves differ substantially between gender and weight group. The normal-weight percentiles are nearly identical with the overall growth charts, but separate percentiles for overweight and obese youths provide considerably higher values, such as 148/91 vs. 136/86 mm Hg for a 17-year-old male and 136/91 vs. 123/81 mm Hg for female, respectively, at the 90th percentile. CONCLUSIONS: Because of substantially higher BP percentiles, separate databases for overweight and obese children and adolescents are strongly recommended.

Low Birth Weight as a Predictor of Cardiovascular Risk Factors in Childhood and Adolescence? The PEP Family Heart Study.

BACKGROUND: Low birth weight is considered a risk factor for cardiovascular disease (CVD) in later life. Because data in children and adolescents are sparse and controversial, we assessed the association of birth weight with CVD risk factors in German youths. METHODS: We categorized 843 urban children and adolescents aged 3-18 years by quintiles of birth weight and measured nine traditional risk factors in terms of body mass index (BMI), waist circumference (WC), systolic (SBP) and diastolic (DBP) blood pressure, total cholesterol (TC), LDL-C, HDL-C, Non HDL-C and triglycerides (TG). SPSS 21 was used for statistical analysis. RESULTS: Mean values and prevalence of nine anthropometric and lipid risk variables were equally distributed over the five birth weight groups. Though risk factors clustered between 3.0 kg and 4.0 kg of birth weight in both genders we found only one significant correlation of birth weight with TG for males and females and another one for HDL-C in males. The strongest clustering of significant regression coefficients occurred in the 2(nd) birth weight quintile for SBP (ß 0.018), TC (ß -0.050), LDL-C (ß -0.039), non LDL-C (ß -0.049) and log TG (ß -0.001) in males and females. CONCLUSIONS: Overall we did not find significant associations between birth weight and nine traditional cardiovascular risk factors in children and adolescents. However, the 2(nd) quintile of birth weight might suggest clustering of risk factors.

Prehypertension and cardiovascular risk factors in children and adolescents participating in the community-based prevention education program family heart study.

BACKGROUND: Because prehypertension identifies children most at risk for the development of future hypertensive disease, the purpose of this study was, to examine the association of prehypertension with risk factors for cardiovascular disease (CVD) in a large sample of youths participating in the community-based prevention education program family heart study. METHODS: We estimated blood pressure and body mass index (BMI) for age and the lipid profile in terms of total cholesterol (TC), low-density-lipoprotein-cholesterol (LDL-C), high-density-lipoprotein-cholesterol (HDL-C), non-HDL-C, triglycerides (TG) and the LDL-C to HDL-C ratio. RESULTS: Among 10,841 (5,628 males) children and adolescents 1,587 (14.6%) had prehypertension (85(th) to <95(th) percentile). This was strongly affected by weight, resulting in 19.7% in overweight (BMI ≥85(th) percentile) and 23.7% in obese (>95(th) percentile) youth. The prevalence of dyslipidemia was similar in prehypertensive boys and girls in terms of LDL-C 11.2% versus 11.8%, non HDL-C 11.9% versus 14.3%, TG 2.4% versus 2.7% and for low HDL-C 2.1% versus 2.3%. The prevalence of low HDL-C increased from 2.1% in non-overweight, through 3.9% in overweight to 5.2% in obese youth and of elevated TG from 1.2% via 4.5% to 6.5% respectively. The number of risk factors is affected by BMI. Significant associations between prehypertension and CVD risk factors were observed in boys and girls for overweight/obesity odds ratios (OR 2.0/2.4), for hypertriglyceridemia (OR 1.9/2.0), for high non HDL-C (OR 1.4/1.4) and for elevated LDL-C (OR 1.3/1.1). CONCLUSIONS: Prehypertension was significantly associated with overweight, obesity and dyslipidemia in 10,841 children and adolescents.

Age- and Gender-Specific Components of the Metabolic Syndrome in 2228 First Graders: The PEP Family Heart Study.

Because first graders are critical for excess weight gain, we assessed components of the metabolic syndrome (MetS) using the pediatric definition of the International Diabetes Federation (IDF). We compared four MetS components as defined by the IDF with age- and gender-specific components in 2228 first graders at the age of 6. The growth curves were derived from 22113 children and adolescents who participated in the PEP Family Heart Study. The aim was to determine in first graders precise values of waist circumference (WC), blood pressure (BP), triglycerides (TG), and HDL-Cholesterol (HDL-C) based on growth curves that were developed for a large German population of youths and to assess the prevalence in terms of both definitions at this critical age. The prevalence of high blood pressure for age was 13% compared with only 2% according to IDF. Because of this considerable divergence, we propose to define MetS components based on national growth curves.

Waist Circumference and Waist-to-Height Ratio Distributions in Polish and German Schoolchildren: Comparative Analysis.

BACKGROUND: To analyze differences in the distributions of waist circumference (WC) and waist-to-height ratio (WHtR) between Polish (PL) and German (GE) children and adolescents. METHODS: Two samples of children and adolescents aged 7-18 y: From PL (n = 11,326) GE (n = 8,218) participated. The two WC cut-off points (WC1 as central fat distribution and WC2 as central obesity) corresponding at age 18 to the adult criteria were determined. Furthermore, the mean WC cut-off points (WC1m, WC2m) for boys and girls aged 14-18 from both countries were evaluated. For the WHtR, values over 0.5 were used as a definition of central fat distribution. The effect of different WC and WHtR criteria on the prevalence of abdominal obesity in both study groups was evaluated. RESULTS: The mean and percentile values of WC and WHtR were generally higher in all German children as compared to their peers from Poland. When WC1m is used, the mean (95% CI) prevalence of central fat distribution in the 14-18 y Polish groups was lower (P < 0.05) than those from Germany (boys: 4.4% (3.6-5.2) vs. 8.9% (7.3-10.5); girls: 10.7% (9.0-12.3) vs. 26.4% (23.2-29.6)), whereas, using the WHtR > 0.5, the results were similar for boys - 6.7% (5.9-7.5) vs. 8.5% (8.1-8.9); they were significantly (P < 0.05) lower for Polish and German girls: 5.3% (5.0-5.6) vs. 12.7% (9.7-16.4). The prevalence of central obesity using WC2m as a criterion in the Polish vs. German groups was as follows: (boys - 1.1% (0.8-1.4) vs. 3.1% (2.2-4.0), P < 0.05; girls - 3.1% (2.5-3.7) vs. 10.2% (8.4-12.0), P < 0.05). CONCLUSIONS: The results highlight the greater central obesity associated with the German children, both in terms of WC and WHtR, in comparison to their peers from Poland. The prevalence of AO is significantly associated with the criteria used. The results demonstrate the need for the development of international WC references for pediatric subjects.

Percentiles of percentage body fat in german children and adolescents: an international comparison.

BACKGROUND: Age- and gender-specific percentiles of body mass index in children and adolescents are a cornerstone categorizing overweight and obesity in youths worldwide. Since corresponding worldwide growth curves of percent body fat (% BF) are missing, the purpose was to contribute smoothed percentiles of percentage body fat from a large urban sample of German youths and to include them in actual national and international percentile curves. METHODS: We estimated % BF in 22 113 German youths aged 3 to 18 years participating in yearly cross-sectional surveys of the PEP Family Heart Study Nuremberg between 1993 and 2007. Percentage body fat was calculated from skinfold thickness using Slaughter equations. Ten smoothed percentile curves were constructed for % BF using the LMS method significant. RESULTS: The age- and gender-specific reference curves demonstrate a continuous age-dependent increase of percentage body fat from age 3 to 18 years in girls; whereas in boys, the percentile curves steeply increase from 5 to 11 years and thereafter slightly decrease. The shape of the percentile curves, the maxima among boys at puberty and the median % BF at age 18 years are consistent with most of the current growth curves. % BF in urban studies seems to be lower than in national surveys . CONCLUSIONS: More than these nine studies should contribute to worldwide-standardized growth charts for % BF to better define overweight and obesity in youth.

Metabolic risk factors, leisure time physical activity, and nutrition in german children and adolescents.

Purpose. We assessed the five components of the metabolic syndrome (MetS) as defined by the International Diabetes Federation (IDF) in 6040 (3158 males) youths aged 6-16 years who participated in the Präventions-Erziehungs-Programm (PEP Family Heart Study) in Nuernberg between 2000 and 2007. The purpose of this cross-sectional study was to examine associations with lifestyle habits. Results and Discussion. The prevalence of MetS was low in children (1.6%) and adolescents (2.3%). High waist circumference (WC) and low HDL-C were slightly higher in females (9.5% and 7.5%, resp.) than in males (8.8% and 5.7%, resp.). Low leisure time physical activity (LTPA) was significantly associated with low HDL-C (odds ratio [OR] 2.4; 95% CI 1.2-5.0) and inversely associated with hypertension (r = -0.146), hypertriglyceridemia (r = -0.141), and central adiposity (r = -0.258). The risk for low HDL-C (≤1.3 mmol/L) was 1.7-fold (CI 1.0-2.6) higher in youth with high (≥33%) saturated fat consumption. A low polyunsaturated/saturated fat ratio (P/S ratio) was significantly associated with fasting hyperglycemia (OR 1.4; 95% CI 1.0-1.2).

Trends of Components of the Metabolic Syndrome in German First Graders Throughout 10 Years: The PEP Family Heart Study.

Although childhood overweight and obesity are increasing worldwide, some countries report trends for stabilization. However, the trend for the potentially atherogenic components of the metabolic syndrome (MetS) in children and adolescents is not well understood. Therefore, the purpose of this study was to analyze the trend of the five components of over 10 years in 2228 first graders aged 6 years. Waist circumference (WC) remained mainly unchanged between 1994 and 2003 whereas the other four components continuously decreased. In boys and girls mean values of triglycerides (-25.9% and -28.6%, resp.), HDL cholesterol (-19.8% and -23.4%, resp.), fasting glucose (-7.3% and -9%, resp.), systolic (-3.8% and -4.1%, resp.), and diastolic (-10.2% and -9.7%, resp.) blood pressure significantly decreased. Whereas the prevalence of abdominal adiposity was stable at baseline and after 10 years (-1% in boys and +2% in girls), the prevalence of hypertension, hypertriglyceridemia, low HDL-C, and glucose was very low without any trend.

Sustained lifestyle advice and cardiovascular risk factors in 687 biological child-parent pairs: the PEP Family Heart Study.

OBJECTIVE: We examined whether associations between improved cardiovascular risk factors and lifestyle changes persist over 1 year in a real life setting. METHODS: Out of 2690 invited healthy parents and their children, 986 accepted the invitation to participate and completed the 1-year rigorous observational study with general lifestyle advice. Body mass index, waist circumference, waist-to-height ratio, waist-to-hip circumference, skin fold thickness, blood pressure; fasting lipids and glucose, nutrition, physical activity, and tobacco smoke exposition within biological families were assessed. SPSS was used to perform statistical analyses. RESULTS: After 1 year of sustained advice of healthy lifestyle, the majority of CVD risk factors had improved in parents and their children most beneficially in daughters. In sons and fathers, the prevalence of fasting hyperglycemia decreased from 22.6% to 6.7% respectively from 27.5% to 10.6%. In daughters, the prevalence of hypertension decreased from 21.8% to 10.6% and the lipid profile improved considerably. Daily fat consumption as percentage of kcal as percentage fat significantly (p < 0.05) decreased by 6% and the ratio polyunsaturated to saturated fat and consequently the P/S ratio increased by 11.7% in all participants. The age and gender adjusted changes in parents (using GEE) after 1 year were predictive in children for reduced energy intake (OR 2.3; 95% CI 1.6-3.1), reduced fat consumption (OR 1.9; 95% CI 1.4-2.6) and a higher P/S ratio (OR 2.6; 95% CI 1.9-3.6). Daily leisure time physical inactivity of parents was associated with low HDL-C (OR 2.0; 95% CI 1.0-4.0) in daughters. Tobacco smoke exposition decreased by 19.3% in all participants whereas alcohol intake in parents decreased by 15% after 1 year. CONCLUSION: Intra-familial lifestyle behavior and cardiovascular risk factors improve after 1 year of sustained advice in schoolchildren and their parents.