Syndrome X in 8-y-old Australian children: stronger associations with current body fatness than with infant size or growth

Obesogenic environment around schools is associated with atherogenic risk in Brazilian children

INTRODUCTION

Cardiometabolic risk factors often emerge in childhood, increasing the risk of cardiovascular diseases in adulthood. The school environments represent an important active space in a child's routine and may influence their health status.

METHODS

In this cross-sectional study, we aimed to evaluate the clustering of cardiometabolic risk factors and its association with the obesogenic and leptogenic environment around schools. A total of 378 children (181 boys; 197 girls) aged 8 and 9 years, enrolled in all urban schools of Viçosa, Minas Gerais, Brazil, were evaluated. Concentrations of high-density lipoprotein-cholesterol (HDL-c) and triglycerides (TG), and the insulin resistance (HOMA-IR), waist circumference (WC), and mean arterial pressure (MAP) were measured. The neighborhood income, walkability index, predominantly ultra-processed food stores, public spaces for leisure and/or physical activities, traffic accidents, crime and green spaces densities were assessed in 400 road network buffers around schools. To test association of the obesogenic and leptogenic environment around schools with cardiometabolic risk clustering, binary logistic regression models were performed with generalized estimating equations.

RESULTS

"Obesogenic school environments" had greater densities of ultra-processed food stores, crime and traffic accidents, and higher walkability. The "↓ Atherogenic risk" cluster consisted of higher HDL-c values. There was an inverse association between the obesogenic environment around schools and a child's "↓ atherogenic risk" clustering (OR = 0.63; p < 0.001).

CONCLUSION

We concluded that public policies aimed at modifying the environment around schools, by providing healthier food options and safe conditions for active mobility, are essential to prevent child's atherogenic risk.

Relationship between elevated triglyceride levels with the increase of HOMA-IR and HOMA-β in healthy children and adolescents with normal weight

To test the hypothesis that mildly elevated triglyceride levels are associated with the increase of homeostasis model assessment of insulin resistance (HOMA-IR) and β-cell function (HOMA-β) indices in healthy children and adolescents with normal weight, we conducted a cross-sectional population study. Based on fasting triglyceride levels, participants were allocated into groups with and without triglyceride levels ≥1.2 mmol/L. Normal weight was defined by body mass index between the 15th and 85th percentiles, for age and gender. Insulin resistance and insulin secretion were estimated using HOMA-IR and HOMA-β indices. A total of 1660 children and adolescents were enrolled, of them 327 (19.7%) with mildly elevated triglycerides. The multivariate linear regression analysis showed that mildly elevated triglyceride levels in children were associated with HOMA-IR (β = 0.214, p < 0.001), HOMA-β (β = 0.139, p = 0.001), systolic (β = 0.094, p = 0.01), and diastolic blood pressure (β = 0.102, p = 0.007), whereas in adolescents, HOMA-IR (β = 0.267, p < 0.001) and HOMA-β (β = 0.154, p < 0.001), but not systolic (β = 0.029, p = 0.38) and diastolic blood pressure (β = 0.015, p = 0.642), showed association with mildly elevated triglycerides.

CONCLUSION

Mildly elevated triglyceride levels are associated with increased HOMA-IR and HOMA-β indices in healthy children and adolescents with normal weight.

Low birthweight or rapid catch-up growth: which is more associated with cardiovascular disease and its risk factors in later life? A systematic review and cryptanalysis

BACKGROUND

The effects of birthweight (the Barker hypothesis) and growth trajectory in early life on the incidence of cardiovascular disease (CVD) and its risk factors in later life have been investigated in a number of studies.

OBJECTIVE

To undertake a systematic review and cryptanalysis of the association of low birthweight (LBW) and the postnatal growth trajectory with CVD and its risk factors.

METHODS

English-language publications in PubMed, ISI Web of Science and Scopus were searched. Initially, two independent reviewers identified relevant papers in several steps and the quality of papers was then determined by a validated quality-appraisal checklist.

RESULTS

By applying maximum sensitivity, 7259 paper were identified, 382 of which were duplicates and 1273 were considered to be relevant to the topic. Then, after title and abstract review, 628 irrelevant papers were excluded; 26 papers were added after reference-checking. Then, 250 other papers were deleted after full text review. Finally, 39 relevant papers remained and were entered into the systematic review. Overall, 79·6% of all CVD risk factors reported in primary studies of the rapid catch-up growth hypothesis were statistically significant, whereas the corresponding figure was 58·5% for the effects of LBW (Barker hypothesis).

CONCLUSIONS

This systematic review highlights the importance of low birthweight in increasing the risk of CVD and its risk factors in later life. The results support rapid postnatal catch-up growth of LBW neonates as a more important factor than LBW alone in CVD and its risk factors.

Adult lipids associated with early life growth in traditional Melanesian societies undergoing rapid modernization: a longitudinal study of the mid-20th century

Both poor fetal development and accelerated post-natal growth have been linked to adult dyslipidemias in many studies conducted in developed societies. It is not known, however, whether these relationships only characterize populations with typical Western diets or if they also may develop in groups at the early stages of a dietary transition. Our longitudinal study of traditional rural populations in the Southwest Pacific during a period of extremely rapid modernization in diet and life-styles shows a nascent association between child growth retardation, subsequent growth acceleration, and adult lipid values in spite of a continuing prevalence of very low lipid levels. However, our results do not entirely conform to results from populations with "modern" diets. Outcome (i.e., young adult) cholesterol and triglyceride levels are more consistently related to initial measures of body fat and growth in body fat measures than with stature, while outcome apo A-1 is more consistently related to initial stature or stature growth than to measures of body fat. We suggest this may reflect a pattern characteristic of the initial stages of "modernization" associated with dietary change, with stronger and more pervasive relationships emerging only later as populations complete the dietary transition.

Clustering of cardiac risk factors associated with the metabolic syndrome and associations with psychosocial distress in a young Asian Indian population

The metabolic syndrome is a precursor for coronary heart disease. However, its pathophysiology is not clear, its phenotypic expression may vary by region; also, the phenotypic manifestation may be exacerbated by psychosocial distress and family history. The purpose of the current study was to assess the factor structure of the metabolic syndrome in young urban Asian Indians. Asian Indian youth (N = 112) were evaluated for body mass index (BMI), waist-hip ratio, blood pressure (systolic: SBP; diastolic: DBP), blood sugar, triglycerides, cholesterol, insulin, psychosocial distress and family health history. Factor analyses were computed on components of the metabolic syndrome. Three factors were identified for the entire sample: hemodynamic-obesity (SBP, DBP, waist-hip ratio), Lipid (cholesterol, triglyceride), and insulin-obesity (blood sugar, BMI, insulin). Similar to previous research with this population, three distinct factors with no overlap were identified. Factors did not correlate with psychosocial distress or family history. Lack of correlation with family history and psychosocial distress may be a function of the young age and demographics of the sample.

Ethnic variability in adiposity, thrifty phenotypes and cardiometabolic risk: addressing the full range of ethnicity, including those of mixed ethnicity

Ethnic groups vary in cardiometabolic risk, but the underlying mechanisms remain unclear. Several components of body composition variability (fat/lean ratio, fat distribution, lean mass composition and metabolism, and adipose tissue biology) are increasingly linked with cardiometabolic risk and vary substantially across ethnic groups. Constituents of lean mass are proposed to contribute to 'metabolic capacity', a generic trait favouring the maintenance of homeostasis. Adiposity is proposed to contribute to 'metabolic load', which at higher levels challenges metabolic homeostasis, elevating cardiometabolic risk. Ethnic differences in body composition, representing different load-capacity ratios, may therefore contribute to ethnic variability in cardiometabolic risk. Ecological and evolutionary factors potentially contributing to ethnic variability in body composition are explored. In contemporary populations, clinicians encounter an increasing range of ethnicity, along with many individuals of mixed-ethnic ancestry. Increasing understanding of the contribution of body composition to cardiometabolic risk may reduce the need to treat ethnic groups as qualitatively different. A conceptual model is proposed, treating insulin sensitivity and stroke risk as composite functions of body composition variables. Operationalizing this model may potentially improve the ability to assess cardiovascular risk across the full ethnicity spectrum, and to predict cardiometabolic consequences of excess weight gain.

Filter paper blood spot enzyme linked immunoassay for insulin and application in the evaluation of determinants of child insulin resistance

Background

In large-scale epidemiology, bloodspot sampling by fingerstick onto filter paper has many advantages, including ease and low costs of collection, processing and transport. We describe the development of an enzyme-linked immunoassay (ELISA) for quantifying insulin from dried blood spots and demonstrate its application in a large trial.

Methods

We adapted an existing commercial kit (Mercodia Human Insulin ELISA, 10-1113-01) to quantify insulin from two 3-mm diameter discs (≈6 µL of blood) punched from whole blood standards and from trial samples. Paediatricians collected dried blood spots in a follow-up of 13,879 fasted children aged 11.5 years (interquartile range 11.3–11.8 years) from 31 trial sites across Belarus. We quantified bloodspot insulin levels and examined their distribution by demography and anthropometry.

Results

Mean intra-assay (n = 157) coefficients of variation were 15% and 6% for ‘low’ (6.7 mU/L) and ‘high’ (23.1 mU/L) values, respectively; the respective inter-assay values (n = 33) were 23% and 11%. The intraclass correlation coefficient between 50 paired whole bloodspot versus serum samples, collected simultaneously, was 0.90 (95% confidence interval 0.85 to 0.95). Bloodspot insulin was stable for at least 31 months at −80°C, for one week at +30°C and following four freeze-thaw cycles. Paediatricians collected a median of 8 blood spots from 13,487 (97%) children. The geometric mean insulin (log standard deviation) concentrations amongst 12,812 children were 3.0 mU/L (1.1) in boys and 4.0 mU/L (1.0) in girls and were positively associated with pubertal stage, measures of central and peripheral adiposity, height and fasting glucose.

Conclusions

Our simple and convenient bloodspot assay is suitable for the measurement of insulin in very small volumes of blood collected on filter paper cards and can be applied to large-scale epidemiology studies of the early-life determinants of circulating insulin.

Swedish Child Health Care nurses conceptions of overweight in children: a qualitative study

BACKGROUND

Registered Sick Children's Nurses and District Nurses employed at Child Health Care centres are in a position to help prevent childhood overweight and obesity. Prevention of this challenging public health threat could be improved through having a better understanding of how this group of nurses perceives childhood obesity. The aim of this study was to elucidate the conceptions of childhood overweight, including obesity, among nurses working in Child Health Care.

METHOD

A qualitative study using a phenomenographic approach, based on open-ended interviews with 18 Child Health Care nurses (CHC-nurses) strategically selected from 17 Child Health Care Centres in the southern part of Sweden.

RESULTS

Four categories of description emerged from the data: Perception of childhood overweight changes, Overweight in younger children a neglected concern, Overweight a delicate issue and Importance of family lifestyle. The participating CHC-nurses conceived overweight in children, primarily obesity in children to be an extensive and serious problem which affects children, families and the surrounding society. Overweight in children was further perceived as a consequence of their parent's lifestyle and their awareness of the problem, which was considered by the CHC-nurses as a sensitive and a provoking issue. It was also perceived that overweight in children is not taken seriously during the pre-school period and that concerns regarding overweight in younger children were mainly about the appearance and not the health of the child. The CHC-nurses perceived that the proportion of overweight children has increased, which Swedish society and the CHC-nurses have adapted to. This adaptation makes it difficult for CHC-nurses to define those children who are overweight.

CONCLUSION

CHC-nurses provide a comprehensive and complex picture of childhood overweight, which includes several difficulties dealing with this issue. Attention to CHC-nurse's conceptions of overweight in children is important since it can affect the parent-nurse relationship and thereby the nurse's, as well as the parent's efforts to influence the children's weight. It is suggested that CHC- nurses should work with person centered counseling and empowerment concerning parent to child relations in cases involving overweight.

APOE genotype and cardio-respiratory fitness interact to determine adiposity in 8-year-old children from the Tasmanian Infant Health Survey

APOE plays a well established role in lipid metabolism. Animal model evidence suggests APOE may also be associated with adiposity, but this has not been thoroughly investigated in humans. We measured adiposity (BMI, truncal fat mass, waist circumference), physical activity (PA), cardiorespiratory fitness and APOE genotype (E2, E3, E4) in 292 8-year-old children from the Tasmanian Infant Health Survey (TIHS), an Australian population-based prospective birth cohort. Our aims were to examine the association of APOE with child adiposity, and to examine the interplay between this association and other measured factors. We found that APOE was associated with child lipid profiles. APOE was also associated with child adiposity measures. The association was E4 allele-specific, with adiposity lower in the E4-containing group (BMI: Mean difference -0.90 kg/m²; 95% confidence intervals (CI) -1.51, -0.28; p = 0.004). The association of APOE4 with lower BMI differed by fitness status (difference in effect p = 0.002), and was more evident among the less fit (mean difference -1.78 kg/m²; 95% CI -2.74, -0.83; p<0.001). Additionally, associations between BMI and lipids were only apparent in those of lower fitness who did not carry APOE4. Similar overall findings were observed when truncal fat mass and waist circumference were used as alternative adiposity measures. APOE4 and cardiorespitatory fitness could interact to influence child adiposity. In studies addressing the genetic determinants of childhood obesity, the context of child fitness should also be taken into account.

Metabolic syndrome in italian obese children and adolescents: stronger association with central fat depot than with insulin sensitivity and birth weight

Aim. To evaluate whether body fat distribution, birth weight, and family history for diabetes (FHD) were associated with metabolic syndrome (MetS) in children and adolescents. Methods. A total of 439 Italian obese children and adolescents (5–18 years) were enrolled. Subjects were divided into 2 groups: prepubertal and pubertal. MetS was diagnosed according to the adapted National Cholesterol Education Program criteria. Birth weight percentile, central obesity index (measured by dual-energy X-ray absorptiometry), insulin sensitivity (ISI), and disposition index were evaluated. Multivariate logistic regression models were used to determine variables associated with MetS. Results. The prevalence of MetS was 17%, with higher percentage in adolescents than in children (21 versus 12%). In the overall population, central obesity index was a stronger predictor of MetS than insulin sensitivity and low birth weight. When the two groups were considered, central fat depot remained the strongest predictor of MetS, with ISI similarly influencing the probability of MetS in the two groups and birth weight being negatively associated to MetS only in pubertal individuals. Neither FHD nor degree of fatness was a significant predictor of MetS. Conclusion. Simple clinical parameters like increased abdominal adiposity and low birth weight could be useful tools to identify European obese adolescents at risk for metabolic complications.

Construct validity of a continuous metabolic syndrome score in children

OBJECTIVE

The primary purpose of this study was to examine the construct validity of a continuous metabolic syndrome score (cMetS) in children. The secondary purpose was to identify a cutpoint value(s) for an adverse cMetS based on receiver operating characteristic (ROC) curve analysis.

METHODS

378 children aged 7 to 9 years were assessed for the metabolic syndrome which was determined by age-modified cutpoints. High-density-lipoprotein cholesterol, triglycerides, the homeostasis assessment model of insulin resistance, mean arterial pressure, and waist circumference were used to create a cMetS for each subject.

RESULTS

About half of the subjects did not possess any risk factors while about 5% possessed the metabolic syndrome. There was a graded relationship between the cMetS and the number of adverse risk factors. The cMetS was lowest in the group with no adverse risk factors (-1.59 +/- 1.76) and highest in those possessing the metabolic syndrome (> or =3 risk factors) (7.05 +/- 2.73). The cutoff level yielding the maximal sensitivity and specificity for predicting the presence of the metabolic syndrome was a cMetS of 3.72 (sensitivity = 100%, specificity = 93.9%, and the area of the curve = 0.978 (0.957-0.990, 95% confidence intervals).

CONCLUSION

The results demonstrate the construct validity for the cMetS in children. Since there are several drawbacks to identifying a single cut-point value for the cMetS based on this sample, we urge researchers to use the approach herein to validate and create a cMetS that is specific to their study population.

Effect of growth on cardiometabolic status at 4 y of age

BACKGROUND

Cardiovascular disease (CVD) risks are increasingly being diagnosed in children and track into adulthood. Growth is associated with CVD risk in adulthood; however, its contribution to CVD risks in children facing the obesity epidemic is unclear.

OBJECTIVE

The objective was to assess relations between growth from age 0 to 4 y and CVD status at 4 y in 323 Chilean children with normal birth weight.

DESIGN

From health records we obtained weight and height every 6 mo from age 0 to 3 y and calculated body mass index (BMI; weight/height(2)). At age 4 y, we measured height, waist circumference, insulin, glucose, and plasma lipids; infant feeding information was provided by the mothers. Outcomes were metabolic score (waist-to-height ratio + glucose + insulin + triglycerides - HDL-cholesterol z scores/5), total cholesterol (TC):HDL cholesterol, and homeostasis model of assessment of insulin resistance.

RESULTS

At 4 y, the prevalence of obesity was 13%. Changes in BMI, particularly from 6 to 24 mo, predicted a higher metabolic score (standardized regression coefficient = 0.29; 95% CI: 0.16, 0.42) but were unrelated to homeostasis model of assessment of insulin resistance and TC:HDL cholesterol. Height changes were not associated with CVD risks at the age of 4 y. Mode of infant feeding was unrelated to CVD status at 4 y; however, in children who were exclusively breastfed at 4 mo, an increase in BMI from 0 to 6 mo was positively associated with TC:HDL cholesterol at 4 y (standardized regression coefficient = 0.24; 95% CI: -0.02, 0.50), whereas in children who were partially or nonbreastfed at 4 mo, it was negatively associated with TC:HDL cholesterol at 4 y (standardized regression coefficient = -0.30; 95% CI: -0.52, -0.08).

CONCLUSION

In children with normal birth weight and a high prevalence of obesity at 4 y, changes in BMI after 6 mo predicted a higher overall CVD risk at 4 y.

[Birth weight and metabolic syndrome in adults: meta-analysis]

OBJECTIVES

To assess published evidences of the effect of birth weight on metabolic syndrome in adults.

METHODS

PubMed and LILACS databases were searched for articles published from 1966 through May 2006. The terms used were: "birth weight", "birthweight", "intra-uterine growth restriction (IUGR)", "fetal growth retardation", "metabolic syndrome", "syndrome X", "Reaven's X syndrome". Two hundred and twenty-four studies reporting estimates of the association between birth weight and metabolic syndrome or its components were considered eligible. Eleven studies provided odds ratios and were included in the meta-analysis.

RESULTS

All but two studies reported an inverse relationship between birth weight and metabolic syndrome. A comparison between low birth weight vs. normal birth weight subjects showed the random effects odds ratio for metabolic syndrome was 2.53 (95% CI: 1.57;4.08). The funnel plot graphic suggests a publication bias but, even in the studies with more than 400 subjects, the results remained significant (pooled odds ratio: 2.37 (95% CI: 1.15;4.90).

CONCLUSIONS

Low birth weight increases the risk of metabolic syndrome in adults.

Adiposity gain during childhood, ACE I/D polymorphisms and metabolic outcomes

We aimed to (i) determine the relative importance of childhood gain in upper body adiposity for insulin resistance (IR) and triglyceridemia (TG); (ii) examine whether the associations between adiposity and metabolic indices were more evident in those with the ACE DD genotype. We examined a birth cohort study of 292 children with measures in the neonatal period (day 4) including subscapular and triceps skinfolds; repeat skinfold measures at age 8, cardiorespiratory (CR) fitness, IR by the homeostasis model assessment (HOMA) equation (HOMA-IR) and serum triglyceride (TG) concentrations and measures of ACE I/D gene variants. A multiple linear regression analysis incorporating a life course approach was undertaken. Childhood gain in upper body adiposity was positively associated with HOMA-IR and TG independently of neonatal skinfolds (P < or = 0.02). The magnitude of these associations was higher among those of the ACE DD genotype. For example, subscapular skinfold gain was not strongly associated with HOMA-IR or TG among those with II or ID genotype (b = 0.03, P = 0.05; b = 0.02, P = 0.18 respectively) but was positively associated among those with the DD genotype (b = 0.11, P = 0.001; b = 0.08, P = 0.003); difference in effect P = 0.05; P = 0.01 respectively. Upper body fat accumulation during childhood was positively associated with HOMA-IR and TG independently of neonatal skinfolds. Further, the stronger associations for those with the ACE DD genotype is consistent with randomised controlled trial findings that ACE inhibition is associated with a reduced risk of developing type 2 diabetes. Further work is required to confirm and extend these findings.

On the use of a continuous metabolic syndrome score in pediatric research

Background

The constellation of elevated levels of abdominal adiposity, blood pressure, glucose, and triglycerides and lowered high-density lipoprotein-cholesterol has been termed the metabolic syndrome. Given the current pediatric obesity epidemic, it is perhaps not surprising that recent reports suggest the emergence of the metabolic syndrome during childhood and adolescence. The aim of this paper is to provide an overview of the derivation and utility of the continuous metabolic syndrome score in pediatric epidemiologic research.

Methods/Design

Data were generated from published papers related to the topic.

Conclusion

Although there is no universal definition in children or adolescence, recent estimates indicate that approximately 2–10% of youth possess the metabolic syndrome phenotype. Since there is no clear definition and the prevalence rate is relatively low, several authors have derived a continuous score representing a composite risk factor index (i.e., the metabolic syndrome score). This paper provides an overview of the derivation and utility of the continuous metabolic syndrome score in pediatric epidemiological research.

On the use of a continuous metabolic syndrome score in pediatric research

BACKGROUND

The constellation of elevated levels of abdominal adiposity, blood pressure, glucose, and triglycerides and lowered high-density lipoprotein-cholesterol has been termed the metabolic syndrome. Given the current pediatric obesity epidemic, it is perhaps not surprising that recent reports suggest the emergence of the metabolic syndrome during childhood and adolescence. The aim of this paper is to provide an overview of the derivation and utility of the continuous metabolic syndrome score in pediatric epidemiologic research.

METHODS/DESIGN

Data were generated from published papers related to the topic.

CONCLUSION

Although there is no universal definition in children or adolescence, recent estimates indicate that approximately 2-10% of youth possess the metabolic syndrome phenotype. Since there is no clear definition and the prevalence rate is relatively low, several authors have derived a continuous score representing a composite risk factor index (i.e., the metabolic syndrome score). This paper provides an overview of the derivation and utility of the continuous metabolic syndrome score in pediatric epidemiological research.

Defining the metabolic syndrome in children and adolescents: will the real definition please stand up?

OBJECTIVES

To review the use of definitions of the metabolic syndrome in studies of children and adolescents and to review results from studies that used factor analysis to examine structure among cardiometabolic variables.

STUDY DESIGN

Literature review.

RESULTS

In 27 publications, authors used 40 unique definitions of the metabolic syndrome. Most of these definitions were adaptations of the adult definition developed by the National Cholesterol Education Program. In 11 studies that used exploratory factor analysis, the number of components ranged from 5 to 19, and the number of factors identified ranged from 1 to 5.

CONCLUSIONS

The use of multiple definitions of the metabolic syndrome argues strongly for the development of a standard pediatric definition.

Discussing childhood overweight and obesity with parents: a health communication dilemma

Childhood obesity has reached alarming levels and the problem has assumed great significance for health care staff who work with overweight children and their families. Anecdotal accounts of the difficulties that may emerge when health care providers communicate that a child's weight is outside of the normal range, were a key stimulus for this review. A local government health department commissioned a review of literature on communicating with parents about childhood overweight and obesity. Literature concerned with communicating a child's overweight to parents was limited and, as a result, this review draws upon a disparate body of literature to examine what is known and what might be helpful for health care providers when discussing a child's weight with the child and parents. This paper identifies a range of factors influencing communication between health care workers and parents and offers a number of practical approaches and strategies for facilitating successful communication between health practitioners and the parents of children.

Newborn size, infant and childhood growth, and body composition and cardiovascular disease risk factors at the age of 6 years: the Pune Maternal Nutrition Study

OBJECTIVE

To study associations of size and body proportions at birth, and growth during infancy and childhood, to body composition and cardiovascular disease (CVD) risk factors at the age of 6 years.

DESIGN

The Pune Maternal Nutrition Study, a prospective population-based study of maternal nutrition and CVD risk in rural Indian children.

METHODS

Body composition and CVD risk factors measured in 698 children at 6 years were related to body proportions and growth from birth.

MEASUREMENTS

Anthropometry was performed every 6 months from birth. At 6 years, fat and lean mass (dual X-ray absorptiometry) and CVD risk factors (insulin resistance, blood pressure, glucose tolerance, plasma lipids) were measured.

RESULTS

Compared with international references (NCHS, WHO) the children were short, light and thin (mean weight <-1.0 s.d. at all ages). Larger size and faster growth in all body measurements from birth to 6 years predicted higher lean and fat mass at 6 years. Weight and height predicted lean mass more strongly than fat mass, mid-upper arm circumference (MUAC) predicted them both approximately equally and skinfolds predicted only fat mass. Neither birthweight nor the 'thin-fat' newborn phenotype, was related to CVD risk factors. Smaller MUAC at 6 months predicted higher insulin resistance (P<0.001) but larger MUAC at 1 year predicted higher systolic blood pressure (P<0.001). After infancy, higher weight, height, MUAC and skinfolds, and faster growth of all these parameters were associated with increased CVD risk factors.

CONCLUSIONS

Slower muscle growth in infancy may increase insulin resistance but reduce blood pressure. After infancy larger size and faster growth of all body measurements are associated with a more adverse childhood CVD risk factor profile. These rural Indian children are growing below international 'norms' for body size and studies are required in other populations to determine the generalizability of the findings.

Is there a single underlying factor for the metabolic syndrome in adolescents? A confirmatory factor analysis

OBJECTIVE

The lack of a universally applicable model for the metabolic syndrome in the pediatric population makes it difficult to define this syndrome and compare its prevalence across studies and diverse populations. We sought to assess whether a single underlying factor could represent the metabolic syndrome in adolescents.

RESEARCH DESIGN AND METHODS

Using data from the National Health and Nutrition Examination Survey (1999-2002), we conducted a confirmatory factor analysis to assess the validity of waist circumference, triglycerides, fasting insulin, and systolic blood pressure (SBP) as potential phenotypic traits for the metabolic syndrome in adolescents aged 12-17 years (n = 1,262). A multiple-group approach was used to test the invariance in factor loadings across sex and race/ethnicity.

RESULTS

The estimates of factor loadings for the total sample were 0.76, 0.46, 0.81, and 0.42 for waist circumference, triglycerides, fasting insulin, and SBP, respectively. The goodness-of-fit indexes were adequate for the total sample (comparative fit index, 0.99; standardized root mean square residual, 0.02), Caucasian boys (1.0; 0.01), African-American boys (0.99; 0.03), Mexican-American boys (1.0; 0.01), Mexican-American girls (1.0; 0.01), and Caucasian girls (0.95; 0.04) and acceptable for African-American girls (0.94; 0.05). There were no significant differences in factor loadings of the four measured variables between boys and girls and among the three racial or ethnic subgroups.

CONCLUSIONS

The metabolic syndrome as a single underlying factor for the four simple phenotypic traits may be plausible in adolescents. The proposed model appears to be generalizable across sex and race/ethnicity.

Factor analysis of risk variables associated with metabolic syndrome in Asian Indian adolescents

The purpose of the present cross-sectional study was to identify components of risk variables associated with metabolic syndrome in Asian Indian adolescents. The sample included 400 adolescents (boys = 200; mean age, 15.0 +/- 4.5 years; girls = 200; mean age, 14.4 +/- 3.8 years) from Calcutta, India. The following variables were considered: body mass index, waist circumference, sum of four skinfolds, subscapular/triceps ratio, total cholesterol, triglycerides, blood glucose, and systolic, diastolic, and mean arterial pressure. Principal component factor analysis revealed four uncorrelated factors for adolescent boys that cumulatively explained 76.3% of the observed variance of metabolic syndrome. Four factors with overlap between factors 1 and 2 were observed for adolescent girls that cumulatively explained 74.3% of the total variation of metabolic syndrome. The four factors identified were central body fat distribution (factor 1), centralized subcutaneous fat (factor 2), lipids-blood glucose (factor 3), and blood pressure (factor 4). Furthermore, the first two factors, i.e., central body fat distribution and centralized subcutaneous fat, cumulatively explained more than 46% (46.5% for boys; 46.4% for girls) of the observed variation of metabolic syndrome. Since more than one factor was identified for metabolic syndrome, more than one physiological mechanism could account for the clustering of risk variables of metabolic syndrome in Asian Indian adolescents. Factor analysis of Asian Indian adults also revealed four uncorrelated factors, similar to the present factors, therefore warranting intervention as early as adolescence.

The dilemma of the metabolic syndrome in children and adolescents: disease or distraction?

BACKGROUND

The alarming increase of obesity in children occurring globally is raising concern about the implications for development, at earlier ages, of atherosclerosis and cardiovascular disease and is driving efforts to evaluate and predict risk in the young. A major component of this undertaking has been directed to adapting for children the criteria described in adults as the metabolic syndrome (MS).

METHODS

This article briefly examines the status of and controversy about definition of the MS in adults and its value, and then it moves on to review the descriptions of the MS in the pediatric age group. This is done primarily from the point of view of its usefulness to the clinician. The ranges of the criteria used by different investigators, the differences in their prevalence and their effectiveness in predicting cardiovascular risk are discussed. Current information about cardiovascular risk factors in children, their progression into adulthood and their correlation with atherosclerosis in children and young adults is outlined. Finally, the current information and recommendations for treatment, in children, of cardiovascular risk factors including those composing the MS are reviewed.

CONCLUSIONS

One conclusion is that there needs to be consensus about the criteria for defining the MS in children if its use as a diagnosis is to be helpful in this age group. A second conclusion questions the value of using this syndromic collection of risk factors in children rather than concentrating on the risk factors themselves, evaluating their importance in early cardiovascular risk and assessing the safety and efficacy of intervention in early life.

Anthropometric predictors of serum fasting insulin in 9- and 15-year-old children and adolescents

BACKGROUND AND AIM

As the prevalence of overweight and obesity increases, the risk of insulin resistance rises. The aim was to study the association between anthropometric measurements and fasting insulin concentration in a population-based sample of 9- and 15-year-old children and adolescents.

METHODS AND RESULTS

Subjects were randomly selected 9- and 15-year-old pupils (n=262) in a cross-sectional, population-based study. Weight and height, waist, hip and mid-arm-circumference and subcutaneous skinfolds were measured using standard procedures. Fasting insulin was measured. In general the mean anthropometric measurements increased across insulin quartiles. Higher fasting insulin concentration was seen in overweight children and adolescents than in those of normal weight (8.3+/-4.4 vs. 4.9+/-3.6 mmol/L and 11.0+/-4.4 vs. 9.0+/-4.2 mmol/L in 9- and 15 year-olds, respectively). The odds ratio for having insulin in the highest quartile (age and gender-specific) was, when compared with the lowest quartile, 7.2 (95% CI 3.0-17.2) for body mass index and 6.9 (2.8-16.7) for waist circumference. Other measurements of body fatness were less predictive. About 14-20% of children defined as being of normal weight had high fasting insulin values, i.e., were in the highest quartile of fasting insulin.

CONCLUSIONS

Body fatness is positively related to fasting insulin concentration in 9- and 15-year-old children. A large number of normal-weight individuals with high fasting insulin concentration was observed, and these children could be at increased risk of weight gain, compared with normal-weight individuals with normal fasting insulin concentration.

Waist circumference percentiles for 7- to 15-year-old Australian children

AIM

The purpose of this study was to develop age- and sex-specific reference values for waist circumference using data obtained from Australian children and adolescents.

METHODS

Subjects were 8439 7-to-15 y olds (4277 males and 4162 females) who participated in the 1985 Australian Health and Fitness Survey. Waist circumference (WC) was measured in the standing position at the level of the umbilicus to the nearest 0.1 cm using a constant tension tape. Descriptive statistics for each whole-year age group (e.g., 10.0-10.99 y, etc.) within sex were calculated. Construction of the smoothed centile curves was performed using the LMS method.

RESULTS

Mean WC increases in both males and females, with the values being similar between males and females prior to age 11 y, after which values are slightly higher in males. The range of values varied by age and sex groups but approximated 30-60 cm. Smoothed percentile curves and percentile values for the 5th, 10th, 25th, 50th, 75th, 90th, and 95th percentiles are presented for boys and girls. WC increases with age in boys and girls, and boys have higher values than girls at nearly every age-specific percentile.

CONCLUSIONS

These data can be added to the existing international reference values for WC of children and adolescents which should be used to create international cut-off points similar to those for the body mass index (BMI). Future studies should consider the immediate and long-term consequences of an elevated WC in children and also examine the interaction of BMI and WC on chronic disease risk factors.

Dysmetabolic syndrome in childhood and adolescence

The dysmetabolic syndrome, consisting of dyslipidaemia, hypertension, hyperinsulinaemia and central obesity, has been well recognized as a major risk for cardiovascular disease in adults. Although the clustering of cardiovascular risk factors has also been identified in childhood, the occurrence of full-blown dysmetabolic syndrome at younger ages has only recently been investigated. In this article we attempted an overview of the data for children and adolescents, focused on the mechanisms and natural history of the disease, the prevalence among paediatric populations, the assessment and the treatment approaches.

CONCLUSION

There is substantial evidence that the dysmetabolic syndrome has its origins in childhood. In the face of the epidemic increase of obesity in children and adolescents, the development of effective screening and preventive strategies would be a major challenge for paediatricians.

Metabolic syndrome in childhood: association with birth weight, maternal obesity, and gestational diabetes mellitus

OBJECTIVE

Childhood obesity has contributed to an increased incidence of type 2 diabetes mellitus and metabolic syndrome (MS) among children. Intrauterine exposure to diabetes and size at birth are risk factors for type 2 diabetes mellitus, but their association with MS in childhood has not been demonstrated. We examined the development of MS among large-for-gestational-age (LGA) and appropriate-for-gestational age (AGA) children.

STUDY DESIGN

The major components of MS (obesity, hypertension, dyslipidemia, and glucose intolerance) were evaluated in a longitudinal cohort study of children at age 6, 7, 9, and 11 years who were LGA (n = 84) or AGA (n = 95) offspring of mothers with or without gestational diabetes mellitus (GDM). The cohort consisted of 4 groups, ie, LGA offspring of control mothers, LGA offspring of mothers with GDM, AGA offspring of control mothers, and AGA offspring of mothers with GDM. Biometric and anthropometric measurements were obtained at 6, 7, 9, and 11 years. Biochemical testing included measurements of postprandial glucose and insulin levels and high-density lipoprotein (HDL) cholesterol levels at 6 and 7 years and of fasting glucose, insulin, triglyceride, and HDL cholesterol levels at 9 and 11 years. We defined the components of MS as (1) obesity (BMI >85th percentile for age), (2) diastolic or systolic blood pressure >95th percentile for age, (3) postprandial glucose level >140 mg/dL or fasting glucose level >110 mg/dL, (4) triglyceride level >95th percentile for age, and (5) HDL level <5th percentile for age.

RESULTS

There were no differences in baseline characteristics (gender, race, socioeconomic status, and maternal weight gain during pregnancy) for the 4 groups except for birth weight, but there was a trend toward a higher prevalence of maternal obesity before pregnancy in the LGA/GDM group. Obesity (BMI >85th percentile) at 11 years was present in 25% to 35% of the children, but rates were not different between LGA and AGA offspring. There was a trend toward a higher incidence of insulin resistance, defined as a fasting glucose/insulin ratio of <7, in the LGA/GDM group at 11 years. Analysis of insulin resistance at 11 years in a multivariate logistic regression revealed that childhood obesity and the combination of LGA status and maternal GDM were associated with insulin resistance, with odds ratios of 4.3 (95% confidence interval [CI]: 1.5-11.9) and 10.4 (95% CI: 1.5-74.4), respectively. The prevalence at any time of > or =2 components of MS was 50% for the LGA/GDM group, which was significantly higher than values for the LGA/control group (29%), AGA/GDM group (21%), and AGA/control group (18%). The prevalence of > or =3 components of MS at age 11 was 15% for the LGA/GDM group, compared with 3.0% to 5.3% for the other groups. Cox regression analysis was performed to determine the independent hazard (risk) of developing MS attributable to birth weight, gender, maternal prepregnancy obesity, and GDM. For Cox analyses, we defined MS as > or =2 of the following 4 components: obesity, hypertension (systolic or diastolic), glucose intolerance, and dyslipidemia (elevated triglyceride levels or low HDL levels). LGA status and maternal obesity increased the risk of MS approximately twofold, with hazard ratios of 2.19 (95% CI: 1.25-3.82) and 1.81 (95% CI: 1.03-3.19), respectively. GDM and gender were not independently significant. To determine the cumulative hazard of developing MS with time, we plotted the risk according to LGA or AGA category for the control and GDM groups from 6 years to 11 years, with Cox regression analyses. The risk of developing MS with time was not significantly different between LGA and AGA offspring in the control group but was significantly different between LGA and AGA offspring in the GDM group, with a 3.6-fold greater risk among LGA children by 11 years.

CONCLUSIONS

We showed that LGA offspring of diabetic mothers were at significant risk of developing MS in childhood. The prevalence of MS in the other groups was similar to the prevalence (4.8%) among white adolescents in the 1988-1994 National Health and Nutrition Examination Survey. This effect of LGA with maternal GDM on childhood MS was previously demonstrated for Pima Indian children but not the general population. We also found that children exposed to maternal obesity were at increased risk of developing MS, which suggests that obese mothers who do not fulfill the clinical criteria for GDM may still have metabolic factors that affect fetal growth and postnatal outcomes. Children who are LGA at birth and exposed to an intrauterine environment of either diabetes or maternal obesity are at increased risk of developing MS. Given the increased obesity prevalence, these findings have implications for perpetuating the cycle of obesity, insulin resistance, and their consequences in subsequent generations.

A quantitative trait locus influences coordinated variation in measures of ApoB-containing lipoproteins

Lipoprotein phenotypes are known to be strongly intercorrelated. These intercorrelations are due to genetic and environmental effects on common metabolic pathways. The purpose of this study was to determine if we could localize genes that exert pleiotropic effects on multiple related lipoprotein traits in humans. Using data from the San Antonio Family Heart Study, we extracted principal components from a set of 12 intercorrelated lipoprotein traits that included phenotypes reflecting lipid and protein concentrations and size distributions for LDLs and HDLs. Five principal components were extracted from the data and all were significantly heritable (h(2) = 0.41-0.57). When subjected to linkage analyses, only one, Component 5, returned a LOD score > or = 3 (LOD score was 3.0 at 38cM on chromosome 15; genome-wide P-value = 0.039). LDL median diameter (-0.529), non-HDLC (-0.422), and ApoB (-0.403) concentrations were the only traits with loadings (absolute value) >0.4, suggesting Component 5 is related to LDL size or perhaps more generally to beta-lipoprotein metabolism. Surprisingly, none of the 12 original lipoprotein traits had a LOD >1 in this region of chromosome 15. These data provide evidence for a novel gene, influencing beta-lipoprotein phenotypes, whose effect(s) is detected only when several lipoprotein traits are considered together.

Emergence of the metabolic syndrome in childhood: an epidemiological overview and mechanistic link to dyslipidemia

Insulin resistance and type 2 diabetes are rapidly emerging as major disorders of childhood and adolescence. This appears to be closely linked to a rapid rise in the prevalence of obesity in the pediatric population. The development of insulin resistance appears to lead to a "metabolic syndrome" which includes a number of major complications such as dyslipidemia and hypertension. Childhood metabolic syndrome promotes the development of premature atherosclerosis and significantly increases cardiovascular disease risk early in life. The mechanisms linking obesity, insulin resistance, and metabolic dyslipidemia are not fully understood. This review will attempt to discuss some of the key mechanistic issues surrounding insulin resistance and its association with metabolic dyslipidemia. Most of the recent progress in this field has come from the use of genetic and diet-induced animal models of insulin resistance. New data from these animal studies particularly the fructose-fed hamster, a model of metabolic syndrome and dyslipidemia, will be reviewed. Evidence from both animal and human studies suggest a key role for insulin sensitive tissues such as adipose tissue, liver, and intestine in the development of an insulin resistant state and its associated lipid and lipoprotein disorders. The critical interaction of metabolic signals among these tissues appears to govern the transition from an insulin sensitive to an insulin resistant state that underlies dyslipidemic conditions.