Overweight in children and adolescents: pathophysiology, consequences, prevention, and treatment

Correlates of adherence to a physical activity program in young African-American girls

OBJECTIVE

The goal was to identify correlates of adherence to a structured physical activity (PA) program.

RESEARCH METHODS AND PROCEDURES

Subjects were 136 8- to 12-year-old African-American girls. Potential correlates at baseline were: 1) fitness index (FI: % body fat from DXA and cardiovascular fitness from treadmill test), and 2) self-esteem, anxiety, attitude to school and teachers, relationship with parents, and interpersonal relations (Behavioral Assessment System for Children). The 10-month PA program included 80 minutes of PA offered 5 days/wk. Regression tree classification was used to model attendance.

RESULTS

Six splits occurred (34% total variance explained). Less anxious subjects attended more often than highly anxious subjects (3 days/wk vs. 1.5 days/wk) did. Subjects with a healthier FI attended more often than those with a less healthy FI (3 days/wk vs. 0.5 days/wk) did. Younger subjects attended more often than older ones (3 days/wk vs. 2.5 days/wk) did. The next two splits were again with anxiety (3.5 days/wk vs. 3 days/wk) and FI (3 days/wk vs. 2.5 days/wk). Finally, subjects with higher levels of self-esteem attended more often than those with lower levels (3.5 days/wk vs. 2 days/wk) did.

DISCUSSION

Subjects who were self-confident, younger, fitter, and less anxious were more likely to participate regularly. This suggests that children who may be more likely to benefit from a PA program are less likely to participate. To enhance participation in PA programs, especially in older African-American girls: 1) psychological concerns should be identified and addressed before enrollment, and 2) programs should be designed to be appealing to children of all fitness levels.

Glomerular hyperfiltration: a new marker of metabolic risk

Chronic kidney disease coexists with metabolic syndrome and this relationship may be apparent before overt manifestations of cardiovascular disease. To investigate early stages of the natural history of associations between renal function and metabolic syndrome, we phenotyped 1572 young (mean age=18.4 years), apparently healthy men for metabolic risk factors and estimated their creatinine clearance based on the Cockcroft-Gault equation. High metabolic risk (clustering of at least three metabolic risk factors) was revealed in 8.7% (137) of the subjects and was associated with a 6.9-fold increase in the odds of glomerular hyperfiltration (95% confidence interval (CI): 3.9-11.5) when compared to reference (from none to two metabolic risk factors). Overweight, elevated blood pressure, and low high-density lipoprotein (HDL) cholesterol increased the multivariate-adjusted odds ratio of glomerular hyperfiltration to 6.6 (95% CI: 3.8-11.6), 1.8 (95% CI: 1.0-3.0), and 2.5 (95% CI: 1.5-4.3), respectively. Systolic and diastolic blood pressures clustered together with leptin in the factor analysis and this blood pressure-adiposity component correlated with estimated creatinine clearance (r=0.329, P<0.0001) and explained on its own 10.2% of the variance in the estimated renal function. Our data reveal the silent epidemics of metabolic risk among young, apparently healthy men. Furthermore, the results indicate that high metabolic risk is associated with glomerular hyperfiltration before overt manifestations of cardiovascular disease.

Family and school determinants of overweight in 13-year-old Portuguese adolescents

AIMS

To identify familial and school determinants of overweight in 13-year-old adolescents.

METHODS

All 27 public and 19 (79%) private schools allowed to contact age eligible students, 77.5% accepting to participate (1116 girls, 1045 boys). Self-administered questionnaires were completed and physical examination performed, including weight and height measurements. Overweight (> 95th percentile) and at risk of overweight (85th-95th) were defined using CDC standards. Its determinants were identified using logistic regression models, entering parents' education and all variables significantly associated in crude analysis.

RESULTS

Prevalence of overweight (10.2%) and at risk of overweight (16.5%) was not influenced by type of school, vending machines and number of school canteen meals. In girls, the prevalence of body mass index (BMI) > 85th percentile increased significantly with decreasing age at menarche (45.7% if menstruating before 11-year and 13.2% when pre-menarche), and increasing parental BMI or time spent on sedentary activities. In multivariate analysis, age at menarche and increasing parental BMI remained significant risks in girls. In boys, besides parental BMI, ever smoking, sleeping < 9 h and sedentary leisure activities were significant determinants.

CONCLUSIONS

Food offered at school had no significant impact on adolescents overweight, which was mainly dependent on parental anthropometrics and leisure time activities.

Lower Birth Weight Associated with Current Overweight Status Is Related with the Metabolic Syndrome in Obese Japanese Children

The purpose of this study was to clarify the relationship between lower birth weight and current overweight status and to examine the involvement of these factors in the development of the metabolic syndrome (MS) in obese Japanese children. We examined 97 obese boys (mean age 11.3 years; mean percentage overweight [POW] 52.4%) and 29 obese girls (mean age 11.1 years; mean POW 58.3%). The anthropometric measurements, blood pressure, fasting serum insulin and blood glucose, liver enzymes, lipids and lipoproteins were measured. Birth weight and gestational weeks were also recorded. The subjects were divided into either an MS group or a Non-MS group using criteria proposed for Japanese children. We compared the weight parameters (birth weight, current weight and current weight-to-birth weight ratio [WBWR]) between the two groups and analyzed the relationships between the weight parameters and metabolic derangements. There were no significant differences in age or anthropometric measurements between the two groups. However, birth weight in the MS group was lower than that in the Non-MS group, while WBWR of the MS group was higher than that in the Non-MS group. Blood pressure and serum insulin correlated positively with WBWR. These findings suggested that lower birth weight with current overweight status was associated with the MS in obese Japanese children. We were unable to clarify whether subjects with lower birth weight who achieved proper weight gains had the same risk as subjects with appropriate birth weight. However, they should be assisted to grow adequately to prevent future metabolic derangements.

Childhood overweight and cardiovascular disease risk factors: the National Heart, Lung, and Blood Institute Growth and Health Study

OBJECTIVE

To estimate the prevalence and incidence of overweight in African-American and Caucasian girls, and to examine associations between adolescent overweight and cardiovascular disease (CVD) risk factors.

STUDY DESIGN

In the National Heart, Lung and Blood Institute Growth and Health Study (NGHS), annual measurements were obtained from girls followed longitudinally between age 9 or 10 and 18 years; self-reported measures were obtained at age 21 to 23 years. A total of 1166 Caucasian girls and 1213 African-American girls participated in the study. Childhood overweight as defined by the Centers for Disease Control and Prevention (CDC) was the independent variable of primary interest. Measured outcomes included blood pressure and lipid levels.

RESULTS

Rates of overweight increased through adolescence from 7% to 10% in the Caucasian girls and from 17% to 24% in the African-American girls. The incidence of overweight was greater at age 9 to 12 than in later adolescence. Girls who were overweight during childhood were 11 to 30 times more likely to be obese in young adulthood. Overweight was significantly associated with increased percent body fat, sum of skinfolds and waist circumference measurements, and unhealthful systolic and diastolic blood pressure, high-density lipoprotein cholesterol, and triglyceride levels.

CONCLUSION

A relationship between CVD risk factors and CDC-defined overweight is present at age 9.

Cardiovascular Risk Reduction in High-Risk Pediatric Patients

Although for most children the process of atherosclerosis is subclinical, dramatically accelerated atherosclerosis occurs in some pediatric disease states, with clinical coronary events occurring in childhood and very early adult life. As with most scientific statements about children and the future risk for cardiovascular disease, there are no randomized trials documenting the effects of risk reduction on hard clinical outcomes. A growing body of literature, however, identifies the importance of premature cardiovascular disease in the course of certain pediatric diagnoses and addresses the response to risk factor reduction. For this scientific statement, a panel of experts reviewed what is known about very premature cardiovascular disease in 8 high-risk pediatric diagnoses and, from the science base, developed practical recommendations for management of cardiovascular risk.

Interventions for the family with diabetes

This article demonstrates that families can make a difference in diabetes outcomes and nurses can make a difference in how families organize and interact around the person with diabetes. Highlighted are key findings from the research on families and diabetes across different phases of the lifespan. Recommendations for general practice with families that might be adapted by nurses to different settings in which they care for families with diabetes are included.

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.

Obesity and obstructive sleep apnea in children

The prevalence and severity of obesity in children and adolescent is dramatically increasing worldwide with a corresponding increase in the prevalence of obesity-associated morbidities particularly those involving OSAS and metabolic and cardiovascular sequelae. Obstructive sleep apnea and obesity hypoventilation syndrome are important and serious consequences of obesity, and may in fact mediate components of the association between obesity and metabolic and cardiovascular morbidities, most likely via potentiation of inflammatory cascades. It is anticipated that the increased prevalence of obesity in children and adolescents in our society will be accompanied by a steady increase in the incidence of OSAS. In this review, we will examine our current understanding of sleep-disordered breathing and associated morbidities in obese children, and summarize the range of therapeutic modalities currently available for this high-risk population.

The metabolic syndrome: concepts and controversy

The metabolic syndrome is an insulin-resistant state characterized by a cluster of cardiovascular risk factors, including various combinations of abdominal obesity, glucose intolerance, hypertension, and atherogenic dyslipidemia (elevated triglyceride values, low high-density lipoprotein cholesterol levels, and small dense low-density lipoprotein cholesterol particles). The current epidemic of obesity and physical inactivity has led to an increased prevalence of this disorder. In this review, we discuss the history and pathogenesis of the metabolic syndrome, the controversy regarding the appropriateness of considering it a distinct diagnosis, and the importance of lifestyle modification in its prevention and treatment. The need for all cardiovascular risk factors to be treated, whether or not they are components of the metabolic syndrome, is emphasized. Recent discussions in the literature regarding the continued use of the term metabolic syndrome should be considered a healthy academic debate that hopefully will stimulate Ideas and innovative research to improve patient care.

Prevalence of elevated blood pressure and association with overweight in children of a rapidly developing country

We assessed the prevalence of elevated blood pressure (BP) and the association with excess body weight among a large sample of children in the Seychelles, a middle-income rapidly developing country in the African region. Weight, height and BP were measured in all children of four school grades in the Seychelles (Indian Ocean). Excess weight categories ('overweight' and 'obesity') were defined according to the criteria of the International Obesity Task Force. Two BP readings were obtained on one occasion. 'Elevated BP' was defined based on US reference tables. Data were available in 15,612 (86%) of 18,119 eligible children aged 5-16 years in 2002-2004. In all, 13.0% of Boys and 18.8% of girls were overweight or obese. The prevalence of elevated BP was 9.1% in boys and 10.1% in girls. Both systolic and diastolic BP were strongly associated with body mass index (BMI) in boys and in girls. In children with 'normal weight', 'overweight (and not obesity)' and 'obesity', respectively, proportions with elevated BP were 7.5, 16.9 and 25.2% in boys, and 7.5, 16.1 and 33.2% in girls. Overweight (including obesity) could account for 18% of cases of elevated BP in boys and 26% in girls. Further studies should examine the impact of the relationship between BMI and elevated BP on the burden of hypertension in the context of the epidemic of paediatric obesity.

Childhood Obesity

The prevalence of child and adolescent obesity has increased dramatically in the last 20 years and has led to a rise in cardiovascular-related comorbidities, including type 2 diabetes, in children and youth. The American Heart Association (AHA) issued a scientific statement with available evidence and guidance for health professionals involved in the prevention and management of childhood obesity. The scientific statement was ranked as 1 of the Top 10 Research Advances of 2005 by the AHA. This article builds on the scientific statement, presents multilevel determinants, and emphasizes individual and population-based approaches to prevention. Treatment of child and youth obesity, along with the implications for nurses and other health professionals, is also included.

Hyperinsulinemia in healthy children and adolescents with a positive family history for type 2 diabetes

OBJECTIVE

Our goal was to determine the relationship between family history of type 2 diabetes and fasting hyperinsulinemia in healthy children and adolescents.

METHODS

A total of 317 children and adolescents, 10 to 14 years of age with Tanner stage 1 or 2, were randomly selected from elementary and middle schools in Durango, northern Mexico, to participate in a cross-sectional, community-based study. Family history was ascertained by a direct, detailed medical examination that included anthropometric and laboratory measurements from both parents. We determined the prevalence of family history of type 2 diabetes, high blood pressure, obesity, hyperinsulinemia, and the adjusted odds ratio that computes the relationship between hyperinsulinemia and family history of type 2 diabetes.

RESULTS

Family history of type 2 diabetes, high blood pressure, and obesity was recognized in 30 (9.2%), 61 (18.7%), and 74 (22.7%) children and adolescents, respectively. Children and adolescents with positive family history showed higher systolic and diastolic blood pressure, were more obese, and exhibited significantly higher fasting insulin and triglycerides levels, as well as a higher homeostasis model analysis insulin resistance index, than children with negative family history. A total of 48 (15.1%) children and adolescents exhibited hyperinsulinemia, 35 (72.9%) with and 13 (27.1%) without family history. The odds ratio adjusted by gender, fat mass (kilograms and percent), waist circumference, BMI, and Tanner stage showed that family history of diabetes, but not high blood pressure and obesity, was independently related with hyperinsulinemia.

CONCLUSIONS

Among children and adolescents, family history of diabetes, but not high blood pressure and obesity, is independently associated with hyperinsulinemia.

Aerobic exercise and snoring in overweight children: a randomized controlled trial

OBJECTIVE

To determine whether regular aerobic exercise improves symptoms of sleep-disordered breathing in overweight children, as has been shown in adults.

RESEARCH METHODS AND PROCEDURES

Healthy but overweight (BMI > or =85th percentile) 7- to 11-year-old children were recruited from public schools for a randomized controlled trial of exercise effects on diabetes risk. One hundred children (53% black, 41% male) were randomly assigned to a control group (n = 27), a low-dose exercise group (n = 36), or a high-dose exercise group (n = 37). Exercise groups underwent a 13 +/- 1.5 week after-school program that provided 20 or 40 minutes per day of aerobic exercise (average heart rate = 164 beats per minute). Group changes were compared on BMI z-score and four Pediatric Sleep Questionnaire scales: Snoring, Sleepiness, Behavior, and a summary scale, Sleep-Related Breathing Disorders. Analyses were adjusted for age.

RESULTS

Both the high-dose and low-dose exercise groups improved more than the control group on the Snoring scale. The high-dose exercise group improved more than the low-dose exercise and control groups on the summary scale. No group differences were found for changes on Sleepiness, Behavior, or BMI z-score. At baseline, 25% screened positive for sleep-disordered breathing; half improved to a negative screen after intervention.

DISCUSSION

Regular vigorous exercise can improve snoring, a symptom of sleep-disordered breathing, in overweight children. Aerobic exercise programs may be valuable for prevention and treatment of sleep-disordered breathing in overweight children.

For comparison: experience with a children’s obesity camp

BACKGROUND

The alarming rise in childhood obesity has resulted in a number of bariatric surgical initiatives. To interpret the outcomes, a comparison with a nonoperative approach is prudent.

METHODS

In 2003, 2004, and 2005, we measured the outcomes produced by an isolated summer camp in North Carolina for 74, 99, and 89 obese children and adolescents with a mean age of 12.7 +/- 2.3, 13.0 +/- 1.9, and 13.2 +/- 1.8 years and initial body mass index (BMI) of 33.1 +/- 5.7, 33.4 +/- 6.4, and 32.9 +/- 7.0 kg/m2, respectively. The camp featured a 1700/d caloric diet, daily aerobic and resistance weight training exercise, nutrition classes, and weekly sessions with a psychologist. The changes in weight, BMI, body shape measurements, and fitness level were assessed. The average length of stay was 4.3, 4.2, and 4.4 weeks, respectively, in 2003, 2004, and 2005.

RESULTS

The BMI, body shape, and weight change measures significantly improved during each of the summers. The campers lost 1.6, 2.0, and 1.8 kg/wk during each of the 3 years. Their waist measurements decreased by 9.1 +/- 5.12 cm, 9.9 +/- 5.6 cm, and 8.1 +/- 5.8 cm. Significant improvements occurred in the timed sprints, .5-mile (0.8-km) run, and vertical jump. Of those campers staying for two summers, 4.4% continued to reduce their BMI despite growth, 56.5% maintained their BMI at less than the initial baseline measurement, and 39.1% increased their BMI to greater than the baseline. The co-morbidities also improved. One camper, aged 15 years, weighing 211 kg, progressed from being able to walk 3 steps to managing the 100-yard (91-m) dash in 42 seconds after losing 35 kg in 8 weeks.

CONCLUSION

Diets, exercise, and behavioral modification are useful approaches in severely obese children that can, in some, produce significant albeit expensive long-term results. Recidivism is a problem. Surgical outcomes must compare favorably with these outcomes.

Overweight and obesity at school entry as predictor of overweight in adolescence in an Arctic child population

BACKGROUND

The aim of this study was to analyse the changes in the prevalence of overweight, obesity, and in mean body mass index (BMI) among school children, and to analyse the predictive value of overweight and obesity at school entry to overweight and obesity in adolescence in an Arctic child population.

METHODS

Retrospective cohort study. A database was created on the basis of files from health examinations. Data on children aged 5-7 years and 13-17 years and the subsample of children followed from school entry to adolescence was analysed.

RESULTS

During the years 1972-2002 the prevalence of overweight and obesity increased significantly, and mean BMI rose by 5.6% at school entry and by 4.7% in adolescence. Sensitivity and specificity: Of the children being obese in adolescence, 56.3% were already obese at school entry; for the overweight children, 50.6% were also overweight or obese at school entry. Of the children with normal weight in adolescence, 91.9% were also normal weight at school entry. The positive predictive value of being overweight or obese combined at school entry was 59.5%, i.e. more than every second retained their overweight or obesity in adolescence. Only 10% of the obese school entry children had gained normal weight in adolescence. The negative predictive value for normal weight children at school entry was 91.3%.

CONCLUSION

The study showed that during 30 years from 1972, overweight and obesity among school children in Greenland have increased dramatically. Overweight and obesity at school entry were shown to be a good predictor of overweight or obesity in adolescence.

Prevalence of the metabolic syndrome in Zhejiang Chinese obese children and adolescents and the effect of metformin combined with lifestyle intervention

OBJECTIVE

We aimed to evaluate the prevalence of metabolic syndrome (MS) in a group of obese children and adolescents in Zhejiang in the south of China, and to compare risk factors such as insulin resistance, adiponectin level and impaired glucose tolerance (IGT) etc with that of simple obese group (SOB) and non-obese healthy group, and also to evaluate the effect of metformin and lifestyle intervention in MS group by up to a 3-month follow-up.

METHODS

Three hundred and forty eight moderately or severely obese adolescents aged between 7 and 16 years were enrolled. Oral glucose tolerance test (OGTT), biochemical indicators, blood pressure and body mass index (BMI) were assessed in all of them. Three subgroups were selected (MS group, SOB and healthy control). Adiponectin levels, Whole body insulin sensitive index (WBISI), homeostasis model of insulin resistance (HOMA-IR), plasma lipid and blood pressure were compared in these three groups. Thirty out of thirty-six MS subjects with age over 10 years received metformin treatment combined with lifestyle modification.

RESULTS

(1) The prevalence of MS was 10.34% among all obese subjects, which increased with the severity of obesity and reached 22.1% in severely obese children and adolescents. The occurrence of more than one complication reached 72.13%. The incidence of type 2 diabetes and IGT were 1.44 and 1.44% respectively. (2) BMI, waist-to-hip ratio (WHR) and HOMA-IR increased stepwise in the control group, SOB and MS group, whereas serum adiponectin and WBISI decreased stepwise (all P<0.01). Systolic pressure, triglyceride, total cholesterol, low-density lipoprotein cholesterol and postprandial 2-h blood glucose in the MS group increased significantly compared to those in control and SOBs (all P<0.01). A correlation analysis showed that serum levels of adiponectin and WBISI were associated with the components of MS (all P<0.05). (3) After metformin and lifestyle intervention, clinical symptoms were ameliorated, serum adiponectin levels were actually increased and HOMA-IR was dropped in 20/30 MS children who had finished a 3-months follow-up (all P<0.01).

CONCLUSION

The prevalence of MS in severely obese children and adolescents in Zhejiang area has reached a high level. Insulin resistance and hypoadiponectinemia were found in these MS children. Metformin combined with lifestyle modification was confirmed to be efficient and safe in treating the obese adolescents with MS.

Methods for assessing body composition, cardiovascular and metabolic function in children and adolescents: implications for exercise studies

PURPOSE OF REVIEW

To critically evaluate the most recent literature on the methods used to assess body composition, cardiovascular and metabolic function in children and adolescents.

RECENT FINDINGS

Although regional body composition can be fairly accurately calculated by dual-energy X-ray absorptiometry, the accuracy of noninvasive estimations of visceral adipose tissue is questionable. Regarding the cardiovascular and metabolic adaptations, there is no doubt that direct and invasive methods provide high accuracy and reproducibility. For instance, exercise until exhaustion, direct Fick equation, nuclear magnetic resonance and magnetic resonance imaging are valid methods to determine maximum oxygen uptake, cardiac output and tissue substrate metabolism, respectively. Except for the direct Fick equation, all have been successfully used in pediatric studies. Relatively new techniques for the assessment of exercise training-induced adaptations in youths include the thoracic bioimpedance and the Modelflow method for cardiac output determination, and magnetic resonance spectroscopy for intramuscular and intrahepatic lipid content. Additional validation and reliability studies in pediatric populations are needed for some of these techniques (e.g. the Modelflow method).

SUMMARY

Most of the techniques used in adults appear not directly applicable to youths. A combination of techniques and/or the application of new, promising and easy to use ones, such as near-infrared spectroscopy and Laser Doppler flowmetry, may advance our knowledge in pediatric exercise science.

Metabolic syndrome in children and adolescents

Metabolic syndrome is a constellation of interrelated risk factors of metabolic origin that often accompany obesity and consist of atherogenic dyslipidemia, elevated blood pressure, impaired glucose tolerance, a prothrombotic state, and a proinflammatory state. Using a modification of the criteria by the National Cholesterol Education Program Adult Treatment Panel III, metabolic syndrome in children and adolescents can be clinically diagnosed when three or more of the following are present: body mass index > or = 2 z score, systolic or diastolic blood pressure greater than 95th percentile, triglyceride level greater than 95th percentile, and/or high-density lipoprotein cholesterol less than 5th percentile and impaired glucose tolerance (fasting glucose > 110 mg/dL ). The prevalence of the metabolic syndrome in adolescents has been shown to be 4% overall, but it is 30% to 50% in overweight adolescents. In the United States, 18% to 22% of children and adolescents are overweight; the prevalence of a metabolic syndrome phenotype among US adolescents has also been increasing significantly over the past decade. All of the features of metabolic syndrome are risk factors for atherosclerosis, and metabolic syndrome has been shown to constitute risk for atherosclerotic cardiovascular disease in adults. In children and adolescents with metabolic syndrome, biomarkers of an increased risk of adverse cardiovascular outcomes are already present. Therefore, there is need for prevention and treatment of metabolic syndrome in this population. The mainstay of the treatment is dietary intervention and promotion of active lifestyle to achieve and maintain optimum weight, normal blood pressure, and normal lipid profile for the height and age. The pharmaceutical intervention is usually not required and its long-term outcome has not been studied. There is need for large studies for the management and long-term outcomes of metabolic syndrome in children and adolescents if the future tides of cardiovascular and other associated complications of metabolic syndrome are to be turned around.

Does maternal smoking during pregnancy have a direct effect on future offspring obesity? Evidence from a prospective birth cohort study

The authors used a population-based birth cohort of 3,253 children (52% males) born in Brisbane, Australia, between 1981 and 1984 to prospectively examine whether maternal smoking during pregnancy was associated with offspring overweight and obesity. The authors compared mean body mass indexes (weight (kg)/height (m)2) and levels of overweight and obesity at age 14 years among offspring by patterns of maternal smoking (never smoked, smoked before and/or after pregnancy but not during pregnancy, or smoked during pregnancy). Adolescent body mass index and prevalences of overweight and obesity were greater in offspring whose mothers had smoked during pregnancy than in those whose mothers had never smoked. Body mass index and levels of overweight and obesity among adolescent offspring whose mothers stopped smoking during pregnancy but smoked at other times in the child's life were similar to those among offspring whose mothers had never smoked. These results were independent of a range of potentially confounding factors and suggest a direct effect of maternal smoking during pregnancy on adolescent overweight and obesity. They provide yet another incentive for pregnant women to be persuaded not to smoke and for young women to be encouraged to never take up smoking.

"Everyone dies, so you might as well have fun!" Attitudes of Dutch youths about their health lifestyle

Most Western societies seem to have embarked on a runaway weight-gain train, equipped with too many accelerators and not enough brakes. Adolescents have been identified as a public health risk group in this area. To uncover youths' attitudes about their health lifestyle, with a focus on overweightness, we conducted a discourse analysis using Q-methodology. Female, Dutch youths between 12 and 15 years rank-ordered statements on issues like eating behaviour, overweightness, health risks, health perceptions and motivations/obstacles for adopting a healthier lifestyle. Q-factor analysis revealed five attitudes: "carefree sporty", "worrying dependent", "contended independent", "looks over content" and "indifferent solitary". The youths were all more or less uninterested in their own health but for different reasons. For most of these youths, neither current nor future health is of major concern, because they feel physically fit, are generally satisfied and happy, or simply do not care. Some are concerned about their eating behaviour due to the consequences it has on appearance, being physically unfit or overweight. Even so, this preoccupation with eating appears far from healthy. Only one of the five health lifestyle attitudes identified combines healthy eating and exercising behaviour. Most youths appear to have little knowledge and many questions regarding health and overweightness.

Pediatric reference intervals for lipids and apolipoproteins on the VITROS 5,1 FS Chemistry System

OBJECTIVES

Lipid biomarkers are integral in the assessment of dyslipidemia and cardiovascular risk, conditions that have become increasingly prevalent in pediatric populations. A comprehensive set of pediatric reference intervals for traditional or recently established lipid analytes is not currently available.

DESIGN AND METHODS

525 outpatient samples from a pediatric population were categorized into five age groups ranging from 0 to 20 years of age. Groups were further partitioned by gender. Serum or plasma samples were analyzed on the VITROS 5,1 FS Chemistry System for cholesterol and triglycerides by dry-film methods, direct HDL-C and LDL-C by selective detergent elimination, and apolipoproteins AI and B by immunoturbidimetry. Reference intervals were established by non-parametric methods at the 2.5th and 97.5th percentiles.

RESULTS

Lipid levels show age- and gender-related differences, particularly during the first year of life and in young adults following puberty. Concentrations of total cholesterol, LDL-C, and apo B were lowest in the 12 months after birth and remained relatively constant throughout childhood, but decreased for males in early adulthood. Triglyceride levels increased gradually throughout childhood and adolescence, and along with cholesterol, the upper limits of these intervals exceeded the recommended concentrations of lipid levels in children. For HDL-C and apo AI, no age- or sex-related differences were found until after puberty when values for males decreased slightly.

CONCLUSIONS

Our current reference intervals in children and adolescents provide an important update for lipid markers and suggest earlier incidence of hypercholesterolemia when compared to previous ranges. Increased profiling of lipids is anticipated, and these will aid in the early assessment of cardiovascular risk in pediatric populations.

Management of Hypertension in Children and Adolescents With the Metabolic Syndrome

Because elevated blood pressure is one of the defining criteria of the metabolic syndrome, treatment of hypertension will be required in many, if not most, children and adolescents diagnosed with the metabolic syndrome. This review highlights several aspects of the approach to treatment of hypertension in young patients with the metabolic syndrome, including the definition of hypertension, use of nonpharmacologic measures, indications for instituting antihypertensive medications, and the potential adjunctive role that insulin-sensitizing agents may play in blood pressure reduction. The choice of antihypertensive agent is also discussed, along with consideration of the diabetogenic effects of various classes of antihypertensive agents. Consideration of all of these issues is important in achieving blood pressure control in children and adolescents with the metabolic syndrome, as appropriate treatment may help to forestall the development not only of type 2 diabetes but also of the cardiovascular disease that is frequently already present at the time of diagnosis of type 2 diabetes in adults.

Cardiovascular risk factors in adolescents

Most children who are normal weight for height and otherwise healthy have risk factor levels associated with the absence of heart disease (ie, they do not smoke, do not have diabetes, are physically active, have low-density lipoprotein levels < 110 mg/dL, and have blood pressure < 120/80 mm Hg). However, by adolescence, the earliest lesions in the atherosclerotic process, fatty streaks and raised lesions, are present in the coronary arteries and the abdominal aorta. The severity of early atherogenesis is related to the coexistence of the major cardiovascular risk factors. Most commonly, the associated risk disturbances are mild: borderline hypertension, mild dyslipidemia, insulin resistance, overweight, physical inactivity, and initiation of tobacco use. Rarely, more severe risk factors are present: familial hypercholesterolemia (a genetic disorder of lipid metabolism), diabetes mellitus, secondary hypertension of long standing, or risk factors associated with chronic conditions such as end-stage renal disease. Thus, cardiovascular risk management in this age group has two components: primordial prevention (the prevention of the development of cardiovascular risk in the first place) and primary prevention (more aggressive treatment of identified risk factors in high-risk individuals either through behavioral or pharmacologic means). Trials beginning in adolescence of the primary prevention of atherosclerosis-related diseases have not been undertaken; thus, the decision to initiate pharmacologic management in high-risk adolescents requires careful thought.

Promoting Cardiovascular Health in Children and Adolescents

Data accumulated over the past 3 decades indicate that cardiovascular disease processes are accelerated over the life course by potentially modifiable risk factors and environmental exposures. Based on available evidence, the American Heart Association and other pediatric agencies issued scientific statements and guidelines with recommendations for promoting the cardiovascular health of children and adolescents and for identifying and managing children at risk for cardiovascular disease. This article presents an overview of the evidence and emphasizes current recommendations for population-based and individually oriented approaches to cardiovascular disease prevention in childhood and adolescence.

Bariatric surgery for morbidly obese adolescents: is there a rationale for early intervention?

Obesity is one of the most common metabolic disorders affecting the US population: 31% of adults and 16% of adolescents now meet the criteria for obesity. Similar to the rising prevalence of morbid obesity in adults, the prevalence of more severe obesity is also increasing in pediatric patients. The most effective treatment for morbid obesity is bariatric surgery, a procedure most commonly performed in the fifth and sixth decades of life. Although it is clear that rapid, profound weight loss can significantly improve multiple comorbid conditions in adults, including disordered carbohydrate metabolism, obstructive sleep apnea, and cardiovascular risk factors, it is not clear to what degree similar comorbidities are affected in adolescents undergoing surgical weight loss. In this paper, the indications, contraindications, and early surgical outcomes of gastric bypass surgery for morbidly obese adolescents are reviewed, and important directions for future research are discussed.

Hypertension in children and adolescents

Hypertension is one of the most common health problems in the United States and a powerful independent risk factor for cardiovascular and renal disease. Until recently, the incidence of persistent hypertension in children has been low, with a range of 1% to 3%. Recent data indicate that over the last decade, however, average blood pressure levels have risen substantially among American children. Obesity and other lifestyle factors, such as physical inactivity and increased intake of high-calorie, high-salt foods, are thought to be responsible for this trend. Hypertension in children is currently recognized as an important health issue. There is increasing evidence that hypertension has its antecedents during childhood, because adult blood pressure often correlates with childhood blood pressure. Hypertension in children also is viewed as a significant risk factor for the development of cardiovascular disease in adulthood.

Type 2 diabetes and the metabolic syndrome in children and adolescents

The prevalence rates of obesity, metabolic syndrome, and type 2 diabetes in children are increasing at an alarming rate. The potential impact of these conditions on the individual, the family, and society, especially in regard to the costs and utilization of health care resources, are very serious. Strategies aimed at reducing caloric intake, increasing caloric expenditure through regular exercise, and treating cardiovascular risk factors and type 2 diabetes early and aggressively are necessary to meet the challenges they impose.

Overweight and obesity: prevalence, consequences, and causes of a growing public health problem

This paper provides an overview of the evidence on the current epidemic of obesity in the United States. The prevalence of overweight and obesity now exceeds 60% among US adults, and the rate is rapidly increasing among children and adolescents. Dismal medical, social, and economic consequences are already apparent and likely to worsen without multipronged intervention. Increased rates of hypertension, diabetes, and dyslipidemia, among other medical conditions, threaten to shorten the longevity of the American populace by as much as 5 years. The incidence of depression is increasing and experts suggest this is linked with the increased prevalence of obesity. The cost of obesity-related medical care has increased astronomically since 1987, in addition to lost productivity and income. Novel multidisciplinary, preventive, and therapeutic approaches, and social changes are needed that address the complex interplay of biologic, genetic, and social factors that have created the current obesity epidemic.

WHO Child Growth Standards based on length/height, weight and age

AIM

To describe the methods used to construct the WHO Child Growth Standards based on length/height, weight and age, and to present resulting growth charts.

METHODS

The WHO Child Growth Standards were derived from an international sample of healthy breastfed infants and young children raised in environments that do not constrain growth. Rigorous methods of data collection and standardized procedures across study sites yielded very high-quality data. The generation of the standards followed methodical, state-of-the-art statistical methodologies. The Box-Cox power exponential (BCPE) method, with curve smoothing by cubic splines, was used to construct the curves. The BCPE accommodates various kinds of distributions, from normal to skewed or kurtotic, as necessary. A set of diagnostic tools was used to detect possible biases in estimated percentiles or z-score curves.

RESULTS

There was wide variability in the degrees of freedom required for the cubic splines to achieve the best model. Except for length/height-for-age, which followed a normal distribution, all other standards needed to model skewness but not kurtosis. Length-for-age and height-for-age standards were constructed by fitting a unique model that reflected the 0.7-cm average difference between these two measurements. The concordance between smoothed percentile curves and empirical percentiles was excellent and free of bias. Percentiles and z-score curves for boys and girls aged 0-60 mo were generated for weight-for-age, length/height-for-age, weight-for-length/height (45 to 110 cm and 65 to 120 cm, respectively) and body mass index-for-age.

CONCLUSION

The WHO Child Growth Standards depict normal growth under optimal environmental conditions and can be used to assess children everywhere, regardless of ethnicity, socio-economic status and type of feeding.

Low-saturated fat dietary counseling starting in infancy improves insulin sensitivity in 9-year-old healthy children: the Special Turku Coronary Risk Factor Intervention Project for Children (STRIP) study

OBJECTIVE

Insulin resistance is promoted already in childhood by obesity and possibly by high-saturated fat intake. We examined the effect of infancy onset biannually given dietary counseling on markers of insulin resistance in healthy 9-year-old children.

RESEARCH DESIGN AND METHODS

Healthy 7-month-old infants (n = 1,062) were randomized to the intervention (n = 540) and control (n = 522) groups. Each year, two individualized counseling sessions were organized to each intervention family. The purpose of counseling was to minimize children's exposure to known environmental atherosclerosis risk factors. Homeostasis model assessment of insulin resistance (HOMA-IR) index, serum lipids, blood pressure, and weight for height were determined in a random subgroup of 78 intervention children and 89 control children at the age of 9 years.

RESULTS

Intervention children consumed less total and saturated fat than the control children (P = 0.002 and < 0.0001, respectively). The HOMA-IR index was lower in intervention children than in control children (P = 0.020). There was a significant association between saturated fat intake and HOMA-IR. In multivariate analyses including saturated fat intake, study group, and other determinants of HOMA-IR (serum triglyceride concentration, weight for height, and systolic blood pressure), study group was, whereas saturated fat intake was not, significantly associated with HOMA-IR. This suggests that the beneficial effect of intervention on insulin sensitivity was largely, but not fully, explained by the decrease in saturated fat intake.

CONCLUSIONS

The long-term biannual dietary intervention decreases the intake of total and saturated fat and has a positive effect on insulin resistance index in 9-year-old children.

Efficacy of exercise for treating overweight in children and adolescents: a systematic review

BACKGROUND

Overweight prevalence among children/adolescents is increasing, while adult obesity may potentially cause a decline in life expectancy. More exercise is uniformly recommended, although treatment efficacy remains unclear.

OBJECTIVE

To determine the efficacy of exercise alone for treating overweight in children/adolescents.

DESIGN

A systematic review and meta-analysis of randomized trials published in English were completed following multiple database searches performed on December 10, 2004. Studies of isolated or adjunctive exercise/physical activity treatment in overweight/obese children or adolescents which reported any overweight outcome were included. Literature searches identified 645 papers which were manually searched, of which 45 were considered for inclusion, of which 13 papers which reported 14 studies were included (N=481 overweight boys and girls, aged approximately 12 years). Two reviewers independently identified relevant papers for potential inclusion and assessed methodological quality. Principal measures of effects included the mean difference (MD) (between treatment and control groups), the weighted MD (WMD), and the standardized MD (SMD).

RESULTS

Few studies were of robust design. The pooled SMD was -0.4 (-0.7, -0.1, P=0.006) for percent body fat, and -0.2 (-0.6, 0.1, P=0.07) for central obesity outcomes, whereas the pooled WMD was -2.7 kg (-6.1 kg, 0.8 kg, P=0.07) for body weight, all of which favored exercise. Pooled effects on body weight were significant and larger for studies of higher doses, whereas nonsignificant and smaller effects were seen for studies of lower doses of exercise (155-180 min/weeks vs 120-150 min/weeks).

CONCLUSIONS

Based on the small number of short-term randomized trials currently available, an aerobic exercise prescription of 155-180 min/weeks at moderate-to-high intensity is effective for reducing body fat in overweight children/adolescents, but effects on body weight and central obesity are inconclusive. Recommendations for future study designs are discussed.

Childhood overweight and elementary school outcomes

OBJECTIVE

To examine the link between childhood overweight status and elementary school outcomes.

DESIGN

Prospective study design: multivariate regression models examining the association between changes in overweight status and school outcomes between kindergarten entry and end of third grade, after controlling for various child, family and school characteristics.

SUBJECTS

Nationally representative sample of US children who entered kindergarten in 1998, with longitudinal data on body mass index (BMI) and school outcomes at kindergarten entry and end of third grade.

MEASUREMENTS

Wide range of elementary school outcomes collected in each wave including academic achievement (math and reading standardized test scores); teacher reported internalizing and externalizing behavior problems (BP), social skills (self-control, interpersonal skills) and approaches to learning; school absences; and grade repetition. Measurements of height and weight in each wave were used to compute BMI and indicators of overweight status based on CDC growth charts. A rich set of control variables capturing child, family, and school characteristics.

RESULTS

Moving from not-overweight to overweight between kindergarten entry and end of third grade was significantly associated (P<0.05) with reductions in test scores, and teacher ratings of social-behavioral outcomes and approaches to learning among girls. However, this link was mostly absent among boys, with two exceptions - boys who became overweight had significantly fewer externalizing BPs (P<0.05), but more absences from school compared to boys who remained normal weight. Being always-overweight was associated with more internalizing BP among girls but fewer externalizing BPs among boys.

CONCLUSION

Change in overweight status during the first 4 years in school is a significant risk factor for adverse school outcomes among girls but not boys. Girls who become overweight during the early school years and those who start school being overweight and remain that way may need to be monitored carefully.

Sleep in Overweight Adolescents: Shorter Sleep, Poorer Sleep Quality, Sleepiness, and Sleep-Disordered Breathing

OBJECTIVE

To document the sleep of overweight adolescents and to explore the degree to which weight-related sleep pathology might account for diminished psychosocial outcome.

METHODS

Sixty children aged 10-16.9 from a weight-management clinic were compared to 22 healthy controls using comprehensive actigraphic, polysomnographic, and parent- and self-report questionnaire assessments.

RESULTS

Overweight participants averaged more symptoms of sleep-disordered breathing, later sleep onset, shorter sleep time, and more disrupted sleep than controls. Although the groups did not differ in self-reported sleep habits, multiple concerns were reported by parents of overweight participants, including daytime sleepiness, parasomnias, and inadequate sleep. Group differences in academic grades and depressive symptoms were at least partially accounted for by short sleep and daytime sleepiness.

CONCLUSIONS

Excessive weight is associated with an increased risk of sleep problems. There is a need for further research in this area and for clinicians who work with overweight children to evaluate their sleep.

Fat as an endocrine organ: relationship to the metabolic syndrome

Obesity and the metabolic syndrome have both reached pandemic proportions. Together they have the potential to impact on the incidence and severity of cardiovascular pathologies, with grave implications for worldwide health care systems. The metabolic syndrome is characterized by visceral obesity, insulin resistance, hypertension, chronic inflammation, and thrombotic disorders contributing to endothelial dysfunction and, subsequently, to accelerated atherosclerosis. Obesity is a key component in development of the metabolic syndrome and it is becoming increasingly clear that a central factor in this is the production by adipose cells of bioactive substances that directly influence insulin sensitivity and vascular injury. In this paper, we review advances in the understanding of biologically active molecules collectively referred to as "adipokines" and how dysregulated production of these factors in obese states mediates the pathogenesis of obesity associated metabolic syndrome.

Vascular risks and management of obesity in children and adolescents

Childhood obesity has reached epidemic proportions in many countries. Pediatric obesity is associated with the development of cardiovascular (CV) risk factors including type 2 diabetes, hypertension, dyslipidemia, and the metabolic syndrome. It is also associated with an increased risk of CV disease (CVD) in adulthood. Moreover, obesity and CVD risk factors in obese youth tend to track into adulthood, further increasing the risk of adult CVD. Consequently, the treatment and prevention of childhood overweight and obesity has become a public health priority. Proper nutrition and increased physical activity are the main focus of these efforts; however, few studies have shown positive results. Treatment options for obesity in youth also include pharmacotherapy and surgery. While pharmacotherapy appears promising, additional evidence is needed, especially with respect to the long-term impact, before it becomes a widespread treatment option in the pediatric population.

Childhood obesity, prevalence and prevention

Childhood obesity has reached epidemic levels in developed countries. Twenty five percent of children in the US are overweight and 11% are obese. Overweight and obesity in childhood are known to have significant impact on both physical and psychological health. The mechanism of obesity development is not fully understood and it is believed to be a disorder with multiple causes. Environmental factors, lifestyle preferences, and cultural environment play pivotal roles in the rising prevalence of obesity worldwide. In general, overweight and obesity are assumed to be the results of an increase in caloric and fat intake. On the other hand, there are supporting evidence that excessive sugar intake by soft drink, increased portion size, and steady decline in physical activity have been playing major roles in the rising rates of obesity all around the world. Consequently, both over-consumption of calories and reduced physical activity are involved in childhood obesity.

Almost all researchers agree that prevention could be the key strategy for controlling the current epidemic of obesity. Prevention may include primary prevention of overweight or obesity, secondary prevention or prevention of weight regains following weight loss, and avoidance of more weight increase in obese persons unable to lose weight. Until now, most approaches have focused on changing the behaviour of individuals in diet and exercise. It seems, however, that these strategies have had little impact on the growing increase of the obesity epidemic. While about 50% of the adults are overweight and obese in many countries, it is difficult to reduce excessive weight once it becomes established. Children should therefore be considered the priority population for intervention strategies. Prevention may be achieved through a variety of interventions targeting built environment, physical activity, and diet. Some of these potential strategies for intervention in children can be implemented by targeting preschool institutions, schools or after-school care services as natural setting for influencing the diet and physical activity. All in all, there is an urgent need to initiate prevention and treatment of obesity in children.