The relation of overweight to cardiovascular risk factors among children and adolescents: the Bogalusa Heart Study

Dietary intake of children at high risk for cardiovascular disease

Cardiovascular disease and obesity begin in childhood, and dietary interventions to prevent them should be initiated then. We hypothesized that children who were at high risk for cardiovascular disease based on family history would have diets that were different than those of children from low-risk families. Two hundred ninety-seven children were screened for family history of early cardiovascular disease; had height, weight, and finger-stick total cholesterol measured; and filled out food frequency questionnaires. Sixty-eight (23%) children were at risk for cardiovascular disease. Cholesterol was significantly higher compared with those not at risk (4.71+/-0.93 mmol/L vs 4.35+/-0.92 mmol/L, P=.005). Intakes of energy, fat, fiber, and cholesterol were similar between groups. Children at high risk for cardiovascular disease were no more likely to meet guidelines for heart-healthy diets than were children at low risk. Families need guidance to change dietary patterns to prevent future disease.

Indicators of Fetal Growth Do Not Independently Predict Blood Pressure in 8-Year-Old Australians

Inverse associations between size at birth and blood pressure (BP) in later life are commonly statistically significant only after adjustment for current size, consistent with change in size as the determinant. Few studies have been prospective or have included a range of potential confounders. Using regression models, including maternal and demographic variables, we examined associations between size at birth and BP in Australian children followed from week 16 of gestation to the age of 8 years. BP measurements were available from 1417 children born after 37 weeks gestation without congenital abnormalities. In models adjusted only for sex, the birthweight (BW), birth length, ponderal index, head circumference, chest circumference, abdominal girth, mid-arm circumference, triceps skinfold, placental weight, or BW/placental weight ratio did not significantly predict SBP in 8-year-olds. With adjustment for current size, associations were inverse but not statistically significant (regression coefficients: BW, −1.11; 95% confidence limits [CL], −2.22, 0.01; birth length, −0.25; 95% CL, −0.52, 0.24) and remained nonsignificant after adjustment for confounders. Current weight, height, or body mass index significantly predicted SBP and DBP ( P <0.001) with differences of 8/4 mm Hg between upper and lower quartiles; effects were similar in infants with lower and higher BW. These findings are consistent with postnatal change in size as the major determinant of BP in 8-year-olds and are important in the context of the worldwide “epidemic” of obesity in childhood as a likely precursor of increasing rates of hypertension in adults.

Does breastfeeding protect against pediatric overweight? Analysis of longitudinal data from the Centers for Disease Control and Prevention Pediatric Nutrition Surveillance System

OBJECTIVE

To examine whether increasing duration of breastfeeding is associated with a lower risk of overweight in a low-income population of 4-year-olds in the United States.

METHODS

Visit data were linked to determine prospectively the duration of breastfeeding (up to 2 years of age) and weight status at 4 years of age. Overweight among 4-year-old children was defined as a body mass index (BMI)-for-age at or above the 95th percentile based on the 2000 Centers for Disease Control and Prevention growth charts. Logistic regression was performed, controlling for gender, race/ethnicity, and birth weight. In a subset of states, links to maternal pregnancy records also permitted regression analysis controlling for mother's age, education, prepregnancy BMI, weight gain during pregnancy, and postpartum smoking. Data from the Pediatric Nutrition Surveillance System, which extracts breastfeeding, height, and weight data from child visits to public health programs, were analyzed. In 7 states, data were linked to Pregnancy Nutrition Surveillance System data. A total of 177 304 children up to 60 months of age were included in our final pediatric-only analysis, and 12 587 were included in the pregnancy-pediatric linked analysis.

RESULTS

The duration of breastfeeding showed a dose-response, protective relationship with the risk of overweight only among non-Hispanic whites; no significant association was found among non-Hispanic blacks or Hispanics. Among non-Hispanic whites, the adjusted odds ratio of overweight by breastfeeding for 6 to 12 months versus never breastfeeding was 0.70 (95% confidence interval: 0.50-0.99) and for >12 months versus never was 0.49 (95% confidence interval: 0.25-0.95). Breastfeeding for any duration was also protective against underweight (BMI-for-age below the 5th percentile).

CONCLUSION

Prolonged breastfeeding is associated with a reduced risk of overweight among non-Hispanic white children. Breastfeeding longer than 6 months provides health benefits to children well beyond the period of breastfeeding.

The metabolic syndrome in overweight Hispanic youth and the role of insulin sensitivity

The prevalence of the metabolic syndrome is highest among Hispanic adults. However, studies exploring the metabolic syndrome in overweight Hispanic youth are lacking. Subjects were 126 overweight children (8-13 yr of age) with a family history for type 2 diabetes. The metabolic syndrome was defined as having at least three of the following: abdominal obesity, low high-density lipoprotein (HDL) cholesterol, hypertriglyceridemia, hypertension, and/or impaired glucose tolerance. Insulin sensitivity was determined by the frequently sampled iv glucose tolerance test and minimal modeling. The prevalence of abdominal obesity, low HDL cholesterol, hypertriglyceridemia, systolic and diastolic hypertension, and impaired glucose tolerance was 62, 67, 26, 22, 4, and 27%, respectively. The presence of zero, one, two, or three or more features of the metabolic syndrome was 9, 22, 38, and 30%, respectively. After controlling for body composition, insulin sensitivity was positively related to HDL cholesterol (P < 0.01) and negatively related to triglycerides (P < 0.001) and systolic (P < 0.01) and diastolic blood pressure (P < 0.05). Insulin sensitivity significantly decreased (P < 0.001) as the number of features of the metabolic syndrome increased. In conclusion, overweight Hispanic youth with a family history for type 2 diabetes are at increased risk for cardiovascular disease and type 2 diabetes, and this appears to be due to decreased insulin sensitivity. Improving insulin resistance may be crucial for the prevention of chronic disease in this at-risk population.

Established and recently identified coronary heart disease risk factors in young people: the influence of physical activity and physical fitness

Epidemiological studies have identified several risk factors for coronary heart disease (CHD), many of which are present in young people. [For the purpose of this review, the phrase "young people" embraces both children and adolescents.] One such risk factor is hypertension. In adults, exercise is thought to have a positive effect on blood pressure levels; however, findings are inconclusive for young people. Despite its association with CHD, obesity is on the increase in Western society's young population; prevention and intervention during early years is needed. An active lifestyle is considered to have a beneficial effect on body fatness. Lipoprotein profiles are directly associated with CHD status. In adults, there is some evidence that physical activity and/or fitness have a favourable effect on lipoprotein levels. Although information regarding the younger population is more ambiguous, it tends to concur with these findings. High levels of lipoprotein(a), are considered an independent risk factor for CHD. Relatively little has been written on young people, although some studies have postulated a favourable relationship with physical activity. An inverse relationship between aerobic fitness and CHD has been confirmed in adults; an association is not as easily verified for young people. Physical activity is similarly deemed to have a beneficial effect on health status. A high-fat diet has been linked to CHD in adults, and evidence to date reports similar findings for young people. Smoking increases the risk of CHD and even moderate smoking during youth could have damaging long-term consequences. There is some evidence that smoking is related to physical activity and fitness levels in young people. In adults, high levels of homocyst(e)ine have been associated with CHD. As yet, little has been written on the relationship between physical activity or physical fitness and homocysteine status in young people. High levels of plasma fibrinogen have been linked to CHD. Several studies have explored the relationship between plasma fibrinogen and physical activity and/or fitness in adults, but findings are inconclusive; for young people, the ambiguity is even greater. C-reactive protein is a molecular marker for CHD but, to date, little attention has been given to this aspect, especially amongst young people. The link between high levels of plasminogen activator inhibitor-1 and CHD has been confirmed, although the essence of this relationship is not established. There is a paucity of data on the younger population and the relevance of collating such information is questionable. For the younger population, most research is limited to the established CHD risk factors and further investigations of recently identified CHD risk factors are needed.

Inter-relationships among childhood BMI, childhood height, and adult obesity: the Bogalusa Heart Study

OBJECTIVE

Although the body mass index (BMI, mass index, kg/m2) is widely used as a surrogate measure of adiposity, it is moderately associated (r approximately 0.3) with height among children. We examined whether the resulting preferential classification of taller children as overweight is appropriate.

DESIGN

Cross-sectional analyses of children (ages, 3-17 y) examined the relation of height to adiposity (as assessed by BMI and skinfold thicknesses) and fasting levels of insulin. Longitudinal analyses examined the relation of childhood height and weight-height indices to adult (mean age, 25 y) levels of adiposity and fasting insulin.

SUBJECTS

Children (n=11,406) and adults (n=2911) who had participated in the Bogalusa Heart Study.

MEASUREMENTS

We constructed three weight-height indices: BMI, W/H3, and W/Hp. The triceps and subscapular skinfolds, as well as fasting levels of insulin, were also measured.

RESULTS

The classification of children as overweight (BMI-for-age > or =95th percentile) varied markedly by height, with a 10-fold difference in the prevalence of overweight across quintiles of height between the ages of 3 and 10 y. Childhood height, however, was also related to skinfold thicknesses and insulin levels, and all associations were modified in a similar manner by age. Furthermore, childhood height was related to adult adiposity, and of the three childhood weight-height indices, BMI showed the strongest associations with adult adiposity.

CONCLUSIONS

Because BMI reflects the positive association between height and adiposity among children, it is a better weight-height index than is either W/H3 or W/Hp.

School-based obesity screening in rural Appalachia

BACKGROUND

Although identification of obesity during childhood is strongly recommended for the prevention of adult disease, access to obesity screening for children is almost exclusively through physicians' office visits. We examined the feasibility and utility of conducting a school-based obesity and cardiovascular disease (CVD) risk factor screening program in a rural Appalachian population.

METHODS

Height, weight, blood pressure, total cholesterol (TC), and high-density lipoprotein (HDL) cholesterol were measured in 1338 fifth-grade children (631 boys and 707 girls) in 14 rural West Virginia counties in 2000-2001.

RESULTS

We found a high prevalence of overweight (17.5%) and obesity (27.0%). Compared with non-overweight children, obese children had greater risk of high TC (OR 2.4), low HDL cholesterol (OR 5.3), high systolic blood pressure (OR 3.3), and high diastolic blood pressure (OR 2.4) (all OR >1.0, P < 0.05). Only 63% of obese and 26% of overweight children were identified by their physician as having a weight above recommended values.

CONCLUSIONS

The high prevalence of obesity, the associated clustering of CVD risk factors, and the low obesity identification rate by physicians suggest that alternative approaches to obesity screening, such as universal school-based programs, may be warranted in high-risk communities.

Obesity in American-Indian children: prevalence, consequences, and prevention

BACKGROUND

American Indians of all ages and both sexes have a high prevalence of obesity. The health risks associated with obesity are numerous and include Type 2 diabetes mellitus, hypertension, dyslipidemia, and respiratory problems. Obesity has become a major health problem in American Indians only in the past few generations and it is believed to be associated with the relative abundance of high-fat, high-calorie foods and the rapid change from active to sedentary lifestyles.

METHODS

The authors reviewed selected literature on prevalence of obesity in American-Indian children, and health consequences of obesity.

RESULTS

Obesity is now one of the most serious public health problems facing American-Indian children, and it has grave implications for the immediate and long-term health of American-Indian youth. Unless this pattern is reversed, American-Indian populations will be burdened by an increased incidence of chronic diseases. Intervention studies are urgently needed in American-Indian communities to develop and test effective strategies for obesity prevention and treatment.

CONCLUSIONS

To be effective, educational and environmental interventions must be developed with full participation of the American-Indian communities.

Prevalência de sobrepeso e obesidade em pacientes com diabetes tipo 1

Para avaliar a prevalência de sobrepeso e obesidade em diabéticos tipo 1 (DM1), estudamos 170 pacientes (89F/81M; 14 crianças, 51 adolescentes e 105 adultos, com 24,4±11,9 anos) e correlacionamos seus dados antropométricos com fatores demográficos e clínicos. A prevalência de obesidade, sobrepeso e/ou risco de sobrepeso foi de 21,2% (n= 36). Houve uma correlação de 0,97 entre o score z do IMC e o percentil do IMC (p= 0,00) no grupo de crianças e adolescentes. Houve diferença na PAS (p= 0,004) e na PAD (p= 0,0007) entre pacientes com IMC normal e alterado. Ocorreu uma tendência a um aumento progressivo da medida da cintura com os níveis de PA (p= 0,0000). O IMC foi dependente da idade (OR: 1,04, 95% IC = 1,01-1,07; p= 0,008) na análise multivariada. Na análise stepwise, a PAS foi dependente da cintura (r= 0,57; p= 0,00) e da idade (r= 0,63; p= 0,00) e a PAD, da cintura (r= 0,53; p= 0,00). A prevalência de sobrepeso e obesidade nos DM1 parece refletir a tendência mundial de aumento de peso e suas conseqüências clínicas, reforçando a necessidade do controle de peso nestes pacientes.

Diagnosis of the metabolic syndrome in children

PURPOSE OF REVIEW

The metabolic syndrome, a cluster of potent risk factors for atherosclerotic cardiovascular disease and type 2 diabetes mellitus in adults, is composed of insulin resistance, obesity, hypertension and hyperlipidemia. Of significant impact in the adult population, atherosclerotic cardiovascular disease and death are rarely seen in the young, but the pathologic processes and risk factors associated with its development have been shown to begin during childhood. The current review summarizes the work published during the past year in the following areas: childhood obesity, insulin resistance, dyslipidemia, hypertension and type 2 diabetes mellitus.

RECENT FINDINGS

Recent studies have revealed the presence of components of the metabolic syndrome in children and adolescents. Obesity has a central role in the syndrome. There is an increasing amount of data to show that being overweight during childhood and adolescence is significantly associated with insulin resistance, abnormal lipids, and elevated blood pressure in young adulthood. Weight loss in these situations results in a decrease in insulin concentration and an increase in insulin sensitivity toward normalcy. With cardiovascular disease, obesity, and type 2 diabetes reaching epidemic proportions, it is of great importance to understand and control the risk factors at an early age.

SUMMARY

The information obtained during the past year has improved our understanding of the pathogenesis, diagnosis and treatment of components of the metabolic syndrome in children, and potentially could improve the risk profiles for cardiovascular disease as children make the transition toward adolescence and young adulthood.

Changes in childhood food consumption patterns: a cause for concern in light of increasing body weights

Childhood obesity is currently at its highest: recent statistics show that 16% of children between the ages of 6 and 11 y are overweight [> or =95th percentile of body mass index (BMI; in kg/m(2)) for age] and that an additional 14.3% are at risk of becoming overweight (> or =85th percentile but < 95th percentile of BMI for age). As children's body weights have increased, so has their consumption of fast foods and soft drinks. The proportion of foods that children consumed from restaurants and fast food outlets increased by nearly 300% between 1977 and 1996. Children's soft drink consumption has also increased during those years, and now soft drinks provide soft drink consumers 188 kcal/d beyond the energy intake of nonconsumers. These changes in food intakes among children may partly explain the rise in childhood obesity observed in the past few years. Although the mechanism of appetite regulation will not be explored in this report, it is hypothesized that the greater energy intakes in children who consume large amounts of soft drinks and fast foods are not compensated for by increased physical activity or decreased energy intakes. Furthermore, overweight and obesity in childhood may predispose persons to morbidity in adulthood. Blood pressure and fasting insulin and cholesterol concentrations are higher in overweight children than in normal-weight children. This review focuses on current food patterns and eating habits of children, in an attempt to explain their increasing BMI. In addition, a critical review of food service and political practices regarding food choices for children at school is included.

Problems in childhood obesity

Clearly, obesity prevention should be at the forefront of our approach to this epidemic problem and the goal of health care providers, public health officials, community, and families. The problems of the obese child are no longer solely those of increased risk for disease, but of disease itself. Health care providers are increasingly challenged to provide evaluation and treatment for the serious comorbidities and complications of obesity in childhood. Many of these comorbidities and complications are "invisible" and require careful and focused history and laboratory evaluation to elicit. Treatment of the complication and comorbidity should be focused on preventing progression, reversing the disease process, and, ultimately, achieving control of obesity with family-based lifestyle changes that will allow the child to maintain a healthy balance between his or her genetic predisposition and the environment.

Comparison of body composition methods in overweight and obese children

The objective of the present study was to investigate the accuracy of percent body fat (%fat) estimates from dual-energy X-ray absorptiometry, air-displacement plethysmography (ADP), and total body water (TBW) against a criterion four-compartment (4C) model in overweight and obese children. A volunteer sample of 30 children (18 male and 12 female), age of (mean ± SD) 14.10 ± 1.83 yr, body mass index of 31.6 ± 5.5 kg/m, and %fat (4C model) of 41.2 ± 8.2%, was assessed. Body density measurements were converted to %fat estimates by using the general equation of Siri (ADPSiri) (Siri WE. Techniques for Measuring Body Composition. 1961) and the age- and gender-specific constants of Lohman (ADPLoh) (Lohman TG. Exercise and Sport Sciences Reviews. 1986). TBW measurements were converted to %fat estimates by assuming that water accounts for 73% of fat-free mass (TBW73) and by utilizing the age- and gender-specific water contents of Lohman (TBWLoh). All estimates of %fat were highly correlated with those of the 4C model ( r ≥ 0.95, P < 0.001; SE ≤ 2.14). For %fat, the total error and mean difference ± 95% limits of agreement compared with the 4C model were 2.50, 1.8 ± 3.5 (ADPSiri); 1.82, -0.04 ± 3.6 (ADPLoh); 2.86, -2.0 ± 4.1 (TBW73); 1.90, -0.3 ± 3.8 (TBWLoh); and 2.74, 1.9 ± 4.0 DXA (dual-energy X-ray absorptiometry), respectively. In conclusion, in overweight and obese children, ADPLoh and TBWLoh were the most accurate methods of measuring %fat compared with a 4C model. However, all methods under consideration produced similar limits of agreement.

Longitudinal study of skipping breakfast and weight change in adolescents

BACKGROUND

Several cross-sectional studies reported that heavier children eat breakfast less often. However, no longitudinal studies have addressed whether skipping breakfast leads to excessive weight gain.

OBJECTIVE

To investigate whether skipping breakfast was prospectively associated with changes in body fatness.

METHODS

A cohort of >14000 boys and girls from all over the US, 9- to 14-y-old in 1996, returned annual mailed questionnaires (1996-1999) for the Growing Up Today Study. We analyzed change in body mass index (BMI; kg/m(2)) over three 1-y periods among children who reported breakfast frequency.

RESULTS

Children who reported that they never eat breakfast had lower energy intakes than those who eat breakfast nearly every day. Children who were more physically active reported higher energy intakes, as did those who reported more time watching television/videos and playing videogames. Like previous studies, skipping breakfast was associated with overweight, cross-sectionally. However, overweight children who never ate breakfast lost BMI over the following year compared to overweight children who ate breakfast nearly every day (boys: -0.66 kg/m(2) (s.e.=0.22); girls: -0.50 kg/m(2) (s.e.=0.14)). But normal weight children who never ate breakfast gained weight relative to peers who ate breakfast nearly every day (boys: +0.21 kg/m(2) (s.e.=0.13); girls: +0.08 kg/m(2) (s.e.=0.05)). Breakfast frequency was positively correlated with self-reported quality of schoolwork.

CONCLUSIONS

Overweight children who never eat breakfast may lose body fat, but normal weight children do not. Since numerous studies link skipping breakfast to poorer academics, children should be encouraged to eat breakfast.

Health consequences of obesity

The recent epidemic of childhood obesity(1) has raised concern because of the possible clinical and public health consequences.(2,)(3) However, there remains a widespread perception among health professionals that childhood obesity is a largely cosmetic problem, with minor clinical effects. No systematic review has yet focused on the diverse array of possible consequences of childhood obesity, though older non-systematic reviews are available.(4,)(5) In addition, no review to date has considered the vast body of evidence on the health impact of childhood obesity which has been published recently. The aim of the present review was therefore to provide a critically appraised, evidence based, summary of the consequences of childhood obesity in the short term (for the child) and longer term (in adulthood).

Hypertension in adolescents: a review of diagnosis and management

Long-term hypertension contributes to significant cardiovascular and renal morbidity and mortality. Although chronic hypertension is much rarer in the adolescent population than in adults, identifying the hypertensive adolescent and intervening with risk factors such as obesity that may promote hypertension is important for the clinician treating adolescents. Since both primary and secondary causes of hypertension may exist in the adolescent, a thorough and sequential clinical and diagnostic evaluation must be undertaken, including screening urinalysis, blood chemistries, and renal sonography. There are pitfalls in interpreting casual blood pressure measurements in adolescents, and the role of ambulatory blood pressure monitoring is evolving. Lifestyle modifications, including diet, exercise, and limitation of sodium intake, remain the foundation of treatment. Commonly used medications include calcium channel blockers, angiotensin receptor blockers and converting enzyme inhibitors, beta blockers, and diuretics. When considering medication in the hypertensive adolescent, potential complications of therapy must be reviewed in light of the physical and psychosocial changes ongoing in this age group.

Prevention of pediatric overweight and obesity

The dramatic increase in the prevalence of childhood overweight and its resultant comorbidities are associated with significant health and financial burdens, warranting strong and comprehensive prevention efforts. This statement proposes strategies for early identification of excessive weight gain by using body mass index, for dietary and physical activity interventions during health supervision encounters, and for advocacy and research.

Coexistence of social inequalities in undernutrition and obesity in preschool children: population based cross sectional study

AIMS

To test for the coexistence of social inequalities in undernutrition and obesity in preschool children.

METHODS

Retrospective, cross sectional, study of routinely collected data from 74 500 children aged 39-42 months in 1998/99. Main outcome measures were weight, height, sex, and age routinely recorded by health visitors. Body mass index (BMI) standardised for age and sex, relative to UK 1990 reference data, was used to define undernutrition (BMI <2nd centile) and obesity (BMI >95th centile; BMI >98th centile). Social deprivation was assessed as Carstairs deprivation category (1 = most affluent to 7 = most deprived).

RESULTS

Both undernutrition (3.3%) and obesity (8.5% above 95th centile; 4.3% above 98th centile) significantly exceeded expected frequencies from UK 1990 reference data. Undernutrition and obesity were significantly more common in the more deprived families. Odds ratios in deprivation category 7 relative to category 1 were 1.51 (95% CI 1.22 to 1.87) for undernutrition (BMI <2nd centile) and 1.30 (95% CI 1.05 to 1.60) for obesity (BMI >98th centile). The cumulative prevalence of under and overnutrition (malnutrition) in the most deprived group was 9.5% compared to 6.9% in the least deprived group.

CONCLUSIONS

Undernutrition and obesity are significantly more common than expected in young children and strongly associated with social deprivation. Both undernutrition and obesity have adverse short and long term health effects. Public health strategies need to tackle malnutrition (both undernutrition and obesity) in children and take into consideration the association with social deprivation.

Trends and predictors of overweight and obesity in East German children

OBJECTIVE

Childhood overweight and obesity seem to be increasing at an alarming rate throughout the Western world. During the 1990's, tremendous socioeconomic changes have taken place in East Germany, and studies about the prevalence and trends of childhood overweight and obesity in Central Eastern European countries are rare. Therefore, we analyzed trends in overweight and obesity in East German school children.

DESIGN AND SUBJECTS

We examined 5- to 7-y-old school entrants, 8- to 10-y-old third graders and sixth-grade school children aged 11-14 y in three consecutive surveys performed in 1992-93, 1995-96, and 1998-99 in Eastern Germany. In total, we received 7611 questionnaires. Information about height and weight was available for 6650 children.

RESULTS

Overweight and obesity showed a significant increasing trend for 11- to 14-y and 8- to 10-y-old children but not for the school entrants aged 5-7 y. After adjustment for age, sex, season and area, the risk of being overweight in 1998-99 compared to 1992-93 was 1.6 (CI 1.4-1.9) and 1.9 (CI 1.4-2.5) for obesity, respectively. Low birth weight and higher parental education were protective factors for overweight and obesity. Breast feeding was protective with regard to obesity. This effect was stronger if the children were exclusively breast-fed.

CONCLUSIONS

In conclusion, our data provide further evidence that the prevalence of overweight and obesity increases. These results might suggest that preventive actions should start as early as possible and children from disadvantaged families might be considered as a susceptible subgroup.

Child and adolescent obesity in the 21st century: an Australian perspective

The early 21st century has seen the development of a global epidemic of obesity in both developed and developing countries. In Australia at least one in five children and adolescents are overweight or obese, with rapid rises in prevalence apparently continuing. Similar trends are seen in other countries. Child and adolescent obesity is associated with both immediate and long-term medical and psychosocial problems, including a clustering of risk factors for the development of cardiovascular disease and diabetes. Thus, obesity poses a major health problem for the paediatric population. Major environmental and societal changes have led to a decrease in physical activity, a rise in sedentary behaviour and the consumption of high fat and high-energy foods, all in turn influencing the development of obesity. Effective management involves a multimodal approach with a developmentally aware approach, involvement of the family, a focus on healthy food choices, incorporation of physical activity and a decrease in sedentary behaviour all being important. Ultimately, however, the obesity epidemic requires a major focus on primary prevention. Australia has a national strategy for the prevention of overweight and obesity that depends upon intersectoral and intergovernmental cooperation, supported by adequate resourcing and significant community ownership.

Application of laparoscopy for bariatric surgery in adolescents

An epidemic increase in adolescent obesity in the United States has resulted in significant obesity-related comorbidities, previously seen only in adults. Although bariatric surgery is an acceptable alternative for weight loss in severely obese adults, no conclusions have been made about the appropriateness of bariatric surgery for individuals younger than 18 years old. Nonetheless, bariatric surgery is increasingly being performed on adolescents with clinically severe obesity and experience suggests that it is effective and safe. Application of the principles of adolescent growth, development, and compliance is essential to avoid adverse physical, cognitive, and psychosocial outcomes following bariatric surgery. Bariatric surgery should be part of a multidisciplinary approach to the management of adolescents with clinically severe obesity and should be performed by specialists dedicated to pediatric care, in institutions capable of meeting the guidelines for surgical treatment outlined by the American Society of Bariatric Surgery.

Measures of overweight status in school-age children

Identifying and intervening with overweight children may decrease their likelihood of developing heart disease later in life. This secondary analysis of 58 children in the 3rd grade examined the prevalence of overweight children, methods for measuring overweight status, and the relationship among these measures and other risk factors for heart disease. Approximately one third of the 58 children were categorized as overweight. Several measures, such as weight, body fat percentage, body mass index (BMI), and skin-fold, are available to school nurses for measuring overweight status. The highest correlations were between BMI and weight and between BMI and body fat. Anthropometric measurements cannot predict cholesterol level, 24-hour diet recall, or family history. Blood pressure can be predicted by weight, body fat percentage, and BMI. BMI and body fat percentage highly correlate; however, body fat percentage is more liberal in identifying children at risk for overweight status. Therefore, body fat percentage is recommended for identification of overweight status in school-age children.

The utility of the international child and adolescent overweight guidelines for predicting coronary heart disease risk factors

The purpose of this study was to assess the association between the international overweight cutoffs for children and youth and coronary heart disease risk factors. The sample included 410 boys and 337 girls 9-18 years of age from the Québec Family Study. Participants were classified as normal weight or overweight using the international BMI cutoffs, and into normal and elevated risk groups based on the 90th percentile of sex-specific age-adjusted risk factors [blood pressure, fasting total cholesterol (CHOL), LDL-C, HDL-C, CHOL/HDL-C, triglycerides, glucose, and physical work capacity]. Overweight participants had between 1.6 and 9.1 times the risk of elevated risk factors compared to normal-weight participants. Further, boys and girls with four or more risk factors were 19 and 43 times more likely to be overweight, respectively, compared to participants with no risk factors. The results add evidence that the international cutoffs are related to health risks in youth, supporting the adoption of the guidelines.

Hostility predicts metabolic syndrome risk factors in children and adolescents

The authors tested in 134 African American and European American children whether hostility measured at study entry predicted the metabolic syndrome risk factors an average of 3 years later. Hostility was measured with the Cook-Medley Hostility Scale (W. W. Cook & D. M. Medley, 1954) and with ratings of Potential for Hostility from interview responses. Metabolic syndrome was based on having at least 2 of the following risk factors above the 75th percentile of scores for their age, race, and gender group: body mass index, insulin resistance index, ratio of triglycerides to high-density lipoprotein cholesterol, and mean arterial blood pressure. Children who exhibited high hostility scores at baseline were likely to exhibit the metabolic syndrome at the follow-up. The results highlight the potential importance of early prevention and intervention of behavioral risk factors for cardiovascular disease.

The prevalence of obesity and undernutrition in Scottish children: growth monitoring within the Child Health Surveillance Programme

OBJECTIVE

To assess whether anthropometric data, routinely collected as part of the Scottish Child Health Surveillance System (CHSP-PS, pre-school children; CHSP-S, school age children) could provide a means of monitoring/surveillance for obesity and undernutrition at national and health board level.

DESIGN

A survey of 15 health boards and both surveillance systems to identify the nature of data collected, format of data, and extent to which data were accessible (e.g., via Information and Statistics Division of the Common Services Agency). Measurements of weight and height collected as part of the CHSP-PS and CHSP-S were extracted from ISD. They were then audited and missing values or implausible values quantified, and degree of dispersion of values used as an index of quality of measurements.

SETTING

Health Board Child Health Surveillance Systems and Information and Statistics Division, Edinburgh.

RESULTS

Data on height and weight are currently available for 9 health boards for pre-school children and 4 health boards for school age children. This represents coverage of around 80% of the pre-school child population. Analysis of a data extract from the 39-42 month check in 1998/99, used as an example, revealed that 8% of weight and height data were missing, and approximately 1% were implausible measures. Population and health board level estimates of prevalence of obesity and undernutrition were possible and are presented. Data on height and weight are routinely collected in school age children in all health boards, however only four health boards have growth data electronically available via the school CHSP.

CONCLUSIONS

Growth data routinely collected as part of child health surveillance for Scotland can be used to estimate population prevalence of undernutrition and obesity. These can in turn be used to monitor trends at local and national level, to monitor achievement in relation to public health targets, identify risk factors and high risk groups, and to follow cohorts over time. We describe a system of surveillance for undernutrition and obesity and identify its strengths and weaknesses.

One-year changes in activity and in inactivity among 10- to 15-year-old boys and girls: relationship to change in body mass index

OBJECTIVE

Cross-sectional studies have suggested that children who were less physically active and children who watched more television (TV) had more excess body weight, but no large nationwide longitudinal studies have addressed whether children who change their personal levels of activity or inactivity, from one year to the next, experience changes in adiposity. Our objective is to study the association between change in body mass index (BMI) over 1 year and same year change in recreational physical activity and change in recreational inactivity (TV/videos/video games).

DESIGN

Cohort study using data from 2 mailed questionnaires, 1 year apart.

PARTICIPANTS

A total of 11 887 boys and girls, aged 10 to 15, who returned questionnaires in both 1997 and 1998 as part of the Growing Up Today Study. Outcome Measure. Change in BMI from 1997-1998, accounting for increases in BMI associated with growth and development.

RESULTS

An increase in physical activity from 1997-1998 was associated with decreasing relative BMI in girls (-0.06 kg/m2 per hour increase in daily activity; 95% confidence interval [CI]: -0.11, -0.01) and in overweight boys (-0.22 kg/m2; CI: -0.33, -0.10). An increase in inactivity was associated with increasing BMI in girls (+0.05 kg/m2 per hour increase in daily TV/videos/video games; CI: +0.02, +0.08). Effects were generally stronger among overweight children. Increasing time doing aerobics/dancing and walking were associated with BMI declines for some groups of children.

CONCLUSIONS

Many children may benefit by increasing their physical activity and by reducing time watching TV or videos and playing video games. In particular, 2 activities accessible to most children, aerobics/dancing and walking, also appeared beneficial.

Secular trends in body dimensions and physical fitness among adolescents in Sweden from 1974 to 1995

AIM

To investigate changes over time in body dimensions, and muscular and aerobic fitness in a representative sample of 16-year-old-girls and boys in secondary schools in Sweden from 1974 to 1995 (n = 855).

METHOD

Height and weight were measured and five tests were performed: run-walk, two-hand-lift, Sargent jump, sit-ups, and bench-press.

RESULTS

In 1995, girls and boys had higher body mass index (BMI) than in 1974. Girls and boys performed less well in bench-press, sit-ups, and run-walk-tests in 1995. Boys, but not girls, performed better in Sargent jump in 1995 than in 1974. Girls and boys performed better in two-hand-lift in 1995 than in 1974. However, after adjustment for body dimensions, there were no differences in performance in two-hand-lift or run-walk-tests between 1974 and 1995.

CONCLUSION

There was a decreased aerobic fitness and an increased maximal static strength among adolescents in Sweden between 1974 and 1995. These changes were partly due to increased BMI. However, decreased daily physical activity level cannot be excluded as a contributing factor to the decreased aerobic fitness. The reduced performance in muscular endurance in 1995 was not related to increased BMI. Instead, it is suggested that it is to be related to a specific decrease in hip flexion and arm muscle endurance.

Fetal origins of obesity

The worldwide epidemic of obesity continues unabated. Obesity is notoriously difficult to treat, and, thus, prevention is critical. A new paradigm for prevention, which evolved from the notion that environmental factors in utero may influence lifelong health, has emerged in recent years. A large number of epidemiological studies have demonstrated a direct relationship between birth weight and BMI attained in later life. Although the data are limited by lack of information on potential confounders, these associations seem robust. Possible mechanisms include lasting changes in proportions of fat and lean body mass, central nervous system appetite control, and pancreatic structure and function. Additionally, lower birth weight seems to be associated with later risk for central obesity, which also confers increased cardiovascular risk. This association may be mediated through changes in the hypothalamic pituitary axis, insulin secretion and sensing, and vascular responsiveness. The combination of lower birth weight and higher attained BMI is most strongly associated with later disease risk. We are faced with the seeming paradox of increased adiposity at both ends of the birth weight spectrum-higher BMI with higher birth weight and increased central obesity with lower birth weight. Future research on molecular genetics, intrauterine growth, growth trajectories after birth, and relationships of fat and lean mass will elucidate relationships between early life experiences and later body proportions. Prevention of obesity starting in childhood is critical and can have lifelong, perhaps multigenerational, impact.

Smoking, physical activity and breakfast consumption among secondary school students in a southwestern Ontario community

OBJECTIVES

To determine the prevalence of smoking, low levels of physical activity, and missing breakfast among students (n=318) in grades 9 through 12 in three schools in southwestern Ontario; to see if these behaviours were associated; and, whether there were gender differences.

METHODS

A self-administered survey was conducted in grade 10 English classes.

RESULTS

The response rate was 87.1%. The prevalence of smoking was 36.2%; there was no gender difference. Only 42.8% of students ate breakfast daily; 48.8% of boys and 36.1% of girls (chi2 = 5.2; p<0.05). A higher proportion of boys (77.1%) were active for at least 30 minutes > or = 3 times/week compared to girls (66.0%) (chi2 = 4.8; p<0.05). Students who were active > or = 3 times/week were more likely to eat breakfast daily and, among boys, 60.4% of non-smokers ate breakfast daily compared to 31.9% of those currently smoking (chi2 = 13.3; p<0.001). There were no differences among girls. More girls (63.9%) were concerned about gaining weight compared to boys (36.1%) (chi2 = 37.7; p<0.001). Among girls, a higher proportion of those who were concerned about gaining weight were less likely to engage in physical activity or smoke, and more likely to skip breakfast compared to those who were not concerned.

DISCUSSION

Weight concern was not associated with frequency of physical activity, smoking, or breakfast consumption among boys. The high prevalence rates for these behaviours suggests that interventions in high schools should include daily physical activity, promotion of breakfast eating (either at home or in the school), and encouragement to quit smoking.

Prolongation of satiety after low versus moderately high glycemic index meals in obese adolescents

BACKGROUND

One in 5 American children is overweight, despite a decrease in total fat consumption. This has sparked an interest in the carbohydrate composition of diets, including the glycemic index (GI).

OBJECTIVE

To investigate whether a low-GI meal replacement (LMR) produced similar metabolic, hormonal, and satiety responses in overweight adolescents as a low-GI whole-food meal (LWM) when compared with a moderately high-GI meal replacement (HMR).

METHODS

Randomized, crossover study comparing LMR, HMR, and LWM in 16 (8 male/8 female) adolescents during 3 separate 24-hour admissions. The meal replacements consisted of a shake and a nutrition bar. Identical test meals were provided at breakfast and lunch. Metabolic and hormonal indices were assessed between meals. Measures of participants' perceived satiety included hunger scales and ad libitum food intake.

RESULTS

The incremental areas under the curve for glucose were 46% and 43% lower after the LMR and LWM, respectively, compared with the HMR. Insulin's incremental area under the curve was also significantly lower after both low GI test meals (LMR = 36%; LWM = 51%) compared with the HMR. Additional food was requested earlier after the HMR than the LMR (3.1 vs 3.9 hours, respectively), although voluntary energy intake did not differ.

CONCLUSIONS

Differences in insulin response between the meal replacements occurred, and prolongation of satiety after the LMR, based on time to request additional food, was observed. We speculate that the prolonged satiety associated with low GI foods may prove an effective method for reducing caloric intake and achieving long-term weight control.

Maternal gestational diabetes, birth weight, and adolescent obesity

OBJECTIVE

Obesity increases risk of many adverse outcomes, but its early origins are obscure. Gestational diabetes mellitus (GDM) reflects a metabolically altered fetal environment associated with high birth weight, itself associated with later obesity. Previous studies of GDM and offspring obesity, however, have been few and conflicting. The objectives of this study were to examine associations of birth weight and GDM with adolescent body mass index (BMI) and to determine the extent to which the effect of GDM is explained by its influence on birth weight or by maternal adiposity.

METHODS

We conducted a survey of 7981 girls and 6900 boys, 9 to 14 years of age, who are participants in the Growing Up Today Study, a US nationwide study of diet, activity, and growth. In 1996, participants reported height, weight, diet, activity, and other variables by self-administered mailed questionnaire. We linked these data with information reported by their mothers, participants in the Nurses' Health Study II, including GDM, height, current weight, and child's birth weight. We excluded births <34 weeks' gestation and mothers who had preexisting diabetes. We defined overweight as BMI (kg/m(2)) >95th percentile, and at risk for overweight as 85th to 95th percentile, for age and gender from US national data.

RESULTS

Mean birth weight was 3.4 kg for girls and 3.6 kg for boys. Among the 465 subjects whose mothers had GDM, 17.1% were at risk for overweight and 9.7% were overweight in early adolescence. In the group without maternal diabetes, these estimates were 14.2% and 6.6%, respectively. In multiple logistic regression analysis, controlling for age, gender, and Tanner stage, the odds ratio for adolescent overweight for each 1-kg increment in birth weight was 1.4 (95% confidence interval: 1.2-1.6). Adjustment for physical activity, television watching, energy intake, breastfeeding duration, mother's BMI, and other maternal and family variables reduced the estimate to 1.3 (1.1-1.5). For offspring of mothers with GDM versus no diabetes, the odds ratio for adolescent overweight was 1.4 (1.1-2.0), which was unchanged after controlling for energy balance and socioeconomic factors. Adjustment for birth weight slightly attenuated the estimate (1.3; 0.9-1.9); adjustment for maternal BMI reduced the odds ratio to 1.2 (0.8-1.7).

CONCLUSIONS

Higher birth weight predicted increased risk of overweight in adolescence. Having been born to a mother with GDM was also associated with increased adolescent overweight. However, the effect of GDM on offspring obesity seemed only partially explained by its influence on birth weight, and adjustment for mother's own BMI attenuated the GDM associations. Our results only modestly support a causal role of altered maternal-fetal glucose metabolism in the genesis of obesity in the offspring. Alternatively, GDM may program risk for a postnatal insult leading to obesity, or it may merely be a risk marker, not in the causal pathway.

Effects of a low-carbohydrate diet on weight loss and cardiovascular risk factor in overweight adolescents

OBJECTIVES

To compare the effects of a low-carbohydrate (LC) diet with those of a low-fat (LF) diet on weight loss and serum lipids in overweight adolescents.

DESIGN

A randomized, controlled 12-week trial.

SETTING

Atherosclerosis prevention referral center.

METHODS

Random, nonblinded assignment of participants referred for weight management. The study group (LC) (n = 16) was instructed to consume <20 g of carbohydrate per day for 2 weeks, then <40 g/day for 10 weeks, and to eat LC foods according to hunger. The control group (LF) (n = 14) was instructed to consume <30% of energy from fat. Diet composition and weight were monitored and recorded every 2 weeks. Serum lipid profiles were obtained at the start of the study and after 12 weeks.

RESULTS

The LC group lost more weight (mean, 9.9 +/- 9.3 kg vs 4.1 +/- 4.9 kg, P <.05) and had improvement in non-HDL cholesterol levels (P <.05). There was improvement in LDL cholesterol levels (P <.05) in the LF group but not in the LC group. There were no adverse effects on the lipid profiles of participants in either group.

CONCLUSIONS

The LC diet appears to be an effective method for short-term weight loss in overweight adolescents and does not harm the lipid profile.

The prevention and treatment of childhood obesity

The effectiveness of interventions used in the prevention and treatment of childhood obesity published in a recent issue of Effective Heath Care is reviewed.

Childhood obesity in Canada: a review of prevalence estimates and risk factors for cardiovascular diseases and type 2 diabetes

Childhood obesity in Canada has become increasingly prevalent over the past 2 decades. Despite inconsistencies regarding different anthropometric indicators, cut-offs, and reference populations, both regional and national investigations have revealed high numbers of overweight and obese children and adolescents. A number of risk factors and health consequences have been associated with increased levels of body fatness in youth. Specifically, risk factors for cardiovascular diseases (CVD) and type 2 diabetes are known to develop early in life and tend to emerge in clusters among overweight youngsters. Unhealthy lifestyle behaviours (i.e., physical inactivity), a genetic disposition, and a centralized body fat distribution, all contribute to increased risk. In order to prevent future generations of children from experiencing increased morbidity and mortality as overweight and obese adults, coordinated efforts at all levels (family, school, community, and government) must be established with a long-term commitment to promote healthy nutrition and physical activity behaviours in our youth.

Cardiovascular risk factor profiles and their social gradient from adolescence to age 74 in a Swiss region

BACKGROUND

Few European studies have investigated how cardiovascular risk factors (CRF) in adults relate to those observed in younger generations.

OBJECTIVE

To explore this issue in a Swiss region using two population health surveys of 3636 adolescents ages 9-19 years and 3299 adults ages 25-74 years.

METHODS

Age patterns of continuous CRF were estimated by robust locally weighted regression and those of high-risk groups were calculated using adult criteria with appropriate adjustment for children.

RESULTS

Gender differences in height, weight, blood pressure, and HDL cholesterol observed in adults were found to emerge in adolescents. Overweight, affecting 10-12% of adolescents, was increasing steeply in young adults (three times among males and twice among females) in parallel with inactivity. Median age at smoking initiation was decreasing rapidly from 18 to 20 years in young adults to 15 in adolescents. A statistically significant social gradient in disfavor of the lower education level was observed for overweight in all age groups of women above 16 (odds ratios (ORs) 2.4 to 3.3, P < 0.01), for inactivity in adult males (ORs 1.6 to 2.0, P < 0.05), and for regular smoking in older adolescents (OR 1.9 for males, 2.7 for females, P < 0.005), but not for elevated blood pressure.

CONCLUSION

Discontinuities in the cross-sectional age patterns of CRF indicated the emergence of a social gradient and the need for preventive actions against the early adoption of persistent unhealthy behaviors, to which low-educated girls and women are particularly exposed.

Body fat percentages measured by dual-energy X-ray absorptiometry corresponding to recently recommended body mass index cutoffs for overweight and obesity in children and adolescents aged 3-18 y

BACKGROUND

Body mass index (BMI; in kg/m2) cutoffs for use with children and adolescents aged 2-18 y that correspond to the well-accepted BMI cutoffs for overweight (> or = 25 but < 30) and obesity (> or = 30) in adults were published recently.

OBJECTIVE

The objective was to estimate the percentage body fat (%BF) values typically associated with these BMI cutoffs in children and adolescents.

DESIGN

The %BF was measured by dual-energy X-ray absorptiometry in 661 subjects (49% male) aged 3-18 y. Regression equations using BMI, age, and sex were developed to predict the %BF associated with BMI cutoffs for overweight (age-specific BMI equivalent to a BMI of 25 in an 18-y-old) and obesity (age-specific BMI equivalent to a BMI of 30 in an 18-y-old) over this age range.

RESULTS

Measurements classified 17.1% of males and 19.8% of females as overweight and 5.5% of males and 7.5% of females as obese. The %BF associated with an obese BMI tended to be higher in peripubertal males (34-36%) than in younger (24-30%) or older (27-30%) males. Although the predicted %BF of young females was similar to that of young males, values rose steadily with age, such that an 18-y-old female with a BMI of 30 had an estimated %BF of 42%, whereas that in males of similar age was 27%.

CONCLUSION

The %BF values associated with BMI classifications of overweight and obesity vary considerably with age in growing children, particularly in girls.

Television viewing and its associations with overweight, sedentary lifestyle, and insufficient consumption of fruits and vegetables among US high school students: differences by race, ethnicity, and gender

Television (TV) viewing has been associated with overweight, decreased physical activity, and unhealthy dietary behavior among children and adolescents, and may represent a modifiable cause of childhood obesity. This study examined race, ethnic, and gender-specific differences in these associations among high school students in the United States. The study analyzed data from the 1999 national Youth Risk Behavior Survey, a representative sample (N = 15,349) of US high school students. Logistic regression tested for significant associations. TV viewing on an average school day exceeded 2 hours/day among 43% of students; it was greater among Black (74%) and Hispanic (52%) than White (34%) students. Overall, 11% of students were overweight, 31% of students were sedentary (i.e., did not participate in moderate or vigorous physical activity at recommended levels), and 76% ate less than five servings/day of fruits and vegetables. Watching TV more than 2 hours/day was associated with being overweight, being sedentary, and eating insufficient fruits and vegetables among White females, and with being overweight among Hispanic females. No significant associations were found among Black females. TV viewing was associated with being overweight and eating insufficient fruits and vegetables among White males. No significant associations were found among Hispanic males. Among Black males, TV viewing was associated with greater participation in physical activity. These findings suggest the presence of cultural factors to consider when developing interventions to promote physical activity, healthy eating, and healthy weight through reduced TV viewing among adolescents.

Overweight and obesity in 6- to 14-year-old Czech children in 1991: protective effect of breast-feeding

OBJECTIVE

To assess the impact of breast-feeding on childhood overweight/obesity in an Eastern European socialist society with relatively homogeneous lifestyles.

STUDY DESIGN

Cross-sectional survey data collected in 1991 on 33,768 school-children aged 6 to 14 years in the Czech Republic were analyzed by using multiple logistic regression analyses (main outcome body mass index [BMI] >90th percentile [overweight] and BMI >97th percentile [obesity]).

RESULTS

Overall prevalence of overweight (obesity) was lower in breast-fed children: ever breast-fed (9.3%; 95% CI, 8.9-9.6 [3.2%; 95% CI, 3.0-3.4]) compared with never breast-fed (12.4%; 95% CI, 11.3-13.6 [4.4%; 95% CI, 3.7-5.2]). The effect of breast-feeding on overweight/obesity did not diminish with age in children 6 to 14 years old and could not be explained by parental education, parental obesity, maternal smoking, high birth weight, watching television, number of siblings, and physical activity. Adjusted odds ratios for breast-feeding were for overweight 0.80 (95% CI, 0.71-0.90) and for obesity 0.80 (95% CI, 0.66-0.96).

CONCLUSIONS

A reduced prevalence of overweight/obesity was associated with breast-feeding in a setting where socioeconomic status was homogeneous. This suggests that the effect of breast-feeding on the prevalence of obesity is not confounded by socioeconomic status.