Obesity and external sexual maturation---the Bogalusa Heart Study

Growth in height and its association with overweight and obesity in Mexican children: an evaluation based on a nationally representative sample (ENSANUT 2018)

The present study aimed to estimate the height growth curve for Mexican boys and girls based on their body mass index (BMI) status (normal and overweight/obese) and to develop a height Lambda, Mu, and Sigma (LMS) growth reference for Mexican children aged 2 to 18 years.

Methods

Chronological age and height records (7,097 boys and 6,167 girls) were obtained from the Mexican National Survey of Health and Nutrition database. Height growth curves were fitted using the Preece-Baines 1 (PB1) model and the LMS method.

Results

Age at peak height velocity (APHV) was 12.4 and 12.7 years for overweight-obese and normal-weight boys, respectively, and was 9.6 and 10.4 years for overweight-obese and normal-weight girls, respectively. Growth velocity was higher at the age of take-off (TO) in overweight-obese children than in normal-weight children (5.2 cm/year vs. 5 cm/year in boys and 6.1 cm/year vs. 5.6 cm/year in girls); nevertheless, the growth velocity at APHV was higher for normal-weight children than for overweight-obese children (7.4 cm/year vs. 6.6 cm/year in boys and 6.8 cm/year vs. 6.6 cm/year in girls, respectively). Distance curves developed in the present study and by the World Health Organization (WHO) using LMS showed similar values for L and S parameters and a higher M value compared with the WHO reference values.

Conclusion

This study concluded that overweight-obese children had earlier APHV and lower PHV than normal-weight children. Furthermore, Mexican children and adolescents were shorter than the WHO growth reference by age and sex.

Adolescent gynecomastia is associated with a high incidence of obesity, dysglycemia, and family background of diabetes mellitus

BACKGROUND

Gynecomastia during adolescence is common though etiology is not clear. We studied the clinical and hormonal profile of adolescent patients with gynecomastia.

METHODOLOGY

Patients who had onset of breast development between age 10 and 20 years were included in this study. Their clinical profile, biochemical, and hormonal parameters were studied.

RESULTS

Of 94 patients with gynecomastia, 4 had hypogonadotropic hypogonadism, 4 had hypergonadotropic hypogonadism, and 1 had fibroadenosis, but in majority (90.4%), no apparent cause for breast enlargement was evident. In the idiopathic group, majority were obese (63%). Fourteen (16%) patients had impaired fasting glucose or impaired glucose tolerance. Another twenty patients had subtle abnormalities (high 1 h glucose or glucose peak at 2 h). Twenty-nine percent of lean and 38% of obese patients had mild abnormalities in glucose profile. Sixty percent of patients had family background of diabetes. Obese patients had lower testosterone as compared to lean patients; however, estradiol, luteinizing hormone, and follicle-stimulating hormone levels were similar in the two groups.

CONCLUSION

Gynecomastia during adolescence is associated with obesity, dysglycemia, and family background of diabetes mellitus.

Steroid Metabolomic Disease Signature of Nonsyndromic Childhood Obesity

CONTEXT

The profile of urinary steroids as measured by gas chromatography-mass spectrometry defines a subject's "steroidal fingerprint."

OBJECTIVE

Here, we clustered steroidal fingerprints to characterize patients with nonsyndromic childhood obesity by "steroid metabolomic signatures."

HYPOTHESIS

Nonsyndromic obesity is a symptom of different diseases and conditions, some of them will have their own signature.

DESIGN

A total of 31 steroid metabolites were quantified by gas chromatography-mass spectrometry, and their excretion rates were z-transformed. Using MetaboAnalyst 3.0, we divided the subjects into 5 distinctive groups by k-means clustering. Steroidal fingerprints and clinical/biochemical data of patients in each cluster were analyzed.

PATIENTS

A total of 87 obese children (44 females), aged 8.5-17.9 years, were clinically characterized, and their 24-hour urine was collected.

RESULTS

Cluster 1 (n = 39, 21 females) had normal steroid profile. Cluster 2 (n = 20, 11 females) showed mild, nonspecific elevation of C19 and C21 steroids, females' resistance to polycystic ovary morphology, and hirsutism. Cluster 3 (n = 7 female), with relative 21-hydroxylase insufficiency, was characterized by partial or full polycystic ovary syndrome. Cluster 4 (n = 4 males), showed markedly elevated C21 steroids and imbalance in the 11β-hydroxysteroid dehydrogenase system, higher insulin, increased frequency of glucose/insulin index more than 0.3, γ-glutamyl transpeptidase activity, systolic blood pressure, and tendency to liver steatosis. Cluster 5 (n = 17, 5 females) had elevated dehydroepiandrosterone and 17-OH-pregnenolone metabolites, suggesting 3β-hydroxysteroid dehydrogenase insufficiency but no clinically unique phenotype. Z-score body mass index values were not significantly different between the clusters.

CONCLUSIONS

We defined a novel concept of disease-specific steroid metabolomic signature based on urinary steroidal gas chromatography-mass spectrometry. Clustering by software designed for metabolic data analysis reclassified childhood obesity into 5 groups with distinctive signatures; groups require further definition and may require cluster-specific therapeutic strategies.

Sexual dimorphisms in the associations of BMI and body fat with indices of pubertal development in girls and boys

CONTEXT

The effect of obesity and concomitant insulin resistance on pubertal development is incompletely elucidated.

OBJECTIVE

To determine how measures of adiposity and insulin resistance are associated with pubertal maturation in boys and girls.

SETTING AND DESIGN

Breast and pubic hair Tanner stage and testicular volume by orchidometry were determined by physical examination in 1066 children. Ovarian volume was estimated by trans-abdominal ultrasound. Fat mass, skeletal age, and fasting serum for insulin and glucose, total T, estradiol, estrone, dehydroepiandrosterone-sulfate, and androstenedione were measured at the National Institutes of Health Clinical Research Center. Convenience sample; 52% obese, 59% female.

RESULTS

Logistic regression identified a significant interaction between sex and obesity for prediction of pubertal development (P ≤ .01). There was a negative association between boys' testicular volume and body mass index (BMI)/fat mass but a positive association between girls' breast stage and BMI/fat mass. Ovarian volume in girls was positively associated with insulin resistance but not with BMI/fat mass. There was a positive association between obesity and measures of estrogen exposure (breast development and skeletal age) in both sexes. Positive correlations were seen for girls between BMI and pubic hair development and between insulin resistance and T production, whereas adiposity was negatively associated with pubic hair in boys.

CONCLUSIONS

Significant sexual dimorphisms in the manifestations of pubertal development are seen in obese girls and boys. Two known effects of obesity, increased peripheral conversion of low-potency androgens to estrogens by adipose tissue-aromatase and increased insulin resistance, may be in large part responsible for these differences.

Pediatric body composition analysis with dual-energy X-ray absorptiometry

Pediatric applications of body composition analysis (BCA) have become of increased interest to pediatricians and other specialists. With the increasing prevalence of morbid obesity and with an increased awareness of anorexia nervosa, pediatric specialists are utilizing BCA data to help identify, treat, and prevent these conditions. Dual-energy X-ray absorptiometry (DXA) can be used to determine the fat mass (FM) and lean tissue mass (LTM), as well as bone mineral content (BMC). Among the readily available BCA techniques, DXA is the most widely used and it has the additional benefit of precisely quantifying regional FM and LTM. This review evaluates the strengths and limitations of DXA as a pediatric BCA method and considers the utilization of DXA to identify trends and variations in FM and LTM measurements in obese and anorexic children.

Pediatric body composition analysis with dual-energy X-ray absorptiometry

Pediatric applications of body composition analysis (BCA) have become of increased interest to pediatricians and other specialists. With the increasing prevalence of morbid obesity and with an increased awareness of anorexia nervosa, pediatric specialists are utilizing BCA data to help identify, treat, and prevent these conditions. Dual-energy X-ray absorptiometry (DXA) can be used to determine the fat mass (FM) and lean tissue mass (LTM), as well as bone mineral content (BMC). Among the readily available BCA techniques, DXA is the most widely used and it has the additional benefit of precisely quantifying regional FM and LTM. This review evaluates the strengths and limitations of DXA as a pediatric BCA method and considers the utilization of DXA to identify trends and variations in FM and LTM measurements in obese and anorexic children.

Examining the evidence for recent secular changes in the timing of puberty in US children in light of increases in the prevalence of obesity

This report reviews the available evidence from large population studies regarding a secular change in the timing and progress of puberty since 1960 in US children in light of concurrent increases in the prevalence of obesity. There probably was a secular decrease in the median age of onset and progression of genital development in Mexican-American boys and breast development Mexican-American girls in the 1980s and 1990s. The data are insufficient to do more than suggest corresponding trends in black boys and black girls, but there is no evidence of breast changes in white girls. Mean age of menarche decreased by approximately 3 months in US white girls and 5.5 months in US black girls between the late 1960s and approximately 1990. Evidence from a single study indicates the secular changes in age at menarche are consistent with the magnitude of secular change in obesity, although other evidence is equivocal.

Concordant and discordant sexual maturation among U.S. children in relation to body weight and BMI

PURPOSE

This study investigates the extent to which discordant Tanner stages for sexual maturity indicators are associated with weight and body mass index (BMI) and their variation during adolescence. Discordant children with large differences in weight and BMI may require additional monitoring of their growth during adolescence.

METHODS

Weight, BMI and Tanner stages, pubic hair in each gender, breast development in girls and genital development in boys, from 2103 boys and 2104 girls aged 8-18 years (average age 13.34 years) from the National Health and Nutrition Examination Survey III (NHANES III, 1988-1994) were analyzed. These cross-sectional data were grouped as concordant: assessed stages for paired indicators were equivalent, or as discordant: assessed stage for one paired indicator was greater or less than the other by one or more stages. Weight and BMI were compared separately by gender and race between concordant and discordant groups using analysis of covariance adjusted for age.

RESULTS

Approximately 65-69% of all children were concordant, genital stage equaled pubic hair stage for boys and breast stage equaled pubic hair stage for girls. For all three racial groups, boys whose genital stage was more advanced than their pubic hair stage had significantly smaller weight and BMI (p<.05) than either concordant boys or boys whose pubic hair stage was more advanced than their genital stage. For all three racial groups, girls whose breast stage was more advanced than their pubic hair stage had significantly greater weight and BMI than girls whose pubic hair stage was more advanced than breast stage. Non-Hispanic black and Mexican-American girls whose breast stage was more advanced than their pubic hair stage had significantly greater weight and BMI that the respective concordant girls.

CONCLUSION

Substantial and significant differences occur in weight and BMI among discordant and concordant children, and these differences are larger than between early and late maturing children.

Early sexual maturation, body composition, and obesity in African-American girls

OBJECTIVE

To describe associations between sexual maturation and body composition in a sample of African-American girls who were participants in phase 1 pilot interventions of the Girls Health Enrichment Multisite Studies.

RESEARCH METHODS AND PROCEDURES

Stature, weight, and waist circumference were measured. Pubic hair and breast development were assessed, and body composition was measured by DXA for 147 African-American girls who were 8 to 10 years of age from three field centers. Participants had BMI > or =25th percentile for age (one site) or BMI > or =50th percentile for age.

RESULTS

Girls Health Enrichment Multisite Studies girls had greater BMI, fat mass, and percentage body fat than national norms and relatively earlier initiation of breast development and pubic hair. Increasing stages of breast development, but not stages of pubic hair, were related to increased stature, waist circumference, BMI, lean mass, fat mass, and percentage of body fat. Pubescent girls (breast stage > or = 2) were greater than six times as likely to be classified as at risk of overweight (BMI > or = 85th percentile) and greater than eight times as likely to be classified as overweight (BMI > or = 95th percentile) as prepubescent counterparts. Adjusted odds ratios for advanced breast development [breast stage > or = 2 (8 years) or > or = 3 (9 and 10 years)] were 3.6 for risk of overweight and for overweight compared to girls with average or less than average breast development.

DISCUSSION

Sexual maturation is important to consider in understanding the classification of overweight and the development of obesity during adolescence. Breast development and pubic hair development should be considered separately for their associations with growth and body composition.

National estimates of the timing of sexual maturation and racial differences among US children

OBJECTIVE

To provide clinically meaningful, normative reference data that describe the timing of sexual maturity indicators among a national sample of US children and to determine the degree of racial/ethnic differences in these estimates for each maturity indicator.

METHODS

Tanner staging assessment of sexual maturity indicators was recorded from 4263 non-Hispanic white, black, and Mexican American girls and boys aged 8.00 to 19.00 years as part of the Third National Health and Nutrition Examination Survey (NHANES III) conducted between 1988 and 1994. NHANES III followed a complex, stratified, multistage probability cluster design. SUDAAN was used to calculate the mean age and standard error for each maturity stage and the proportion of entry into a maturity stage and to incorporate the sampling weight and design effects of the NHANES III complex sampling design. Probit analysis and median age at entry into a maturity stage and its fiducial limits were calculated using SAS 8.2.

RESULTS

Reference data for age at entry for maturity stages are presented in tabular and graphical format. Non-Hispanic black girls had an earlier sexual development for pubic hair and breast development either by median age at entry for a stage or for the mean age for a stage than Mexican American or non-Hispanic white girls. There were few to no significant differences between the Mexican American and non-Hispanic white girls. Non-Hispanic black boys also had earlier median and mean ages for sexual maturity stages than the non-Hispanic white and Mexican American boys.

CONCLUSION

Non-Hispanic black girls and boys mature early, but US children completed their sexual development at approximately the same ages. The present reference data for the timing of sexual maturation are recommended for the interpretation of assessments of sexual maturity in US children.

Causes of gynaecomastia in young adult males and factors associated with idiopathic gynaecomastia

Gynaecomastia is a common clinical condition. Persistent pubertal or late onset idiopathic gynaecomastia is the leading cause of gynaecomastia in different series. The aim of this study was the assessment of the prevalence and characteristics of different causes of gynaecomastia in young adult males, and evaluation of the factors associated with idiopathic gynaecomastia. Fifty-three male patients (mean age 22.04 +/- 2.22, range 19-29), who had been admitted to our outpatient clinics with gynaecomastia as the main presenting symptom were enrolled in the study. Patients were evaluated with breast palpation, breast ultrasonography, anthropometric measurements and sex steroid levels. Secondary causes of gynaecomastia were ruled out. Thirty age-matched healthy individuals were also studied as healthy control group. Idiopathic gynaecomastia was diagnosed in 31 of 53 patients (58%), with 17 (32%) persistent pubertal and 14 (24%) late onset course. Other causes of gynaecomastia were hypogonadism in 13 cases (25%), hyperprolactinaemia in five (9%), chronic liver disease in two (4%), and drug induced (prolonged use of H2 antagonists) in two (4%). Patients with idiopathic gynaecomastia, either pubertal or late onset, were compared with the healthy control group in order to find out associated factors. Anthropometric measurements revealed a significant increase in body weight and body mass index (BMI) in the patient group compared with healthy controls (72.4 +/- 13.3 vs. 63.6 +/- 7.9 kg, p = 0.0086 and 25.2 +/- 4.0 vs. 21.5 +/- 2.7 kg/m2, p = 0.0001). Total skin fold thickness (SFT) of four different regions were also higher in the patient group (50.9 +/- 22.1 vs. 32.6 +/- 10.2 mm, p = 0.0006) indicating a higher body fat percentage. Total serum testosterone (4.76 +/- 1.31 vs. 5.70 +/- 1.06 microg/mL, p = 0.0038) and luteinizing hormone (LH) (4.80 +/- 1.92 vs. 7.32 +/- 1.90 mIU/mL, p < 0.0001) levels were significantly lower in the patient group while oestradiol levels were similar. There was a significant correlation between total testosterone and LH levels (r = 0.27, p = 0.0445). Total testosterone and LH levels were negatively correlated with BMI and total SFT. As a result most common form of gynaecomastia is idiopathic gynaecomastia either as persistent pubertal or late onset forms in young adult males. Idiopathic gynaecomastia is closely correlated with generalized obesity, reduced LH and testosterone levels which may be the result of increased conversion of testosterone to oestradiol in increased adipose tissue mass.

Self-assessment of sexual maturity status in children with Crohn's disease

OBJECTIVE

To evaluate the validity of self-assessment of sexual maturity status (SMS) in children with Crohn's disease (CD), a pediatric chronic disease that often affects growth and development.

STUDY DESIGN

Self-assessment of SMS in 100 children (34 girls) ages 8 to 18 years with CD from the Children's Hospital of Philadelphia was compared with an independent assessment by one well trained pediatrician, using drawings and written descriptions of Tanner stages of breast, genital, and pubic hair development.

RESULTS

Overall, subjects with CD (age, 14.3 +/- 2.8 years) had delayed growth status based on height-for-age (HAZ) and weight-for-age Z scores (WAZ). Boys were more growth delayed (HAZ, -0.90 +/- 1.1; WAZ, -0.75 +/- 1.3) than girls (HAZ, -0.45 +/- 1.3; WAZ, -0.20 +/- 1.1). Kappa coefficients (kappa) showed excellent agreement between child and physician assessment of SMS, ranging from kappa = 0.74 to 0.85, depending on sex and SMS component, corresponding to a 79% to 88% agreement. When not in agreement, children tended to overestimate their SMS. Boys who overestimated (n = 8) had significantly higher weight and BMI status than boys who assessed accurately.

CONCLUSIONS

Self-assessment of SMS was a reliable and valid method in children with CD and is useful in screening for maturational delay in children with chronic disease.

Relation of childhood height to obesity among adults: the Bogalusa Heart Study

OBJECTIVE

In a previous study of the role of various predictors of adult obesity, we found that relatively tall children had a higher body mass index (BMI; kg/m2) in early adulthood. In this study, the objective was to determine whether childhood height is related to adult adiposity and whether the association is independent of childhood levels of BMI and triceps skinfold thickness.

METHODS

The longitudinal relations of childhood height to relative weight and skinfold (sum of subscapular and triceps) thicknesses in adulthood were examined in a larger sample (N = 1055) of 2- to 8-year-olds who were followed for an average of 18 years.

RESULTS

Compared with children whose heights were below the gender- and age-specific median, a child with a height-for-age above the 95th percentile (P) was approximately 2.5 times as likely to have a BMI > or =30 kg/m2 and approximately 5 times as likely to have a skinfold sum >90th P in adulthood. Although height and adiposity were associated (r = 0.29) among children, the observed longitudinal relations persisted after controlling for BMI and the triceps skinfold thickness in childhood. For example, among children with the same BMI, each 10-cm difference in height was associated with differences in adulthood of 0.9 kg/m2 for BMI and 4 mm for the skinfold sum.

CONCLUSIONS

Although these results need to be confirmed in other studies, it is possible that information on childhood height could be used to identify more accurately children who are likely to be obese in later life.

BMI rebound, childhood height and obesity among adults: the Bogalusa Heart Study

OBJECTIVE

The beginning of the post-infancy rise in the body mass index (BMI, kg/m2) has been termed the adiposity rebound, and several studies have found that an early rebound increases the risk for overweight in adulthood. We examined whether this relation is independent of childhood BMI levels.

DESIGN

A longitudinal study of 105 subjects who examined at ages 5, 6, 7, 8 and 19-23 y.

RESULTS

Subjects with an age at the BMI rebound (age(min)) of < or =5 y were, on average, 4-5 kg/m2 heavier in early adulthood than were subjects whose age(min) was > or =7 y. Age(min), however, was also correlated with childhood BMI levels (r approximately -0.5), and we found that age(min) provided no additional information on adult overweight if the BMI level at age 7 y (or 8 y) was known. In contrast, childhood height, which was also correlated with age(min) (r=-0.47), was independently related to adult BMI. Among relatively heavy (BMI=16.0 kg/m2) 5-y-olds, a child with a height of 120 cm was estimated to be 1.2 kg/m2 heavier in adulthood than would a 104 cm tall child.

CONCLUSIONS

Although an early BMI rebound was related to higher levels of relative weight in adulthood, this association was not independent of childhood BMI levels. The relation of childhood height to adult BMI needs to confirmed in other cohorts, but it is possible that childhood height may help identify children who are likely to become overweight adults.

Childhood weight, stature, and body mass index among never overweight, early-onset overweight, and late-onset overweight groups

OBJECTIVE

To determine the effects of timing of onset of overweight (OW) on childhood anthropometric adiposity levels using long-term serial data from the Fels Longitudinal Study.

CLASSIFICATION

OW was defined as body mass index (BMI; kg/m(2)) >25, and the age at first measurement of BMI >25 was the age of onset of OW. Early onset of OW (early-OW) and late onset of OW (late-OW) were defined as having onset of OW before and after 25 years of age, respectively, whereas never OW (never-OW) was defined as never having a BMI >25.

SUBJECTS

Subjects consisted of 67 males and 47 females in early-OW groups, 62 males and 48 females in late-OW groups, and 80 males and 114 females in never-OW groups.

RESULTS

Levels of weight and BMI in early-OW males and females were significantly greater than those in never-OW and late-OW males and females beginning at the time of adiposity rebound, which generally occurs between 4 and 8 years of age. Median BMI and weight patterns between never-OW and late-OW males were similar throughout childhood. However, significant differences in median levels of BMI for never-OW and late-OW females began at 11 years of age, although onset of OW was not until >25 years of age in the latter group.

CONCLUSIONS

For both males and females, adiposity rebound is likely an effective time in a child's development to detect and initiate prevention for childhood and early adulthood onset of OW. Although later-onset OW needs additional study, puberty seems to be a critical phase in the development of later adult onset of OW in females.

Black/white differences in relative weight and obesity among girls: the Bogalusa Heart Study

BACKGROUND AND OBJECTIVE

Although black women have a higher prevalence of overweight and obesity than do white women, it is unclear if a similar pattern exists among youths. We therefore examined the development of black/white differences in relative weight and adiposity among 5 to 17-year-old girls.

METHODS

Cross-sectional analyses of 4542 black and 4542 white girls who were examined between 1973 and 1994. Quetelet Index (kg/m(2)), Rohrer Index (kg/m;s(3)), and height-adjusted weight were used as measures of relative weight, and subscapular and triceps skinfolds as measures of adiposity. Breast development was used as an index of sexual maturation.

RESULTS

On average, black girls were 1 to 3 kg heavier than were similarly aged white girls, and before adolescence, they were 2 to 3 cm taller. After adjusting for differences in height, the mean relative weight of black girls was consistently greater than that of white girls only after age 13; furthermore, sexual maturation was a stronger correlate of relative weight among black girls than among white girls. Comparable differences were seen for the subscapular skinfold thickness, but white girls consistently had a thicker mean triceps skinfold than did black girls.

CONCLUSION

Sexual maturation should be considered in comparisons of relative weight and obesity among youths, and as compared with white girls, black girls do not have a higher mean relative weight until adolescence. The use of different indices of overweight and adiposity can lead to contrasting results, with simple comparisons of Quetelet Index tending to overstate the relative weights of taller children.

Childhood obesity, adipose tissue distribution, and the pediatric practitioner

The prevalence of pediatric obesity is increasing in the United States. Sequelae from pediatric obesity are increasingly being seen, and long-term complications can be anticipated. Obesity is the most common cause of abnormal growth acceleration in childhood. Obesity in females is associated with an early onset of puberty and early menarche. Puberty is now occurring earlier in females than in the past, and this is probably related either directly or indirectly to the population increase in body weight. The effect of obesity on male pubertal maturation is more variable, and obesity can lead to both early and delayed puberty. Pubertal gynecomastia is a common problem in the obese male. Many of the complications of obesity seen in adults appear to be related to increased accumulation of visceral fat. It has been proposed that subcutaneous fat may be protective against the adverse effects of visceral fat. Males typically accumulate fat in the upper segment of the body, both subcutaneously and intraabdominally. In females, adiposity is usually subcutaneous and is found particularly over the thighs, although visceral fat deposition also occurs. Gender-related patterns of fat deposition become established during puberty and show significant familial associations. There are no reliable means for assessing childhood and adolescent visceral fat other than radiologically. Noninsulin-dependent diabetes is being seen more commonly in the pediatric population. Diabetes and impaired glucose tolerance are noted particularly in obese children with a family history of diabetes. In this situation, a glucose tolerance test may be indicated, even in the presence of fasting normoglycemia. Hypertriglyceridemia and low high-density lipoprotein-cholesterol levels are the primary lipid abnormalities of obesity and are related primarily to the amount of visceral fat. Low-density lipoprotein-cholesterol levels are not typically elevated in simple obesity. The offspring of parents with early coronary disease tend to be obese. Very low-density lipoprotein and intermediate-density lipoprotein particles, which are small in size, may be important in atherogenesis but they cannot be identified in a fasting lipid panel. The propensity to atherogenesis cannot be interpreted readily from a fasting lipid panel, which therefore should be interpreted in conjunction with a family history for coronary risk factors. Hypertriglyceridemia may be indicative of increased visceral fat, familial combined hyperlipidemia, familial dyslipidemic hypertension, impaired glucose tolerance, or diabetes. Almost half of adult females with polycystic ovary syndrome are obese and many have a central distribution of body fat. This condition frequently has its origins in adolescence. It is associated with increased androgen secretion, hirsutism, menstrual abnormalities, and infertility, although these may not be present in every case. Adults with polycystic ovary syndrome adults are hyperlipidemic, have a high incidence of impaired glucose tolerance and noninsulin-dependent diabetes, and are at increased risk for coronary artery disease. Weight reduction and lipid lowering therefore are an important part of therapy. Obstructive sleep apnea with daytime somnolence is a common problem in obese adults. Pediatric studies suggest that obstructive sleep apnea occurs in approximately 17% of obese children and adolescents. Sleep disorders in the obese may be a major cause of learning disability and school failure, although this remains to be confirmed. Symptoms suggestive of a sleep disorder include snoring, restlessness at night with difficulty breathing, arousals and sweating, nocturnal enuresis, and daytime somnolence. Questions to exclude obstructive sleep apnea should be part of the history of all obese children, particularly for the morbidly obese. For many children and adolescents with mild obesity, and particularly for females, one can speculate that obesity may not be a great health risk

Tracking of left ventricular mass in children: race and sex comparisons: the MCV Twin Study. Medical College of Virginia

BACKGROUND

Increased left ventricular (LV) mass is a predictor of cardiovascular disease in adults. The mechanism(s) for these observations are not fully understood.

METHODS AND RESULTS

We repeatedly studied a biracial sample of children from ages 11 through 17 years. At visits 1 through 5, height, weight, and pubertal stage were determined. Blood pressure and heart rate were measured. M-mode and two-dimensional echocardiograms were performed with a 3.5-MHz transducer with the subject in the supine position. LV mass was calculated. Repeated-measures analysis using a mixed modeling approach was performed for LV mass. At all ages, boys had greater LV mass than girls. For the population as a whole, we found significant tracking correlations for LV mass between each interval of measurement and throughout the entire period of examination. The tracking correlation for the entire sample from visit 1 through visit 5 was r=.41. The LV mass in white children tracked from the youngest to the oldest. Black children tracked similarly from ages 1 to 15 years, but tracking was not significant across the widest interval, visit 1 through visit 5. Racial differences were found in the interactions of systolic blood pressure and heart rate, which magnified the differences in LV mass. During adolescence, LV mass tracks significantly in both black and white children.

CONCLUSIONS

Interactive effects such as weight, blood pressure, and heart rate magnify sex and race differences in LV mass.

Secular increases in relative weight and adiposity among children over two decades: the Bogalusa Heart Study

OBJECTIVE

To examine trends in relative weight and obesity among 5- to 24-year-olds between 1973 and 1994.

DESIGN

A panel design consisting of seven cross-sectional surveys of schoolchildren and three surveys of post-high-school subjects. Anthropometric measurements included height, weight, and subscapular and triceps skinfolds.

STUDY POPULATION

All schoolchildren residing in Ward 4 of Washington Parish, Louisiana, a biracial community, were considered eligible; participation rates were >80%. Young adults were eligible if they had participated previously as schoolchildren. A total of 26,371 examinations were performed on 11,564 persons.

RESULTS

During the study period, substantial increases in mean levels of weight (0.2 kg/y) and skinfold thickness (0.15 mm/y) were observed; these changes were independent of height, age, and other covariates. The prevalence of overweight, defined by the 85th percentile of weight-for-height in 1973 to 1974, increased approximately twofold by 1994. Although secular increases were seen both among boys and girls and among blacks and whites, the largest increases were seen among 19- to 24-year-olds. Furthermore, the yearly increases in relative weight and obesity during the latter part of the study period (1983 through 1994) were approximately 50% greater than those between 1973 and 1982.

CONCLUSIONS

The increasing prevalence of obesity in early life indicates a need for primary prevention. Additional study is needed to determine whether these trends are continuing to accelerate and to examine possible explanations, such as diet and physical activity, for these changes.

Indexes of obesity and comparisons with previous national survey data in 9- and 10-year-old black and white girls: the National Heart, Lung, and Blood Institute Growth and Health Study

OBJECTIVE

To (1) describe anthropometric and body-size measurements in the National Heart, Lung, and Blood Institute Growth and Health Study (NGHS) population at baseline and (2) examine potential secular trends in the prevalence of obesity in young black and white girls by comparing NGHS baseline data with those of the two National Health and Nutrition Examination Surveys (NHANES I and II) (measured before the NGHS).

DESIGN

Cross-sectional analysis of cohort baseline data.

SETTING

Recruitment in selected schools (Cincinnati and Berkeley) and among the membership of a group health association (Westat).

PATIENTS

Enrolled 2379 girls, 9 and 10 years of age, including 1213 black and 1166 white.

MEASUREMENTS

Anthropometric measures, including height, weight, and triceps and subscapular skin folds. Body mass index was used as a measure of body size. Nine- and ten-year-old black girls were taller, heavier, and had larger skin folds than white girls. Compared with age-similar girls in the 1970s, girls in the present study are taller and heavier and have thicker skin folds. The differences in body size were most notable among black girls.

CONCLUSIONS

Black girls have a greater body mass than white girls even as young as 9 and 10 years of age. The prevalence of obesity appears to be increasing among young girls, especially in black girls. This progression, if not altered, could lead to increased disease in the future for adult women, particularly black women.

Racial contrasts in hemoglobin levels and dietary patterns related to hematopoiesis in children: the Bogalusa Heart Study

Racial differences in hemoglobin (Hgb) levels were explored in two groups of children at different maturational stages, the pre-adolescent (10-year-olds: Whites n = 160, Blacks n = 56,) and the adolescent (15-year-olds; Whites n = 60, Blacks n = 44). Mean Hgb levels were higher for Whites than Blacks in both age groups. When all the dietary components (i.e., iron, zinc, copper, folacin, ascorbic acid and vitamins B12, E and B6) were considered as a group, they accounted for 8.4 per cent of the Hgb variance in 10-year-olds and 10.1 per cent of variance in 15-year-olds. However, even after controlling for the variations in dietary patterns of the adolescents and pre-adolescents, race still accounted for a notable proportion of Hgb variance in both age groups (9.1 per cent in 10-year-olds and 7.0 per cent in 15-year-olds). Within each race, gender accounted for a greater percentage of the Hgb variance in the adolescents than in the pre-adolescents. Our results indicate that in all likelihood racial differences in Hgb levels during childhood exist independent of racial differences in intake of specific "blood building" nutrients and maturational changes.

Influence of persistent obesity in children on cardiovascular risk factors: the Bogalusa Heart Study

The relationship between body fat indexes, lipid and lipoprotein levels, and blood pressure was studied in 2230 children, each examined during 1973, 1976, and 1978. The children were grouped with the use of seven percentile (P) intervals of triceps skinfold thickness that were specific for race, sex, and age; cardiovascular risk factor variables were assessed over time. Of the 238 children initially in the lowest P group (less than 15P), 44% remained there, and 65% had skinfold thicknesses below 30P on the three occasions. Of the 352 children in the highest P group (greater than or equal to 85P), who were considered to be very obese, 39% remained at this level while 69% remained at 70P or greater. Of the 366 considered to be obese (greater than or equal to 70, less than 85%P), 38% remained at or above 70P. At baseline, children in the seven groups differed in weight, ponderosity (wt/ht3), systolic and diastolic blood pressures, serum triglyceride levels, and pre-beta- and beta-lipoprotein cholesterol levels. Pairwise comparison of data from children in each of the six other groups with those from children in the middle range (greater than or equal to 40, less than 60P) showed that the obese and very obese children had significantly higher systolic blood pressures (p less than .05), while only those in the highest P group had significantly greater diastolic blood pressures (p less than .05). These differences increased and diverged over time. Those in the obese and very obese groups showed a striking drop over time in alpha-lipoprotein cholesterol levels and increases in pre-beta-lipoprotein cholesterol levels and systolic blood pressure. Triglyceride levels decreased over time for the lowest and middle range groups but remained at higher levels in obese and very obese children. There was a strong tendency for tracking (remaining in the same P group over time) in lean, obese, and very obese children. Those who tracked showed definite differences in risk factor variables at the baseline level and over time when compared with the middle range group. Since consistent obesity in early life enhances cardiovascular risk, the measurement over time of skinfold thickness in children is a useful method to detect the potential for adult cardiovascular disease.