Influence of leptin on changes in body fat during growth in African American and white children.

OBJECTIVE: The aim of this study was to determine whether initial levels or temporal changes in fasting leptin were associated with longitudinal changes in body-fat mass in children. RESEARCH METHODS AND PROCEDURES: The study group consisted of 85 children (42 white and 43 African American) with a mean initial age of 8.1 +/- 0.1 years. The children had between three and six annual visits for repeated measurements of body composition by DXA and fasting leptin level. Fat mass and fasting leptin level were not normally distributed and were log-transformed. Data were analyzed using SAS Proc mixed growth models, with log fat as the dependent variable. RESULTS: Initial leptin level was a significant predictor of the change in fat mass over time (p < 0.0001), with high initial leptin levels resulting in increased fat gain, independent of initial fat levels. This relationship remained significant when the data were analyzed separately by race (whites, p < 0.0001; African Americans, p = 0.008). The relationship between the initial level of leptin and the change in fat mass was not modified by race, sex, or Tanner Stage. The rate of change in leptin during the study was significantly related to the rate of change in fat mass in African Americans (p = 0.008) but not in whites (p = 0.490). DISCUSSION: In conclusion, high fasting leptin level at the start of the study was significantly associated with increasing fat mass in this cohort, indicating that the children may be developing resistance to the effects of leptin.

Longitudinal changes in body fat in African American and Caucasian children: influence of fasting insulin and insulin sensitivity.

Obesity is associated with hyperinsulinemia and reduced insulin sensitivity, both risk factors for type 2 diabetes. However, it is not clear whether these risk factors occur as a result of obesity or whether they contribute to the development of obesity. The aims of this study were to determine whether baseline (first visit) or changes in insulin measures over time were associated with longitudinal changes in body fat mass during growth in children. The study group consisted of 137 children (83 Caucasian and 54 African American) with a mean age of 8.1 yr at baseline. The children returned for 3-6 annual visits for measurement of fasting insulin, insulin sensitivity (Si), and acute insulin response (AIR) from the tolbutamide-modified frequent sampling iv glucose tolerance test and for determination of body composition by dual energy x-ray absorptiometry. Data were analyzed using SAS Proc mixed growth models. Total fat mass increased with time by 15.6%/yr (P = 0.013), but the rate of increase was not significantly influenced by race, sex, or Tanner stage. However, fasting insulin (positive effect), Si (negative effect), and AIR (positive effect) were significantly associated with the rate of increase in fat mass. In conclusion, in this cohort of children, growth-related increases in body fat were significantly associated with increases in fasting insulin and AIR and decreases in Si.

Growth of visceral fat, subcutaneous abdominal fat, and total body fat in children.

OBJECTIVE: To examine the patterns of growth of visceral fat, subcutaneous abdominal fat, and total body fat over a 3- to 5-year period in white and African American children. RESEARCH METHODS AND PROCEDURES: Children (mean age: 8.1 +/- 1.6 years at baseline) were recruited from Birmingham, Alabama, and those with three or more repeated annual measurements were included in the analysis (N = 138 children and 601 observations). Abdominal adipose tissue (visceral and subcutaneous) was measured using computed tomography. Total body fat and lean tissue mass were measured by DXA. Random growth curve modeling was performed to estimate growth rates of the different body fat compartments. RESULTS: Visceral fat and total body fat both exhibited significant growth effects before and after adjusting for subcutaneous abdominal fat and lean tissue mass, respectively, and for gender, race, and baseline age (5.2 +/- 2.2 cm(2)/yr and 1.9 +/- 0.8 kg/yr, respectively). After adjusting for total body fat, the growth of subcutaneous abdominal fat was not significant. Whites showed a higher visceral fat growth than did African Americans (difference: 1.9 +/- 0.8 cm(2)/yr), but there was no ethnic difference for growth of subcutaneous abdominal fat or total body fat. There were no gender differences found for any of the growth rates. DISCUSSION: Growth of visceral fat remained significant after adjusting for growth of subcutaneous abdominal fat, implying that the acquisition of the two abdominal fat compartments may involve different physiologic mechanisms. In contrast, growth of subcutaneous abdominal fat was explained by growth in total body fat, suggesting that subcutaneous fat may not be preferentially deposited in the abdominal area during this phase of growth. Finally, significantly higher growth of visceral fat in white compared with African American children is consistent with cross-sectional findings.

Cervical myelopathy and congenital stenosis from hypoplasia of the atlas: report of three cases and literature review.

STUDY DESIGN: Case reports of patients with cervical myelopathy to hypoplasia of the atlas. OBJECTIVES: To report cases of cervical myelopathy due to congenital hypoplasia of the atlas and to review the literature. SUMMARY OF BACKGROUND DATA: Six previously documented cases of congenital hypoplasia of the atlas as a cause of cervical myelopathy are reported in the literature. METHODS: Three patient's clinical record and radiologic imaging studies as well as a thorough literature search are reported. Plain radiographs, computed tomography scans, magnetic resonance images, as well as somatosensory-evoked potential changes are displayed. RESULTS: Cervical myelopathy developed in three patients who were found to have congenital hypoplasia of the atlas. Laminectomy of C1 provided neurologic improvement in all three patients presented. CONCLUSION: Congenital hypoplasia of the atlas is a rare cause of cervical myelopathy. This report should broaden the radiographic differential diagnosis when seeking an explanation for the signs and symptoms of cervical myelopathy.

A longitudinal study of resting energy expenditure relative to body composition during puberty in African American and white children.

BACKGROUND: Body composition and resting energy expenditure (REE) have not been examined longitudinally during puberty. OBJECTIVE: The purpose of this longitudinal study was to examine the influence of pubertal maturation on REE relative to body composition in African American and white children. DESIGN: The study included 92 white and 64 African American children (mean age at baseline: 8.3 and 7.9 y, respectively) from Birmingham, AL. The children had 2-5 annual measurements of fat mass (FM), lean mass (LM), and REE. The Tanner stages of the children ranged from 1 to 5. Mixed-model repeated-measures analyses were used to test the change in REE relative to body composition with increasing Tanner stage among ethnic and sex groups. RESULTS: LM increased from Tanner stage 1 to subsequent stages. FM relative to LM decreased from Tanner stage 1 to stages 3, 4, and 5 but not from stage 1 to stage 2. The African American children had relatively higher limb LM and lower trunk LM than did the white children. REE declined with Tanner stage after adjustment for ethnicity, sex, FM, and LM. This decline was significant from Tanner stage 1 to stages 3, 4, and 5 but not to Tanner stage 2. After adjustment for age, Tanner stage, FM, and LM or LM distribution, REE was significantly higher in white than in African American children (by approximately 250 kJ/d). CONCLUSION: In a large sample of children at various Tanner stages, we found an ethnic difference in REE after adjustment for age, Tanner stage, FM, and LM that was not explained by the difference in LM distribution.

The relationship between psychosocial factors and condom use among African-American adolescents.

The present investigation explored the relationship between psychosocial factors and condom use by African-American adolescents. Two hundred twenty-nine males, aged 14 to 19 years, responded to a health behavior survey that gathered information on demographics, HIV knowledge, perceived certainty of future condom use, present and past use of condoms, and intention to use condoms in the next six months. Several psychological variables, including sexual self-efficacy and self-esteem, were also measured. It was found that the majority of participants were sexually active by age 13, had four or more lifetime sexual partners, and were using condoms regularly. Multiple linear regression analysis indicated that sexual self-efficacy predicted perceived certainty of condom use. In addition, self-esteem and sexual self-efficacy predicted intention to use condoms. These findings highlight the need to develop HIV prevention curricula for African-American male adolescents that not only emphasize the potential risks associated with having multiple sexual partners, but also include components to enhance self-worth and sexual self-efficacy.

Aerobic fitness, not energy expenditure, influences subsequent increase in adiposity in black and white children.

BACKGROUND: Low levels of energy expenditure and aerobic fitness have been hypothesized to be risk factors for obesity. Longitudinal studies to determine whether energy expenditure influences weight gain in whites have provided conflicting results. To date, no studies have examined this relationship in blacks or whether aerobic fitness influences weight gain in white or black children. METHODS: One hundred fifteen children, 72 white (55 girls and 17 boys) and 43 black (24 girls and 19 boys) were recruited for this study. Aerobic fitness, resting, total, and activity-related energy expenditure and body composition were measured at baseline. The children returned annually for 3 to 5 repeated measures of body composition. The influence of the initial measures of energy expenditure and fitness on the subsequent rate of increase in adiposity was examined, adjusting for initial body composition, age, ethnicity, gender, and Tanner stage. Because 20 children did not attain maximum oxygen consumption, the sample size for the combined analysis was 95. RESULTS: Initial fat mass was the main predictor of increasing adiposity in this cohort of children, with greater initial fat predicting a higher rate of increase of adiposity. There was also a significant negative relationship between aerobic fitness and the rate of increasing adiposity (F(1,82) = 3.92). With every increase of.1 L/minute of fitness, there was a decrease of.081 kg fat per kg of lean mass gained. None of the measures of energy expenditure significantly predicted increasing adiposity in white or black children. CONCLUSIONS: Initial fat mass was the dominant factor influencing increasing adiposity; however, aerobic fitness was also a significant independent predictor of increasing adiposity in this cohort of children. Resting, total, or activity-related energy expenditure did not predict increasing adiposity. It seems that aerobic fitness may be more important than absolute energy expenditure in the development of obesity in white or black children. energy expenditure, fitness, longitudinal, obesity.

Reliability of treadmill measures and criteria to determine VO2max in prepubertal girls.

PURPOSE: The main objective of this study was to determine the reliability of measuring treadmill exercise economy (VO2submax) and the maximal oxygen uptake (VO2max) in prepubertal girls tested twice, 6 wk apart. We also wanted to examine the percentage of young girls who were able to reach the criteria for achieving VO2max and to describe methods that would allow a high proportion of young children to achieve criteria for reaching a true VO2max. METHODS: We studied 61 normal-weight, prepubertal girls with a mean (+/- SD) age 7.3+/-1.3 yr (range 4.8 to 10.3 yr). VO2submax was determined while walking for 4 min at 2.5 mph with 0% grade. VO2max was measured during a progressive, all-out, continuous treadmill test using standardized procedures and criteria. Heart rate (HR) was measured using a Polar monitor. Respiratory rate (RR), respiratory exchange ratio (RER), ventilation (V), and VO2 were measured using a Sensormedics metabolic monitor. RESULTS: There were no significant differences between visits I and 2 in mean HR, RR, RER, V, VO2submax (421 vs 422 mL x min(-1), respectively), and VO2max (1036 vs 1049 mL x min(-1), respectively). Intra-individual coefficients of variation (CV) between visits 1 and 2 for submaximal tests were: HR = 5.1%, RR = 12.4%, RER = 7.2%, V = 12.5%, and VO2 = 12.4%. Intra-individual CVs for the maximum tests were: HRmax = 2.1%, RRmax = 10.8%, RERmax = 5.3%, Vmax = 11.7%, and VO2max = 7.5%. A high proportion of the girls reached criteria for VO2max [RER> 1.00, HR>85% of age predicted maximum, and plateauing of VO2max] in both visits: 99% reached one of three criteria, 92% reached two of three criteria, and 70% reached all three criteria. Twenty girls [mean age 7.2+/-1.2 yr] reached at least two criteria in both visits, whereas 32 girls [mean (+/- SD) age 8.6+/-1.0 yr] reached three criteria in both visits. CONCLUSION: Exercise measurements using treadmill testing were reliable in healthy, normal-weight, prepubertal girls. Older girls when compared to the younger girls were able to reach criteria for VO2max more often. Thus, we recommend that one testing should give researchers an accurate measure of walking economy and aerobic capacity, and that two criteria are enough for determining VO2max.

Paternal body fat is a longitudinal predictor of changes in body fat in premenarcheal girls.

BACKGROUND: Longitudinal studies in infants and children suggest that low total energy expenditure (EE) (TEE) and parental body composition are important predisposing factors to obesity. OBJECTIVE: The aim of this study was to examine potential predictors of changes in total or percentage body fat over 2.7 y in premenarcheal girls. DESIGN: We studied 47 normal-weight prepubertal girls aged 4.8-8.9 y in 3 visits. The girls' age, total and percentage body fat at baseline, sleep EE (SEE) and activity-related EE (AEE) adjusted for fat-free mass (FFM) and total body fat, mothers' and fathers' total and percentage body fat and FFM at baseline, and time to follow-up visits were measured; 24-h EE and SEE were measured by whole-room indirect calorimetry. AEE was calculated as TEE minus (SEE + 0.1 TEE), with the assumption that the thermic effect of food was 10% of TEE. The girls' body composition was measured at each visit and that of the parents was measured at the time of the girls' enrollment by using dual-energy X-ray absorptiometry. RESULTS: From baseline to the first (mean: 1.6 y) and the second (mean: 2.7 y) follow-up visits, the girls' mean (+/-SD) change in total fat adjusted for FFM was 1.2 +/- 2.7 and 3.3 +/- 4.0 kg, respectively, and the mean change in percentage body fat was -2.0 +/- 5.0% and -0. 8 +/- 5.9%, respectively. Fathers' total and percentage body fat were the main predictors of changes in the girls' total and percentage body fat. For the first follow-up visit, SEE, girls' age at baseline, and AEE were significant predictors of percentage body fat. CONCLUSION: Fathers' total and percentage body fat were predictors of changes in body fat of premenarcheal girls during a 2. 7-y period.

Effects of strength training on intra-abdominal adipose tissue in obese prepubertal girls.

PURPOSE: The purpose of this study was to determine the effects of strength training on fat distribution and its relationship to glucose tolerance in obese prepubertal girls. METHODS: A strength training intervention study was designed in which the children exercised three times per week for 5 months. Twelve healthy, obese prepubertal girls (ages 7-10 yr, > 95th percentile weight for height) were enrolled in the study. Body composition was measured by dual-energy x-ray absorptiometry and computed tomography, and glucose tolerance was measured by a 3-h oral glucose tolerance test at baseline and after training. RESULTS: Significant increases in height, weight, fat-free mass, fat mass, and subcutaneous abdominal adipose tissue occurred after training (P < 0.05), whereas intra-abdominal adipose tissue (IAAT) remained stable (N = 11). Insulin area was highly correlated with IAAT before (r = 0.91) and after (r = 0.90) training (both P < 0.01, N = 9). CONCLUSION: In growing obese prepubertal girls undergoing a strength training program, IAAT remains unchanged, whereas subcutaneous abdominal fat and total body fat increased; insulin area is related to IAAT in these children.

Variability of abdominal adipose tissue measurements using computed tomography in prepubertal girls.

OBJECTIVE: To determine the variability of measuring regional adipose tissue area using abdominal computed tomography (CT) in normal-weight, prepubertal girls. DESIGN: Measurements of abdominal CT were performed twice, 6 weeks apart. SUBJECTS: Sixty-one normal-weight, prepubertal girls (age: 4.8-10.3 y, mean (s.d.) BMI: 16.7 +/- 1.5 kg/m2). MEASUREMENTS: Abdominal adipose tissue by CT at baseline and 6 weeks later. RESULTS: There were no significant differences between visits 1 and 2 with regard to the children's average abdominal CT derived intraabdominal adipose tissue (21.64 cm2 vs 23.74 cm2) and subcutaneous adipose tissue (62.49 cm2 vs 65.28 cm2). The Pearson coefficient of correlation (r), P-value, total coefficient of variation (CV) and standard error of the difference (SEdelta) for intra-individual measurements between visits 1 and 2 by abdominal CT were: total abdominal adipose tissue, r = 0.94, P < 0.0001, CV = 12.34%, SEdelta 2.25 cm2; subcutaneous abdominal adipose tissue, r = 0.96, P < 0.0001, CV = 10.67%, SEdelta = 1.57 cm2; and intraabdominal adipose tissue, r = 0.67, P < 0.0001, CV = 21.5%, SEdelta = 1.11 cm2. The mean ratios of intraabdominal to subcutaneous adipose tissue on visits 1 and 2 were 0.42 +/- 0.2 and 0.44 +/- 0.24, respectively. CONCLUSION: Regional adipose tissue area measurements using abdominal CT were reliable in healthy, normal-weight, prepubertal girls.

Body composition changes in Caucasian and African American children and adolescents with obesity using dual-energy X-ray absorptiometry measurements after a 10-week weight loss program.

OBJECTIVE: Changes in body composition during a weight loss program have not been described in children. We wanted to test the hypothesis that weight loss can be achieved while maintaining total body fat-free mass. RESEARCH METHODS AND PROCEDURES: We determined body composition changes by using dual-energy X-ray absorptiometry measured at baseline and after the first 10 weeks of a multidisciplinary weight loss program. The program consisted of 10 weekly group sessions where the children were provided instruction in lifestyle modification, including diet and exercise. Program leaders included a pediatrician, psychologist, registered dietitian, and exercise instructor. RESULTS: We studied 59 obese children, mean (+/-SD) age 12.8+/-2.6 years, 29% boys and 71% girls, 49% Caucasian, and 51% African American. At enrollment, the children's mean height and body mass index were 157 cm and 38.9 kg/m2, respectively. The children's dual-energy X-ray absorptiometry-derived mean at baseline and at 10 weeks and corresponding p values were: weight (94.6 kg vs. 92.3 kg, p<0.0001), total body fat mass (46.9 kg vs. 44.3 kg, p<0.0001), percentage total body fat (49.2% vs. 47.5%, p<0.0001), total trunk mass (43.0 kg vs. 41.5 kg, p<0.0001), total trunk fat (21.2 kg vs. 20.0 kg, p<0.0001), total body fat-free mass (47.6 kg vs. 47.9 kg, p=0.33), total body bone mass (2.7 kg vs. 2.7 kg, p=0.99), and total body bone mineral density (1.14 g/cm2 vs. 1.15 g/cm2, p=0.0119). The children's race, gender, or Tanner stage did not affect these changes. DISCUSSION: Decreases in total body fat mass was achieved, and total body fat-free mass was maintained among boy and girl Caucasian and African American children participating in this lifestyle modification weight loss program.

Reproducibility of dual-energy X-ray absorptiometry measurements in prepubertal girls.

OBJECTIVE: Regulation of growth and development, clinical assessment, and obesity are among the areas of nutrition-related research, wherein accurate assessment of body composition is important. We want to test the hypothesis that dual-energy X-ray absorptiometry (DXA) measurements are reproducible in healthy girls. RESEARCH METHODS AND PROCEDURES: We determined total body composition measurements in healthy prepubertal girls using DXA twice, 6 weeks apart. RESULTS: We studied 61 healthy, normal-weight, prepubertal girls, aged 4.8 years to 10.3 years. The girls' DXA-derived mean weight between visits 1 and 2 significantly increased (27.14 kg vs. 27.80 kg, p<0.0001). The increased weight was due to significant increases in total body fat-free mass (FFM) (19.53 kg vs. 19.89 kg, p<0.001), total body bone mass (1.05 kg vs. 1.07 kg, p<0.0001), and total body fat mass (7.61 kg vs. 7.91 kg, p<0.03). The girls' DXA-derived mean total trunk mass between visits 1 and 2 significantly increased ( 11.23 kg vs. 11.63 kg, p<0.0001), as did total leg mass (9.33 kg vs. 9.53 kg, p<0.00), although no significant differences were observed in total arm mass (2.52 kg vs. 2.54 kg, p=0.37). The Pearson coefficient of correlation (r) and total coefficient of variation (CV) for intraindividual measurements by DXA were: weight--r=0.99, CV = 1.97%; total body FFM--r = 0.96, CV = 2.30%; total body bone mass--r = 0.99, CV=2.08%; total body fat mass--r=0.96, CV=6.55%; percentage total body fat--r=0.91, CV=5.69%; total trunk mass--r=0.96, CV= 3.59%; total arm mass--r= 0.95, CV =4.09%; and total leg mass--r = 0.99, CV = 2.75%. DISCUSSION: Total body FFM, total body bone mass, total body fat mass, percentage of total body fat mass, as well as regional mass determinations by DXA, were highly reproducible in healthy, normal-weight, prepubertal girls. We highly recommend the use of DXA for total body composition studies in girls aged 5 years to 10 years.

Effect of N-methyl-D-aspartate receptor blockade on the control of cerebral O2 supply/consumption balance during hypoxia in newborn pigs.

Using dizocilpine (MK-801), we tested the hypothesis that N-methyl-D-aspartate (NMDA) receptors are important controllers of cerebral O2 supply/consumption balance in newborn piglets both during normoxia and hypoxia. Twenty-five 2 to 7-day-old piglets were anesthetized and divided into four groups: (1) Normoxia (n = 6), (2) Normoxia + MK-801 (n = 6), (3) Hypoxia (n = 6), and (4) Hypoxia + MK-801 (n = 7). Regional cerebral blood flow (rCBF) in ml/min/100 g was measured using 14C-iodoantipyrine, and we determined arterial and venous O2 saturations by microspectrophotometry, calculating cerebral O2 consumption (VO2) in ml O2/min/100 g in the cortex, hypothalamus and pons. MK-801 did not significantly affect regional VO2 or rCBF in normoxic piglets. Hypoxia resulted in an increase in local rCBF compared to controls: from 41 +/- 6 to 103 +/- 18 in the cortex; 34 +/- 7 to 101 +/- 20 in the hypothalamus; and 45 +/- 10 to 95 +/- 11 in the pons. Pretreatment with MK-801 abolished this hypoxic flow effect in the cortex (51 +/- 2) and hypothalamus (49 +/- 5), but not in the pons (91 +/- 17). Similar results were observed for VO2 with control values of 1.9 +/- 0.3, 1.6 +/- 0.2 and 2.1 +/- 0.3 for the cortex, hypothalamus and pons respectively. Hypoxia resulted in an increase in the VO2 to 3.9 +/- 0.4 (cortex), 3.8 +/- 0.6 (hypothalamus) and 3.9 +/- 0.8 (pons). Pretreatment with MK-801 prior to hypoxia abolished these effects in the cortex (2.1 +/- 0.2) and hypothalamus (2.1 +/- 0.2), but not in the pons (2.9 +/- 0.2). These findings suggest that NMDA receptors may play a role in the control of cerebral metabolism during hypoxia in this immature porcine model.

Fitness and energy expenditure after strength training in obese prepubertal girls.

PURPOSE: The purpose of this study was to determine the effects of a school-based, low-volume strength training program on energy expenditure, strength, and physical fitness in obese prepubertal girls. METHODS: A longitudinal, 5-month strength training exercise program was undertaken by healthy, obese (> 95th percentile weight-for-height, N = 11) girls age 7-10 yr. The following were measured: strength by the one-repetition maximum test; fitness (VO2peak) by a treadmill exercise test; resting metabolic rate (RMR), 24-h sedentary energy expenditure (SEE), and sleeping metabolic rate (SMR) by room respiration calorimetry; and total energy expenditure (TEE) by the doubly labeled water method. Physical activity energy expenditure (AEE) was calculated as TEE-(RMR + 0.1.TEE) and physical activity level (PAL) as TEE/RMR. An age-matched, nonoverweight control group was measured for (VO2peak) and RMR over the same time period. RESULTS: Strength increased by 19.6 and 20.0% in the upper and lower body (P < 0.01), respectively. (VO2peak) (mL.min-1) increased in both groups over time (P < 0.05), but not when covaried for fat-free mass (FFM) or weight. After adjusting for FFM or weight, RMR did not change, but SMR and 24-h SEE decreased significantly in the exercise group. There were no changes in nonprotein respiratory quotient or substrate oxidation. No changes in TEE, AEE, and PAL occurred, either unadjusted or adjusted for FFM or weight. CONCLUSION: This long-term, school-based, low-volume strength training program favorably increases strength in obese prepubertal girls but does not increase their daily energy expenditure.

Identification of 2-methoxyhexadecanoic acid in amphimedon compressa

The phospholipid fatty acid composition of Amphimedoncompressa was reinvestigated and the 2-methoxyhexadecanoic acid was identified for the first time in nature. Structure characterization was accomplished by means of gas chromatography-mass spectrometry and total synthesis from commercially available 2-hydroxyhexadecanoic acid.

Energy expenditure and physical fitness in overweight vs non-overweight prepubertal girls.

OBJECTIVE: To determine whether overweight children have lower physical activity energy expenditure (EE) and fitness levels than non-overweight children. STUDY DESIGN: Twenty-four healthy girls aged 7-10 y were divided into overweight (> 95th percentile weight-for-height) and non-overweight (10-90th percentile) groups. Basal metabolic rate (BMR), sleeping metabolic rate (SMR), 24 h sedentary EE (SEE) and total EE (TEE) were measured by room respiration calorimetry and doubly labelled water. Physical activity EE and physical activity level (PAL) were calculated. Fitness (VO2peak) was measured by a treadmill exercise test. RESULTS: The overweight group had significantly higher body weight, percent fat, fat mass and fat-free mass (FFM) (P < 0.001). The overweight girls had higher BMR, SMR, SEE and TEE (P < 0.001), but not after adjustment for FFM. Physical activity EE and PAL were not significantly different between groups. After adjusting for FFM or weight, submaximal and peak VO2 were not significantly different between groups. CONCLUSIONS: We conclude that these overweight girls do not have lower physical activity EE or fitness levels than the non-overweight prepubertal girls, however, the rather high body fat of the non-overweight group may have precluded us from finding any differences between groups.

Prevalence of obesity with increased blood pressure in elementary school-aged children.

The objectives of this study were to estimate the prevalence of obesity in school-aged children in Jefferson County, Alabama; to learn when school-aged children become obese; to determine the susceptible groups; and to study the association between obesity and blood pressure. During the school year, 5,953 children, ranging in age from 5 years to 11 years, were screened for weight, height, and blood pressure, using standardized techniques. We found that obesity, defined as > or = 120% of ideal body weight for height, is prevalent in 5-year-old to 11-year-old children. The prevalence of obesity in girls at age 5 was 23% in blacks and 10% in whites, rising to 47% in blacks and 27% in whites by age 11. In boys, the prevalence of obesity at age 5 was 13% in blacks and 6% in whites, rising to 29% in blacks and 22% in whites by age 11. The prevalence of obesity is significantly greater in black than in white children and is also significantly greater in girls than boys. The systolic and diastolic blood pressures were significantly higher in obese than in non-obese children. We conclude that the significant prevalence of childhood obesity and an associated complication, increased blood pressure, emerge in school-aged children. Thus, we recommend investigations of prevention and intervention programs to be used in the school setting.

Reproducibility of measurement of resting energy expenditure in prepubertal girls.

We determined the reproducibility of measuring resting energy expenditure (REE) and the effect on REE of spending the night before testing at home compared with in a clinical research center. We studied 19 prepubertal girls aged 6.0-10.1 y with a mean weight-for-height of 108% of ideal. REE was measured for 30 min with a metabolic monitor after 12 h of fasting on three consecutive mornings during two different hospitalizations 6 wk apart. The initial REE measurement of each hospitalization was obtained on admission and the second and third measurements were performed during the 3-d hospitalization. Energy intake was ad libitum and was recorded while the children were in the research center. Body composition was determined twice with dual-energy X-ray absorptiometry. No significant effect on REE of day within visit was found across visits. There was no significant difference between the initial REE measurement and the second and third measurements. The mean REEs for the two hospitalizations were highly correlated. The mean CV in intraindividual REE (ie, all six measurements) was 5.8% and was unchanged when adjusted for fat-free body mass (FFM) or body weight. The mean CV in interindividual REE decreased when adjusted for FFM or body weight. Because REE was highly reproducible, a single measurement can suffice for energy expenditure studies in girls aged 6-10 y. Admission to a clinical research setting is not necessary for a reliable determination of REE.