Differences in resting energy expenditure in prepubertal black children and white children

OBJECTIVE: To evaluate differences in resting energy expenditure (REE) of black and white prepubertal children. SUBJECTS: The study subjects were 34 prepubertal children 5 to 12 years of age and weighing 90% to 206% ideal body weight. Girls represented 59% of the study subjects; 44% were white children and 56% were black children. METHODS: Fat-free mass (FFM), fat mass, and the percentage of body fat were determined by total body electrical conductivity. Fasting REE was measured by open-circuit indirect calorimetry. RESULTS: Although weight, height, FFM, fat mass, percentage of body fat, and age were similar between the ethnic groups (black vs. white children), the black subjects had a significantly lower REE (1312 +/- 38 kcal/day) compared with the white subjects (1524 +/- 43 kcal/day) after adjusting for age, gender, weight, FFM, and fat mass. Fat-free mass and ethnic group were the only significant predictors of REE (R2 = 0.70). CONCLUSION: Resting energy expenditure is significantly higher in this sample of white children compared with the black children after adjusting for body size and composition. Both FFM and ethnic background were significant determinants of REE in prepubertal children.     

Gender differences in body fat content are present well before puberty

To determine whether gender differences in body fat could be detected in prepubertal children using dual energy X-ray absorptiometry (DEXA), body composition was measured in 20 healthy boys aged 3-8 y matched for age, height and weight with 20 healthy girls. Although boys and girls did not differ in age, height, weight, body mass index (BMI) or bone mineral content, the boys had a lower percentage of body fat (13.5 +/- 5.1 vs 20.4 +/- 6.1%, P < 0.01), a lower fat mass (3.2 +/- 2.0 vs 4.9 +/- 3.1 kg, P < 0.01), and a higher bone-free lean tissue mass (18.6 +/- 4.3 vs 17.0 +/- 3.5 kg, P < 0.01) than the girls. Girls had approximately 50% more body fat than the boys. This is the first DEXA study to show that boys aged 3-8 y have less body fat than girls of similar age, height and weight. Thus, this technology demonstrates that significant gender differences in body composition are evident, well before the onset of puberty.     

Complicated bone and soft-tissue infections. Imaging with 0.1 T MR and 99mTc-HMPAO-labeled leukocytes. ff

OBJECTIVE: To determine the relationship between resting energy expenditure and body cell mass in a group of children with spastic quadriplegic cerebral palsy (SQCP) in comparison with a group of healthy volunteers. SUBJECTS AND METHODS: Children with SQCP (n = 13) and healthy control subjects (n = 21) participated in the study. Resting energy expenditure (REE) by indirect calorimetry, as well as body composition measurements were obtained. Those included skinfold measurements, isotope dilution methods for total body water and extracellular water (2H2O or H2(18)O and NaBr, respectively), and bioelectrical impedance analysis. Intracellular water was calculated as total body water minus extracellular water. RESULTS: Overall REE in children with SQCP was significantly less than in control subjects or from predicted World Health Organization equations. There was a poor correlation between REE and weight or height for children with SQCP and those for control subjects. Children with SQCP showed a higher variance and small improvement in the correlation between REE and lean body mass or intracellular water in comparison with control subjects. Nine of the thirteen children with SQCP had significantly reduced REE per unit of lean tissue or intracellular water. Furthermore, bioelectrical impedance analysis was validated against dilution methods as a suitable technique for measuring total body water (r2 = 0.90, r = 0.95) and extracellular water (r2 = 0.84, r = 0.92) in children with SQCP. CONCLUSION: REE in children with SQCP is poorly correlated with body cell mass. We postulate that the central nervous system plays a crucial role in energy regulation. In children with SQCP, individual energy expenditure should be measured so that optimal nutritional status can be achieved. Bioelectrical impedance analysis can be used in this population to measure body water spaces.     

Factors influencing malnutrition in children waiting for liver transplants

Nutrition deficiencies are common in children with chronic liver disease. To determine whether age, hepatic dysfunction, or energy intake influences this malnutrition, we evaluated the nutritional status of 49 children aged 2.5 mo to 13 y (mean: 35 mo; median: 12 mo). The children were divided into two groups according to age: group 1-29 patients aged < or = 1 y (mean: 7 mo; median: 7 mo); and group 2-20 patients > 1 y (mean: 75 mo; median: 59 mo). Hepatic dysfunction was defined according to the Malatack criteria. Seventy-two-hour dietary intakes were recorded by a nutritionist. Nutritional status was assessed by anthropometric measures when the patients were enrolled on the waiting list for liver transplants. We evaluated the following indexes: weight, height, fat body mass, and lean body mass on the basis of height-age (age at which height reached 50th Italian height percentile). Mean height Z scores were low in both groups, but the difference was not significant. Mean weight Z scores and mean percentages of fat body mass were significantly lower (P < 0.001) in group 1 than in group 2 patients. In group 2, lean body mass and fat body mass were significantly lower (P < 0.05) in patients with moderate-to-severe hepatic failure than in patients with mild hepatic dysfunction. The mean energy intake was in the range of the recommended daily allowances for age but was insufficient for both groups of patients. The evidence of significant acute and chronic malnutrition confirmed the need for nutritional support, especially for younger and older children with moderate-to-severe hepatic dysfunction. We emphasize the necessity of accurate assessment of nutritional status by simple anthropometric measurements to be sure of the effects and adequacy of the nutritional intervention.     

Growth hormone improves body composition, fat utilization, physical strength and agility, and growth in Prader-Willi syndrome: A controlled study

BACKGROUND: Obesity and hypotonia in children with Prader-Willi syndrome (PWS) are accompanied by abnormal body composition and diminished energy expenditure resembling a growth hormone deficient state. Hypothalamic dysfunction in PWS often includes decreased growth hormone (GH) secretion, suggesting a possible therapeutic role for exogenous GH treatment. OBJECTIVES AND METHODS: After 6 months of observation to determine baseline growth rate, and with the use of a 12-month randomized controlled study design, the effects of GH treatment (1 mg/m2/d) on growth, body composition, strength and agility, pulmonary function, resting energy expenditure (REE), and fat utilization were assessed in 54 children with PWS (n = 35 treatment and n = 19 control). Percent body fat and bone mineral density were measured by dual x-ray absorptiometry. Indirect calorimetry was used to determine REE and to calculate respiratory quotients. RESULTS: Stimulated levels of GH in response to clonidine testing were low in all patients (peak, 2.0 ng/mL). After 12 months, GH-treated subjects showed significantly increased height velocity Z scores (mean, 1.0 1.7 to 4.6 2.9; P <.001), decreased percent body fat (mean, 46.3% 8.4% to 38.3% 10.7%; P <.001), and improved respiratory muscle function, physical strength, and agility (sit-ups, weight-lifts, running speed, and coordination). A significant decline in respiratory quotients occurred during GH therapy (0.81 to 0.77, P <.001), but total REE did not change. CONCLUSIONS: GH treatment of children with PWS accelerated growth, decreased percent body fat, and increased fat oxidation but did not significantly increase total REE. Improvements in respiratory muscle strength, physical strength, and agility also occurred, suggesting that GH treatment may have value in reducing some physical disabilities experienced by children with PWS.     

Physique and body composition: comparisons of methods and results

Body mass is the most investigated measurement for the evaluation of the nutritional and health status of children and adults. To apply it requires consideration of its correlations with sex, height and age, and if possible the type of body shape. It requires also the consideration of body composition, in particular the total body fat content. Here a problem arises. While classic anthropometric techniques are suitable for field investigations with large samples, the investigation of body composition needs the highly technical equipment of a laboratory as a rule. Based on a representative sample of 21,648 males and 21,391 females from all the new federal states of Germany this paper tries to find easily obtained anthropometric measurements which are usable for a type specific estimation of body composition under field conditions. For this reason body mass by sex and height is classified by three different concepts: the skeletal concept with categories of frame size, estimated by the frame index, the whole body concept with categories of corpulence, estimated by the metric index, and the fat concept with categories of subcutaneous fat layer thicknesses. Focussing on a type-specific body mass by height for an assessment of the nutritional status, the skeletal concept is proved to be the best. The summary of body mass and height by the body mass index (BMI), measured in kg/m2, gives the possibility of bringing two measurements into one dimension and to leave the second dimension free for the important variable of age. BMI by sex, age and frame type is found to be a good and practical instrument for the assessment of the nutritional and health status.     

Serum leptin and energy expenditure in children

Leptin has been hypothesized to play an important role in energy balance by affecting both energy intake and energy expenditure. The purpose of our study was to determine the relationship between fasting serum leptin concentrations and measures of energy expenditure in prepubertal children. We measured total energy expenditure (TEE; by the doubly labeled water technique), resting energy expenditure (REE; after an overnight fast), activity energy expenditure (AEE; TEE-REE), body composition (by dual energy x-ray absorptiometry), and fasting serum leptin concentration (by RIA) in 76 children. Simple correlations showed that all measures of energy expenditure (TEE, REE, and AEE) were positively related to the serum leptin concentration (r = 0.50, P < 0.001; r = 0.45, P < 0.001; and r = 0.30, P < 0.01, respectively). However, after adjusting for body composition (fat-free mass and fat mass), gender, and ethnicity, serum leptin concentrations were not related to any measure of energy expenditure (TEE, P = 0.61; REE, P = 0.97; AEE, P = 0.65). These latter findings were further confirmed using structural equation models with leptin and energy expenditure as dependent variables, and fat-free mass and fat mass as independent variables. Results from these models showed no direct effect of leptin and no indirect effect of fat mass (through leptin) on any measure of energy expenditure, when a path between fat mass and energy expenditure was present in the model. Thus, our data do not support the hypothesis that the serum leptin concentration (independent of fat mass) is related to measures of energy expenditure in children.     

Influence of chronic alcohol abuse on body weight and energy metabolism: is excess ethanol consumption a risk factor for obesity or malnutrition?

OBJECTIVES: To evaluate the influence of chronic alcohol abuse on body composition and energy metabolism in patients affected by chronic alcoholism (group A) compared with a group of healthy social drinkers (group B). SETTING: A university hospital clinic in Italy. SUBJECTS: A total of 32 alcoholics without clinical or laboratory signs of liver cirrhosis and malabsorption. MEASUREMENTS: Body composition was assessed by anthropometric measurements. Resting energy expenditure (REE) and substrate oxidation rate was measured by indirect calorimetry. Daily caloric intake was computed on the basis of a food diary compiled over 7 days. RESULTS: Alcoholics showed a significantly lower body weight (P < 0.05) and a significant lower fat mass (P < 0.05) compared with controls. A higher waist-to-hip ratio was found in group A than in group B, both as a whole group (P < 0.01) or separated by gender (females, P < 0.01) and males, P < 0.001), indicating a prevalence of fat distribution in the abdominal region in alcoholics. REE was significantly higher in group A than in group B (P < 0.05). The non-protein respiratory quotient was significantly lower in group A than in group B (P < 0.001) with a consequent higher utilization of lipids (P < 0.01) and a lower carbohydrate oxidation (P < 0.05) in group A. The energy intake provided only by food ingestion was found to be significantly higher in group B (P < 0.01), whilst the total caloric intake, computed as food intake plus alcohol intake, was higher in group A (P < 0.01). CONCLUSIONS: Alcoholics, as compared with social drinkers, showed a lower body weight due essentially to a fat mass reduction, a higher REE value normalized by fat-free mass, and a preferential utilization of lipids as energy substrate. These findings might suggest that chronic ethanol abuse is able to determine an impairment of nutritional status due, at least in part, to an alteration of the substrate oxidation.     

Protection of both auditory hair cells and auditory neurons from cisplatin induced damage

Knowledge about body composition is important in metabolic and nutritional studies. In this cross-sectional study the body composition of 403 healthy white Dutch children and adolescents was evaluated by using dual-energy X-ray absorptiometry (DXA). Possible determinants of body composition were analyzed. In 85 subjects the results of bioelectrical impedance analysis (BIA) were compared with DXA. Fat mass, lean tissue mass, and bone mineral content were greater in older boys and girls. Percentage body fat was greater in older girls but not in boys and it was higher in girls than in boys at all ages. From the age of 14 y boys had higher lean tissue mass and bone mineral content than girls. Tanner stage had a significant relation with body composition in both sexes. Percentage body fat was lower in boys in stage 4 than in stage 3 and was higher in consecutive Tanner stages in girls. After adjustment for age, Tanner stage was significantly positively related to lean tissue mass and bone mineral content in boys and girls and to percentage body fat and fat mass in girls. The profession of the parents and the education of the father had a significant negative correlation with percentage body fat and fat mass in girls (P < 0.01). Physical activity was related to lean tissue mass (P = 0.001) but not to fat mass in boys after adjustment for age. A high correlation and a small difference was found between lean body mass by BIA and lean tissue mass by DXA. Body composition in healthy Dutch children and adolescents is related to age, sex, Tanner stage, socioeconomic status, and physical activity.     

Obesity among offspring of women with type 1 diabetes

OBJECTIVE: To determine subsequent growth and body composition of children born to women with type 1 diabetes compared with controls. DESIGN: Prospective cohort study. SETTING: Follow-up of offspring born to women with type 1 diabetes and controls from an earlier study of diabetes and lactation. SUBJECTS: Seventeen nondiabetic offspring of women with type 1 diabetes and 18 offspring of control women (age range 5.9 to 9.0 years). OUTCOME MEASURES: Anthropometric measures at follow-up included height, weight, triceps and subscapular skinfold thickness. Information on usual nutrient intakes and physical activity patterns was elicited through questionnaires. Body composition was determined from skinfold thickness measures and bioelectrical impedance analysis. A child was identified as obese if he or she met at least 2 of the following 4 criteria for obesity: (1) weight-for-height equal to or greater than 120% of the National Center for Health Statistics (NCHS) reference median plus triceps skinfold greater than the 85th percentile; (2) body mass index (BMI) greater than the 95th percentile for age and sex; (3) percent body fat (from impedance measures) equal to or greater than 25 for boys and 30 for girls; or (4) percent body fat (from sum of skinfold measures) equal to or greater than 25 for boys and 30 for girls. RESULTS: There were 7 obese children in the type 1 diabetes group and none in the control group (p = 0.007). Obese children did not differ from nonobese children in birth weight, body fat patterning, nutrient intake, physical activity patterns, maternal pregravid weight or blood glucose control during the last trimester of pregnancy. Mothers of obese children, however, had fewer years of education and gained more weight during pregnancy compared with mothers of nonobese children in the type 1 diabetes group (p < 0.05). CONCLUSION: Obesity during childhood is a significant problem among nondiabetic children of women with type 1 diabetes. The association of childhood obesity with lower maternal education and excessive pregnancy weight gain warrants further investigation.     

Widespread growth retardation and variable growth recovery in foster children in the first year after initial placement

OBJECTIVES: To determine children's growth patterns in the first year of foster care placement and to compare catch-up growth with initial height percentile as indicators of prior growth retardation. DESIGN: Inception cohort. SUBJECTS: Forty-five children aged 1 1/2 to 6.0 years in their first year of foster care. SETTING: Urban, community-based primary care center. MAIN OUTCOME MEASURES: Height, weight, weight-for-height, and annual growth velocity z scores 1 year after placement. RESULTS: The group entered foster care with an overall height deficit (height z = -0.21), grew at an above-average rate (velocity z = +0.33), and eliminated the height deficit by the end of the year (height z = -0.02; P < .05). Weight increased (baseline weight z = -0.16; year-end weight z = +0.35) and correlated with height z change (r = 0.385, P = .009). Weight for expected weight-for-height-age was above average and did not change (baseline weight for expected weight-for-height-age z = +0.30; year-end weight for expected weight-for-height-age z = +0.40). Baseline age correlated with velocity z (r = .413, P = .005) but not with change in height z. Baseline height z did not correlate with either velocity z or change in height z. Three patterns of growth were seen: 21 (47%) showed catch-up growth (height velocity z = 1.34; gain in height z = +0.61); 16 (36%) showed stable growth; and 8 (18%) showed poor growth (height velocity z = -1.49; decrease in height z = -0.49). CONCLUSIONS: Almost half of the children showed significant catch-up growth in the first year after foster care placement, indicating probable prior growth failure. Initial height was not predictive of future growth, and simple screening (such as height less than the fifth percentile) would have missed the majority of children who showed catch-up growth. A substantial minority (18%) continued to decline across height percentiles after placement. The initial and subsequent growth failure and catch-up growth in this population did not appear to be related to nutritional changes.     

Results after resection of intraoral cancer and reconstruction with the free radial forearm flap

OBJECTIVE: Prospectively evaluate the effect on the nutritional status of a glucose polymer as energy supplementation alone in chronic hemodialysis patients with moderate and severe malnutrition. MATERIAL AND METHODS: The nutritional status of 55 hemodialysis patients was assessed by using a score that included Iron binding capacity, albumin, cholesterol, body mass index, mid brachial circumference, arm muscle area, triceps skinfold, and clinical impression. Twenty-two of 27 patients (14 men and 8 women, mean age 43 +/- 15 years, time on dialysis 65 +/- 49 months) were classified as moderately or severely malnourished and were supplemented for 6 months with 100 g of glucose polymers per day (equivalent to 380 kcal or 1590 kJ) added to the usual food intake. The patients were reevaluated at 3 and 6 months. RESULTS: Only body weight, body mass index, triceps skinfold, and brachial circumference and clinical impression increased significantly at the end of the third month (P < .05) in the 22 patients. These results were confirmed at 6 months in 18 patients that completed the study. Mean body weight increase was 2.4 kg (range, .2 to 6.3 kg). The nutritional status, evaluated through the score, improved in only 4 patients at the end of the study. Few gastrointestinal side effects were observed. Triglycerides increased from 136 +/- 40 mg/dL to 235 +/- 120 mg/dL. Follow-up of the patients showed that fat mass (assessed by anthropometry) was maintained for 6 months after supplementation was discontinued. CONCLUSION: Energy supplementation alone in patients with moderate and severe malnutrition on chronic hemodialysis resulted in an increase in body weight, owing to an increase in body fat, but the nutritional status did not improve.     

Bioelectrical impedance analysis and anthropometry in Ecuadorian children of African ancestry

In the city of Esmeraldas, north-western coast of Ecuador, height, weight, and body composition of 600 male and female schoolchildren of African ancestry in the age groups four, five and six years were investigated. All the children were apparently healthy without any obvious or reported pathologies and in accordance with data from personal information were assigned to one of two socio-economic classes. The greater values for weight and height shown by children in the higher socio-economic group than in the less well off are compatible with those for more fat and water as obtained by the BIA investigation. Additional information on nutritional, muscular and general health status was obtained from positioning and degree of dispersion of the 'Biagram' ellipses. It seems that both the anthropometric and the bioelectrical impedance methods provide useful information on the differences due to belonging to one or other of the socio-economic groups.     

Serum leptin levels in women with anorexia nervosa

Leptin is a protein encoded by the ob gene that is expressed in adipocytes and regulates eating behavior via central neuroendocrine mechanisms. Serum leptin levels have been shown to correlate with weight and percent body fat in normal and obese individuals; however, it is not known whether the regulation of leptin is normal below a critical threshold of body fat in chronic undernutrition. We investigated serum leptin levels in 22 women, aged 23 +/- 4 yr, with anorexia nervosa. Duration of disease, weight, BMI, percent body fat, and serum leptin levels were determined for each patient. Nutritional status was assessed further by caloric intake and measurement of insulin and insulin-like growth factor I (IGF-I) levels. Twenty-three healthy women, aged 23 +/- 4 yr, taking no medications, with normal menstrual function and body mass index (BMI) between 20-26 kg/m2 (mean, 23.7 +/- 1.7 kg/m2), served as a control population for comparison of leptin levels. Subjects with anorexia nervosa were low weight (BMI, 16.3 +/- 1.6 kg/m2; normal, 20-26 kg/m2) and exhibited a striking reduction in percent body fat (7 +/- 2%; normal, 20-30%). The mean serum leptin level was significantly decreased in subjects with anorexia nervosa compared with that in age- and sex-matched controls of normal body weight (5.6 +/- 3.7 vs. 19.1 +/- 8.1 ng/mL; P < 0.0001). Serum leptin levels were correlated highly with weight, as expressed either BMI (r = 0.66; P = 0.002) or percent ideal body weight (r = 0.68; P = 0.0005), body fat (r = 0.70; P = 0.0003), and IGF-I (r = 0.64; P = 0.001), but not with caloric intake or serum levels of estradiol or insulin in subjects with anorexia nervosa. The correlation between leptin and body fat was linear, with progressively lower, but detectable, leptin levels measured even in patients with less than 5% body fat, but was not significant when the effects of weight were taken into account. In contrast, the correlation between leptin and IGF-I remained significant when the effects of weight, body fat, and caloric intake were taken into account. In normal controls, leptin correlated with BMI (r = 0.55; P = 0.007) and IGF-I (r = 0.44; P < 0.05), but not with fat mass. These data demonstrate that serum leptin levels are reduced in association with low weight and percent body fat in subjects with anorexia nervosa compared to normal controls. Leptin levels correlate highly with weight, percent body fat, and IGF-I in subjects with anorexia nervosa, suggesting that the physiological regulation of leptin is maintained in relation to nutritional status even at an extreme of low weight and body fat.     

Peripheral nerve maturation in English, West Indian and Turkish newborn infants

Forty-five patients who underwent a 14 by 4 inch jejunoileal bypass for morbid obesity were studied before the operation and at periodic intervals after operation to determine the complications and changes in body composition resulting from this procedure. Body composition studies were determined using 3H2O and 42K. Rapid weight loss occurred in the first 3 months, with a mean loss of 30 percent of excess weight. This weight loss was accompanied by a decrease in exchangeable potassium (Ke) and total body water (TBW) during this interval by 14 and 10 percent, respectively. Although most patients continued to lose excess weight Ke and TBW stabilized at the end of the first year and returned to preoperative values in six patients at the end of 24 months. Analysis of the ratios of body cell mass and total body water to weight shows an improvement of body composition 12 months after operation. Body composition studies permit a quantitative assessment of the nutritional status in patients undergoing jejunoileal bypass. In spite of significant complications (23 percent), surgery for morbid obesity appears to satisfy the objective of allowing desirable loss of fat with relative sparing of muscle and other supporting tissues.     

Two types of intraoral distribution of fluorotic enamel

Assessment of body composition remains a goal for the routine assessment of nutritional status of patients on long-term dialysis. Methods generally available for estimation of body fat in healthy individuals are limited by practicality and availability for use in this patient population. Anthropometry, which is cost effective and easy to perform, is limited by the lack of appropriate reference standards for patients on dialysis and artifact caused by hydration status. Bioelectrical impedance affords new opportunities for non-invasive assessment of fluid volume, its distribution, and body cell mass; estimation of fat-free mass and body fat can be affected by hydration status. Dual x-ray absorptiometry permits estimation of bone status and fat mass because changes in hydration status are reflected in estimates of fat-free mass. Evaluation of validity of techniques for fluid status and body composition assessment requires the use of appropriate reference methods and proper statistical procedures to examine error, not only between groups, but by individual. Use of body composition assessment methods together with biochemical measurements will enhance the nutritional assessment of end-stage renal disease patients on long-term hemodialysis.     

Energy balance in nonsmall cell lung carcinoma patients before and after surgical resection of their tumors

BACKGROUND: The purpose of this study was to investigate whether surgical removal of a tumor influences energy balance, body weight, and body composition in lung carcinoma patients. METHODS: In 53 nonsmall cell lung carcinoma (NSCLC) patients, resting energy expenditure (REE, measured by ventilated hood), energy intake (EI, determined by diet history), body weight, and body composition (fat free mass [FFM], measured by bioelectrical impedance analysis) were all determined before tumor resection. In 39 of 53 patients, REE, EI, body weight, and body composition were also measured 3, 6, and 12 months after tumor resection. RESULTS: Thirty-six of 53 patients (68%) were found to be hypermetabolic. Fourteen patients were excluded from the repeated measurements. Patients with curative tumor resection (n = 30) showed an increase in body weight over a 1-year period, in contrast to patients with tumor recurrence (n = 9), who lost weight (+3.5 vs. -3.6 kg, P < 0.005). The weight gain was caused predominantly by an increase in fat mass (FM), while the weight loss was caused for more than half by a decrease in FFM. Body weight was increased in hypermetabolic patients (n = 20) as well as patients with normal metabolism (n = 10) 1 year after successful removal of their tumors. However, although EI/REE was significantly increased in hypermetabolic patients (from 106% to 140%, P < 0.05), it was not changed in patients with normal metabolism. CONCLUSIONS: Hypermetabolic NSCLC patients undergoing curative resection show an improvement in energy balance caused by both a decrease in REE and an increase in EI. This positive energy balance results in weight gain, which is caused predominantly by an increase in FM.     

Gray matter and white matter perfusion imaging in patients with severe carotid artery lesions

BACKGROUND: There are limited data on the influence of body composition, sex, seasonality, ethnicity, and geographic location on the components of energy expenditure in children. OBJECTIVE: The objective was to examine the determinants of total energy expenditure (TEE), resting energy expenditure (REE), and activity-related energy expenditure (AEE) in children. DESIGN: Cross-sectional data from 232 children (4-10 y of age) from 4 ethnic groups (white American, African American, Guatemalan Mestizo, and Native American Mohawk) were examined. RESULTS: In 104 white children studied in Vermont and Alabama, TEE was significantly higher in spring than in fall, higher in boys than in girls, and higher in children in Vermont (all effects: approximately 0.42 MJ/d, P < 0.05). The significant effect of sex was explained through REE; the influences of season and location were explained through AEE. In all children, there was no effect of sex but a significant effect of ethnicity (P < 0.01) on TEE: a significant effect of sex (P < 0.01) and no effect of ethnicity (P = 0.16) on REE; and no effect of sex and a significant effect of ethnicity on AEE. The significant effects of ethnicity were due to lower values in Guatemalan children. TEE correlated most strongly with weight (r = 0.81) and fat-free mass (r = 0.79-0.81); REE with weight (r = 0.85) and fat-free mass (r = 0.80-0.87); and AEE with maximal oxygen consumption (r = 0.54), fat-free mass (r = 0.50), and fat mass (r = 0.49). CONCLUSIONS: 1) Season and location influenced TEE in children through their effects on AEE, 2) a higher REE in boys was consistent across all groups examined, 3) Guatemalan children had lower TEE due to a lower AEE, 4) body weight may be the best predictor of TEE, and 5) maximal oxygen consumption was the strongest marker of AEE.     

Quantitative assessment of cross-sectional muscle area, functional status, and muscle strength in men with the acquired immunodeficiency syndrome wasting syndrome

The acquired immunodeficiency syndrome wasting syndrome (AWS) in men is characterized by the loss of lean body mass out of proportion to weight. Although the wasting syndrome has been thought to contribute to reduced functional capacity, the relationships among lean body mass, muscle size, functional status, and regional muscle strength have not previously been investigated in this population. In this study, 24 eugonadal men with the AWS (weight <90% of the ideal body weight or weight loss >10% from preillness maximum) underwent determination of body composition by dual energy x-ray absorptiometry (DXA), 40K isotope analysis, urinary creatinine excretion, and quantitative computed tomographic analysis of cross-sectional muscle areas of the midarm and thigh. Overall exercise functional capacity was evaluated using the 6-min walk test, and performance of upper and lower extremities was determined with the quantitative muscle function test. Subjects were 37 +/- 1 yr of age and weighed 95.5 +/- 3.0% of ideal body weight, with a body mass index of 21.9 +/- 0.7 kg/m2 and an average weight loss of 15 +/- 1%. The mean CD4 count among the subjects was 354 +/- 70 cells/mm3, and viral load was 58,561 +/- 32,205 copies. Sixty-two percent of subjects were receiving protease inhibitor therapy. The subjects demonstrated 90% of the expected muscle mass by the creatinine height index method. Overall performance status on the Karnofsky scale was highly correlated to weight (r = 0.51; P = 0.018; by body mass index), lean body mass (r = 0.46; P = 0.036; by DXA), and body cell mass (r = 0.47; P = 0.037; by 40K isotope analysis). Cross-sectional muscle area of the upper extremity was the best predictor (P < 0.001) of Karnofsky score, accounting for 52% of the variability in a stepwise regression analysis. Upper body muscle strength was most significantly predicted by lean body mass (by DXA; r2 = 0.78; P < 0.0001), whereas lower body strength and performance on the 6-min walk test were best predicted by lower extremity cross-sectional muscle area (r2 = 0.70; P < 0.0001 and r2 = 0.26; P = 0.030, respectively). These data demonstrate that cross-sectional muscle area is highly predictive of functional status and muscle strength in men with the AWS.     

Defining obesity in children by biological endpoint rather than population distribution

OBJECTIVE: To investigate the association of fatness in children with dyslipoproteinemia and high blood pressure, with the purpose of proposing standards for childhood obesity which are directly related to intermediate biological parameters that predict future disease. DESIGN: A cross-sectional study of a large, nationally representative sample of Australian schoolchildren. SUBJECTS: 1834 children aged 9 or 15 years, with skinfolds blood lipid measurements on 1144 and with skinfolds and blood pressure measurements on 1757. MEASUREMENTS: Skinfolds thicknesses measured at four locations (triceps, biceps, subscapular and suprailiac) using holtain calipers, percent body fat calculated from the sum of four skinfolds, Quetelet's index calculated from weight and height, waist and hip circumferences, plasma total cholesterol and triglycerides determined using a Technicon Autoanalyser II, high density lipoprotein cholesterol (HDLC) analysed following precipitation with heparin manganese, and systolic blood pressure (SBP) measured using a standard mercury sphygmomanometer. RESULTS: For 9 years old girls, 15 year old girls and 9 years old boys, dichotomising their HDLC and SBP measurements by percent body fat defined the two groups most homogeneous in terms of a measure of within-group variation. The cut-points in percent body fat were in the ranges 29-35% (girls) and 17-20% (boys). CONCLUSION: It is feasible to use the current biomedical status of individual children to define criteria for obesity. A cut-off point of 30% body mass as fat for girls and 20% for boys appears to be an appropriate standard.