Greater male variability in daily energy expenditure develops through puberty.

There is considerably greater variation in metabolic rates between men than between women, in terms of basal, activity and total (daily) energy expenditure (EE). One possible explanation is that EE is associated with male sexual characteristics (which are known to vary more than other traits) such as musculature and athletic capacity. Such traits might be predicted to be most prominent during periods of adolescence and young adulthood, when sexual behaviour develops and peaks. We tested this hypothesis on a large dataset by comparing the amount of male variation and female variation in total EE, activity EE and basal EE, at different life stages, along with several morphological traits: height, fat free mass and fat mass. Total EE, and to some degree also activity EE, exhibit considerable greater male variation (GMV) in young adults, and then a decreasing GMV in progressively older individuals. Arguably, basal EE, and also morphometrics, do not exhibit this pattern. These findings suggest that single male sexual characteristics may not exhibit peak GMV in young adulthood, however total and perhaps also activity EE, associated with many morphological and physiological traits combined, do exhibit GMV most prominently during the reproductive life stages.

Total daily energy expenditure has declined over the past three decades due to declining basal expenditure, not reduced activity expenditure.

Obesity is caused by a prolonged positive energy balance1,2. Whether reduced energy expenditure stemming from reduced activity levels contributes is debated3,4. Here we show that in both sexes, total energy expenditure (TEE) adjusted for body composition and age declined since the late 1980s, while adjusted activity energy expenditure increased over time. We use the International Atomic Energy Agency Doubly Labelled Water database on energy expenditure of adults in the United States and Europe (n = 4,799) to explore patterns in total (TEE: n = 4,799), basal (BEE: n = 1,432) and physical activity energy expenditure (n = 1,432) over time. In males, adjusted BEE decreased significantly, but in females this did not reach significance. A larger dataset of basal metabolic rate (equivalent to BEE) measurements of 9,912 adults across 163 studies spanning 100 years replicates the decline in BEE in both sexes. We conclude that increasing obesity in the United States/Europe has probably not been fuelled by reduced physical activity leading to lowered TEE. We identify here a decline in adjusted BEE as a previously unrecognized factor.

External validation of a prediction model for estimating fat mass in children and adolescents in 19 countries: individual participant data meta-analysis.

OBJECTIVE: To evaluate the performance of a UK based prediction model for estimating fat-free mass (and indirectly fat mass) in children and adolescents in non-UK settings. DESIGN: Individual participant data meta-analysis. SETTING: 19 countries. PARTICIPANTS: 5693 children and adolescents (49.7% boys) aged 4 to 15 years with complete data on the predictors included in the UK based model (weight, height, age, sex, and ethnicity) and on the independently assessed outcome measure (fat-free mass determined by deuterium dilution assessment). MAIN OUTCOME MEASURES: The outcome of the UK based prediction model was natural log transformed fat-free mass (lnFFM). Predictive performance statistics of R2, calibration slope, calibration-in-the-large, and root mean square error were assessed in each of the 19 countries and then pooled through random effects meta-analysis. Calibration plots were also derived for each country, including flexible calibration curves. RESULTS: The model showed good predictive ability in non-UK populations of children and adolescents, providing R2 values of >75% in all countries and >90% in 11 of the 19 countries, and with good calibration (ie, agreement) of observed and predicted values. Root mean square error values (on fat-free mass scale) were <4 kg in 17 of the 19 settings. Pooled values (95% confidence intervals) of R2, calibration slope, and calibration-in-the-large were 88.7% (85.9% to 91.4%), 0.98 (0.97 to 1.00), and 0.01 (-0.02 to 0.04), respectively. Heterogeneity was evident in the R2 and calibration-in-the-large values across settings, but not in the calibration slope. Model performance did not vary markedly between boys and girls, age, ethnicity, and national income groups. To further improve the accuracy of the predictions, the model equation was recalibrated for the intercept in each setting so that country specific equations are available for future use. CONCLUSION: The UK based prediction model, which is based on readily available measures, provides predictions of childhood fat-free mass, and hence fat mass, in a range of non-UK settings that explain a large proportion of the variability in observed fat-free mass, and exhibit good calibration performance, especially after recalibration of the intercept for each population. The model demonstrates good generalisability in both low-middle income and high income populations of healthy children and adolescents aged 4-15 years.

The "drive to eat" hypothesis: energy expenditure and fat-free mass but not adiposity are associated with milk intake and energy intake in 12 week infants.

BACKGROUND: Recent work has challenged the long-held assumption that appetite functions to maintain stable body mass and fat mass (FM), suggesting instead that appetite matches food intake to energy expenditure and its correlate, fat-free mass (FFM). Whether this scenario applies to young infants, in chronic positive energy balance, remains unknown. OBJECTIVES: To test associations of components of energy expenditure and body composition with milk intake (MI) and energy intake (EI) in 12-week infants, by reanalyzing published cross-sectional data. METHODS: Data were available for 48 infants. In addition to anthropometric measurements, we assessed MI and EI by test-weighing, sleeping metabolic rate (SMR) by indirect calorimetry, and FFM, FM, and total energy expenditure (TEE) by doubly labeled water. Mean parental height was calculated as a marker of infant growth drive. Correlation and multiple regression analyses were applied. RESULTS: MI and EI correlated with FFM (r = 0.47 and 0.57, respectively; P < 0.01), but not FM (P > 0.6). MI and EI correlated with SMR (r = 0.42 and 0.53, respectively; P < 0.01) and TEE (r = 0.50 and 0.49, respectively; P < 0.01). SMR and TEE correlated with FFM (r = 0.41 and 0.42, respectively; P < 0.01), but not FM (P > 0.2). In a multiple regression analysis, MI was independently associated with TEE (partial r = 0.39) and FFM (partial r = 0.35). EI showed similar associations. Mean parental height was correlated with weight gain, MI, and EI. CONCLUSIONS: As in adults, MI and EI in young infants were strongly associated with FFM and with total and sleeping components of energy expenditure, but not with fatness. The infant's growth drive contributed to these associations. This suggests that appetite is regulated by the rate of energy expenditure, the size of energy-using tissues, and tissue deposition rate, and that the high levels of body fat characteristic of infants may not constrain weight gain.

Validation and calibration of the Eating Assessment in Toddlers FFQ (EAT FFQ) for children, used in the Growing Up Milk - Lite (GUMLi) randomised controlled trial.

The Eating Assessment in Toddlers FFQ (EAT FFQ) has been shown to have good reliability and comparative validity for ranking nutrient intakes in young children. With the addition of food items (n 4), we aimed to re-assess the validity of the EAT FFQ and estimate calibration factors in a sub-sample of children (n 97) participating in the Growing Up Milk - Lite (GUMLi) randomised control trial (2015-2017). Participants completed the ninety-nine-item GUMLi EAT FFQ and record-assisted 24-h recalls (24HR) on two occasions. Energy and nutrient intakes were assessed at months 9 and 12 post-randomisation and calibration factors calculated to determine predicted estimates from the GUMLi EAT FFQ. Validity was assessed using Pearson correlation coefficients, weighted kappa (κ) and exact quartile categorisation. Calibration was calculated using linear regression models on 24HR, adjusted for sex and treatment group. Nutrient intakes were significantly correlated between the GUMLi EAT FFQ and 24HR at both time points. Energy-adjusted, de-attenuated Pearson correlations ranged from 0·3 (fibre) to 0·8 (Fe) at 9 months and from 0·3 (Ca) to 0·7 (Fe) at 12 months. Weighted κ for the quartiles ranged from 0·2 (Zn) to 0·6 (Fe) at 9 months and from 0·1 (total fat) to 0·5 (Fe) at 12 months. Exact agreement ranged from 30 to 74 %. Calibration factors predicted up to 56 % of the variation in the 24HR at 9 months and 44 % at 12 months. The GUMLi EAT FFQ remained a useful tool for ranking nutrient intakes with similar estimated validity compared with other FFQ used in children under 2 years.

The Pediatric Subjective Global Nutrition Assessment Classifies More Children With Cerebral Palsy as Malnourished Compared With Anthropometry.

BACKGROUND: Nutrition assessment is multidimensional; however, much of the literature examining the nutritional status of children with cerebral palsy (CP) focuses on a single dimension. OBJECTIVE: The aim of the study was to evaluate nutritional status in children and adolescents with CP by comparing results from the Pediatric Subjective Global Nutrition Assessment (SGNA) with results from traditional anthropometric measures. DESIGN: This study was a cross-sectional observational study. PARTICIPANTS/SETTING: This study was conducted in a tertiary hospital outpatient setting in Brisbane, Australia, from February 2017 to March 2018. A total of 89 children (63 boys) with CP aged between 2 and 18 years of age were included. All Gross Motor Function Classification System levels were observed. The majority of children were in Gross Motor Function Classification System I and II (57, 64%) compared with Gross Motor Function Classification System III to V (32, 36%). Children with feeding tubes and those acutely unwell or hospitalized were excluded. MAIN OUTCOME MEASURES: Children were classified as well nourished, moderately malnourished, or severely malnourished by dietitians using the SGNA. Weight, height, body mass index (BMI), triceps skinfold thickness, subscapular skinfold thickness, and mid upper arm circumference were measured and converted to z scores to account for age and sex differences. Moderate malnutrition was defined by z scores -2.00 to -2.99 and severe malnutrition as ≤-3.00 z scores. STATISTICAL ANALYSIS PERFORMED: Multinomial logistic analyses were used to compare results from the SGNA and each single measurement. Continuous outcomes were transformed into z scores. Agreement was assessed with 2 categories: not malnourished and malnourished. Comparison statistics included percent agreement, sensitivity, and specificity. RESULTS: More children were classified as moderately or severely malnourished by SGNA than any of the anthropometric z score cutoffs. The majority of children were well nourished (n = 63) with 20 (22%) moderately malnourished and 6 (7%) severely malnourished by SGNA. The SGNA classified 11 children as malnourished that were not classified as malnourished by BMI. Children with moderate or severe malnutrition by SGNA had lower weight (P < .001, P < .001), BMI (P < .001, P < .001), mid upper arm circumference (P < .001, P < .001), triceps skinfold thickness (P = .01, P = .007), and subscapular skinfold thickness (P = .005, P = .02) z scores than well-nourished children. CONCLUSION: The SGNA identified more potentially malnourished children including children classified as well nourished by the single measurements such as BMI, height, and weight. The SGNA provided a clinically useful multidimensional approach to nutrition assessment for children with CP.

Accuracy of Longitudinal Assessment of Visceral Adipose Tissue by Dual-Energy X-Ray Absorptiometry in Children with Obesity.

Background: Increased visceral adipose tissue (VAT) is strongly associated with cardiometabolic risk factors. Accurate quantification of VAT is available through magnetic resonance imaging (MRI), which incurs a significant financial and time burden. We aimed to assess the accuracy of dual-energy X-ray absorptiometry- (DXA-) derived VAT (DXA-VAT) against a gold standard MRI protocol (MRI-VAT) in children with normal weight and obesity cross-sectionally, and over the course of a lifestyle intervention. Methodology: MRI-VAT and DXA-VAT were quantified in 61 children (30 normal weight and 31 with obesity) at baseline. Children with obesity entered a three-month exercise and/or nutrition intervention after which VAT was reassessed. MRI- and DXA-VAT cross-sectional area, volume, and mass were quantified, and associations were calculated at baseline (n = 61) and pre-post intervention (n = 28, 3 participants dropped out). Method agreement was assessed through Bland-Altman analysis, linear regression, and Passing-Bablok regression. Results: At baseline, all DXA- and MRI-VAT outcomes were strongly associated (r = 0.90, P < 0.001). However, there were no significant associations between absolute or relative change in DXA- and MRI-VAT outcomes (r = 0.25-0.36, P > 0.05). DXA significantly overestimated VAT CSA (cross-sectional area), volume, and mass when compared with MRI (P < 0.001) at baseline. Significant proportional bias was observed for all DXA-VAT outcomes at baseline and for relative longitudinal changes in DXA-VAT. Conclusions: Although DXA-VAT outcomes were strongly associated with MRI-VAT outcomes at baseline, estimates were subject to proportional bias in children with obesity and normal weight. DXA lacks validity for detecting changes in VAT among children with obesity. This trial is registered with NCT01991106.

Assessment of the 5-Minute Oxygen Uptake Efficiency Slope in Children With Obesity.

PURPOSE: Poor cardiorespiratory fitness is associated with increased all cause morbidity and mortality. In children with obesity, maximum oxygen uptake (V̇O2max) may not be achieved due to reduced motivation and peripheral fatigue. We aimed to identify a valid submaximal surrogate for V̇O2max in children with obesity. METHOD: Ninety-two children with obesity (7-16 years) completed a maximal exercise treadmill test and entered a three-month exercise and/or nutrition intervention after which the exercise test was repeated (n = 63). Participants were required to reach V̇O2max to be included in this analysis (n = 32 at baseline and n = 13 at both time-points). The oxygen uptake efficiency slope (OUES) was determined as the slope of the line when V̇O2 (L/min) was plotted against log V̇E. Associations between the maximal OUES, submaximal OUES (at 3, 4, 5 and 6 min of the exercise test) and V̇O2max were calculated. RESULTS: In the cross-sectional analysis, V̇O2max (L/min) was strongly correlated with 5-min OUES independent of Tanner puberty stage and sex (R2 = .80, p < .001). Longitudinal changes in V̇O2max were closely reflected by changes in 5-min OUES independent of change in percent body fat (R2 = .63, p < .05). CONCLUSION: The 5-min OUES is a viable alternative to V̇O2max when assessing children with obesity.

Infant feeding knowledge, attitudes, and beliefs predict antenatal intention among first-time mothers in Queensland.

AIM: This study assessed infant feeding knowledge, attitudes, and beliefs among women from Queensland, Australia, in their first pregnancy. Antenatal feeding intention in this group was described, and the hypothesis was tested that antenatal knowledge, attitudes, and beliefs about infant feeding are associated with antenatal intention for the duration and exclusivity of breastfeeding for the infant's first year. SUBJECTS AND METHODS: The Feeding Queensland Babies Study is a prospective survey of infant feeding attitudes and behaviors among first-time mothers in Queensland, Australia. Data on infant feeding knowledge, attitudes, beliefs, and intention were collected antenatally, and an Infant Feeding Attitudes Score was calculated. RESULTS: Although 85% of respondents endorsed breastfeeding as most appropriate for infants, 11% valued formula feeding equally. Intention to give any breastmilk during the first weeks was 98%, but it fell to 18% during the second year. More than one-quarter of women reported intention to introduce foods other than breastmilk before 5 months of infant age. The infant feeding attitudes and beliefs score correlated positively with feeding intention for breastfeeding and the introduction of complementary solids. CONCLUSIONS: Enhancing women's knowledge of recommendations and their understanding of breastfeeding's specific benefits and the reasons for recommended scheduling of feeding transitions may positively impact breastfeeding exclusivity and duration and the age-appropriate introduction of complementary solids. Communication of detailed feeding recommendations for the infant's first year and specific information about the health benefits of breastfeeding should be a goal of healthcare providers working with pregnant women.

Comparison of energy intake in toddlers assessed by food frequency questionnaire and total energy expenditure measured by the doubly labeled water method.

The ability of parents to accurately report energy intake in toddlers has rarely been validated using the gold-standard doubly labeled water (DLW) method to assess total energy expenditure (TEE). The aim of the study was to evaluate the accuracy of toddler energy intake (EI), estimated using the Australian Child and Adolescent Eating Survey (ACAES) food frequency questionnaire (FFQ) by parent report compared with a weighed food record (WFR) and TEE measured by DLW. Twelve toddlers had TEE assessed over 10 days using DLW. Usual energy intake was estimated by the primary caregiver, using standard toddler portions in ACAES-FFQ and a 4-day WFR and daily EI (in kilocalories) derived using national nutrient databases. Accuracy of reporting was calculated from absolute (EI-TEE) and percentage (EI/TEE×100) differences between EI and TEE and Pearson correlations and limits of agreement from Bland-Altman plots. Toddlers (n=12, 7 boys) had a mean age of 3.2±0.5 years, body mass index 16.2±0.9 kg, body mass index z score 0.1±0.8, EI from ACAES-FFQ 1,183±281kcal/day, and WFR 1,179±278 kcal/day and DLW TEE 1,251±149 kcal/day. The mean difference and limits of agreement (±2 standard deviations) compared with DLW was -68 (-623, 488) kcal/day for the FFQ and for the WFR -72 (-499, 354) kcal/day. Although both a semiquantitative FFQ and WFR can adequately estimate toddler energy intake at the group level in this population, toddler-specific portion size estimates should be assigned to foods listed in the FFQ. Choice of method is likely to depend on practical issues, including cost and burden.

Predicting resting energy expenditure in boys with Duchenne muscular dystrophy.

BACKGROUND: Understanding how best to predict energy needs in Duchenne muscular dystrophy (DMD) is fundamental to weight management in clinical practice; however there is a large gap in the literature regarding information on the most appropriate method. We aimed to ascertain the most valid predictive equation that can be used to predict REE in steroid treated ambulatory boys with DMD. METHODS: REE was measured in 9 boys with DMD using indirect calorimetry after an overnight fast. REE was predicted using five different equations, based on height, weight, or body composition variables. RESULTS: Mean measured REE was 5.4 (SD 0.4) MJ/day. The inclusion of fat free mass in the prediction equation provided no benefit over body weight. The exclusion of height, when compared with weight alone, improved predictive performance, as seen with the Schofield equations, in which a minimal bias and root means squared error is seen. CONCLUSIONS: The most accurate and precise equation was the Schofield weight equation (Bias -0.2 MJ, 95% CI: -1.3-0.9 MJ), which can easily be calculated in a clinical setting and provides a solid foundation from which clinicians can establish energy requirements to support nutritional management in boys with DMD.

Ability of commonly used prediction equations to predict resting energy expenditure in children with inflammatory bowel disease.

BACKGROUND: Paediatric onset inflammatory bowel disease (IBD) may cause alterations in energy requirements and invalidate the use of standard prediction equations. Our aim was to evaluate four commonly used prediction equations for resting energy expenditure (REE) in children with IBD. METHODS: Sixty-three children had repeated measurements of REE as part of a longitudinal research study yielding a total of 243 measurements. These were compared with predicted REE from Schofield, Oxford, FAO/WHO/UNU, and Harris-Benedict equations using the Bland-Altman method. RESULTS: Mean (±SD) age of the patients was 14.2 (2.4) years. Mean measured REE was 1566 (336) kcal per day compared with 1491 (236), 1441 (255), 1481 (232), and 1435 (212) kcal per day calculated from Schofield, Oxford, FAO/WHO/UNU, and Harris-Benedict, respectively. While the Schofield equation demonstrated the least difference between measured and predicted REE, it, along with the other equations tested, did not perform uniformly across all subjects, indicating greater errors at either end of the spectrum of energy expenditure. Smaller differences were found for all prediction equations for Crohn's disease compared with ulcerative colitis. CONCLUSIONS: Of the commonly used equations, the equation of Schofield should be used in pediatric patients with IBD when measured values are not able to be obtained.

Development of height-weight based equation for assessment of body composition in Sri Lankan children.

OBJECTIVE: To develop a height and weight based equation to estimate total body water (TBW) in Sri Lankan children. METHODS: Cross sectional descriptive study done involving 5-15 year old healthy children. Height and weight were measured. TBW was assessed using isotope dilution method (D(2)O) and fat free mass (FFM) calculated. Multiple regression analysis was used to develop prediction equation and validated using PRESS statistical technique. Height, weight and sex code (male=1; female=0) were used as prediction variables. RESULTS: This study provides height and weight equation for the prediction of TBW in Sri Lankan children. To the best of our knowledge there are no published height weight prediction equations validated on South Asian populations. CONCLUSION: Results of this study need to be affirmed by more studies on other closely related populations by using multicomponent body composition.

Evaluation of nutrition assessment tools compared with body cell mass for the assessment of malnutrition in chronic kidney disease.

OBJECTIVE: We compared the subjective global assessment (SGA) and a range of SGA-based assessment tools with body cell mass (BCM) in patients with stage IV and V predialysis chronic kidney disease (CKD). STUDY DESIGN: This was a cross-sectional, observational study. SETTING: The study took place at a public tertiary hospital predialysis outpatient clinic. PATIENTS: A total of 56 consecutive consenting patients with CKD (61% were male; age [mean +/- standard deviation] 70.2 +/- 11.6 years; glomerular filtration rate 22.2 +/- 6.8 mL/min). MAIN OUTCOME MEASURE: Nutrition status was the main outcome measure. RESULTS: In this population, the prevalence of malnutrition was 19.6% (n = 11, SGA B; no C ratings). Malnutrition was associated with lower BCM (mean BCM, 26.3 vs. 33.4 kg, P = .007, measured by total body potassium), body weight (64.8 vs. 76.1 kg, P = .042), body mass index (23.7 vs. 27.6 kg/m(2), P = .015), and greater weight loss over the previous 6 months (-6.2 vs. -0.1 kg, P = .004). BCM had a weak relationship with 7-point SGA (P = .267), malnutrition inflammation score (r = -0.27 P = .063), and patient-generated SGA (r = -0.27 P = .060). There was no association for either measure of nutrition status (SGA or BCM) with albumin, glomerular filtration rate, or C-reactive protein. CONCLUSION: SGA in its original form most accurately delineated malnutrition by depleted BCM and is the most appropriate tool for cross-sectional assessment of nutrition status in patients with predialysis CKD.

Resting energy expenditure in patients with solid tumors undergoing anticancer therapy.

OBJECTIVE: Few studies have investigated the resting energy expenditure (REE) of, or determined the individual predictive accuracy of prediction equations in, cancer patients undergoing anticancer therapy. This study compared the measured REE of patients with cancer undergoing anticancer therapy with (1) healthy subjects and (2) REE estimated from commonly used prediction methods. METHODS: Resting energy expenditure was measured in 18 cancer patients and 17 healthy subjects by using indirect calorimetry under standard conditions and was estimated from seven prediction methods. Fat-free mass (FFM) was measured by bioelectrical impedance analysis. Data were analyzed with regression modeling to adjust REE for FFM. Agreement between measured and predicted REE values was analyzed using the Bland-Altman approach. RESULTS: There was no significant difference in FFM-adjusted REE between cancer patients and healthy subjects (mean difference 10%). Limits of agreement were wide for all prediction methods in estimating REE as much as 40% below and up to 30% above measured REE. CONCLUSIONS: REE in cancer patients undergoing anticancer therapies does not appear to be as high as commonly thought. None of the prediction equations examined were acceptable for predicting REE of individual cancer patients or healthy subjects.

Reducing the time period of steady state does not affect the accuracy of energy expenditure measurements by indirect calorimetry.

Achievement of steady state during indirect calorimetry measurements of resting energy expenditure (REE) is necessary to reduce error and ensure accuracy in the measurement. Steady state is often defined as 5 consecutive min (5-min SS) during which oxygen consumption and carbon dioxide production vary by +/-10%. These criteria, however, are stringent and often difficult to satisfy. This study aimed to assess whether reducing the time period for steady state (4-min SS or 3-min SS) produced measurements of REE that were significantly different from 5-min SS. REE was measured with the use of open-circuit indirect calorimetry in 39 subjects, of whom only 21 (54%) met the 5-min SS criteria. In these 21 subjects, median biases in REE between 5-min SS and 4-min SS and between 5-min SS and 3-min SS were 0.1 and 0.01%, respectively. For individuals, 4-min SS measured REE within a clinically acceptable range of +/-2% of 5-min SS, whereas 3-min SS measured REE within a range of -2-3% of 5-min SS. Harris-Benedict prediction equations estimated REE for individuals within +/-20-30% of 5-min SS. Reducing the time period of steady state to 4 min produced measurements of REE for individuals that were within clinically acceptable, predetermined limits. The limits of agreement for 3-min SS fell outside the predefined limits of +/-2%; however, both 4-min SS and 3-min SS criteria greatly increased the proportion of subjects who satisfied steady state within smaller limits than would be achieved if relying on prediction equations.

Physical activity cost in children following an acquired brain injury--a comparative study.

BACKGROUND: Alterations in energy expenditure during activity post head injury has not been investigated due primarily to the difficulty of measurement. OBJECTIVE: The aim of this study was to compare energy expenditure during activity and body composition of children following acquired brain injury (ABI) with data from a group of normal controls. DESIGN: Energy expenditure was measured using the Cosmed K4b(2) in a group of 15 children with ABI and a group of 67 normal children during rest and when walking and running. Mean number of steps taken per 3 min run was also recorded and body composition was measured. RESULTS: The energy expended during walking was not significantly different between both groups. A significant difference was found between the two groups in the energy expended during running and also for the number of steps taken as children with ABI took significantly less steps than the normal controls during a 3 min run. CONCLUSIONS: Children with ABI exert more energy per activity than healthy controls when controlled for velocity or distance. However, they expend less energy to walk and run when they are free to choose their own desirable, comfortable pace than normal controls.

Assessment of bioelectrical impedance analysis for the prediction of total body water in cystic fibrosis.

The aim of this study was to compare the measurement of total body water (TBW) by deuterium (2H2O) dilution and bioelectrical impedance analysis (BIA) in patients with cystic fibrosis (CF) and healthy controls. Thirty-six clinically stable patients with CF (age 25.4+/-5.6 yrs) and 42 healthy controls (age 25.4+/-4.8) were recruited into this study. TBW was measured by 2H2O dilution and predicted by BIA in patients and controls. The TBW predicted from BIA was significantly different from TBW as measured using 2H2O in patients (P<0.05) but not in controls. Mean (+/-SD) values for predicted and measured TBW differed by 5.6 (+/-9.1) L in patients and 0.4 (+/-3.6)L in controls. This bias was consistent for all controls but not for patients. In CF, BIA over predicted TBW determined by 2H2O dilution to an increasing extent at larger TBW volumes. There was a strong correlation between height2/impedance and TBW in patients with CF (r=0.90; y=0.67x+2.50) and in controls (r=0.81; y=0.57x+9.60). The slope of the regression lines was similar for both groups, however the y intercepts were significantly different (P<0.05). BIA overestimates TBW in patients with CF, possibly due to invalid factory installed regression equations within BIA instrumentation. Future studies employing BIA as a measure of TBW or FFM in CF should use alternative predictive equations to those that have been developed for healthy individuals. A large scale study to develop specific regression equations for use in CF is warranted.

Resting energy expenditure and body composition in children with myelomeningocele.

PURPOSE: Myelomeningocele is a complex disease often complicated by obesity for reasons not well understood. The objectives of this study were to determine body composition and energy expenditure of children with MMC. METHODS: Resting energy expenditure (REE), body composition and anthropometry were measured in 19 children with MMC (12 M, 7 F). Total energy expenditure (TEE) was estimated using a 3-day activity record. Energy intake (EI) was measured in seven children (5 M, 2 F) with MMC. Data were then compared with predicted values. RESULTS: Mean REE (n = 19) was 4680 +/- 1452 kJ/day (96.1 +/- 18.1% of predicted REE). The range was large (45.8-125.7% of predicted REE). TEE (n = 7) was 4344 +/- 2376 kJ/day, hence only 73 34% of predicted TEE. EI (n = 7) was 6560 +/- 1329 kJ/day, approximating a normal energy requirement. Overall, BCM was lower than expected values. CONCLUSIONS: REE in children with MMC is variable when compared to predicted values. TEE was found to be lower in children with MMC than predicted values and EI was similar to predicted values in this group of seven children. BCM is reduced in children with MMC when compared to expected values.