Bioelectrical Impedance Vector Analysis: A Valuable Tool to Monitor Daily Body Hydration Dynamics at Altitude

Bioelectrical impedance vector analysis (BIVA) is a method used to estimate variation in body hydration. We assessed the potential of BIVA for monitoring daily body hydration fluctuations in nine healthy, normally active males under matching normoxic (NX) and hypobaric hypoxic (HH) experimental conditions. Furthermore, we aimed to investigate whether changes in BIVA may correspond with the development of acute mountain sickness (AMS). Subjects were exposed in a hypobaric chamber to both NX (corresponding to an altitude of 262 m) and HH conditions corresponding to an altitude of 3500 m during two four-day sojourns within which food, water intake and physical activity were controlled. Bioimpedance and body weight measurements were performed three times a day and medical symptoms were assessed every morning using the Lake Louise score (LLS). Total body water (TBW) was also assessed on the last day of both sojourns using the deuterium dilution technique. We detected circadian changes in vector length, indicating circadian body water variations that did not differ between NX and HH conditions (ANOVA effects: time: p = 0.018, eta2 = 0.149; interaction: p = 0.214, eta2 = 0.083; condition: p = 0.920, eta2 = 0.001). Even though none of the subjects developed AMS, four subjects showed clinical symptoms according to the LLS during the first 24 hours of HH conditions. These subjects showed a pronounced (Cohen’s d: 1.09), yet not statistically significant (p = 0.206) decrease in phase angle 6 hours after exposure, which may indicate fluid shift from the intracellular to the extracellular compartment. At the end of each sojourn, vector length correlated with deuterium dilution TBW “gold standard” measurements (linear regression: NX: p = 0.002 and r2 = 0.756, HH: p < 0.001 and r2 = 0.84). BIVA can be considered a valuable method for monitoring body hydration changes at altitude. Whether such changes are related to the development of clinical symptoms associated with AMS, as indicated in the present investigation, must be confirmed in future studies.

Schweres Lungenemphysem: Zusammenhänge zwischen klinischen Verläufen nach bronchoskopischer Volumenreduktion und metabolischen Parametern erkennen

<b>Background:</b> Hypermetabolism and muscle wasting frequently occur in patients with severe emphysema. Improving respiratory mechanics by bronchoscopic lung volume reduction (BLVR) might contribute to muscle maintenance by decreasing energy requirements and alleviating eating-related dyspnoea. <b>Objective:</b> The goal was to assess the impact of BLVR on energy balance regulation. <b>Design:</b> Twenty emphysematous subjects participated in a controlled clinical experiment before and 6 months after BLVR. Energy requirements were assessed: basal metabolic rate (BMR) by ventilated hood, total daily energy expenditure (TDEE) by doubly labelled water, whole body fat-free mass (FFM) by deuterium dilution, and physical activity by accelerometry. Oxygen saturation, breathing rate, and heart rate were monitored before, during, and after a standardized meal via pulse oximetry and dyspnoea was rated. <b>Results:</b> Sixteen patients completed follow-up, and among those, 10 patients exceeded the minimal clinically important difference of residual volume (RV) reduction. RV was reduced with median (range) 1,285 mL (–2,430, –540). Before BLVR, 90% of patients was FFM-depleted despite a normal BMI (24.3 ± 4.3 kg/m2). BMR was elevated by 130%. TDEE/BMR was 1.4 ± 0.2 despite a very low median (range) daily step count of 2,188 (739, 7,110). Following BLVR, the components of energy metabolism did not change significantly after intervention compared to before intervention, but BLVR treatment decreased meal-related dyspnoea (4.1 vs. 1.7, <i>p</i> = 0.019). <b>Conclusions:</b> Impaired respiratory mechanics in hyperinflated emphysematous patients did not explain hypermetabolism. <b>Clinical Trial Registry Number:</b> NCT02500004 at www.clinicaltrial.gov.

Quantifying childhood fat mass: comparison of a novel height-and-weight-based prediction approach with DXA and bioelectrical impedance

Accurate assessment of childhood adiposity is important both for individuals and populations. We compared fat mass (FM) predictions from a novel prediction model based on height, weight and demographic factors (height–weight equation) with FM from bioelectrical impedance (BIA) and dual-energy X-ray absorptiometry (DXA), using the deuterium dilution method as a reference standard. FM data from all four methods were available for 174 ALSPAC Study participants, seen 2002–2003, aged 11–12-years. FM predictions from the three approaches were compared to the reference standard using; R2, calibration (slope and intercept) and root mean square error (RMSE). R2 values were high from ‘height–weight equation’ (90%) but lower than from DXA (95%) and BIA (91%). Whilst calibration intercepts from all three approaches were close to the ideal of 0, the calibration slope from the ‘height–weight equation’ (slope = 1.02) was closer to the ideal of 1 than DXA (slope = 0.88) and BIA (slope = 0.87) assessments. The ‘height–weight equation’ provided more accurate individual predictions with a smaller RMSE value (2.6 kg) than BIA (3.1 kg) or DXA (3.4 kg). Predictions from the ‘height–weight equation’ were at least as accurate as DXA and BIA and were based on simpler measurements and open-source equation, emphasising its potential for both individual and population-level FM assessments.

Association between admission criteria and body composition among young children with moderate acute malnutrition, a cross-sectional study from Burkina Faso

Children with moderate acute malnutrition (MAM) are treated based on low weight-for-length z-score (WLZ), low mid-upper arm circumference (MUAC) or both. This study aimed to assess associations of admission criteria and body composition (BC), to improve treatment of MAM. We undertook a cross-sectional study among 6–23 months old Burkinabe children with MAM. Fat-free (FFM) and fat mass (FM) were determined by deuterium dilution and expressed as FFM (FFMI) and FM index (FMI). Of 1,489 children, 439 (29.5%) were recruited by low MUAC only (MUAC-O), 734 (49.3%) by low WLZ and low MUAC (WLZ-MUAC) and 316 (21.2%) by low WLZ only (WLZ-O). Thus, 1,173 (78.8%) were recruited by low MUAC, with or without low WLZ (ALL-MUAC). After adjustments, WLZ-O had 89 g (95% confidence interval (CI) 5; 172) lower FFM compared to MUAC-O. Similarly, WLZ-O had 0.89 kg/m2 (95% CI 0.77; 1.01) lower FFMI compared to MUAC-O, whereas there was no difference for FMI. However, boys included by WLZ-O compared to MUAC-O had 0.21 kg/m2 (95% CI 0.05; 0.38) higher FMI. In contrast, girls included by WLZ-O had 0.17 (95% CI 0.01; 0.33) kg/m2 lower FMI compared to MUAC-O (interaction, p = 0.002). We found that different criteria for admission into MAM treatment programmes select children with differences in BC, especially FFMI. Trial registration: ISRCTN42569496.

Relationship between maternal body composition during pregnancy and infant’s birth weight in Nairobi informal settlements, Kenya

BackgroundMaternal nutrition depletion during pregnancy compromises fetal programming, and is a cause of adverse birth outcomes. Maternal body composition measurement using direct body composition assessment methods such as the deuterium dilution technique provides better prediction of birth outcomes as compared with commonly used techniques like anthropometry. This study assessed body composition of pregnant mothers in urban informal settlements in Nairobi, Kenya, and established the relationship between maternal body composition and infant birth weight.MethodsDeuterium dilution technique was used to determine body composition, including total body water (TBW), fat-free mass (FFM) and fat mass (FM), among 129 pregnant women who were enrolled into the study in their first or second trimester. Descriptive statistics and regression analysis were applied using Stata V.13.ResultsThe mean TBW, FFM and FM were 33.3 L (±4.7), 45.7 kg (±6.5) and 17.01 kg (±7.4), respectively. Both TBW and FFM were significantly related to maternal age and gestation/pregnancy stage during body composition assessment while FM was significantly associated with gestation stage during body composition assessment. TBW and FFM were significantly lower in younger mothers (<20 years) compared with older mothers (≥20 years). The mean birth weight was 3.3 kg±0.42 kg. There was a positive association between infant birth weight and maternal TBW (p=0.031) and FFM (p=0.027), but not FM (p=0.88).ConclusionNon-fat components of the body (TBW and FFM) have a positive association with birth weight. Therefore, interventions to improve optimal maternal feeding practices, to enhance optimal gains in FFM and TBW during pregnancy are recommended, especially among young mothers.

Effectiveness of a Food-Based Intervention to Increase Breast Milk Vitamin A Content at One Month of Infancy

Objectives Vitamin A requirements in early infancy are met only by breast milk intake. It is critical to ensure adequate breast milk vitamin A levels which also helps develop liver stores. The objective of the study was to evaluate the effect of a maternal food-based intervention on breast milk vitamin A content Methods Pregnant women (n = 50; 24 ± 1 week of gestation) were recruited for the randomized study. A 10 g of a green leafy vegetable powder (mint/coriander/curry) providing about 3200 μg β-carotene/day, for a period of 4 months up to 1 month of lactation were provided for intervention arm. Breast milk (BM) retinol concentration and BM volume were assessed. BM retinol and beta-carotene were assayed by HPLC and BM fat by creamatocrit method. BM retinol: fat ratio was calculated. The dose-to-mother deuterium dilution technique was used to estimate BM volume through enrichment of saliva measured by Fourier Transform Infrared Spectroscopy. Total BM retinol content was calculated from BM volume and the BM retinol (including beta-carotene:1 vitamin A RAE = 12 μg β-carotene). Inadequacy of intake was defined as proportion of infants with intake below a requirement of 400 μg RAE/day. Analysis of co-variance was performed after adjusting for age of mother, change in maternal blood retinol from baseline and BM fat, to compare outcomes between intervention and control arm. Results Maternal age, gestational age, socio-demographic characteristics and baseline vitamin A intake were comparable in both arms. Mean BM volume was similar in the 2 arms (676 ± 102 in intervention vs 630 ± 100 ml/day in control). BM retinol content (0.72 ± 0.12 vs 0.64 ± 0.11 μg/mL; P = 0.029) and BM retinol: fat ratio [0.41 (0.31, 0.47) vs 0.29 (0.21, 0.41), P = 0.011] were significantly higher in the intervention arm. The mean total BM retinol content was significantly higher in the intervention (482.2 ± 100.7 vs 406.5 ± 89.2 μg/day; P = 0.015; Cohen's effect size 0.80). Inadequacy of infant vitamin A intake was 14.3% in the intervention arm as against 39.1% in the control arm (P = 0.065). Conclusions The food-based intervention was effective in increasing vitamin A content in breast milk and thereby vitamin A intake in infants. Funding Sources International Atomic Energy Agency.

Changes in Body Composition Using Deuterium Dilution Technique Among Young Children Receiving Specialized Nutritious Foods for Moderate Acute Malnutrition in Sierra Leone (P10-141-19)

Objectives To determine differential changes in children's body composition—fat-free mass (FFM) and fat mass (FM)—after 4 weeks of treatment for moderate acute malnutrition (MAM) with one of 4 four specialized nutritious foods (SNFs). Methods This sub-study was nested within a larger cluster-randomized trial comparing the cost-effectiveness of 4 isocaloric SNFs in treating MAM among children 6–59 months in Pujehun District, Sierra Leone: Corn-Soy Blend Plus w/oil (CSB + w/oil), Super Cereal Plus w/amylase (SC + A), Corn-Soy-Whey Blend w/oil (CSWB w/oil) and Ready-to-use-Supplementary Food (RUSF). Children with mid-upper arm circumference (MUAC) ≥11.5 cm and <12.5 cm with no clinical complications were enrolled and received an SNF ration bi-weekly until they reached MUAC ≥12.5 cm or up to 12 weeks. Body composition was assessed using the deuterium dilution technique at program enrollment and after 4 weeks of treatment. Changes in weight, FM, FFM and %FFM overall and by study arm were calculated; statistical significance was determined using t-tests and ANOVA (unadjusted). Results Among 336 subjects at enrollment, mean ± SD age was 11.8 ± 6.5 mos, weight was 6.5 ± 0.9 kg, FM was 1.3 ± 0.5 kg, FFM was 5.2 ± 0.9 kg, and %FFM was 80.4 ± 7.3. After 4 weeks of treatment, mean ± SD change in weight was 0.44 ± 0.39 kg (P < 0.001), FM was 0.09 ± 0.60 kg (P = 0.005), FFM was 0.35 ± 0.56 (P < 0.001), and %FFM was 0.003 ± 8.5 (NS). Overall, weight gain consisted on average of 20.9% FM and 79.8% FFM. By study arm, mean ± SD changes in FM and FFM respectively, were: 0.12 ± 0.53 kg and 0.32 ± 0.49 kg in CSB + w/oil; 0.13 ± 0.67 kg and 0.34 ± 0.64 kg in SC + A; 0.08 ± 0.65 kg and 0.36 ± 0.57 kg in CSWB w/oil; 0.02 ± 0.49 kg and 0.39 ± 0.5 kg in RUSF. These changes were not significantly different across study arms. Conclusions Over 4 weeks of treatment for MAM, children gained roughly 80% lean mass relative to 20% fat mass. This body composition is consistent with predicted sustainability of recovery from MAM and healthier long-term disease risk. Differential effects on body composition by type of SNF were not detected after 4 weeks of treatment in this study. Funding Sources The Office of Food for Peace, Bureau for Democracy, Conflict, and Humanitarian Assistance, U.S. Agency for International Development.