A comparison of bioimpedance analysis vs. dual x-ray absorptiometry for body composition assessment in postpartum women and non-postpartum controls

Postpartum fat mass (FM) and fat-free mass (FFM) may be informative predictors of future disease risk among women; hence, there is growing use of bioelectrical impedance analysis (BIA) to quantify FFM and FM among postpartum women due to the quick, non-invasive, and inexpensive nature of BIA. Despite this, very few studies have examined BIA\u27s performance, and it remains unclear as to whether specific BIA equations are needed for postpartum women. To explore these questions, we measured total body FFM and FM with a multi-frequency, segmental BIA, and dual-X-ray absorptiometry (DXA) in (1) women at one and four months postpartum

Self-Reported Low Vitality, Poor Mental Health, and Low Dietary Restraint Are Associated with Overperception of Physical Exertion

Objective. We investigated whether perceived exertion, in comparison to the physiological response to exercise, was associated with self-reported vitality, mental health, and physical function during daily activities, or weight control behaviors. Design. Weight-reduced, formerly overweight women (n = 126, aged 22–46 years), completed health and dietary control questionnaires, and underwent a treadmill-walking task while heart rate, ventilation, respiratory exchange ratio, and ratings of perceived exertion were recorded. Results. Overperception of exertion (perceived exertion physiological exertion) was inversely associated with vitality (r = −0.190, P < .05), mental health (r = −0.188, P < .05), and dietary control (r values range −0.231 to −0.317, P < .05). In linear regression modeling, vitality or mental health, and cognitive dietary restraint were independently associated with accuracy of perceived exertion, independent of age, ethnicity, and engagement in exercise during weight loss. Each model explained 7%-8% of the variance in accuracy of perceived exertion. Conclusion. Women with low vitality or poor mental health, and poor dietary control may overperceive exertion. Such overperception may be a barrier to engage in physical activity and thus increase susceptibility to weight gain

The relationship between hourly energy balance and fat mass in female collegiate soccer players

Introduction: Soccer athletes have better performance if they maintain low fat mass (FM) relative to fat-free mass. Recent evidence suggests that maintenance of energy balance (EB) is associated with lower FM in athletes. Prior studies have used daily EB rather than hourly, but this approach does not consider duration of time athletes spend in EB versus surplus or deficit. Objective: Test the hypotheses that (1) time spent in EB is inversely associated with FM, and (2) athletes with mean hourly EB in the deficit range have lower FM than those in balance or surplus. Methods: Collegiate female soccer players (n=20) were enrolled in this cross-sectional study. A 3-day diet/activity record was obtained and analysed to estimate EB in hourly increments. Hourly EB was categorized as: Surplus, >400 kcal EB; Balance, between ±400 kcal EB; Deficit, <-400 kcal EB. Total hours spent in each category and mean EB (kcals) was calculated from the 3-day period. Bioelectrical Impedance Analysis was used to derive indices of FM (total FM in kg, % fat, fat mass index). Pearson correlations evaluated associations between FM measures and time spent in each EB category. One-way ANOVA with Tukey post-hoc testing was used to assess differences in FM among athletes stratified into surplus, balance, or deficit based on mean hourly EB. Results: Hourly energy deficit was associated with higher FM compared to energy surplus or balance. Conclusion: Female collegiate soccer players who sustain EB during the day, and limit time spent in energy deficit, had lower FM measures.CEB is supported by Grant Number (T32HL105349) from The National Heart, Lung, and Blood Institute. Additional support was provided by Award Number (P30DK056336) from The National Institute of Diabetes and Digestive and Kidney Diseases

Monitoring of Infant Feeding Behavior Using a Jaw Motion Sensor

Rapid weight gain during infancy increases the risk of obesity. Given that infant feeding may contribute to rapid weight gain, it would be useful to develop objective tools which can monitor infant feeding behavior. This paper presents an objective method for examining infant sucking count during meals. A piezoelectric jaw motion sensor and a video camera were used to monitor jaw motions of 10 infants during a meal. Videotapes and sensor signals were annotated by two independent human raters, counting the number of sucks in each 10 second epoch. Annotated data were used as a gold standard for the development of the computer algorithms. The sensor signal was de-noised and normalized prior to computing the per-epoch sucking counts. A leave-one-out cross-validation scheme resulted in a mean error rate of -9.7% and an average intra-class correlation coefficient value of 0.86 between the human raters and the algorithm

Body composition at 6 months of life: comparison of air displacement plethysmography and dual-energy X-ray absorptiometry

Body composition assessment during infancy is important because it is a critical period for obesity risk development, thus valid tools are needed to accurately, precisely, and quickly determine both fat and fat-free mass. The purpose of this study was to compare body composition estimates using dual-energy x-ray absorptiometry (DXA) and air displacement plethysmography (ADP) at 6 months old. We assessed the agreement between whole body composition using DXA and ADP in 84 full-term average-for-gestational-age boys and girls using DXA (Lunar iDXA v11-30.062; Infant whole body analysis enCore 2007 software, GE, Fairfield, CT) and ADP (Infant Body Composition System v3.1.0, COSMED USA, Concord, CA). Although the correlations between DXA and ADP for %fat (r = 0.925), absolute fat mass (r = 0.969), and absolute fat-free mass (r = 0.945) were all significant, body composition estimates by DXA were greater for both %fat (31.1 \ub1 3.6% vs. 26.7 \ub1 4.7%; P < 0.001) and absolute fat mass (2,284 \ub1 449 vs. 1,921 \ub1 492 g; P < 0.001), and lower for fat-free mass (5,022 \ub1 532 vs. 5,188 \ub1 508 g; P < 0.001) vs. ADP. Inter-method differences in %fat decreased with increasing adiposity and differences in fat-free mass decreased with increasing infant age. Estimates of body composition determined by DXA and ADP at 6 months of age were highly correlated, but did differ significantly. Additional work is required to identify the technical basis for these rather large inter-method differences in infant body composition

Epigenetic Age Acceleration in Mothers and Offspring 4&ndash;10 Years after a Pregnancy Complicated by Gestational Diabetes and Obesity

A known association exists between exposure to gestational diabetes mellitus (GDM) and epigenetic age acceleration (EAA) in GDM-exposed offspring compared to those without GDM exposure. This association has not been assessed previously in mothers with pregnancies complicated by GDM. A total of 137 mother-child dyads with an index pregnancy 4&ndash;10 years before study enrollment were included. Clinical data and whole blood samples were collected and quantified to obtain DNA methylation (DNAm) estimates using the Illumina MethylEPIC 850K array in mothers and offspring. DNAm age and age acceleration were evaluated using the Horvath and Hannum clocks. Multivariable linear regression models were performed to determine the association between EAA and leptin, high-density lipoprotein cholesterol (HDL-C), fasting glucose, fasting insulin, and HOMA-IR. Mothers with a GDM and non-GDM pregnancy had strong correlations between chronological age and DNAm age (r &gt; 0.70). Offspring of GDM mothers had moderate to strong correlations, whereas offspring of non-GDM mothers had moderate correlations between chronological age and DNAm age. Association analyses revealed a significant association between EAA and fasting insulin in offspring (FDR &lt; 0.05), while HDL-C was the only metabolic marker significantly associated with EAA in mothers (FDR &lt; 0.05). Mothers in the GDM group had a higher predicted epigenetic age and age acceleration than mothers in the non-GDM group. The association between EAA with elevated fasting insulin in offspring and elevated HDL-C in mothers suggests possible biomarkers that can better elucidate the effects of exposure to a GDM pregnancy and future cardiometabolic outcomes

A Comparison of Bioimpedance Analysis vs. Dual X-ray Absorptiometry for Body Composition Assessment in Postpartum Women and Non-Postpartum Controls

Postpartum fat mass (FM) and fat-free mass (FFM) may be informative predictors of future disease risk among women; hence, there is growing use of bioelectrical impedance analysis (BIA) to quantify FFM and FM among postpartum women due to the quick, non-invasive, and inexpensive nature of BIA. Despite this, very few studies have examined BIA&rsquo;s performance, and it remains unclear as to whether specific BIA equations are needed for postpartum women. To explore these questions, we measured total body FFM and FM with a multi-frequency, segmental BIA, and dual-X-ray absorptiometry (DXA) in (1) women at one and four months postpartum (n = 21); and (2) height- and weight-matched non-postpartum women (controls, n = 21). BIA was compared to DXA using Deming regression models, paired t-tests, and Bland&ndash;Altman plots. Between-group comparisons were performed using an analysis of variance models. The mean difference between DXA and BIA was 1.2 &plusmn; 1.7 kg FFM (p &lt; 0.01) and &minus;1.0 &plusmn; 1.7 kg FM (p &lt; 0.05) in postpartum women at both time points. The measurements of longitudinal changes in FFM and FM were not significantly different between BIA and DXA. Furthermore, there was no significant difference in BIA&rsquo;s performance in postpartum vs. non-postpartum women (p = 0.29), which suggests that population-specific equations are not needed for postpartum women. The results of this study suggest that BIA is a suitable method to assess postpartum body composition among women at one and four months postpartum, using existing age-, race-, and sex-adjusted equations

WHY ADIPOSITY NEGATIVELY INFLUENCES DYNAMIC BALANCE IN CHILDREN: A ROLE FOR MUSCULO-TENDON STIFFNESS?

BACKGROUND: Potential physiological mechanisms contributing to reduced physical activity in children with obesity or at risk for obesity include poor neuromuscular performance. Children with obesity demonstrate poorer neuromuscular performance, particularly in activities that involve simultaneous body movement and control (dynamic balance) compared to more static object-control tasks. However, the relationship between adiposity and dynamic balance in children is unknown. Emerging evidence in adults suggests that muscle stiffness positively contributes to dynamic balance, but whether this applies to children remains unclear. Understanding these factors can provide insights into the physiological mechanisms influencing a child\u27s level of physical activity. Therefore, the aim of this study was to examine the relationships between body composition, musculo-tendon stiffness, and dynamic balance in children. METHODS: Nine children aged 5 to 16, consisting of 2 males and 7 females, participated in the study. Height and weight were assessed using standard clinical procedures. Body mass index (BMI) percentile was determined using the CDC reference data. Measures of adiposity such as percent total body fat and leg fat (g) were estimated via a total body Dual energy X-ray absorptiometry (DXA) scan. A handheld device (Myoton) was used to assess musculo-tendon stiffness (N/m) in a relaxed state, at the gluteus maximus, vastus lateralis, lateral head of the gastrocnemius, quadriceps tendon, patellar tendon, and Achilles tendon. Dynamic balance was evaluated by the Four-square step test (FSST), which is a multi-directional, timed clinical test of balance, where a greater time taken to complete FSST depicts poor performance. RESULTS: FSST was positively related to percent total body fat (r=0.77, p=0.01), BMI percentile (r=0.78, p=0.01), and leg fat (r=0.75, p=0.02). Stiffness of the quadriceps tendon was negatively related to BMI percentile (r=-0.84, p \u3c 0.01) and leg fat (r=-0.72, p=0.03) while showing a negative trend with percent total body fat (r=-0.61, p=0.08). Additionally, the FSST was negatively related to the quadriceps tendon stiffness (r=-0.84, p=0.005) only. CONCLUSIONS: We provide preliminary evidence that adiposity is negatively related to dynamic balance and musculo-tendon stiffness in children. Specifically, our results suggest that poor dynamic balance in children may be partially explained by the negative relationship between adiposity and stiffness of the quadriceps tendon