Bone Mineral Content as a Driver of Energy Expenditure in Prepubertal and Early Pubertal Boys

Barbosa F, Fleury M. Predictive Equations Overestimated the Rest Energy Expenditure by Indirect Calorimetry in Adults with Sickle Cell Disease

Background: Traditionally, hypermetabolism is described in sickle cell disease (SCD). Despite this, few studies have compared rest energy expenditure (REE) with estimated by predictive equations (EEE) in the assessment of adults with SCD. Aims:  To compare REE values determined by indirect calorimetry (IC) with that EEE in adults with SCD. Subjects and Methods: A cross-sectional observational study was performed with 46 individuals over 34 years old in the treatment from two reference centers for SCD located in the city of Rio de Janeiro, Brazil. The dual-energy X-ray absorptiometry (DXA) and IC  were used to assess BC and REE, respectively. Blood levels were measured to assess hemolytic and protein markers. Pearson’s correlation test was used in the univariate correlation. The Intraclass Correlation Coefficient (ICC) and the Bland-Altman analysis were used in the comparison between EEE and IC. P-values ≤ 0.05 were considered statistically significant. Results: Most participants were from the female sex, Hb SS genotype (80.4%) and with black color (52.2%). The mean age was 50 years old. Weight (r= 0.469; p=0,001), LM (r = 0.631; p=0.000), BMC (r = 0.508; p=0.000) and CRP(r=0.319; p = 0.002) correlated positively with the REE. There was no linear correlation between makers of hemolysis with REE. The REE was overestimated in the EEE when compared to IC (p<0.001). Conclusions: The prediction equations developed for healthy populations are not accurate enough to determine the energy requirements and more studies are needed to better understand how REE role in middle-aged and elderly adults with SCD.

Resting Energy Expenditure and Related Factors in 6- to 9-Year-Old Southern African Children of Diverse Population Groups

Lower resting energy expenditure (REE) may partially explain the disproportionate prevalence of overweight/obesity among black African women. As no previous studies have investigated the REE of Southern African (South. Afr.) children, we aimed to determine, by sex and population group, the REE of 6- to 9-year-old urban school children. In a cross-sectional study with quota sampling, REE was measured with indirect calorimetry (IC). Confounders considered were: body composition (BC) (fat-free mass (FFM), FFM index, fat mass (FM), FM index), assessed using multifrequency bioelectrical impedance analysis, and physical activity (PA) measured with a pedometer. Multivariate regression was used to calculate REE adjusted for phenotypes (BC, z-scores of weight-for-age, height-for-age, body mass index-for-age) and PA. Sex and population differences in REE were determined with two-way ANOVA. Ninety-four healthy children (59.6% girls; 52.1% black) with similar socioeconomic status and PA opportunities participated. Despite BC variations, sex differences in REE were not significant (41 kcal/day; P = 0.375). The REE of black participants was lower than of white (146 kcal/day; P = 0.002). When adjusted for FFM and HFA z-score, the differences in REE declined but remained clinically meaningful at 91 kcal/day (P = 0.039) and 82 kcal/day (P = 0.108), respectively. We recommend the development of population-specific REE prediction equations for South. Afr. children.

Upper Airway Obstruction Elicited Energy Imbalance Leads to Growth Retardation that Persists after the Obstruction Removal

Upper airway obstruction can lead to growth retardation by unclear mechanisms. We explored the effect of upper airway obstruction in juvenile rats on whole-body energy balance, growth plate metabolism, and growth. We show that after seven weeks, obstructed animals’ ventilation during room air breathing increased, and animals grew less due to abnormal growth plate metabolism. Increased caloric intake in upper airway-obstructed animals did not meet increased energy expenditure associated with increased work of breathing. Decreased whole-body energy balance induced hindrance of bone elongation following obstruction removal, and array pathways regulating growth plate development and marrow adiposity. This is the first study to show that rapidly growing animals cannot consume enough calories to maintain their energy homeostasis, leading to an impediment in growth in the effort to save energy.

Energy expenditure and intake during puberty in healthy nonobese adolescents: a systematic review

BACKGROUND

Puberty is a time of rapid growth and changing energy requirements and is a risk period for obesity. There is little high-quality evidence on the pubertal alterations of energy expenditure and intake, and this has limited our understanding of energy balance during this important life stage.

OBJECTIVE

The purpose of this study was to summarize existing evidence on pubertal energy expenditure and intake in healthy nonobese adolescents.

DESIGN

Studies were identified through CINAHL, the Cochrane Library, Embase, MEDLINE, and Web of Science databases up to August 2015. Articles presenting objectively measured data for basal or resting metabolic rate (BMR/RMR), total daily energy expenditure (TDEE), and/or energy intake (EI) for ≥2 categories of puberty were included. Relevant data adjusted for fat-free mass (FFM) also were extracted. Data were dichotomized into prepubertal and pubertal groups and compared through the use of standardized mean differences (SMDs). Heterogeneous study methodologies precluded meta-analysis.

RESULTS

The search netted 6770 articles, with 12 included for review. From these, 6 of 9 studies supported significantly higher absolute BMR/RMR during puberty (SMD: 1.10-5.93), and all of the studies favored significantly higher absolute TDEE during puberty (SMD: 0.46-9.55). These corresponded to a 12% difference and an 18% difference in absolute BMR/RMR and TDEE, respectively. Results adjusted for FFM were equivocal, with 3 studies favoring higher (1 significantly) and 3 favoring significantly lower adjusted BMR/RMR during puberty. Only 1 study reported EI, showing 41% and 25% greater absolute intakes in pubertal males and females, respectively. These differences were not significant after adjustment for FFM.

CONCLUSIONS

Reasonably consistent evidence exists to support higher absolute BMR/RMR and TDEE in pubertal than in prepubertal adolescents. Differences are largely accounted for by FFM, among other potential factors such as growth- and puberty-related hormones. This review argues for further research into hormonal influences on pubertal energy balance and subsequent effects on obesity risk.