Energy Expenditure and Body Composition in Preterm Newborns with Bronchopulmonary Dysplasia at Term Age

A cross-sectional study was carried out in a cohort of newborns with less than 32 weeks of gestational age. We aimed to evaluate and compare resting energy expenditure (REE) and body composition between newborns who did or did not develop bronchopulmonary dysplasia. The resting energy expenditure and body composition were assessed at the corrected term age using air displacement plethysmography. Anthropometric measurements (weight, head circumference, and length) were performed and transformed into Z-scores per the Fenton curve (2013) at birth and corrected term age. Forty-two newborns were included, of which 26.2% developed bronchopulmonary dysplasia. Newborns with bronchopulmonary dysplasia (BPD) had significantly higher energy expenditure at corrected term age, with no differences in body composition between the two groups. Conclusion: Newborns with bronchopulmonary dysplasia had higher resting energy expenditure at the corrected term, with no difference in body composition compared to those who did not develop bronchopulmonary dysplasia.

Reliability of Repeated Trials Protocols for Body Composition Assessment by Air Displacement Plethysmography

Air displacement plethysmography (ADP) is fast, accurate, and reliable. Nevertheless, in about 3% of the cases, standard ADP tests provide rogue results. To spot these outliers and improve precision, repeated trials protocols have been devised, but few works have addressed their reliability. This study was conducted to evaluate the test–retest reliabilities of two known protocols and a new one, proposed here. Ninety-two healthy adults (46 men and 46 women) completed six consecutive ADP tests. To evaluate the reliability of single measurements, we used the results of the first two tests; for multiple measures protocols, we computed the test result from trials 1–3 and the retest result from trials 4–6. Bland–Altman analysis revealed that the bias and the width of the 95% interval of agreement were smaller for multiple trials than for single ones. For percent body fat (%BF)/fat-free mass, the technical error of measurement was 1% BF/0.68 kg for single trials and 0.62% BF/0.46 kg for the new protocol of multiple trials, which proved to be the most reliable. The minimal detectable change (MDC) was 2.77% BF/1.87 kg for single trials and 1.72% BF/1.26 kg for the new protocol.

Extensive Study of Breast Milk and Infant Growth: Protocol of the Cambridge Baby Growth and Breastfeeding Study (CBGS-BF)

Growth and nutrition during early life have been strongly linked to future health and metabolic risks. The Cambridge Baby Growth Study (CBGS), a longitudinal birth cohort of 2229 mother–infant pairs, was set up in 2001 to investigate early life determinant factors of infant growth and body composition in the UK setting. To carry out extensive profiling of breastmilk intakes and composition in relation to infancy growth, the Cambridge Baby Growth and Breastfeeding Study (CBGS-BF) was established upon the original CBGS. The strict inclusion criteria were applied, focusing on a normal birth weight vaginally delivered infant cohort born of healthy and non-obese mothers. Crucially, only infants who were exclusively breastfed for the first 6 weeks of life were retained in the analysed study sample. At each visit from birth, 2 weeks, 6 weeks, and then at 3, 6, 12, 24, and 36 months, longitudinal anthropometric measurements and blood spot collections were conducted. Infant body composition was assessed using air displacement plethysmography (ADP) at 6 weeks and 3 months of age. Breast milk was collected for macronutrients and human milk oligosaccharides (HMO) measurements. Breast milk intake volume was also estimated, as well as sterile breastmilk and infant stool collection for microbiome study.

Which Body Density Equations Calculate Body Fat Percentage Better in Olympic Wrestlers?—Comparison Study with Air Displacement Plethysmography

Although skinfold-derived equations seem to be practical for field application in estimating body fat percentage (BF%) and minimum body mass in Olympic wrestlers, prediction equations applied first need to be cross-validated in Olympic wrestlers to define the best prediction equation. This study aimed to evaluate the most accurate field method to predict BF% in Olympic wrestlers compared to BF% estimated by air displacement plethysmography (ADP). Sixty-one male (body mass 72.4 ± 13.5 kg; height 170.3 ± 7.0 cm; body mass index (BMI) 24.9 ± 3.5 kg.m−2; BF% 8.5 ± 4.9%) and twenty-five female wrestlers (body mass 60.3 ± 9.9 kg; height 161.3 ± 7.1 cm; BMI 23.1 ± 2.5 kg.m−2; BF% 18.7 ± 4.7%) undertook body composition assessments including ADP and nine-site skinfold measurements. Correlations, bias, limits of agreement, and standardized differences between alterations in BF% measured by ADP and other prediction equations were evaluated to validate measures, and multiple regression analyses to develop an Olympic wrestlers-specific prediction formula. The Stewart and Hannan equation for male wrestlers and the Durnin and Womersley equation for female wrestlers provided the most accurate BF% compared to the measured BF% by ADP, with the lowest bias and presented no significant differences between the measured and predicted BF%. A new prediction equation was developed using only abdominal skinfold and sex as variables, predicting 83.2% of the variance. The findings suggest the use of the new wrestler-specific prediction equation proposed in the study as a valid and accurate alternative to ADP to quantify BF% among Olympic wrestlers.

IGF-I, Growth, and Body Composition in Preterm Infants up to Term Equivalent Age

Context There are concerns that a higher fat mass in the early life of preterm infants is associated with adverse cardiometabolic outcomes in young adulthood. Objective To investigate the role of IGF-I and growth in determining body composition of preterm infants at term equivalent age. Methods An observational study was conducted from August 2015 to August 2018. From birth to term equivalent age, IGF-I levels were measured bi-weekly and growth was assessed weekly. At term equivalent age, body composition was assessed through air displacement plethysmography; 65 infants with a gestational age of 24 to 32 weeks were assessed at term equivalent age, of whom 58 completed body composition measurement. The main outcome measures were fat (free) mass (g) and fat (free) mass percentage at term equivalent age. Results In the first month of life, each 0.1 nmol/L per week increase in IGF-I was associated with a 465 g (SE 125 g) increase in fat free mass. A greater increase in weight SDS in the first month of life was associated with a higher fat free mass percentage (B 200.9; 95% CI, 12.1-389.6). A higher head circumference SDS was associated with more fat free mass (r = 0.46; 95% CI, 0.21-0.65). However, a greater increase in weight SDS up to term equivalent age was associated with a lower fat free mass percentage (B −55.7, SE 9.4). Conclusion These findings suggest that impaired growth in the first month of life is associated with a less favorable body composition at term equivalent age.

Metabolic adaptation is associated with less weight and fat mass loss in response to low-energy diets

Background The practical relevance of metabolic adaptation remains a controversial issue. To the best of our knowledge, no study has properly evaluated the role of metabolic adaptation in modulating weight loss outcomes. Therefore, the aim of this study was to determine the association between metabolic adaptation, at the level of resting metabolic rate (RMR), and weight and fat mass (FM) loss after low-energy diets (LED), after adjusting for dietary adherence and other confounders. Methods 71 individuals with obesity (BMI: 34.6 ± 3.4 kg/m2; age: 45.4 ± 8.2 years; 33 males) were randomized to one of three 1000 kcal/day diets for 8 weeks. Body weight, FM and fat-free mass (FFM) (air displacement plethysmography), RMR (indirect calorimetry) and physical activity level (PAL) (armbands) were measured at baseline and at week 9. Metabolic adaptation at week 9 was defined as measured RMR minus predicted RMR at week 9. An equation to predict RMR was derived from baseline data of all participants that were part of this analysis and included age, sex, FM and FFM as predictors. Dietary adherence was calculated from RMR, PAL and body composition changes. Linear regression was used to assess the potential role of metabolic adaptation in predicting weight and FM loss after adjusting for dietary adherence, average PAL, sex, baseline FM and FFM and randomization group. Results Participants lost on average 14 ± 4 kg of body weight (13 ± 3%) and presented with metabolic adaptation (−92 ± 110 kcal/day, P < 0.001). Metabolic adaptation was a significant predictor of both weight (β = −0.009, P < 0.001) and FM loss (β = −0.008, P < 0.001), even after adjusting for confounders (R2 = 0.88, 0.93, respectively, P < 0.001 for both). On average, an increase in metabolic adaptation of 50 kcal/day was associated with a 0.5 kg lower weight and FM loss in response to the LED. Conclusion In individuals with obesity, metabolic adaptation at the level of RMR is associated with less weight and FM loss in response to LED. Trial registration ID: NCT02944253.

Comparison of Body Scanner and Manual Anthropometric Measurements of Body Shape: A Systematic Review

Anthropometrics are a set of direct quantitative measurements of the human body’s external dimensions, which can be used as indirect measures of body composition. Due to a number of limitations of conventional manual techniques for the collection of body measurements, advanced systems using three-dimensional (3D) scanners are currently being employed, despite being a relatively new technique. A systematic review was carried out using Pubmed, Medline and the Cochrane Library to assess whether 3D scanners offer reproducible, reliable and accurate data with respect to anthropometrics. Although significant differences were found, 3D measurements correlated strongly with measurements made by conventional anthropometry, dual-energy X-ray absorptiometry (DXA) and air displacement plethysmography (ADP), among others. In most studies (61.1%), 3D scanners were more accurate than these other techniques; in fact, these scanners presented excellent accuracy or reliability. 3D scanners allow automated, quick and easy measurements of different body tissues. Moreover, they seem to provide reproducible, reliable and accurate data that correlate well with the other techniques used.

Determinants of Infant Adiposity across the First 6 Months of Life: Evidence from the Baby-bod study

Excess adiposity in infancy may predispose individuals to obesity later in life. The literature on determinants of adiposity in infants is equivocal. In this longitudinal cohort study, we investigated pre-pregnancy, prenatal and postnatal determinants of different adiposity indices in infants, i.e., fat mass (FM), percent FM (%FM), fat mass index (FMI) and log-log index (FM/FFMp), from birth to 6 months, using linear mixed-effects regression. Body composition was measured in 322, 174 and 109 infants at birth and 3 and 6 months afterwards, respectively, utilising air displacement plethysmography. Positive associations were observed between gestation length and infant FM, maternal self-reported pre-pregnancy body mass index and infant %FM, and parity and infant %FM and FMI at birth. Surprisingly, maternal intake of iron supplements during pregnancy was associated with infant FM, %FM and FMI at 3 months and FM/FFMp at 6 months. Male infant sex and formula feeding were negatively associated with all adiposity indices at 6 months. In conclusion, pre-pregnancy and pregnancy factors influence adiposity during early life, and any unfavourable impacts may be modulated postnatally via infant feeding practices. Moreover, as these associations are dependent on the adiposity indices used, it is crucial that researchers use conceptually and statistically robust approaches such as FM/FFMp.