Association of body composition with pubertal timing in children and adolescents from Guangzhou, China

The diagnostic utility of bioelectrical impedance analysis in distinguishing precocious puberty from premature thelarche

OBJECTIVES

Clinical (assessing breast development), laboratory (FSH, LH, estradiol, and GnRH stimulation test), and radiological methods (bone age and pelvic ultrasonography) are used to distinguish central precocious puberty (CPP) from premature thelarche (PT). We examined also via bioelectrical impedance analysis (BIA).

METHODS

The fat mass (FM), fat-free mass (FFM), muscle mass (MM), bone mass (BM), total body water, and percentages (%), basal metabolic rate, phase angle (PhA), muscle-to-fat ratio (MFR), sarcopenic index, and segmental body proportions were determined via Tanita MC-780 MA model measuring device.

RESULTS

A total of 111 girls, 34 with CPP, 35 with PT, and 42 with healthy controls, were included. Although the baseline weight, height, and BMI SDS of the groups were not statistically different, the FM (%) was found to be lower (p=0.021), and the FFM (%) (p=0.021), MM (%) (p=0.015), BM (%) (p=0.022), and MFR values (p=0.017) were higher in CPP group. In CPP group, right arm FM (%) (p=0.016), left arm FM (%) (p=0.007), and trunk FM (%) (p=0.008) were lower than other groups.

CONCLUSIONS

We detected a MFR cutoff value of (2.96) with 58.8 % sensitivity and 58.4 % specificity, a cutoff value of (3.57) with 50 % sensitivity and 82 % specificity to differentiate CPP cases from others (PT and healthy controls). These rates are relatively low, but these are the first results in this field and may be guiding for studies conducted in large series.

Associations between prenatal exposure to PFAS and cardiometabolic health in preadolescents

INTRODUCTION

While a number of studies have examined the effects of prenatal exposure to per- and polyfluoroalkyl substances (PFAS) on childhood obesity, the results reported have been inconsistent and few studies have integrated biological markers. The aim of this study was to investigate the associations between prenatal exposure to PFAS and cardiometabolic health parameters at age 12, taking pubertal stage into consideration.

METHOD

This study included 394 mother-child pairs enrolled in the PELAGIE mother-child cohort (France). Nine PFAS were measured in umbilical cord blood, and the children attended a clinical examination at age 12. Anthropometry, blood metabolic markers, and blood pressure were measured and used to build an internal cardiometabolic score. Linear regression and Quantile G-computation models were used to evaluate individual and mixture PFAS effects, adjusting for confounders and stratifying by sex and pubertal stage.

RESULTS

No statistically significant association was observed between prenatal exposure to PFAS and cardiometabolic score at age 12. In post-menarche girls, perfluorohexane sulfonate (PFHxS) and perfluorodecanoic acid (PFDA) were statistically significantly associated with a decrease in a number of adiposity parameters (e.g., Body mass index z-score: beta [95%CI] = -0.37 [-0.67; -0.07]), as well as a decrease in low-density lipoproteins (LDL) and leptin levels. Similar results were observed with PFAS mixture, with statistically significantly decreased tricipital skinfolds (beta [95%CI] = -1.30 [(-2.54;-0.06)]). Isolated associations, including higher systolic blood pressure, changes in cholesterol levels, and lower adiponectin levels were observed in specific subgroups.

CONCLUSION

There is no clear evidence of an association between prenatal exposure to PFAS and the cardiometabolic health at earlier stage of pubertal development. However, inverse associations between PFAS and anthropometric measures have been observed in post-menarche girls. While the literature on this topic is scarce in pre-adolescents, these results suggest the importance of considering sex and pubertal stage in these associations.

Timing, velocity, and magnitude of pubertal changes in body composition: a longitudinal study

BACKGROUND

Pubertal changes in body composition significantly influence future health, with links to various diseases. This study aimed to evaluate the weight changes, fat-free mass (FFM), and body fat mass (BFM) during pubertal growth in Korean children and adolescents.

METHODS

We utilized mixed longitudinal data, employing bioelectrical impedance analysis for 4641 height measurements (2204 boys, 2437 girls) from 361 individuals (170 boys, 191 girls) aged 7-18 years. Utilizing the Superimposition by Translation and Rotation (SITAR) model, a shape-invariant growth curve model, reference curves for height, weight, and body composition change velocities were estimated.

RESULTS

Korean boys experience peak weight velocity (PWV) at an average age of 12.41 years, with a rate of 8.19 kg/year, peak fat-free mass velocity (PFFV) at 12.70 years (7.60 kg/year), and peak body fat mass velocity (PBFV) at 9.69 years (2.67 kg/year). Korean girls show PWV at 11.28 years (6.33 kg/year), PFFV at 11.13 years (4.86 kg/year), and PBFV at 12.33 years (2.72 kg/year). Positive correlations exist among the ages of peak height velocity, PWV, PFFV, and PBFV.

CONCLUSIONS

This research represents the groundbreaking application of the SITAR model in analyzing changes in body composition during pubertal growth in Korean children and adolescents.

IMPACT

This study utilized the SITAR model to analyze longitudinal changes in the body composition of the general pediatric population in Korea across pre- and post-pubertal stages, addressing overlooked aspects in cross-sectional studies. Examining growth parameters, including size (mean mass), tempo (timing), and velocity (compression and expansion) for each body component, revealed positive correlations among ages at peak velocities for various body composition parameters. This study can be employed for further investigations that compare the tempo, size, and velocity of various body composition parameters in pediatric disease cohorts and the general population.

Differences in physical activity, sedentary time, and anthropometric variables among children and adolescents: The TUBON project

BACKGROUND

Although physical inactivity may lead to increasing obesity prevalence, research on anthropometric variables changes based on physical activity (PA) in children and adolescents is limited. PA decreases with age, while sedentary behavior increases. The study aimed to examine differences in objectively measured sedentary time, light-intensity physical activity (LPA), and moderate-to-vigorous intensity physical activity (MVPA) between children and adolescents, and the differences in the percentiles of anthropometric variables between physically active and inactive groups according to World Health Organization PA recommendations.

METHODS

A total of 759 participants aged 6-17 years (boys, n=358; girls, n=401) were included in the study. The ActiGraph wGT3x-BT accelerometer was used to measure sedentary time, LPA, and MVPA. Height, weight, waist circumference (WC), triceps skinfold thickness (T-SFT), and medial-calf skinfold thickness (M-SFT) were measured. Body fat percentage (BF%) and body mass index (BMI) were calculated, and the percentiles of anthropometric variables were categorized.

RESULTS

The findings showed that children had less sedentary time and a higher LPA than adolescents for both genders (p<0.05). Children had a higher MVPA than adolescents in girls (p<0.05), but the difference was insignificant in boys (p>0.05). In boys, physically active children were in lower percentiles for T-SFT and BF% than those who did not (p<0.05). In boys, adolescents who were physically inactive were in higher percentiles for BMI, T-SFT, M-SFT, and BF% (p<0.05). In addition, in girls, adolescents who were physically active were in lower percentiles of BMI, M-SFT, and BF%, whereas children who were physically active were in lower percentiles of M-SFT and BF% (p<0.05).

CONCLUSION

Sedentary time increases while PA decreases with age. Children and adolescents who met the WHO PA recommendation had lower percentiles of anthropometric variables, indicating the importance of PA in preventing obesity in these age groups.

Association between body fat distribution and age at menarche: a two sample Mendelian randomization study

Background

Numerous studies have examined the association between obesity and age at menarche (AAM), with most focusing on traditional obesity indicators such as body mass index. However, there are limited studies that explored the connection between body fat distribution and AAM, as well as a scarcity of Mendelian randomization (MR) studies.

Methods

In this study, we conducted a two-sample MR study to evaluate the causal effects of eight body fat distribution indicators on AAM. Inverse variance weighted (IVW) method was used for primary analysis, while supplementary approaches such as MR-Egger and weighted median were also utilized. Considering that the eight exposures were highly correlated, we performed an MR Bayesian model averaging (MR-BMA) analysis to prioritize the effect of major exposure on AAM. A series of sensitivity analyses were also performed.

Results

From a range of 82-105 single nucleotide polymorphisms (SNPs) were utilized as genetic instrumental variables for each of the exposure factors. After Bonferroni correction, we found that whole body fat mass (β: -0.17; 95% CI: -0.24, -0.11), left leg fat percentage (β: -0.14; 95% CI: -0.21, -0.07), left leg fat mass (β: -0.20; 95% CI: -0.27, -0.12), left arm fat percentage (β: -0.18; 95% CI: -0.26, -0.11) and left arm fat mass (β: -0.18; 95%CI: -0.26, -0.10) were associated with decreased AAM using random effects IVW method. And the beta coefficients for all MR evaluation methods exhibited consistent trends. MR-BMA method validated that left arm fat percentage plays a dominant role in AAM.

Conclusions

Our MR study suggested that body fat has broad impacts on AAM. Obtaining more information on body measurements would greatly enhance our comprehension of pubertal development.

The Influence of Somatic Maturity on Anthropometrics and Body Composition in Youth Soccer Players

The primary aim of this investigation was to compare players' anthropometric (AP) and body composition (BC) characteristics between distinct maturity bands (pre-PHV, circa-PHV, post-PHV) in youth elite soccer. This study considered 320 male soccer players (mean age 13.8 y). Participants were from U14 (n = 157) and U15 (n = 163) age categories. The Khamis-Roche method was applied to calculate the percentage of predicted adult height (PAH) at the time of assessment based on which the players were further divided into maturity bands (pre-PHV ≤ 87%, circa-PHV = 88-95%, post-PHV > 95%). The findings indicated that most of the players were in the circa-PHV stage at the time of investigation. Measurements included height and weight. The estimates of BC parameters were derived using bioelectrical impedance (BIA) analysis. These various AP and BC attributes displayed significant differences among the maturity bands (F = 139.344-7.925; p < 0.001; large effect sizes) except in body fat mass (BFM) (F = 2.998; p = 0.051; small effect size). The current somatic maturity stage of the athletes should be considered when evaluating BC results, otherwise there is a risk of misinterpretation.