Body-Fat-Percentile Curves for Thai Children and Adolescents

Body composition trajectories during childhood predict skeletal maturation at puberty: A longitudinal study

Nutritional status significantly impacts linear bone growth. We aimed to determine the relationship between the trajectories of four body composition indicators and pubertal advanced bone age. Trajectories of body mass index z-score (BMI z-score), visceral fat area z-score (VFA z-score), fat mass index z-score (FMI z-score), and fat-free mass index z-score (FFMI z-score) were identified based on three body composition measurements conducted from October 2018 to April 2023 within a pediatric cohort (the PROC study). We assessed pubertal bone age using the Tanner-Whitehouse 3-Chinese Radius-Ulna-Short (TW3-C RUS) method among 1402 primary school children. Children with a trajectory of higher BMI z-score, VFA z-score, FMI z-score, and FFMI z-score since childhood were more likely to have advanced bone age. The risk of advanced bone age was higher in children who were consistently in the high VFA z-score group (odds ratio [OR] = 6.73) or consistently in the high BMI z-score group (OR = 5.57), as compared to those in the low VFA z-score and low BMI z-score groups. Regular monitoring and maintenance of normal VFA during childhood may reduce the risk of advanced bone age at puberty. Furthermore, BMI monitoring is optional, especially in cases where specialized body composition equipment is not available.

First body fat reference curves for Macedonian children and adolescents: the MAKFIT study

Introduction

Introduction: childhood obesity is a worldwide chief health problem. Along with body mass index, body fat percentile values can also be used to predict future cardiovascular and metabolic health risks. Objective: the study's aim is to define the percentile values and curves about the fat tissue percentage through which the childhood and adolescent overweight/obesity in the Republic of North Macedonia will be diagnosed. Methods: the research was conducted on a sample of 15,075 children and adolescents aged six to 14 years (7,627 boys and 7,448 girls). Body fat percentage was established by bioelectrical impedance. The LMS method was used in percentile values and curves' construction. Results: the boys' 50th percentile curve shows that the body fat percentage average value has a slight growth from seven to ten years of age, but after their 10th it begins to drop continuously until the age of 14 years. At the same time, the girls' body fat percentage average value increases continuously from six to 14 years of age. Conclusion: since body mass index cannot always establish body fat content, the direct assessment of body fat by bioelectrical impedance would be of great advantage for pediatric and clinical decisions. Therefore, the study provides referent percentile norms for the body fat percentage of healthy Macedonian children and adolescents. For this purpose, a practical and clinically applicable method was used. The obtained referent percentile norms can be useful in assessing overweight and obesity in Macedonian children and adolescents.

Predictive factors of bone strength variation in adolescent girls according to body composition

PURPOSE

This study examined correlations among anthropometric parameters, body composition, bone parameters and predictive factors of bone mass in adolescent girls with different body fat percentages (%fat).

METHODS

A total of 129 females aged 15-18 years were categorized into 3 groups using %fat-for-age at the 50th and 95th percentiles as cutoff points (normal, over, and excess %fat groups). We recorded anthropometric data and measured the speed of sound at the tibia and radius using quantitative ultrasound. Dual-energy x-ray absorptiometry (DXA) was used to measure body composition and bone parameters, including bone mineral density (BMD), bone mineral content (BMC), and the BMD-z-score (z-score) in the lumbar spine (LS) and whole body (WB). These parameters were compared among the 3 groups using bivariate and multivariate correlation analyses.

RESULTS

There were strong correlations among all anthropometric parameters, body composition, and DXA in the over %fat group. Lean parameters strongly correlated with LS and WB in the normal %fat group, whereas both lean mass (LM) and fat mass (FM) were positively correlated with BMC in the excess %fat group. The predictive factors of bone mass differed among the groups, as follows: lean body mass was predictive of BMD and BMC at both sites in the normal and over %fat groups; LM and body weight were predictive of LS-BMC and WB-bones, respectively, in the over %fat group; and FM was predictive of WB-bones in the excess %fat group. Body fat and waist circumference were negative predictors of bone mass.

CONCLUSION

Predictive factors of bone strength appear to depend on the amount of body fat in adolescent girls.