The prediction of body fatness by BMI and skinfold thicknesses among children and adolescents

Associations between anthropometry, body composition, and body image in athletes: a systematic review

Introduction

Poor body image is a potent risk factor for disordered eating and eating disorders. Athletes are a population at increased risk for eating disorders despite reports of lower body image concerns compared to non-athletes. Body size and composition may influence an athlete's susceptibility to poor body image.

Methods

Five electronic databases (PubMed, Cochrane Library, PsycINFO, Web of Science, SPORTDiscus) were searched to systematically evaluate the literature regarding the association between body measures (i.e., anthropometric and body composition indicators) and body image in athletes. The systematic review was completed following PRISMA guidelines and 27 cross-sectional studies were identified for inclusion and evaluated using the Joanna Briggs Institute Critical Appraisal Checklist for Analytical Cross-Sectional Studies.

Results

Studies differed in methodological assessment of anthropometry or body composition (i.e., self-reported versus researcher-measured), methods for evaluating aspects of body image, geographic location, and sport type. Higher body mass index (BMI) or percent body fat (%BF) was significantly associated with greater body dissatisfaction in 16 of 22 studies (72.7%). Positive associations between body measures and aspects of negative body image were most consistently observed among studies that assessed BMI based on self-reported heights and weights, while significant associations between body composition measures (e.g., %BF, fat mass, fat-free mass) were less common. Four of seven studies assessing relationships between BMI and an aspect of positive body image reported significant inverse relationships, while three revealed insignificant associations.

Discussion

Overall, higher BMI and body fat were associated with body dissatisfaction among athletes. Future studies are needed to confirm these findings within focused populations and utilizing body composition methods (e.g., bioelectrical impedance techniques).

Systematic review registration

https://www.crd.york.ac.uk/prospero/, CRD42023446518.

Fetal bisphenol and phthalate exposure and early childhood growth in a New York City birth cohort

BACKGROUND

Exposure to endocrine-disrupting chemicals such as bisphenols and phthalates during pregnancy may disrupt fetal developmental programming and influence early-life growth. We hypothesized that prenatal bisphenol and phthalate exposure was associated with alterations in adiposity through 4 years. This associations might change over time.

METHODS

Among 1091 mother-child pairs in a New York City birth cohort study, we measured maternal urinary concentrations of bisphenols and phthalates at three time points in pregnancy and child weight, height, and triceps and subscapular skinfold thickness at ages 1, 2, 3, and 4 years. We used linear mixed models to assess associations of prenatal individual and grouped bisphenols and phthalates with overall and time-point-specific adiposity outcomes from birth to 4 years.

RESULTS

We observed associations of higher maternal urinary second trimester total bisphenol and bisphenol A concentrations in pregnancy and overall child weight between birth and 4 years only (Beta 0.10 (95 % confidence interval 0.04, 0.16) and 0.07 (0.02, 0.12) standard deviation score (SDS) change in weight per natural log increase in exposure), We reported an interaction of the exposures with time, and analysis showed associations of higher pregnancy-averaged mono-(2-carboxymethyl) phthalate with higher child weight at 3 years (0.14 (0.06, 0.22)), and of higher high-molecular-weight phthalate, di-2-ethylhexyl phthalate, mono-(2-ethyl-5-carboxypentyl) phthalate, mono-(2-carboxymethyl) phthalate, and mono-(2-ethylhexyl) phthalate with higher child weight at 4 years (0.16 (0.04, 0.28), 0.15 (0.03, 0.27), 0.19 (0.07, 0.31), 0.16 (0.07, 0.24), 0.11 (0.03, 0.19)). Higher pregnancy-averaged high-molecular-weight phthalate, di-2-ethylhexyl phthalate, mono-(2-ethyl-5-carboxypentyl) phthalate, mono-(2-ethyl-5-hydroxyhexyl) phthalate, and mono-2(ethyl-5-oxohexyl) phthalate concentrations were associated with higher child BMI at 4 years (0.20 (0.05, 0.35), 0.20 (0.05, 0.35), 0.22 (0.06, 0.37), 0.20 (0.05, 0.34), 0.20 (0.05, 0.34)). For skinfold thicknesses, we observed no associations.

DISCUSSION

This study contributes to the evidence suggesting associations of prenatal exposure to bisphenols and high-molecular-weight phthalates on childhood weight and BMI.

Measurement of body composition by deuterium oxide dilution technique and development of a predictive equation for body fat mass among severe neurologically impaired children

Introduction

Neurologically impaired (NI) children are at risk of malnutrition, which consequently impacts their health and quality of life. Accurate nutrition assessment is an important step in guiding appropriate nutrition support. Conventional anthropometric measurements among NI children have some limitations. Determining body composition requires more complex equipment, which is not routinely performed. This study was conducted to evaluate the association between anthropometric parameters and body composition assessed using the deuterium dilution technique (DDT) in NI children.

Methods

A cross-sectional study enrolled severe NI children aged 1-20 years who received home enteral nutrition for at least 3 months. Weight, length, and 4-site skinfold thickness were measured. Body composition was determined using DDT following the International Atomic Energy Agency (IAEA) protocol.

Results

A total of 37 NI children (56.76% male, median age 7.2 years) were enrolled. The prevalence of underweight, stunting, and overweight were 22, 38, and 35%, respectively. Body composition analysis showed the mean (SD) of total body water (TBW) and fat mass (FM) were 10.52 (4.51) kg and 9.51 (6.04) kg, respectively. Multivariate GLM analysis showed that the factors associated with FM were age (β = 0.07 [0.05,0.08]; p < 0.001), body mass index (BMI) (β = 0.82 [0.52, 1.12]; p < 0.001), biceps skinfold thickness (BSF) (β = 0.49 [0.23,0.75]; p = 0.001), and subscapular skinfold thickness (SSF) (β = -0.24 [-0.46,0.03]; p = 0.030). A predictive equation for FM was constructed.

Conclusion

A high prevalence of malnutrition was found among severe NI children despite enteral nutrition support. Our findings showed that age, BMI, BSF, and SSF were associated with FM. The predictive equation of FM was proposed and needed to be further validated and applied to clinical practice.

The association between skinfold thicknesses and estimated glomerular filtration rate in adolescents: a cross-sectional study

Background

Obesity is one of the causes of glomerular hyperfiltration. Studies on the relationship between body fat content and glomerular hyperfiltration have been limited to special children. Therefore, we aimed to evaluate the correlation between skinfold thickness, which represents body fat content, and estimated glomerular filtration rate (eGFR).

Methods

The cross-sectional study included 6655 participants (3532 boys and 3123 girls; age: 12 − 17.99 years); data was obtained from the National Health and Nutrition Examination Survey (NHANES; 2001–2010). The independent variables were subscapular skinfold thickness and triceps skinfold thickness. The dependent variable was eGFR. We used multivariate linear regression models to evaluate their associations and also performed subgroup analyses.

Results

After adjusting for age, standing height, race, family income, blood urea nitrogen and uric acid variables, multivariate regression analysis identified that triceps skinfold thickness and subscapular skinfold thickness were positively correlated with eGFR and glomerular hyperfiltration in boys. In subgroup analyses stratified by age and body mass index, triceps skinfold thickness was also associated with glomerular hyperfiltration in boys. There was a linear relationship between triceps skinfold thickness and eGFR in boys (β = 0.389, P < 0.001) and girls (β = 0.159, P = 0.0003).

Conclusions

Triceps skinfold thickness and subscapular skinfold thickness are positively correlated with eGFR and glomerular hyperfiltration in US male adolescents. In all adolescents, there is a linear relationship between triceps skinfold thickness and eGFR.

Further reductions in the prevalence of obesity in 4-year-old New Zealand children from 2017 to 2019

Objective

To examine whether the prevalence of age- and sex-adjusted BMI at, or above, the 85th, 95th and 99.7th percentiles continues to decline in New Zealand preschool children, over time.

Methods

As part of a national screening programme, 438,972 New Zealand 4-year-old children had their height and weight measured between 2011 and 2019. Age- and sex-adjusted BMI was calculated using WHO Growth Standards and the prevalence of children at, or above, the 85th, 95th, and 99.7th percentiles and at, or below, the 2nd percentile were determined. Log-binomial models were used to estimate linear time trends of ≥85th, ≥95th and ≥99.7th percentiles for the overall sample and separately by sex, deprivation, ethnicity and urban-rural classification.

Results

The percentage of children at, or above, the 85th, 95th and 99.7th percentile reduced by 4.9% [95% CI: 4.1%, 5.7%], 3.5% [95% CI: 2.9%, 4.1%], and 0.9% [95% CI: 0.7%, 1.2%], respectively, between ‘2011/12’ and ‘2018/19’. There was evidence of a decreasing linear trend (risk reduction, per year) for the percentage of children ≥85th (risk ratio (RR): 0.980 [95% CI: 0.978, 0.982]), ≥95th (RR: 0.966 [95% CI: 0.962, 0.969]) and ≥99.7th (RR: 0.957 [95% CI: 0.950, 0.964]) percentiles. Downward trends were also evident across all socioeconomic indicators (sex, ethnicity, deprivation, and urban-rural classification), for each of the BMI thresholds. Larger absolute decreases were evident for children residing in the most deprived compared with the least deprived areas, at each BMI threshold. There appeared to be no consistent trend for the percentage of children ≤2nd percentile.

Conclusions

Reassuringly, continued declines of children with age- and sex-adjusted BMI at, or above, the 85th, 95th and 99.7th percentiles are occurring over time, overall and across all sociodemographic indicators, with little evidence for consistent trends in the prevalence of children at, or below, the 2nd percentile.

Neck circumference cut-offs for overweight and obesity in a group of Mexican adolescents

BACKGROUND/OBJECTIVES

Neck circumference (NC) has been used for screening overweight/obesity for its high correlation with age, weight, body mass index (BMI), and waist circumference (WC). Cut-offs should be population specific. The aim of the study was to obtain cut-offs of NC for overweight/obesity in Mexican adolescents and to correlate them with anthropometric indicators.

SUBJECTS/METHODS

Weight, height, BMI, NC, WC, and mid-upper arm circumference (MUAC) of 465 12-14-year-old Mexican-mestizo students attending a public school in Mexico City were assessed. Using receiver operating characteristics analyses, neck cut-offs were obtained according to the WHO age and sex criteria for overweight/obesity.

RESULTS

NC cut-offs with the highest sensitivity and specificity for males and females, respectively, were as follows: 30.0 and 29.3 cm for 12-year-olds; 31.9 and 30.4 cm for 13-year-olds; and, 33.5 and 30.7 cm for 14-year-old adolescents. Overweight/obesity was identified with NC cut-offs in 80% of males and 86% of females, and showed significant correlations (p < 0.01) in males and females with weight (r = 0.821 and r = 0.840, respectively), BMI (r = 0.649 and r = 0.819, respectively), WC (r = 0.710 and r = 0.813, respectively) and MUAC (r = 0.736 and r = 0.815, respectively).

CONCLUSIONS

Neck circumference may be used as a first-stage screening tool or jointly with BMI to identify overweight/obesity in 12-14-year-old Mexican adolescents.

Placental Epigenome-Wide Association Study Identified Loci Associated with Childhood Adiposity at 3 Years of Age

The aim of this study was to identify placental DNA methylation (DNAm) variations associated with adiposity at 3 years of age. We quantified placental DNAm using the Infinium MethylationEPIC BeadChips. We assessed associations between DNAm at single-CpGs and skinfold thickness using robust linear regression models adjusted for gestational age, child's sex, age at follow-up and cellular heterogeneity. We sought replication of DNAm association with child adiposity in an independent cohort. We quantified placental mRNA levels for annotated gene using qRT-PCR and tested for correlation with DNAm. Lower DNAm at cg22593959 and cg22436429 was associated with higher adiposity (β = -1.18, q = 0.002 and β = -0.82, q = 0.04). The cg22593959 is located in an intergenic region (chr7q31.3), whereas cg22436429 is within the TFAP2E gene (1p34.3). DNAm at cg22593959 and cg22436429 was correlated with mRNA levels at FAM3C (r_s = -0.279, p = 0.005) and TFAP2E (r_s = 0.216, p = 0.03). In an independent cohort, the association between placental DNAm at cg22593959 and childhood adiposity was of similar strength and direction (β = -3.8 ± 4.1, p = 0.36), yet non-significant. Four genomic regions were also associated with skinfold thickness within FMN1, MAGI2, SKAP2 and BMPR1B genes. We identified placental epigenetic variations associated with adiposity at 3 years of age suggesting that childhood fat accretion patterns might be established during fetal life.

Secular trends in adiposity within the context of changes in BMI across developmental periods among Polish schoolchildren-application of the Slaughter equation

OBJECTIVES

To estimate secular changes in the body fatness, assessed using the Slaughter equation, in the context of changes in BMI in different developmental periods among Polish schoolchildren studied over nearly 50 years.

METHODS

Data were collected during Polish Anthropological Surveys (1966, 1978, 1988, 2012). The total random sample consisted of 69,746 schoolchildren, aged 7-18. Three periods of development were identified: childhood, early adolescence, and late adolescence. Raw data of BMI were standardized for age classes. Based on the body fat percentage, calculated using Slaughter equation (involving triceps and subscapular skinfold thickness), fat mass (FM; kg), and then fat mass index (FMI = FM/height⁶; kg/m⁶) was assessed to enable comparison between body fatness and BMI. Statistical analyses included two-way ANOVA and post-hoc Tukey's tests.

RESULTS

In boys, in terms of changes per decade, between 1966 and 2012 acceleration in Z-BMI and deceleration in FMI were found, irrespective of developmental period. Regarding girls, deceleration of trend was found in terms of both features, with different intensity, depending on developmental period and year of study. The pattern of changes in FMI depending on developmental period was, to some extent, similar for both sexes.

CONCLUSIONS

Slaughter equation for abovementioned two skinfolds, as a method of body fatness assessment, might be a useful tool for research on boys across different developmental periods, but not on girls. Moreover, it should be used with caution when applied to secular changes in adiposity in both sexes, since the distribution of fat tissue varies across ontogenesis, but also over generations.

Evaluation of anthropometric measures for assessment of cardiometabolic risk in early childhood

OBJECTIVE

Waist-to-height ratio has been shown to be an important indicator of cardiometabolic risk. There are few studies evaluating this measure against existing measures of adiposity and cardiometabolic markers in early childhood. The objectives were: (i) to determine in young children the ability of waist-to-height ratio, BMI z-score, weight for length, and sum of skin fold thickness to predict cardiometabolic risk and (ii) to examine this association at ages 1, 3 and 5 years.

DESIGN

Prospective cohort study.

SETTING

A university hospital in Toronto, Ontario.

PARTICIPANTS

Infants at 1 (n 406), 3 (n 112) and 5 years of age (n 94) born to mothers with and without gestational diabetes mellitus.

RESULTS

Weight for length and BMI z-score demonstrated the strongest correlations with biochemical measures compared to waist-to-height ratio, including leptin (at 5 years, weight for length z-score: ρ = 0·65, P < 0·001; BMI z-score: ρ = 0·67, P < 0·001) and measures of insulin resistance (at 3 years, weight for length z-score: ρ = 0·25, P = 0·02; BMI z-score: ρ = 0·24, P = 0·02). The magnitude of associations between anthropometric measures and biochemical measures strengthened over time. Weight for length and BMI z-scores were moderately correlated with overall measures of fat mass as measured by dual-energy X-ray absorptiometry (ρ = 0·65, P = 0·00; ρ = 0·61, P = 0·01).

CONCLUSIONS

Waist-to-height ratio was not superior to existing measures in predicting cardiometabolic risk in young children. BMI z-score is a preferred measure of adiposity between birth and 5 years of age.

Ability of 2 estimation methods of body fat percentage in identifying unfavorable levels of cardiometabolic biomarkers in adolescents: Results from the LabMed study

Background:

To assess and compare the ability of body fat percentage (BF%) estimated by 2 methods, bioelectrical impedance analysis (BIA) and by the Slaughter et al equations for triceps and subscapular skinfold thickness (SKF), in identifying unfavorable levels of several biomarkers of cardiometabolic risk.

Methods:

Cross-sectional school-based study with 529 apparently healthy adolescents (267 girls), aged 14.3 ± 1.7 years.

Results:

BF% estimated by both methods always showed higher areas under the curve (AUC) for each biomarker in girls than in boys (with the exception of BIA for leptin). BF% estimated by BIA and by SKF presented a discriminatory ability in identifying unfavorable levels in all biomarkers of cardiometabolic risk in girls; however, BF% estimated by BIA displayed the highest AUC (except for C-reactive protein). In boys, BF% estimated by SKF presented higher AUC for C-reactive protein, fibrinogen and erythrocyte sedimentation rate; and BF% estimated by BIA for complement C3 and leptin. Positive and significant associations between BIA and SKF with all biomarkers (P < .05) were found (except for SKF and complement C4 in girls, and SKF and fibrinogen and erythrocyte sedimentation rate in boys), after adjustments for pubertal stage, cardiorespiratory fitness, adherence to the Mediterranean diet and socioeconomic status.

Conclusions:

Overall, diagnostic performance was more accurate in girls. BF% estimated by BIA presented a slightly better overall discriminatory ability for each biomarker than BF% estimated by SKF in girls, while in boys no method clearly prevailed over the other.

B-vitamins and body composition: integrating observational and experimental evidence from the B-PROOF study

Purpose

Higher folate and vitamin-B12 have been linked to lower risk of overweight. However, whether this is a causal effect of these B-vitamins on obesity risk remains unclear and evidence in older individuals is scarce. This study aimed to assess the role of B-vitamin supplementation and levels on body composition in older individuals.

Methods

A double-blind, randomized controlled trial in 2919 participants aged ≥ 65 years with elevated homocysteine levels. The intervention comprised a 2-year supplementation with a combination of folic acid (400 µg) and vitamin B12 (500 µg), or with placebo. Serum folate, vitamin-B12, active vitamin-B12 (HoloTC), methylmalonic acid (MMA), and anthropometrics were measured at baseline and after 2 years of follow-up. Dietary intake of folate and vitamin-B12 was measured at baseline in a subsample (n = 603) using a validated food-frequency questionnaire. Fat mass index (FMI) and fat-free mass index (FFMI) were assessed with Dual Energy X-ray absorptiometry (DXA).

Results

Cross-sectional analyses showed that a 1 nmol/L higher serum folate was associated with a 0.021 kg/m² lower BMI (95% CI − 0.039; − 0.004). Higher HoloTC (per pmol/L log-transformed) was associated with a 0.955 kg/m² higher FMI (95% CI 0.262; 1.647), and higher MMA (per μgmol/L) was associated with a 1.108 kg/m² lower FMI (95% CI − 1.899; − 0.316). However, random allocation of B-vitamins did not have a significant effect on changes in BMI, FMI or FFMI during 2 years of intervention.

Conclusions

Although observational data suggested that folate and vitamin B12 status are associated with body composition, random allocation of a supplement with both B-vitamins combined versus placebo did not confirm an effect on BMI or body composition.

Electronic supplementary material

The online version of this article (10.1007/s00394-019-01985-8) contains supplementary material, which is available to authorized users.

Subcutaneous fat mass in infancy and abdominal, pericardial and liver fat assessed by Magnetic Resonance Imaging at the age of 10 years

BACKGROUND/OBJECTIVES

Fat mass development in infancy contributes to later adiposity, but its relation to ectopic fat depots is unknown. We examined the associations of infant subcutaneous fat with childhood general and organ-specific fat.

SUBJECTS/METHODS

Among 593 children from a population-based prospective cohort study, we obtained total subcutaneous fat mass (as sum of biceps, triceps, suprailiacal, and subscapular skinfolds thickness), central-to-total subcutaneous fat ratio (sum of suprailiacal and subscapular skinfold thickness/total subcutaneous fat) at 1.5, 6 and 24 months of age. At 10 years, we assessed BMI, fat mass index (FMI) based on total body fat by dual-energy X-ray absorptiometry, and abdominal subcutaneous, visceral and pericardial fat mass indices, and liver fat fraction by Magnetic Resonance Imaging.

RESULTS

A higher central-to-total subcutaneous fat ratio at 1.5 months only and higher total subcutaneous fat at 6 and 24 months were associated with higher BMI, FMI and subcutaneous fat mass index at 10 years. The observed associations were the strongest between total subcutaneous fat at 24 months and these childhood outcomes (difference per 1-SDS increase in total subcutaneous fat: 0.15 SDS (95% Confidence Interval (CI) 0.08, 0.23), 0.17 SDS (95% CI 0.10, 0.24), 0.16 SDS (95% CI 0.08, 0.23) for BMI, FMI and childhood subcutaneous fat mass index, respectively). Infant subcutaneous fat measures at any time point were not associated with visceral and pericardial fat mass indices, and liver fat fraction at 10 years.

CONCLUSIONS

Our results suggest that infant subcutaneous fat is associated with later childhood abdominal subcutaneous fat and general adiposity, but not with other organ-specific fat depots.

Validity of Body Mass Index as a Measure of Adiposity in Infancy

OBJECTIVES

To assess the validity of body mass index (BMI) and age- and sex-standardized BMI z-score (BMIZ) as surrogates for adiposity (body fat percentage [BF%], fat mass, and fat mass index [kg/m²]) at 3 time points in infancy (1, 4, and 7 months) and to assess the extent to which the change in BMIZ represents change in adiposity.

STUDY DESIGN

We performed a secondary analysis of 447 full-term infants in a previous trial of maternal vitamin D supplementation during lactation. Study staff measured infant anthropometrics and assessed body composition with dual-energy x-ray absorptiometry at 1, 4, and 7 months of age. We calculated Spearman correlations (r_s) among BMI, BMIZ, and adiposity at each time point, and between change in BMIZ and change in adiposity between time points.

RESULTS

Infants (N = 447) were 52% male, 38% white, 31% black, and 29% Hispanic. The BMIZ was moderately correlated with BF% (r_s = 0.43, 0.55, 0.48 at 1, 4, and 7 months of age, respectively). BMIZ correlated more strongly with fat mass and fat mass index, particularly at 4 and 7 months of age (fat mass r_s = 0.72-0.76; fat mass index r_s = 0.75-0.79). Changes in BMIZ were moderately correlated with adiposity changes from 1 to 4 months of age (r_s = 0.44 with BF% change; r_s = 0.53 with fat mass change), but only weakly correlated from 4 to 7 months of age (r_s = 0.21 with BF% change; r_s = 0.27 with fat mass change).

CONCLUSIONS

BMIZ is moderately correlated with adiposity in infancy. Changes in BMIZ are a poor indicator of adiposity changes in later infancy. BMI and BMIZ are limited as surrogates for adiposity and especially adiposity changes in infancy.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT00412074.

Twelve Weeks of Plyometric Training Improves Motor Performance of 7- to 9-Year-Old Boys Who Were Overweight/Obese: A Randomized Controlled Intervention

Nobre, GG, de Almeida, MB, Nobre, IG, dos Santos, FK, Brinco, RA, Arruda-Lima, TR, de-Vasconcelos, KL, de-Lima, JG, Borba-Neto, ME, Damasceno-Rodrigues, EM, Santos-Silva, SM, Leandro, CG, and Moura-dos-Santos, MA. Twelve weeks of plyometric training improves motor performance of 7- to 9-year-old boys who were overweight/obese: a randomized controlled intervention. J Strength Cond Res 31(8): 2091-2099, 2017-The prevalence of childhood overweight/obesity has increased, and physical training at school may to be effective to combat this scenario. We analyzed the effects of a protocol of plyometric training on body composition and motor performance of boys who were overweight/obese aged 7-9 years. The sample was randomly assigned into 2 groups: plyometric training group (T, n = 40) and control group (C, n = 19). Training consisted of 20 min·d (twice a week, during 12 weeks) of lower extremity plyometric exercise. Health-related physical fitness was measured by handgrip strength, standing long jump (SLJ), curl-ups, sit and reach, square test, running speed, and mile run test. Gross motor coordination was evaluated by means of the Körperkoordinations-test für Kinder (KTK) tests. Baseline and postintervention differences were investigated, and effect size was estimated through Cohen's d coefficient. Both groups showed increased body weight, height, and sitting height after intervention with a negligible effect size. Only T group showed increased fat-free mass (p = 0.011) compared with baseline values with small effect size. Plyometric training improved handgrip strength (d = 0.23), sit and reach (d = 0.18), curl-ups (d = 0.39), SLJ (d = 0.80), agility (d = 0.48), and time in the mile run test (d = 0.38). For gross motor coordination results, T group showed better performance in all tests after plyometric training with moderate/large effect size. Thus, 12 weeks of PT improved health-related physical fitness components and motor coordination acquisition of 7- to 9-year-old boys who were overweight/obese.

Childhood adiposity and fertility difficulties: the Bogalusa Heart Study

BACKGROUND

Adult obesity is associated with infertility; however, childhood obesity has received little consideration.

OBJECTIVES

The present study sought to evaluate the impact of childhood adiposity on fertility.

METHODS

Associations between childhood adiposity and self-reported fertility difficulties were estimated among women participating in a long-term study of cardiovascular risks and reproductive health (n = 1061).

RESULTS

Participants with obesity between ages 9 and 12 were more likely to report fertility difficulties (adjusted relative risk [aRR], 1.82, 95% CI 1.17-2.82) and inability to become pregnant when trying (aRR = 1.94, 95% CI 1.22-3.08) as were those with obesity prior to age 9 (aRR = 1.76, 95% CI 1.04-2.97). Similar associations were seen among those ever overweight or obese in childhood. High subscapular skinfold thickness (age < 12) increased risk of receiving help becoming pregnant (aRR = 2.16, 95% CI 1.15-4.06), inability to become pregnant (aRR = 1.46, 95% CI 1.05-2.04) and any fertility difficulties (aRR = 1.56, 95% CI 1.13-2.14); associations for triceps skinfold were attenuated. Participants with increased adiposity also had fewer pregnancies and live births. Effects persisted, excluding women with polycystic ovarian syndrome.

CONCLUSIONS

This study supports an association between childhood adiposity and infertility, not solely driven by polycystic ovarian syndrome.

Skinfold reference curves and their use in predicting metabolic syndrome risk in children

OBJECTIVES

To draw skinfold (SF) reference curves (subscapular, suprailiac, biceps, triceps) and to determine SF cutoff points for predicting the risk of metabolic syndrome (MetS) in children aged 6-10 years old.

METHODS

This was a cross-sectional study with a random sample of 1480 children aged 6-10 years old, 52.2% females, from public and private schools located in the urban and rural areas of the municipality of Uberaba (MG). Anthropometry, blood pressure, and fasting blood samples were taken at school, following specific protocols. The LMS method was used to draw the reference curves and ROC curve analysis to determine the accuracy and cutoff points for the evaluated skinfolds.

RESULTS

The four SF evaluated (subscapular, suprailiac, biceps, and triceps) and their sum (∑4SF) were accurate in predicting MetS for both girls and boys. Additionally, cutoffs have been proposed and percentile curves (p5, p10, p25, p50, p75, p90, and p95) were outlined for the four SF and ∑4SF, for both genders.

CONCLUSION

SF measurements were accurate in predicting metabolic syndrome in children aged 6-10 years old. Age- and gender-specific smoothed percentiles curves of SF provide a reference for the detection of risk for MetS in children.

Utility of T1-weighted MRI as a predictor of liver lesion visibility on ultrasound: A clinical tool to determine feasibility of ultrasound-guided percutaneous interventions

PURPOSE

To determine the utility of fat-suppressed T1-weighted gradient recalled echo (FS-T1W-GRE) MRI to predict visibility of focal liver lesions (FLL) on abdominal ultrasound (US).

MATERIALS AND METHODS

With IRB approval, between 2010 and 2013, 109 patients (28.4% females, age 66.9±10.9years) with 177 FLL (hepatocellular carcinoma=132, metastases=44, other=1) underwent MRI and prospective, radiologist-performed treatment-planning US (to determine eligibility for US-guided ablation). MRI examinations were reviewed by a blinded radiologist who assessed: a) size and location of FLL, b) presence of hepatic steatosis on dual-echo T1W-GRE, and c) quantitative signal intensity of FLL relative to liver on FS-T1W-GRE. Associations between MR imaging findings and visibility on US were assessed using independent t-tests and the chi-squares test.

RESULTS

69.5% (123/177) FLL were identified with US and 30.5% (54/177) were not visible. Size of FLL on MRI was associated with visibility on US (p<0.0001) with no association between FLL visibility on US and segmental or subcapsular location (p=0.29 and p=0.25, respectively). 20.2% (22/109) patients had hepatic steatosis on MRI, which was not associated with non-visibility of FLL on US (p=0.67). 38.4% (68/177) FLL were isointense to liver on FS-T1W-GRE which was associated with non-visibility on US (p=0.036) particularly in non-steatotic livers (p=0.014).

CONCLUSION

FLL size and isointensity of FLL to liver parenchyma on FS-T1W-GRE MRI are associated with non-visibility on US, particularly in non-steatotic livers. These results have implications when planning US-guided percutaneous interventions of FLL detected with MRI.

Relationship between motor proficiency and body composition in 6- to 10-year-old children

AIM

The aim of this study is to examine the relationship between motor skill competence and body composition of 6- to 10-year-old children.

METHODS

Seventy girls and 86 boys participated. Body composition was measured by body mass index and skinfold thickness. Motor proficiency was evaluated through the Bruininks-Oseretsky Test of Motor Proficiency-Short Form, which included measures of gross motor skills and fine motor skills.

RESULTS

Significant associations were found for both sexes between the percentage of body fat and (i) the performance in each gross motor task, (ii) the composite score for gross motor skills and (iii) the motor proficiency score. The percentage of body fat was not significantly associated with the majority of the fine motor skills items and with the respective composite score. Considering body weigh categories, children with normal weight had significantly higher scores than their peers with overweight or with obesity in gross motor skills and in overall motor proficiency.

CONCLUSIONS

Children's motor proficiency is negatively associated with body fat, and normal weight children show better motor competence than those who are overweight or obese. The negative impact of excessive body weight is stronger for gross motor skills that involve dynamic body movements than for stationary object control skills; fine motor skills appear to be relatively independent of the constraints imposed by excessive body weight.

Overweight and obesity in Mexican children and adolescents during the last 25 years

BACKGROUND/OBJECTIVE

The objective of the study was to provide current estimates of the prevalence and trends of overweight and obesity (OW+OB) in Mexican children and adolescents.

SUBJECTS/METHODS

Body mass index objectively measured was analyzed for 37 147 children and adolescents aged 0-19 years obtained in 2012 as part of the National Health and Nutrition Survey (ENSANUT-2012), a nationally representative sample of the Mexican population. In addition, data from previous National Nutrition Surveys obtained in 1988, 1999 and 2006 were compared with analyze trends over a 24-year period (1988-2012) for children <5 years of age and adolescents and over a 13-year period (1999-2012) for school-age children. World Health Organization Child Growth Standard was used to define OW+OB.

RESULTS

In 2012, 33.5% of children <5 years of age (both sexes) were at risk of overweight or were overweight (OW); 32% and 36.9% of girls and boys 5-11 years of age were OW+OB, respectively, and 35.8% and 34.1% of female and male adolescents were OW+OB, respectively. Statistically significant trends were documented for all age groups during the study period. Overall change in the combined prevalence in preschool children was 6.3±1.0 percentage points (pp; P<0.001; 0.26 pp per year) in the last 24 years, showing the highest increase between 1988 and 1999, whereas for school-age girls (from 1999 to 2012) and adolescent females (from 1988 to 2012), OW+OB increased across all periods at a declining trend, with an overall change of 0.5 and 1.0 pp per year, respectively. Changes in the prevalence of OW+OB were highest among children and adolescents in the lowest quintile of the household living condition index.

CONCLUSIONS

Prevalence of OW+OB among children and adolescents increased significantly during the last 13-24 years. The rate of increase has declined in the last 6 years in all age groups. Changes in prevalence of OW+OB presented here suggest that, in Mexico, the burden of obesity is shifting toward the groups with lower socioeconomic level.

The Relationship Between Strength Measurements and Anthropometric Indicators (BMI and Skinfold Thickness) in Ellisras Rural Adolescents Aged 9–15 Years: Ellisras Longitudinal Study

Purpose. Handgrip strength and arm hang have been recognized as predictors of muscle strength and presented as biomarkers for important health outcomes and overall fitness of an individual. The aim of the study was to investigate the relationship between arm hang and handgrip strength with BMI and skinfold thickness.

Method. The total of 769 children (391 boys and 378 girls) aged 9-15 years underwent a series of anthropometric and strength measurements with the use of standard procedures. Linear regression was applied to assess the relationship of arm hang and handgrip strengths with body mass index and skinfold thickness.

Results. The prevalence of undernutrition and low strength measurements was high (1.7-85%) while the prevalence of overweight and obesity was low (1.5-4.2%) in the Ellisras children aged 9-15 years. Boys showed a significantly higher (p < 0.05) mean arm hang (9.6-13.1 kg) than girls (4.0-5.1 kg) aged 11-15 years. There was a significant (p < 0.05) association between low strength and underweight among Ellisras rural children when unadjusted (OR = 0.650; 95% CI = 0.487-0.867) and adjusted (OR = 0.650; 95% CI = 0.489-0.868) for age and gender.

Conclusions. The prevalence of undernutrition and poor strength was high. An association was observed between arm hang and anthropometric indicators while handgrip showed no significant association with anthropometric indicators. Further studies are needed to investigate the association between strength and undernutrition over time.

Secular trends for skinfolds differ from those for BMI and waist circumference among adults examined in NHANES from 1988-1994 through 2009-2010

BACKGROUND

Although the prevalence of a body mass index [BMI (in kg/m²)] ≥30 has tripled among US adults since the 1960s, BMI is only moderately correlated with body fatness. Because skinfolds can more accurately estimate body fatness than can BMI, it is possible that skinfolds could be useful in monitoring secular trends in body fatness.

OBJECTIVE

We examined whether there were similar secular trends for skinfolds (triceps and subscapular), BMI, and waist circumference between US adults.

DESIGN

This study was an analysis of 45,754 adults who participated in the NHANES from 1988-1994 through 2009-2010. Approximately 19% of the subjects were missing ≥1 skinfold-thickness measurement. These missing values were imputed from other characteristics.

RESULTS

Trends in mean levels and in the prevalence of high levels of the 4 body size measures were fairly similar between men, with mean levels increasing by ≥5% from 1988-1994 through 2009-2010. Slightly larger increases were seen in women for BMI and waist circumference (7-8%), but trends in skinfolds were markedly different. The mean triceps skinfold, for example, increased by 2 mm through 2003-2004, but subsequently decreased so that the mean in 2009-2010 did not differ from that in 1988-1994. Compared with obese women in 1988-1994, the mean BMI of obese women in 2009-2010 was 1 higher, but mean levels of both skinfolds were 5-10% lower.

CONCLUSIONS

Although there were fairly similar trends in levels of BMI, waist circumference, and skinfold thicknesses in men in the United States from 1988-1994 through 2009-2010, there were substantial differences in women. Our results indicate that it is unlikely that skinfold thicknesses could be used to monitor trends in obesity.

Associations of Infant Subcutaneous Fat Mass with Total and Abdominal Fat Mass at School-Age: The Generation R Study

BACKGROUND

Skinfold thickness enables the measurement of overall and regional subcutaneous fatness in infancy and may be associated with total and abdominal body fat in later childhood. We examined the associations of subcutaneous fat in infancy with total and abdominal fat at school-age.

METHODS

In a population-based prospective cohort study among 821 children, we calculated total subcutaneous fat (sum of biceps, triceps, suprailiacal, and subscapular skinfold thicknesses) and central-to-total subcutaneous fat ratio (sum of suprailiacal and subscapular skinfold thicknesses/total subcutaneous fat) at 1.5 and 24 months. At 6 years, we measured fat mass index (total fat/height(3) ), central-to-total fat ratio (trunk fat/total fat), and android-to-gynoid fat ratio (android fat/gynoid fat) by dual-energy X-ray absorptiometry and preperitoneal fat mass area by abdominal ultrasound.

RESULTS

Central-to-total subcutaneous fat ratio at 1.5 months was positively associated with fat mass index and central-to-total fat ratio at 6 years, whereas both total and central-to-total subcutaneous fat ratio at 24 months were positively associated with all childhood adiposity measures. A 1-standard-deviation scores higher total subcutaneous fat at 24 months was associated with an increased risk of childhood overweight (odds ratio 1.70, 95% confidence interval 1.36, 2.12). These associations were weaker than those for body mass index and stronger among girls than boys.

CONCLUSIONS

Subcutaneous fat in infancy is positively associated with total and abdominal fat at school-age. Our results also suggest that skinfold thicknesses add little value to estimate later body fat, as compared with body mass index.

Comparison of Eight Equations That Predict Percent Body Fat Using Skinfolds in American Youth

BACKGROUND

Skinfolds are often used in equations to predict percent body fat (PBF) in youth. Although there are numerous such equations published, there is limited information to help researchers determine which equation to use for their sample.

METHODS

Using data from the 1999-2006 National Health and Nutrition Examination Surveys (NHANES), we compared eight published equations for prediction of PBF. These published equations all included triceps and/or subscapular skinfold measurements. We examined the PBF equations in a nationally representative sample of American youth that was matched by age, sex, and race/ethnicity to the original equation development population and a full sample of 8- to 18-year-olds. We compared the equation-predicted PBF to the dual-emission X-ray absorptiometry (DXA)-measured PBF. The adjusted R(2), root mean square error (RMSE), and mean signed difference (MSD) were compared. The MSDs were used to examine accuracy and differential bias by age, sex, and race/ethnicity.

RESULTS

When applied to the full range of 8- 18-year-old youth, the R(2) values ranged from 0.495 to 0.738. The MSD between predicted and DXA-measured PBF indicated high average accuracy (MSD between -1.0 and 1.0) for only three equations (Bray subscapular equation and Dezenberg equations [with and without race/ethnicity]). The majority of the equations showed differential bias by sex, race/ethnicity, weight status, or age.

CONCLUSIONS

These findings indicate that investigators should use caution in the selection of an equation to predict PBF in youth given that results may vary systematically in important subgroups.

Maternal smoking in pregnancy association with childhood adiposity and blood pressure

BACKGROUND

Maternal smoking during pregnancy has been associated with increased risk of childhood overweight/obesity defined by body mass index (BMI). We examined its association with a range of adiposity measures and cardiovascular indicators in children aged 3-10 years.

METHODS

We used data from a cross-sectional study of schoolchildren across mainland Portuguese districts (2009-2010). We applied quantile regressions to examine maternal smoking associations with adiposity (n = 17 286), blood pressure (BP) and resting pulse rate (RPR) (n ≈ 2500) measures across the age range, adjusting for prenatal and early life factors.

RESULTS

Maternal smoking during pregnancy was associated with increases in offspring adiposity levels. The difference in median BMI between children of smokers and non-smokers was 0.39 kg m(-2) (95% confidence interval: 0.25, 0.53) in boys and 0.46 kg m(-2) (0.31, 0.62) in girls; 0.55 cm (0.24, 0.87) and 0.82 cm (0.45, 1.19), respectively, in median waist circumference; and 0.94 mm (0.49, 1.40) and 1.47 mm (0.87, 2.07) in median sum of (triceps, subscapular, suprailiac) skin-folds. The associations appeared to be stronger with increasing age. The differences in the 90th centile tended to be greater than those in median. There was no consistent association of maternal smoking with BP and RPR.

CONCLUSIONS

Children whose mother smoked during pregnancy had higher adiposity levels than children of non-smokers, across several measures, particularly among older children. Although there was no consistent association with cardiovascular indicators, maternal smoking association with childhood obesity may have implications for cardiovascular risk factors over the life course.

Subcutaneous fat mass in infancy and cardiovascular risk factors at school-age: The generation R study

OBJECTIVE

To examine the associations of infant subcutaneous fat with cardiovascular risk factors at school-age.

METHODS

In a population-based prospective cohort study among 808 children, total subcutaneous fat (sum of biceps, triceps, suprailiacal, and subscapular skinfold thicknesses) and central-to-total subcutaneous fat ratio (sum of suprailiacal and subscapular skinfold thicknesses/total subcutaneous fat) at 1.5 and 24 months were estimated. At 6 years, body mass index, blood pressure, cholesterol, triglycerides, and insulin levels were measured.

RESULTS

Infant subcutaneous fat measures were not associated with childhood blood pressure, triglycerides, or insulin levels. A 1-standard-deviation score (SDS) higher total subcutaneous fat at 1.5 months was, independently of body mass index, associated with lower low-density lipoprotein (LDL)-cholesterol levels at 6 years. In contrast, a 1-SDS higher total subcutaneous fat at 24 months was associated with higher total-cholesterol [difference 0.13 (95% confidence interval (CI) 0.03, 0.23) SDS] and LDL-cholesterol levels [difference 0.12 (95% CI 0.02, 0.21) SDS] at 6 years. There were no associations of central-to-total subcutaneous fat ratio with childhood cholesterol levels.

CONCLUSIONS

These results suggest that infant total subcutaneous fat is weakly associated with cholesterol levels at school-age. Further studies are needed to assess the long-term cardiometabolic consequences of infant body fat.

Interrelationships between BMI, skinfold thicknesses, percent body fat, and cardiovascular disease risk factors among U.S. children and adolescents

Background

Although the estimation of body fatness by Slaughter skinfold thickness equations (PBF_Slaughter) has been widely used, the accuracy of this method is uncertain. We have previously examined the interrelationships among the body mass index (BMI), PBF_Slaughter, percent body fat from dual energy X-ray absorptiometry (PBF_DXA) and CVD risk factor levels among children who were examined in the Bogalusa Heart Study and in the Pediatric Rosetta Body Composition Project. The current analyses examine these associations among 7599 8- to 19-year-olds who participated in the (U.S.) National Health and Nutrition Examination Survey from 1999 to 2004.

Methods

We analyzed (1) the agreement between (1) estimates of percent body fat calculated from the Slaughter skinfold thickness equations and from DXA, and (2) the relation of lipid, lipoprotein, and blood pressure levels to BMI, PBF_Slaughter and PBF_DXA.

Results

PBF_Slaughter was highly correlated (r ~ 0.85) with PBF_DXA. However, among children with a relatively low skinfold thicknesses sum (triceps + subscapular), PBF_Slaughter underestimated PBF_DXA by 8 to 9 percentage points. In contrast, PBF_Slaughter overestimated PBF_DXA by 10 points among boys with a skinfold thickness sum ≥ 50 mm. After adjustment for sex and age, lipid levels were related similarly to the body mass index, PBF_DXA and PBF_Slaughter. There were, however, small differences in associations with blood pressure levels: systolic blood pressure was more strongly associated with body mass index, but diastolic blood pressure was more strongly associated with percent body fat.

Conclusions

The Slaughter equations yield biased estimates of body fatness. In general, lipid and blood pressure levels are related similarly to levels of BMI (following adjustment for sex and age), PBF_Slaughter, and PBF_DXA.

Trends in overweight and obesity prevalence in Tuscan schoolchildren (2002-2012)

Objective

The aim of the present study was to examine the prevalence and time trends in childhood overweight including obesity and obesity among Tuscan children from 2002 to 2012.

Design

Cross-sectional study at five time points (Tuscan Nutritional Surveillance Surveys conducted in the years of 2002, 2006, 2008, 2010 and 2012). Trained personnel directly measured the height and weight of the subjects. BMI was assessed by means of the International Obesity Task Force (IOTF) and WHO cut-offs.

Setting

Representative sample of children in the Tuscany region (Italy).

Subjects

Children (n 7183) aged between 7·5 and 9·5 years (3711 boys and 3472 girls).

Results

With respect to the estimation of the absolute prevalence level of childhood overweight, a discrepancy was observed between the two criteria. In all surveys, more boys than girls were overweight (including obesity). Trend analysis showed a significant decrease in the prevalence of overweight including obesity and obesity in Tuscan children from 2002 to 2012 (32·0 % v. 25·8 %, P<0·001 on using IOTF criteria and 37·7 % v. 34·3 %, P<0·001 on using WHO criteria for overweight including obesity; and 10·0 % v. 6·7 %, P<0·001 on using IOTF criteria and 12·5 % v. 11·3 %, P=0·035 on using WHO criteria for obesity).

Conclusions

The present study is the first report from an Italian region showing a significant decrease in childhood obesity and overweight in the last 10 years. This reduction is probably a result of regional and local actions that have taken place in many sectors of society. However, efforts should be made to lower the prevalence of childhood obesity and overweight further.

Distribution of subcutaneous fat and the relationship with blood pressure in obese children and adolescents in Shandong, China

BACKGROUND

The association between elevated blood pressure (BP) and childhood obesity has been documented in several studies. However, the association between BP and body fat distribution in obese children remains poorly understood. We examined the distribution of subcutaneous fat and its association with BP in obese children and adolescents.

METHODS

Data for this study were obtained from a large cross-sectional survey of school children. A total of 38,873 students (19,485 boys and 19,388 girls) aged 7-17 years participated in this study. Height, weight, BP, subscapular and triceps skinfold thicknesses (SFT) of all subjects were measured. Obesity was defined by using body mass index (BMI) criteria recommended by the Working Group on Obesity in China. A total of 3,579 obese children and adolescents (2,367 boys and 1,212 girls) were examined.

RESULTS

Most of the obese children and adolescents had high subcutaneous fat. However, a small number of the obese individuals had a lower SFT levels. Obese children and adolescents with high SFT and central distribution had higher BP levels than those with low SFT and peripheral distribution.

CONCLUSION

Obese children and adolescents assessed by BMI might not necessarily have a high SFT level. The BP level of obese individuals is associated with the level and distribution pattern of SFT. Additional measurement of SFT is better than BMI alone to help identify high BP risks.

Pediatric adiposity stabilized in Switzerland between 1999 and 2012

PURPOSE

Several countries have recently reported stabilization and/or a decrease in the prevalence of pediatric obesity. However, systematic, repeated national monitoring studies are scarce, and it is unclear whether this trend would be sustained. The objective was to present the latest overweight and obesity prevalence in Swiss children and to investigate trends in prevalence from 1999 to 2012.

METHODS

Using probability-proportionate-to-size cluster sampling, nationally representative samples of children aged 6-12 years were recruited in 1999 (n = 594), 2002 (n = 2,493), 2004 (n = 328), 2007 (n = 2,218), 2009 (n = 907), and 2012 (n = 2,963). Height and weight were measured to calculate BMI (kg/m²). BMI cutoffs proposed by the Centers for Disease Control and Prevention (CDC) and by the International Obesity Task Force were used to determine the prevalence of overweight (excluding obesity) and obesity. Waist circumference was measured in 2007 and 2012, and multiple skinfold thicknesses assessed in 2002 and 2012.

RESULTS

Using the CDC criteria, prevalences of overweight and obesity in 2012 were 11.9 % (95 % CI 10.7-13.1) and 7.1 % (95 % CI 6.2-8.0), respectively, and did not change between 1999 and 2012 (β = -0.144, p = 0.293 and β = -0.063, p = 0.552, respectively). Boys had significantly higher obesity prevalence than girls in 2007 (5.6 vs. 3.4 %) and 2012 (8.1 vs. 5.9 %). Percentage of children with excess waist circumference and body fat percentage did not differ between 2007 and 2012, and 2002 and 2012, respectively.

CONCLUSION

Our data indicate the prevalence of childhood adiposity in Switzerland stabilized between 1999 and 2012, but ≈1 in 5 children remain overweight or obese and further efforts are needed to control the epidemic.

Childhood obesity-an insight into preventive strategies

Childhood obesity is now a global problem throughout the world. The major factors affecting weight regulation and the development of obesity in children are the result of a large number of biological, behavioral, social, environmental, and economic factors and the complex interactions between them that promote a positive energy balance. The changes in the dietary habits with the adoption of sedentary life style increases manifold obesity-related diseases and their complications. An obese child later on grows up to become an obese adult. Therefore, the role of primary prevention along with methodical diet control, behavioral changes, and physical activity are the important strategies against the battle of childhood obesity.

Anthropometry and physical activity level in the prediction of metabolic syndrome in children

OBJECTIVE

To evaluate the effectiveness of anthropometric measures and physical activity level in the prediction of metabolic syndrome (MetS) in children.

DESIGN

Cross-sectional study with children from public and private schools. Children underwent an anthropometric assessment, blood pressure measurement and biochemical evaluation of serum for determination of TAG, HDL-cholesterol and glucose. Physical activity level was calculated and number of steps per day obtained using a pedometer for seven consecutive days.

SETTING

Viçosa, south-eastern Brazil.

SUBJECTS

Boys and girls (n 187), mean age 9·90 (SD 0·7) years.

RESULTS

Conicity index, sum of four skinfolds, physical activity level and number of steps per day were accurate in predicting MetS in boys. Anthropometric indicators were accurate in predicting MetS for girls, specifically BMI, waist circumference measured at the narrowest point and at the level of the umbilicus, four skinfold thickness measures evaluated separately, the sum of subscapular and triceps skinfold thickness, the sum of four skinfolds and body fat percentage.

CONCLUSIONS

The sum of four skinfolds was the most accurate method in predicting MetS in both genders.

Percent body fat prediction equations for 8- to 17-year-old American children

BACKGROUND

Percent body fat equations are usually developed in specific populations and have low generalizability.

OBJECTIVES

To use a nationally representative sample of the American youth population (8-17 years old) from the 1999-2004 National Health and Nutrition Examination Survey data to develop gender-specific percent body fat equations.

METHODS

Percent body fat equations were developed for girls and boys using information on weight, height, waist circumference, triceps skin-folds, age, race/ethnicity and menses status compared to dual-emission X-ray absorptiometry. Terms were selected using forward and backward selection in regression models in a 2/3 development sample and were cross-validated in the remaining sample. Final coefficients were estimated in the full sample.

RESULTS

Final equations included ten terms in girls and eight terms in boys including interactions with age and race/ethnicity. In the cross-validation sample, the adjusted R2 was 0.818 and the root mean squared error was 2.758 in girls. Comparable estimates in boys were 0.893 and 2.525. Systematic bias was not detected in the estimates by race/ethnicity or by body mass index categories.

CONCLUSION

Gender-specific percent body fat equations were developed in youth with a strong potential for generalizability and utilization by other investigators studying adiposity-related issues in youth.

Interrelationships between anthropometric variables and overweight in childhood and adolescence

Objectives

To answer the questions: how does body mass index (BMI) correlate to five overweight related anthropometric variables during different ages in childhood, and which anthropometric variables contribute most to variation in BMI during childhood?

Methods

Data on BMI, height (H), sitting height (SH), waist circumference (WC), waist to height ratio (WHtR), waist to sitting height ratio (WSHtR), subscapular skinfold (SSF), and triceps skinfold (TSF), from 4,576 Norwegian children 4.00–15.99 years of age, were transformed to standard deviation scores (SDS) and studied using correlation and multiple regression analyses.

Results

The correlations between BMI SDS and the standardized anthropometric variables were in general strong and positive. For all variables, the correlations were weakest in the youngest age group and highest between 7 and 12 years. WC SDS and WHtR SDS were most strongly correlated with BMI SDS through all ages and in both sexes. A model with seven anthropometric variables adjusted for age and sex explained 81.4% of the variation in BMI SDS. When adjusted for all other variables, WC SDS contributed most to the variation in BMI SDS (b = 0.467, CI [0.372, 0.562]). Age group, but not sex, contributed significantly to variation in BMI SDS.

Conclusion

The interrelationships between BMI SDS and five standardized overweight related anthropometric variables were dependent on age, being weakest in the youngest age group. Independent of sex and age, WC SDS was in this study superior to other anthropometric variables in contributing to variation in BMI SDS during childhood. Am. J. Hum. Biol. 26:502–510, 2014. © 2014 The Authors American Journal of Human Biology Published by Wiley Periodicals, Inc.

Association between the summer season and body fatness and aerobic fitness among Hispanic children

BACKGROUND

Few studies have investigated changes in adiposity and fitness during the academic year (AY) and summer season (SS) in minority children. This study aimed to assess if adiposity indicators and fitness change during the school AY and SS in Hispanic children.

METHODS

One hundred nineteen low-income Hispanic children (9.2 ± 0.8) participated in the study. Demographic, body weight and height, percent body fat (% BF), and aerobic endurance were assessed at 3 time points: measurement 1 (M1), beginning of AY; M2, end of AY; and M3, end of SS. Using weight and height, body mass index (BMI) was calculated and normalized (BMI z-scores). Mixed effects between-within-subjects analysis of variance (ANOVA) design was used to examine changes in selected variables.

RESULTS

A significant decrease of BMI z-scores in overweight children (p = .024) was observed during the AY only, but not during the SS. Percent BF increased significantly over the AY and SS (p < .001), particularly in girls. Aerobic endurance showed a significant increase over the AY (p < .001), but it did not change over the SS (p = .552).

CONCLUSIONS

Results indicated that the SS might place Hispanic children at increased risk for additional adiposity and lower fitness.

Identification of obesity and cardiovascular risk factors in childhood and adolescence

Obesity in the child and adolescent population is a growing problem. This article discusses the identification of obesity and overweight youth using body mass index and anthropometry and reviews literature to show the relationship between obesity and premature cardiovascular disease.

Body fat throughout childhood in 2647 healthy Danish children: agreement of BMI, waist circumference, skinfolds with dual X-ray absorptiometry

BACKGROUND/OBJECTIVES

Total body fat percentage (%BF) evaluated by dual energy X-ray absorptiometry (DXA) scans (DXA %BF) is widely recognized as a precise measure of fatness. We aimed to establish national reference curves for DXA %BF, %BF calculated from skinfolds (SF %BF) and waist circumference (WC) in healthy children, and to compare agreement between the different methods.

SUBJECTS/METHODS

Based on 11 481 physical examinations (anthropometry) and 1200 DXA scans from a longitudinal cohort of Danish children (n=2647), we established reference curves (LMS-method) for SF %BF, WC (birth to 14 years) and DXA %BF (8-14 years). Age- and sex-specific Z-scores for body mass index (BMI), WC and SF %BF were compared. Sensitivity and specificity were calculated for agreement of WC, SF %BF and BMI with DXA %BF to identify obese children (>+1 s.d.).

RESULTS

%BF differed with age, sex, pubertal stage and social class. SF %BF correlated strongly with DXA %BF (r=0.86). BMI and WC also correlated positively with DXA %BF (Z-scores; r= 0.78 and 0.69). Sensitivity and specificity were 79.5 and 93.8 for SF %BF, 75.9 and 90.3 for BMI and 59.2 and 95.4 for WC.

CONCLUSIONS

SF %BF showed the highest correlation and best agreement with DXA %BF in identifying children with excess fat (+1 s.d.).

A comparison of the Slaughter skinfold-thickness equations and BMI in predicting body fatness and cardiovascular disease risk factor levels in children

BACKGROUND

Although estimation of percentage body fat with the Slaughter skinfold-thickness equations (PBF(Slaughter)) is widely used, the accuracy of this method has not been well studied.

OBJECTIVE

The objective was to determine the accuracy of the Slaughter skinfold-thickness equations.

DESIGN

We compared agreement between PBF(Slaughter) and estimations derived from dual-energy X-ray absorptiometry (PBF(DXA)) in 1169 children in the Pediatric Rosetta Body Composition Project and the relation to cardiovascular disease risk factors, as compared with body mass index (BMI), in 6725 children in the Bogalusa Heart Study.

RESULTS

PBF(Slaughter) was highly correlated (r = 0.90) with PBF(DXA), but it markedly overestimated levels of PBF(DXA) in children with large skinfold thicknesses. In the 65 boys with a sum of skinfold thicknesses (subscapular- plus triceps-skinfold thicknesses) ≥ 50 mm, PBF(Slaughter) overestimated PBF(DXA) by 12 percentage points. The comparable overestimation in girls with a high skinfold sum was 6 percentage points. We also found that, after adjustment for sex and age, BMI showed slightly stronger associations with lipid, lipoprotein, insulin, and blood pressure values than did PBF(Slaughter).

CONCLUSIONS

These results indicate that PBF(Slaughter), which was developed among a group of much thinner children and adolescents, is fairly accurate among nonobese children, but markedly overestimates the body fatness of children who have thick skinfold thicknesses. Furthermore, PBF(Slaughter) has no advantage over sex- and age-adjusted BMIs at identifying children who are at increased risk of cardiovascular disease based on lipid, lipoprotein, insulin, and blood pressure values.

Mediators of longitudinal changes in measures of adiposity in teenagers using parallel process latent growth modeling

OBJECTIVE

The aim of the study was to evaluate mediating effects of energy balance-related behaviors on measures of adiposity in the Dutch Obesity Intervention in Teenagers-study (DOiT).

DESIGN AND METHODS

DOiT was an 8-month behavioral intervention program consisting of educational and environmental components and evaluated in 18 prevocational secondary schools in the Netherlands (n = 1,108, baseline age 12.7 years, 50% girls). Outcome measures were changes in body mass index (BMI), waist circumference, and sum of skinfold thickness. Self-reported consumption of sugar-containing beverages and high caloric snacks, active transport to/from school, and screen-viewing behaviors were the hypothesized mediators. Data were collected at 0, 8, 12, and 20 months. For the data analysis, parallel process latent growth modeling was used.

RESULTS

Total sugar-containing beverages consumption mediated the intervention effects on BMI (ab = -0.01, 95%CI = -0.20, -0.001). The intervention group lowered their sugar-containing beverages consumption more than controls (B = -0.14, 95%CI = -0.22, -0.11) and this, in turn, led to smaller increases in BMI. No significant mediated effect by the targeted behaviors was found for waist circumference or sum of skinfolds.

CONCLUSIONS

Future school-based overweight prevention interventions may target decreasing sugar-containing beverages consumption.

[Prevalence of obesity and overweight among children in primary schools in Marrakech, Morocco]

BACKGROUND

Childhood obesity is a phenomenon of growing concern today because of its rapid growth worldwide. The aim of our study was to estimate the prevalence of overweight and obesity among school age children in Marrakech.

METHODS

We conducted a cross-sectional study of a random sample of 1418 schoolchildren aged 8-15 years in the public sector in Marrakech in May 2011. Trained physicians measured the weight and size of respondents. The body mass index (BMI) was calculated for each child. Overweight was assessed by comparing BMI with World Health Organization (WHO) and International Obesity Task Force (IOTF) references. Statistical analysis was performed using SPSS version 16.0 and using a macro of WHO Anthro for SPSS.

RESULTS

The mean age was 10.8 ± 1.6 years. The sex ratio (girl/boy) was 1. The prevalence of overweight and obesity were 8 % (95 % CI [6.7, 9.6]) and 3 % (95 % CI [2.2, 4.1] based on WHO reference. This prevalence were respectively 12.2 % (95 % IC [10.5; 14.0]) and 5.4 % (95 % IC [4.3; 6.7]) using the IOTF reference.

CONCLUSION

In the absence of national data, our results reflect the importance of the phenomenon in our context, hence the importance of monitoring the nutritional status on both individual and collective levels and the need to develop strategies for prevention, diagnosis and early treatment before the problem becomes more widespread.

Trends in prevalence of overweight and obesity in danish infants, children and adolescents--are we still on a plateau?

BACKGROUND

After the worldwide steep increase in child and adolescent overweight and obesity during the last decades, there is now evidence of a levelling off in the prevalence in many countries in the Western world.

AIM

To examine whether there still is a plateau in the prevalence of overweight and obesity in Danish children and adolescents, or whether the prevalence is decreasing or rising again.

METHODS

THE TRENDS IN THE PREVALENCE RATES WERE BASED ON THREE DATA SETS PROVIDING COMPARABLE REPEATED ESTIMATES: 1) the Danish Health Visitors Child Health Database (DHVCHD) with measurements on infant and childhood height and weight from 2002 to 2011 (n up to 39,984), 2) the Danish National Birth Cohort (DNBC) with maternal reports of measured infant and childhood height and weight from 1998 to 2010 (n up to 56,826) and 3) the Danish part of the Health Behaviour in School-aged Children survey (HBSC) with self-reported information on adolescent height and weight from the years 2002 to 2010 (n = 16,557). Overweight and obesity were categorized according to WHO growth standards. Trends were assessed by repeated point estimates and linear regression analyses providing regression coefficients for changes in per cent per year with 95% confidence intervals (CI).

RESULTS

The prevalence rates of overweight and obesity for infants, children and adolescents showed a mixed pattern of decline, stability and increase (ranging from -1.10 through 0.29 per cent per year with CI's from -3.10 through 2.37). Overall, there were no consistent statistically significant trends upwards or downwards, although some significant downward trends in childhood and adolescence were observed.

CONCLUSION

This study, based on data from 1998 through 2011, showed that the prevalence rates of overweight and obesity among Danish infants, children and adolescents were largely still on a plateau with tendencies for a decline among children and adolescents.

The abilities of body mass index and skinfold thicknesses to identify children with low or elevated levels of dual-energy X-ray absorptiometry-determined body fatness

OBJECTIVE

To examine the accuracies of body mass index (BMI) and skinfold thicknesses in classifying the body fatness of 7365 8- to 19-year-old subjects in a national sample.

STUDY DESIGN

We used percent body fat determined by dual-energy x-ray absorptiometry (PBFDXA) between 1999 and 2004. Categories of PBFDXA and the skinfold sum (triceps plus subscapular) were constructed so that that numbers of children in each category were similar to the number in each of 5 BMI categories based on the Centers for Disease Control and Prevention growth charts.

RESULTS

Approximately 75% of the children and adolescents who had a BMI-for-age ≥ 95th percentile (considered obese) had elevated body fatness, but PBFDXA levels were more variable at lower BMIs. For example, only 41% of the boys who had a BMI < 25th percentile, had a similarly low PBFDXA. The use of the skinfold sum, rather than BMI, slightly improved the identification of elevated levels of body fatness among boys (P = .03), but not among girls (P > .10). A low sum of the triceps and subscapular skinfold thicknesses was a better indicator of low PBFDXA than was a low BMI, but differences were smaller among children with greater levels of body fatness. Among girls who had a PBFDXA above the median, for example, BMI and the skinfold sum were correlated similarly (r = 0.77-0.79) with body fatness.

CONCLUSIONS

Both BMI and skinfold thicknesses are fairly accurate in identifying children who have excess body fatness. In contrast, if the goal is to identify children who have low body fatness, skinfold thicknesses would be preferred.

Correlations among adiposity measures in school-aged children

BACKGROUND

Given that it is not feasible to use dual x-ray absorptiometry (DXA) or other reference methods to measure adiposity in all pediatric clinical and research settings, it is important to identify reasonable alternatives. Therefore, we sought to determine the extent to which other adiposity measures were correlated with DXA fat mass in school-aged children.

METHODS

In 1110 children aged 6.5-10.9 years in the pre-birth cohort Project Viva, we calculated Spearman correlation coefficients between DXA (n=875) and other adiposity measures including body mass index (BMI), skinfold thickness, circumferences, and bioimpedance. We also computed correlations between lean body mass measures.

RESULTS

50.0% of the children were female and 36.5% were non-white. Mean (SD) BMI was 17.2 (3.1) and total fat mass by DXA was 7.5 (3.9) kg. DXA total fat mass was highly correlated with BMI (r(s)=0.83), bioimpedance total fat (r(s)=0.87), and sum of skinfolds (r(s)=0.90), and DXA trunk fat was highly correlated with waist circumference (r(s)=0.79). Correlations of BMI with other adiposity indices were high, e.g., with waist circumference (r(s)=0.86) and sum of subscapular plus triceps skinfolds (r(s)=0.79). DXA fat-free mass and bioimpedance fat-free mass were highly correlated (r(s)=0.94).

CONCLUSIONS

In school-aged children, BMI, sum of skinfolds, and other adiposity measures were strongly correlated with DXA fat mass. Although these measurement methods have limitations, BMI and skinfolds are adequate surrogate measures of relative adiposity in children when DXA is not practical.