Obesity measured as percent body fat, relationship with body mass index, and percentile curves for Mexican pediatric population

Secular trends in BMI, excess weight and body fat skinfolds in Peruvian children living at high altitude

BACKGROUND

There is limited evidence on secular trends in adiposity among high-altitude children.

AIMS

To describe secular trends in body mass index (BMI), excess weight and body fat skinfolds (SKF) among Peruvian children living at high altitude and to investigate the risk for excess weight in 2019 relative to 2009.

SUBJECTS AND METHODS

We sampled 1585 Peruvians aged 6-11 years from the Junín region. Height and weight were measured, and BMI was calculated. WHO cut-offs were used to classify children by weight status. The sum of SKF was used for analysis. BMI and sum SKF were log-transformed. Two-factor ANOVA and post-hoc contrasts were used together with trend plots for BMIlog and SKFlog. Relative risks for excess weight were estimated with 95% confidence intervals. All analyses were done in STATA.

RESULTS

BMIlog and SKFlog means increased in both sexes from 2009 to 2019, with age-specific variation. Between 2009 and 2019, BMI values shifted from near P50 to P75 on WHO percentiles for both sexes in most age groups. The risk of excess weight was not significantly higher for most children in 2019 compared to 2009.

CONCLUSIONS

Positive secular trends in BMIlog and SKFlog were observed, with significant increases at specific ages.

Association between percent body fat and the risk of prediabetes among Chinese adults: a 5-years longitudinal cohort study

This study aimed to explore the influence of percent body fat (PBF) on the risk of developing prediabetes among Chinese individuals, given the limited evidence on this relationship. We conducted a retrospective cohort study involving 185,586 Chinese adults. We applied Cox proportional hazards regression models, cubic spline functions, and smooth curve fitting to analyze the relationship between initial PBF and the likelihood of prediabetes, focusing on its nonlinear connection. We conducted various sensitivity and subgroup analyses to strengthen our results. After adjusting for covariates, we found a positive correlation between PBF and the risk of prediabetes (HR = 1.13, 95% CI: 1.12-1.15, p < 0.0001). Moreover, a nonlinear correlation was identified between PBF and the likelihood of prediabetes, with a turning point at 29.5. On the left side of the turning point, the hazard ratio was 1.01 (95% CI: 0.99-1.03, p = 0.4128), while on the right side, it was 1.52 (95% CI: 1.45-1.59, p < 0.0001). Furthermore, sensitivity and subgroup analyses reaffirmed the robustness of these findings. Our research identified a nonlinear relationship between PBF and the development of prediabetes in the Chinese population, marked by a turning point at 29.5. Lowering PBF below 29.5 may reduce the risk of developing prediabetes.

Big data-based reference centiles for body composition in Korean children and adolescents: a cross-sectional study

BACKGROUND

The changes in body composition during puberty not only contribute to the differences in body composition between adult males and females but also have associations with growth problems and metabolic disorders, including obesity. Therefore, understanding the changes in body composition during the pubertal period and analyzing reference values based on race and gender are essential research resources. The objective of this study was to generate reference centiles for body composition on a monthly basis using an extensive dataset of body composition information from Korean children and adolescents.

METHODS

A total of 88,069 measurements from 22,515 children (11,062 boys and 11,453 girls) aged 7-16 years using a bioelectrical impedance analysis were included in the study after performing a Z-score-based data management procedure. Height, weight, body fat mass (BFM), and fat-free mass (FFM) were measured and used to derive body fat percentage (BF%), body mass index (BMI), fat mass index (FMI), and fat-free mass index (FFMI). Sex- and age-specific centiles were estimated using generalized additive models for location, scale, and shape with the Box-Cox Cole and Green distribution (i.e., lambda-mu-sigma method).

RESULTS

The sex- and age-related disparities in body composition were most pronounced when weight was partitioned into BFM and FFM. In boys, the FFM increased markedly during pubertal growth spurts, whereas BFM remained relatively stable. In girls, the BFM increased steadily, whereas the rate of FFM increased slowly. The BMI increased steadily with age in both sexes. However, when BMI was parsed into FMI and FFMI, it became clear that the FFMI increased substantially during pubertal growth in boys, whereas the FMI peaked around age 11 and then declined. Conversely, the FMI increased steadily in girls, albeit with a slowing rate in the increase of the FFMI beginning around age 12.

CONCLUSIONS

This study produced age- and sex-specific reference percentiles for body composition indices in Korean children and adolescents using extensive biometric data.

Bayesian modeling of quantiles of body mass index among under-five children in Ethiopia

BACKGROUND

Body Mass Index (BMI) is a measurement of nutritional status, which is a vital pre-condition for good health. The prevalence of childhood malnutrition and the potential long-term health risks associated with obesity in Ethiopia have recently increased globally. The main objective of this study was to investigate the factors associated with the quantiles of under-five children's BMI in Ethiopia.

METHODS

Data on 5,323 children, aged between 0-59 months from March 21, 2019, to June 28, 2019, were obtained from the Ethiopian Mini Demographic Health Survey (EMDHS, 2019), based on the standards set by the World Health Organization. The study used a Bayesian quantile regression model to investigate the association of factors with the quantiles of under-five children's body mass index. Markov Chain Monte Carlo (MCMC) with Gibbs sampling was used to estimate the country-specific marginal posterior distribution estimates of model parameters, using the Brq R package.

RESULTS

Out of a total of 5323 children included in this study, 5.09% were underweight (less than 12.92 BMI), 10.05% were overweight (BMI: 17.06 - 18.27), and 5.02% were obese (greater than or equal to 18.27 BMI) children's. The result of the Bayesian quantile regression model, including marginal posterior credible intervals (CIs), showed that for the prediction of the 0.05 quantile of BMI, the current age of children [ β = -0.007, 95% CI :(-0.01, -0.004)], the region Afar [ β = - 0.32, 95% CI: (-0.57, -0.08)] and Somalia[ β = -0.72, 95% CI: (-0.96, -0.49)] were negatively associated with body mass index while maternal age [ β = 0.01, 95% CI: (0.005, 0.02)], mothers primary education [ β = 0.19, 95% CI: (0.08, 0.29)], secondary and above [ β = 0.44, 95% CI: (0.29, 0.58)], and family follows protestant [ β = 0.22, 95% CI: (0.07, 0.37)] were positively associated with body mass index. In the prediction of the 0.95 (or 0.85?) quantile of BMI, in the upper quantile, still breastfeeding [ β = -0.25, 95% CI: (-0.41, -0.10)], being female [ β = -0.13, 95% CI: (-0.23, -0.03)] were negatively related while wealth index [ β = 0.436, 95% CI: (0.25, 0.62)] was positively associated with under-five children's BMI.

CONCLUSIONS

In conclusion, the research findings indicate that the percentage of lower and higher BMI for under-five children in Ethiopia is high. Factors such as the current age of children, sex of children, maternal age, religion of the family, region and wealth index were found to have a significant impact on the BMI of under-five children both at lower and upper quantile levels. Thus, these findings highlight the need for administrators and policymakers to devise and implement strategies aimed at enhancing the normal or healthy weight status among under-five children in Ethiopia.

FTO and MC4R polymorphisms, and selected pre-, peri- and postnatal factors as determinants of body mass index and fatness in children: a thorough analysis of the associations

BACKGROUND

Overweight and obesity among children have become significant global health concerns. Previous studies have highlighted the potential role of genetic factors, particularly polymorphisms in the FTO and MC4R genes, as well as environmental factors in the development of childhood obesity. This study aimed to investigate the relationships between genetic, socioeconomic and perinatal factors, adverse childhood events (ACEs), and lifestyle, and their impact on overweight, obesity and body composition parameters in children. Additionally, we explored potential interactions between genetic factors and ACEs.

METHODS

Four hundred fifty-six children aged 6-12 years participated in our study. Information on the socioeconomic status, perinatal factors, ACEs and lifestyle of the children was collected with a questionnaire completed by their parents/guardians. We examined the children's body weight and conducted an electrical bioimpedance analysis. Overweight and obesity were diagnosed based on the International Obesity Task Force and McCarthy criteria. We genotyped two selected polymorphisms in the FTO and MC4R genes using the TaqMan SNP allelic discrimination method.

RESULTS

Higher BMI (Body Mass Index) z scores were related to higher paternal BMI and lower maternal age at the child's birth. Higher FMI (Fat Mass Index) z scores were associated with higher paternal BMI, increased gestational weight, lower maternal education and the presence of the FTO risk allele. Higher FatM (fat mass in kg) z scores were linked to lower maternal education, lower maternal age at the child's birth, higher maternal body weight gain, paternal BMI and the presence of the FTO risk allele. Moreover, interaction effects were observed on BMI z scores between ACE and FTO AA, and on FMI z scores and FatM z scored between ACE and MC4R CC.

CONCLUSIONS

The contribution of environmental factors is more strongly related to changes in body composition than genetic ones. Additionally, the presence of the risk allele combined with unfavourable environmental factors like ACEs leads to visible interaction effects, resulting in increased BMI z scores and FMI z scores in children.

"Profiles of motor competence and its perception accuracy among children: Association with physical fitness and body fat"

The main goals of this study were to identify profiles in school-aged children based on actual Motor Competence (MC) and accuracy of Perceived Motor Competence (PMC) and to examine how children with different profiles differ in terms of Physical Fitness (PF) and Body Fat percentage (BF%). The MC of a total of 287 children (51.6% boys, aged between 6 and 10 years-old) was assessed using the Motor Competence Assessment (MCA) instrument, and the accuracy of the PMC was measured using motor tasks (standing long jump, throwing, kicking, and walking backwards). PF and BF% were assessed using the 20m shuttle run test and TANITA, respectively. Cluster (C) analysis revealed four profiles, two of which were aligned - high MC-accurate PMC (C4) and low-inaccurate (C2), and two that were non-aligned - high-inaccurate (C1) and low-accurate (C3). Children in C4 performed better on PF and had less BF% than children in C3 and C2.

Estimation of Hydration and Density of Fat-Free Mass in Indian Children Using a 4-Compartment Model: Implications for the Estimation of Body Composition Using 2-Compartment Models

BACKGROUND

Accurate methods are needed to measure body fat mass (FM), particularly in South Asian children who are thought to have greater adiposity for a given body size. The accuracy of simple 2-compartment (2C) models of measuring FM depends on the primary measurement of the fat free mass (FFM) and the validity of assumed constants for FFM hydration and density. These have not been measured in this particular ethnic group.

OBJECTIVES

To measure FFM hydration and density in South Indian children using a 4-compartment (4C) model and to compare FM estimates from this 4C-model with 2C-model-based estimates from hydrometry and densitometry, using literature-reported FFM hydration and density in children.

METHODS

This study included 299 children (45% boys), aged 6-16 y from Bengaluru, India. Total body water (TBW), bone mineral content (BMC), and body volume were measured using deuterium dilution, dual-energy X-ray absorptiometry, and air displacement plethysmography, respectively, to calculate the FFM hydration and density, and the FM using 4C and 2C models. The agreement between FM estimates from 2C and 4C models was also evaluated.

RESULTS

Mean FFM hydration and density were 74.2% ± 2.1% and 71.4% ± 2.0% and 1.095 ± 0.008 kg/L and 1.105 ± 0.008 kg/L in boys and girls respectively, which were significantly different from published values. Using the presently estimated constants, the mean hydrometry-based FM (as % body weight) estimates decreased by 3.5% but increased by 5.2% for densitometry-based 2C methods. When 2C-FM (using previously reported FFM hydration and density) were compared with 4C-FM estimates, the mean difference was -1.1 ± 0.9 kg for hydrometry and 1.6 ± 1.1 kg for densitometry.

CONCLUSIONS

Previously published constants of hydration and density of FFM may induce errors of -12% to +17% in FM (kg) when using different 2C models in comparison to the 4C models in Indian children. J Nutr 20xx;x:xx.

Body-Fat-Percentile Curves for Thai Children and Adolescents

This study aimed to generate sex-specific percentile curves for the percentage of body fat (PBF) in Thai children using a bioelectrical impedance analysis (BIA). The secondary objective of this study was to determine the association between body fat and other anthropometric measurements. A cross-sectional study was conducted on 3455 Thai school children aged 6-18 years. The body-fat contents were measured using BIA. Smoothed percentile curves of PBF were derived using a scatter plot with a smooth curve fitted by the Loess method. The correlations between the body fat and the anthropometric measurements were assessed using the Spearman's rank correlation. The 50th and lower body-fat-percentile curves of the boys slowly increased until age 12, after which they slightly decreased until age 15 and then slightly increased until age 18. In the higher boys' percentiles, the body fat sharply increased until age 11 and then decreased until age 18. In the girls, the PBF percentiles increased steadily from 6 to 18 years. The body-mass index was strongly correlated with PBF and fat mass in both sexes. The waist-to-height ratios showed strong correlations with PBF and fat mass in the boys but were moderate in the girls. The use of PBF percentile curves can be an additional metric for the evaluation of obesity in Thai children.

Effect of after-school physical activity on body composition in primary school children: The Slovak "PAD" project

Physical activity is associated with many physical and mental health benefits. This study aimed to investigate the effect of a 24-month after-school physical activity intervention on body composition in normal-weight children. Participating students (6-7 years of age at baseline) were divided by reason of their parental preference to intervention and control groups. Children in the intervention group (n = 20; 10 boys and 10 girls) followed an aerobic training program (two 60-min sessions per week), whereas children in the control group (n = 20; 10 boys and 10 girls) participated in the usual practice. Body composition characteristics were repeatedly measured by means of bioelectrical impedance method. At 2 years, finally, intervention boys had a smaller rise in BMI (mean difference, MD: -0.97 kg/m2 , p < 0.05), BMI z-score (-0.44, p < 0.09), body fat % (BF%) (-6.47%, p < 0.01), and fat mass index (FMI) (-1.32 kg/m2 , p < 0.001) than controls. In girls, however, the intervention program induced no significant differences (p > 0.9) in the measured variables compared to controls at the final follow-up (MD: -0.04 kg/m2 for BMI and -0.01 for BMI z-score). Changes in BF% and FMI in a positive direction occurred at 18 months (MD: -3.38%, p < 0.05 and -0.99 kg/m2 , p < 0.01, respectively), but did not persist over time (p > 0.07). In addition, no significant changes (p > 0.07) in the fat-free mass index were associated with the physical activity intervention in either boys or girls. In conclusion, compared to the controls, a long-term physical activity intervention in boys was associated with a significantly smaller rise in BMI and improvement of body composition by reducing both BF % and FMI. In girls, however, this intervention did not result in any statistically significant changes in body composition variables.

Association between CLOCK gene polymorphisms and ADHD in Mexican teenagers: A comprehensive assessment

This study aimed to evaluate markers of the CLOCK gene rs1801260 and rs4864548 in Mexican adolescents, addressing clinical and biological aspects previously associated with ADHD. 347 Mexican adolescents were assessed for mental disorders, metabolic disruption and related conditions, circadian preference, as well as genotyping for the CLOCK. We found a significant association between ADHD and the AA and AG genotypes of rs1801260. Also, we identified in the ADHD group that the total Triiodothyronine and total Thyroxine values were respectively 10 ng/dl units and 0.58 ug/dl units lower in females than in males. Previously reported common variations of the CLOCK gene have been associated with ADHD like the Rs1801260 polymorphism hereby we could consider it as risk factor, but genetic, biochemical and clinical studies in the Mexican population are entailed.

The relation between prenatal stress, overweight and obesity in children diagnosed according to BMI and percentage fat tissue

BACKGROUND

One of the environmental factors contributing to abnormal weight changes in children may be maternal exposure to adverse environmental factors during pregnancy, which in previous studies led to inconclusive results showing both overweight or obesity and underweight in children. The aim of the study was to assess the influence of prenatal stress on the BMI status and cut-off points for the percentage of fat content.

METHODS

The cohort study included 254 girls and 276 boys. Information on prenatal stress was collected retrospectively with a questionnaire on objective adverse events completed by a parent/guardian of a 6-12-year-old child. We examined the body weight of children and performed an electrical bioimpedance analysis of their body composition. We assessed the BMI status according to the International Obesity Task Force (IOTF) criterion and on the basis of body fat according to McCarthy criterion.

RESULTS

The results of our study show that the prenatal stress was related to increased risk of overweight (OR 2.14, 95% CI: 1.25-3.65) diagnosed on the basis of body fat cut-off points, but not when the BMI was a diagnostic criterion (OR 1.03, 95% CI: 0.58-1.83).

CONCLUSION

The method of diagnosis based on the fat content appears to be an indicator of the occurrence of abnormalities in body composition due to prenatal stress more sensitive than that based on the BMI.

LEVEL OF EVIDENCE

Level III evidence obtained from well-designed cohort or case-control analytic studies.

Does it fit better? Measures of physical activity among adolescents in relation to health indicators

BACKGROUND

Measuring physical activity (PA) is one of the pillars of successful health promotion; however, we struggle to find a tool enabling the identification of risk groups. The current standard approach of assessing moderate-to-vigorous physical activity (MVPA) every day does this inadequately. The aim of this study is to explore whether three other indicators of adolescents' PA can identify such risk groups in a better way.

METHODS

We used data on 888 11- to 15-year-old adolescents (mean age = 13.5, 56% boys) from the Health Behaviour in School-aged Children study conducted in 2018 in Slovakia. Sufficient PA was indicated by the following four indicators: (i) MVPA every day, (ii) MVPA 5-7 days a week, (iii) engagement in organized sports (team or individual) and (iv) combining MVPA 5-7 days a week and engagement in organized sports. We used binary logistic regression analysis to assess the association of various indicators of adolescents' PA with body composition, cardiovascular fitness and self-rated health (SRH), considering age and gender.

RESULTS

Being active based on various indicators was associated with better health outcomes, with the strongest associations for the indicator combining MVPA 5-7 days a week and engagement in organized sports. The only exceptions were the non-significant associations of active adolescents (being active 5-7 days per week or engaged in organized sports) with cardiovascular fitness and SRH.

CONCLUSIONS

Measuring PA using an indicator that combines MVPA 5-7 days a week and engagement in organized sports is the most valid using three health indicators as criteria.

Nutritional Status of Saudi Children with Celiac Disease Following the Ministry of Health’s Gluten-Free Diet Program

This study aimed to evaluate the nutritional status of Saudi children with celiac disease (CD) who followed the Ministry of Health’s gluten-free diet (GFD) program. This study involved 66 children with CD (29 boys and 37 girls) from 5 hospitals belonging to the Ministry of Health. Socioeconomic characteristics were obtained using a structured questionnaire. Anthropometric indices were measured using a body composition analyzer. Dietary intake was assessed using three 24 h dietary records. The biochemical parameters were determined in the hospitals’ laboratories. According to the findings, the majority of respondents had ages ranging from 10 to 13 years, a father and mother with a university education, a high family income, and 5 to 7 family members. Carbohydrates and protein intake for both genders were significantly higher than the DRI’s recommended dietary intake. However, the majority of nutrients consumed were at levels significantly lower than the DRI. Both genders had normal anthropometric indices, with girls having at significantly higher indices than boys. The biochemical parameters of both genders were comparable and within the normal range, except for vitamin D, which was below the normal range. The most important factors influencing nutritional status were age for both genders, and family income and number of family members for boys. In conclusion, data obtained for nutrient intake, anthropometric indicators, body composition, and biochemical analysis indicated that CD children following the Ministry of Health GFD program have a generally good nutritional status.

Body image, body composition and environment: do they affect adolescents' physical activity?

BACKGROUND

Most adolescents are less physically active than recommended, despite the strong effort of various stakeholders to promote physical activity (PA). Body image and body composition may play an important role not only in directly facilitating adolescents' PA but also in enabling environment-related factors. As evidence is lacking, we aimed to assess the associations of adolescents' PA with body-related and environment-related factors, whether this differs by age and gender, and whether these factors interact.

METHODS

We used data on 888 11- to 15-year-old adolescents (mean age = 13.5, 56% boys) from the Health Behaviour in School-aged Children study conducted in 2018 in Slovakia. We used multinomial logistic regression analysis to assess the association of adolescents' PA with body-related factors (body image, body composition) and environment-related factors (PA-promoting environment, less leisure constraints), taking into account age and gender.

RESULTS

Adolescents who perceived their body as not too fat were more likely to be physically very active rather than inactive [odds ratios (ORs)/95% confidence interval (CI) 2.15/1.44-3.22], and similarly those who were not overweight/obese (3.24/2.09-5.01) and perceived less leisure constraints (1.74/1.44-2.11). In older adolescents and in girls, the association of adolescents' PA with body composition and environment-related factors was stronger. The association of adolescents' PA with perceiving less leisure constraints was stronger among adolescents who did not perceive their body as too fat (OR/95% CI 1.98/1.26-3.14), and for those who were not overweight/obese (OR/95% CI 1.62/1.01-2.57).

CONCLUSION

Adolescents' PA is associated with both body-related and environment-related factors. These associations are stronger in girls and older adolescents, if co-occurring.

Body Composition Assessment in Mexican Children and Adolescents. Part 1: Comparisons between Skinfold-Thickness, Dual X-ray Absorptiometry, Air-Displacement Plethysmography, Deuterium Oxide Dilution, and Magnetic Resonance Imaging with the 4-C Model

The evaluation of body composition (BC) is relevant in the evaluation of children’s health-disease states. Different methods and devices are used to estimate BC. The availability of methods and the clinical condition of the patient usually defines the ideal approach to be used. In this cross-sectional study, we evaluate the accuracy of different methods to estimate BC in Mexican children and adolescents, using the 4-C model as the reference. In a sample of 288 Mexican children and adolescents, 4-C body composition assessment, skinfold-thickness (SF), dual-energy X-ray absorptiometry (DXA), air displacement plethysmography (ADP), and deuterium dilution (D₂O) were performed, along with MRI in a subsample (52 participants). The analysis of validity was performed by correlation analysis, linear regression, and the Bland–Altman method. All methods analyzed showed strong correlations for FM with 4-C values and between each other; however, DXA and MRI overestimated FM, whereas skinfolds and ADP under-estimated FM. Conclusion: The clinical assessment of BC by means of SF, ADP, DXA, MRI and D₂O correlated well with the 4-C model and between them, providing evidence of their clinical validity and utility. The results from different methods are not interchangeable. Preference between methods may depend on their availability and the specific clinical setting.

Validity and accuracy of body fat prediction equations using anthropometric measurements in children 7 – 10 years old

abstract Children with a deficit of growth because of perinatal malnutrition present specificities in the percentage of body fat (%BF) that could not be detected by previous fat mass-based equations. This study developed and validated predictive equations of the %BF derived from anthropometric variables in children aged 7 to 10 living in Northeast Brazil, using dual-energy x-ray absorptiometry (DXA) as a reference. Body composition data from 58 children were utilized. DXA was used as a reference. A stepwise (forward) multiple regression statistical model was used to develop the new equations. The Bland-Altman analysis (CI: 95%), paired Student's t-test, and the intraclass correlation coefficient (ICC) was used to validate and compare the developed equations. Two new equations were developed for either gender: boys: %BF: 13.642 + (1.527*BMI) + (-0.345*Height) + (0.875*Triceps) + (0.290* Waist Circumference) and girls: %BF: -13.445 + (2.061*Tight). The Bland-Altman analysis showed good agreement, with limits ranging from -1.33 to 1.24% for boys and -3.35 to 4.08% for girls. The paired Student’s t-test showed no difference between %BF-DXA and the two new equations (p> 0.05), and the ICC was 0.948 and 0.915, respectively. DXA-based anthropometric equations provide an accurate and noninvasive method to measure changes in the %BF in children.

Are adolescents' physical activity and body-related factors associated with medically attended injuries?

BACKGROUND

Injuries are the major cause of disability and death during adolescence, representing a significant public health burden among youth. Body-related factors such as body composition and cardiovascular fitness (CVF) may affect adolescents' vulnerability to injuries. As evidence is lacking, we aimed to explore the associations of medically attended injuries with adolescents' physical activity (PA) and body-related factors, and whether these associations are modified by age, gender and family affluence.

METHODS

We used data on 888 11- to 15-year-old adolescents (mean age = 13.5, 56% boys) from the Health Behaviour in School-aged Children study conducted in 2018 in Slovakia. We used binary logistic regression analysis to assess the association of medically attended injuries with adolescents' PA and body-related factors (body composition, CVF), considering age, gender and family affluence.

RESULTS

Adolescents were more likely to report medically attended injuries if they were physically very active (odds ratio/confidence interval OR/CI:2.76/1.83-4.15) or active (OR/CI:1.91/1.27-2.87) rather than inactive. Body-related factors were not associated with medically attended injuries among adolescents. Moreover, age, gender and family affluence did not modify the association of medically attended injuries with adolescents' PA and body-related factors. The only exception was the modifying effect of gender: the association of medically attended injuries with being very active was stronger in boys (OR/CI: 3.04/1.32-6.99).

CONCLUSION

Very physically active adolescent boys are the most vulnerable group of adolescents in terms of injuries. PA promotion programmes should further consider gender-specific strategies aimed at preventing injuries.

Modification of the association by sex between the prenatal exposure to di(2-ethylhexyl) phthalate and fat percentage in a cohort of Mexicans schoolchildren

INTRODUCTION

Children's overweight and obesity are global public health problems, children with obesity have grater obesity risk as adults, thus leading to develop cardiometabolic diseases. Previous studies have found positive and significant associations between the exposure to phthalates and body mass index and body composition.

OBJECTIVE

To evaluate the modification of the association by sex between DEHP exposure during pregnancy and the percentage of body fat in a cohort of Mexican schoolchildren.

MATERIAL AND METHODS

The sample was comprised by children which had previously participated in a POSGRAD longitudinal study. A subsample of 190 mother-children binomials were included. Mothers' DEHP concentrations and its metabolites had been measured in the second trimester of pregnancy: Mono-2-ethylhexyl phthalate (MEHP), Mono-2-ethyl-5-carboxypentyl phthalate (MECPP), Mono-2-ethyl-5-hidroxyhexyl phthalate (MEHHP), and Mono-2-ethyl-5-oxohexyl phthalate (MEOHP). The children's adipose mass was measured at age 8, 9, and 10. Longitudinal data were analyzed using the mixed effects linear regression model, with intercept and random slope, adjusted by important confounders and stratified by sex.

RESULTS

We found a differentiated effect by sex, the exposure to DEHP during pregnancy significantly increases the adipose mass in boys. The average increase was 0.058% (p = 0.02) for every 1% variation in MECPP; 0.047% (p = 0.04) in MEHHP; 0.051% (p = 0.03) in MEOHP, and 0.066% (p = 0.007) in MECPP.

CONCLUSIONS

The results suggest an effect differentiated by sex; with boys being the main ones affected by the prenatal exposure to phthalates. However, we cannot rule out effects in girls.

Dyslipidemia, Obesity, and Ethnicity in Mexican Children

The aim of this study was to assess lipid disorders in children from five ethnic groups, both urban and indigenous, from northern and central Mexico. We measured the lipid profile to determine the ability of the body mass index (BMI) to discriminate an abnormally high lipid level using receiving operating characteristics (ROC). We analyzed the association and interaction of obesity and ethnicity with lipid disorders using generalized linear models in 977 children. The highest prevalence of lipid disorders (high TG, high TC, high LDL, high APOB, and dyslipidemia) was found in central Mexico-Mexico City and urban northern Mexico. The BMI performed better at predicting low HDL in Seris, a northern indigenous group (0.95, CI: 0.69-0.85), and Mexico City (0.75, CI: 0.69-0.82), and high LDL in Puebla (central Mexico, 0.80, CI: 0.69-0.85). Obesity significantly (p < 0.05) increases lipid disorders by around two times (OR~2) for almost all lipid markers. Obesity and ethnic interaction increase the lipid disorders by more than five times for different lipid markers and ethnic groups (high total cholesterol OR = 5.31; low HDL OR = 5.11, and dyslipidemia OR = 5.68). Lipid disorders are not restricted to children with high BMIs, but obesity exacerbates these. The emerging lipid disorder risk depends on the ethnic group.

Relationship between BMI with percentage body fat and obesity in Singaporean adults - The Yishun Study

BACKGROUND

The main aim of this study was to the determine relationship between Body Mass Index (BMI) and percentage body fat (BF%) in Singaporean adults, derive a prediction model to estimate BF%, and to report population BF%. The secondary aim was to determine the prevalence of overweight and obesity based on BF% threshold and the new risk categories for obesity in Singaporean population.

METHODS

This was a population-based study of 542 community-dwelling Singaporeans (21-90 years old, 43.1% men). Anthropometry and body composition were assessed. Relationship between BMI and BF% were analysed using multiple regression models. Prevalence of overweight and obesity were estimated using WHO and Singapore Ministry of Health (MOH) Clinical Practice Guidelines for BMI classification, and BF% cut-off points of 25 and 35% for men and women respectively.

RESULTS

We derived a prediction model to estimate BF% based on BMI, age and sex. The current cohort of Singaporeans when compared to Caucasians in the US and Europe as well as a Singapore cohort from 20 years age have higher BF% when matched for BMI, age, and sex. The overall population-adjusted prevalence of obesity according to WHO International classification (BMI ≥30 kg/m2) was 12.9% (14.9% men; 11.0% women); and 26.6% (30.7% men; 22.8% women) according to the MOH classification (BMI ≥27.5 kg/m2). However, using the BF% cut-off (> 25% for men and > 35% for women) resulted in very high prevalence of obesity of 82.0% (80.2% men; 83.8% women).

CONCLUSION

There is a large discrepancy between BF% and BMI measured obesity in Singaporean adults. The results confirmed that Singaporean adults have higher BF% at lower BMI compared to US and Europe white counterparts; and that BF% in our population has increased over two decades.

eHealth Intervention to Improve Health Habits in the Adolescent Population: Mixed Methods Study

Background

Technology has provided a new way of life for the adolescent population. Indeed, strategies aimed at improving health-related behaviors through digital platforms can offer promising results. However, since it has been shown that peers are capable of modifying behaviors related to food and physical exercise, it is important to study whether digital interventions based on peer influence are capable of improving the weight status of adolescents.

Objective

The purpose of this study was to assess the effectiveness of an eHealth app in an adolescent population in terms of improvements in their age- and sex-adjusted BMI percentiles. Other goals of the study were to examine the social relationships of adolescents pre- and postintervention, and to identify the group leaders and study their profiles, eating and physical activity habits, and use of the web app.

Methods

The BMI percentiles were calculated in accordance with the reference guidelines of the World Health Organization. Participants’ diets and levels of physical activity were assessed using the Mediterranean Diet Quality Index (KIDMED) questionnaire and the Physical Activity Questionnaire for Adolescents (PAQ-A), respectively. The variables related to social networks were analyzed using the social network analysis (SNA) methodology. In this respect, peer relationships that were considered reciprocal friendships were used to compute the “degree” measure, which was used as an indicative parameter of centrality.

Results

The sample population comprised 210 individuals in the intervention group (IG) and 91 individuals in the control group (CG). A participation rate of 60.1% (301/501) was obtained. After checking for homogeneity between the IG and the CG, it was found that adolescents in the IG at BMI percentiles both below and above the 50th percentile (P50) modified their BMI to approach this reference value (with a significance of P<.001 among individuals with an initial BMI below the P50 and P=.04 for those with an initial BMI above the P50). The diet was also improved in the IG compared with the CG (P<.001). After verifying that the social network had increased postintervention, it was seen that the group leaders (according to the degree SNA measure) were also leaders in physical activity performed (P=.002) and use of the app.

Conclusions

The eHealth app was able to modify behaviors related to P50 compliance and exert a positive influence in relation to diet and physical exercise. Digital interventions in the adolescent population, based on the improvement in behaviors related to healthy habits and optimizing the social network, can offer promising results that help in the fight against obesity.

Beyond Body Mass Index - Body Composition Assessment by Bioimpedance in Routine Endocrine Practice

OBJECTIVE

To explore the body composition of pediatric patients referred for endocrine evaluation.

METHODS

This real-life observational study conducted between January 2018 and January 2020 included 10 001 clinic visits of 3500 children and adolescents; first visits of 5 to 18-year-old patients were included. Anthropometric data, blood pressure levels, pubertal status, and bioelectrical impedance analysis (BIA, Tanita MC-780 MA) were extracted from medical files. Excluded from the analysis were patients participating in other studies.

RESULTS

A total of 1001 patients (48% boys, mean age 11.3 ± 3.4 years, 33.5% prepubertal) were included. Mean anthropometric z-scores were normal and similar for boys and girls. Sex differences in body composition were as follows: boys had lower fat percentage, lower truncal fat percentage, higher appendicular skeletal muscle mass, and a higher muscle-to-fat ratio (MFR) than girls (P < .001 for all). MFR correlated with body mass index-standard deviation scores (BMI-SDS) in overweight/obese patients (r = -0.558, P < .001), although not in underweight patients. Systolic blood pressure (SBP) correlated with BMI-SDS in overweight/obese patients (r = 0.262, P < .001), although not in underweight patients. Diastolic blood pressure (DBP) did not correlate with BMI-SDS in either group of extreme weight status. MFR correlated with SBP and DBP in overweight/obese patients (r = -0.230, P < .001 and r = -0.141, P = .018, respectively) as well as in underweight patients (r = 0.331, P < .001 and r = 0.264, P = .005, respectively).

CONCLUSIONS

Our findings support BIA for a more refined characterization of patients referred for endocrine evaluation than BMI-SDS. MFR may be a better surrogate marker of blood pressure levels than BMI-SDS in both underweight and overweight/obese pediatric patients.

Comparative assessment of anthropometric and bioimpedence methods for determining adiposity

Background

Obesity is a risk factor for different chronic conditions. Over the years, obesity has become a pandemic and it is therefore important that effective diagnostic tools are developed. Obesity is a measure of adiposity and it has become increasingly evident that anthropometric measures such as body mass index (BMI) used to estimate adiposity are inadequate. This study therefore examined the ability of different anthropometric measurements to diagnose obesity within a cross-section of Ghanaian women.

Methods

We obtained anthropometric measurements and used that to generate derived measures of adiposity such as body adiposity index (BAI) and conicity index. Furthermore we also measured adiposity using a bioimpedance analyser. Associations between these measurements and percentage body fat (%BF) were drawn in order to determine the suitability of the various measures to predict obesity. The prevalence of obesity was determined using both %BF and BMI.

Results

BMI, Waist and hip circumference and visceral fat (VF) were positively correlated with % BF whereas skeletal muscle mass was negatively correlated. Prevalence of obesity was 16% and 31.6% using BMI and %BF respectively. Receiver operating characteristic (ROC) analysis showed that these differences in prevalence was due to BMI based misclassification of persons who have obesity as overweight. Similar, shortfalls were observed for the other anthropometric measurements using ROC.

Conclusions

No single measure investigated could adequately predict obesity as an accumulation of fat using current established cut-off points within our study population. Large scale epidemiological studies are therefore needed to define appropriate population based cut-off points if anthropometric measurements are to be employed in diagnosing obesity within a particular population.

Comparisons of conventional and novel anthropometric obesity indices to predict metabolic syndrome among vegetarians in Malaysia

Our study aimed to compare the ability of anthropometric obesity indices to predict MetS and to determine the sex-specific optimal cut-off values for MetS among Malaysian vegetarians. Body weight, height, waist circumference (WC), blood pressure (BP), fasting venous blood sample were collected from 273 vegetarians in Selangor and Kuala Lumpur, Malaysia. The abilities of body mass index (BMI), body fat percentage (BF%), waist to height ratio (WHtR), lipid accumulation product (LAP), visceral adiposity index (VAI), a body shape index (ABSI), and body roundness index (BRI) to identify MetS were tested using receiver operating characteristic (ROC) curve analyses. MetS was defined according to the Joint Interim Statement 2009. The ROC curve analyses show that BMI, BF%, WHtR, LAP and VAI were able to discriminate MetS in both sexes. LAP was a better predictor to predict MetS, followed by WHtR for male and female vegetarians. The suggested WHtR’s optimal cut-offs and LAP’s optimal cut-offs for MetS for male and female vegetarians were 0.541, 0.532, 41.435 and 21.743, respectively. In conclusion, LAP was a better predictor to predict MetS than other anthropometric obesity indices. However, WHtR could be an alternative obesity index in large epidemiology survey due to its convenient and cost-effective characteristics.

Body Fat Mediates Association between Active Living and Health among Adolescents

The aim of this study was to explore the association of moderate-to-vigorous physical activity and organized leisure-time activities with self-rated health among adolescents and whether these associations are mediated by body fat percentage. We used data on 888 adolescents (mean age 12.97, SD 1.20, 56.0% boys) from the Health Behaviour in School-aged Children (HBSC) study conducted in 2018 in Slovakia. We used logistic regression models to examine associations within self-reported data (moderate-to-vigorous physical activity and organized leisure-time activities with self-rated health) and their mediation by anthropometric data (body fat percentage). The adolescents who were sufficiently physically active and with normal body fat were more likely to report good or excellent health (odds ratios-OR/95% confidence intervals-95% CI: 3.52/1.50-8.27 and 3.66/2.37-5.68). Similarly, the adolescents who were engaged in individual/team sport and with normal body fat were more likely to report good or excellent health (OR/95% CI: 2.04/1.31-3.17 and 3.66/2.37-5.68). Adjustment for body fat percentage reduced the association between moderate-to-vigorous physical activity and self-rated health by 27.6% and the association between leisure-time activities and self-rated health by 30.7%. Active living and normal body fat might contribute to better health in adolescence. Programs and efforts to increase physical activity and leisure-time activities in childhood and adolescence need to identify which aspects of these activities are important, effective, and crucial for the population of adolescents.

Antioxidant Enzymes Haplotypes and Polymorphisms Associated with Obesity in Mexican Children

Obesity is a major health problem worldwide and constitutes a sanitary emergency in Mexico, especially childhood obesity. Several studies have proved the relationship between obesity and oxidative stress and the influence of genetic predisposition. This work was aimed to analyze the association of antioxidant enzyme polymorphisms with overweight and obesity in Mexican children and adolescents. A case-control study was performed in 585 children and adolescents aged 3 to 17 years, using two criteria to classify obesity: body mass index (BMI) and body fat percentage (BFP). Anthropometric and biochemical measurements were carried out, and malondialdehyde serum levels were determined. Genotyping was done with the Axiom Genome-Wide LAT microarray, including 68 single nucleotide polymorphisms (SNPs) of the glutathione peroxidase (GPX) and paraoxonase (PON) families. We found six haplotypes associated with obesity—two of them (one in GPX3 and the other in GPX5 and GPX6) in a protective direction when obesity was classified by BMI. The other four haplotypes were associated with obesity when classification was based on BFP—one of them in GPX3 in a protective direction and the others in PON genes conferring obesity risk. In addition, two SNPs, GPX3 rs922429 and GPX4 rs2074451 showed protection against obesity classified by BFP. This study showed genetic susceptibility to oxidative stress in relation to obesity in Mexican children and opens up the possibility that some genetic loci related to obesity are not identified when weight classification is based on BMI.

Is BMI a Valid Indicator of Overweight and Obesity for Adolescents?

Background: Overweight and obesity are mostly monitored via the Body Mass Index (BMI), based on self-reported or measured height and weight. Previous studies have shown that BMI as a measure of obesity can introduce important misclassification problems. The aim of this study was to assess the validity of overweight and obesity classification based on self-reported and on measured height and weight versus the proportion of body fat as the criterion. Methods: We used data on 782 adolescents (mean age = 13.5, 55.8% boys) from the Health Behaviour in School-Aged Children (HBSC) study conducted in 2018 in Slovakia. We obtained self-reported (height and weight) and objective measures (height, weight) and the proportion of fat (as the criterion measure) measured via bioimpedance body composition analysis (BIA) with an InBody 230 from the adolescents. Results: Both measured and self-reported BMI indicated overweight and obesity with relatively low sensitivity (66-82%), but high specificity (90-92%). The superior accuracy of measured BMI in comparison to self-reported BMI was confirmed by the area under the curve (AUC) based on the receiver operating characteristics (ROC) curves (AUC measured/self-reported: 0.94/0.89; p < 0.001). The misclassification of overweight and obesity was significantly higher when using self-reported BMI than when using measured BMI. Conclusion: Both self-reported and measured BMI as indicators of overweight and obesity underestimate the prevalence of adolescents with overweight and obesity.

Obesogenic Lifestyle and Its Influence on Adiposity in Children and Adolescents, Evidence from Mexico

Overweight (OW) and obesity (OB) during childhood/adolescence are major public health problems in Mexico. Several obesogenic lifestyle (OL) risk factors have been identified, but the burden and consequences of them in Mexican children/adolescents remain unclear. The objective of this study was to estimate the prevalence of OL components and describe their relationships with adiposity, and OW/OB. A population-based cross-sectional study of Mexican children/adolescents with nutritional assessment, data collection on daily habits and adiposity as fat-mass index (FMI) by dual-energy X-ray absorptiometry was performed. Individual OL-components: “inactivity,” “excessive screen time,” “insufficient sleep,” “unhealthy-diet”, were defined according to non-adherence to previously published healthy recommendations. Results: 1449 subjects were assessed between March 2015 to April 2018. Sixteen percent of subjects had all four OL-components, 40% had three, 35% had two, 9% had one, and 0.5% had none. A cumulative OL score showed a significant dose–response effect with FMI. The combination of inactivity, excessive screen time, and insufficient sleep showed the highest risk association to OW/OB and higher values of FMI. Conclusions: The prevalence of OL-components was extremely high and associated with increased adiposity and OW/OB. Several interventions are needed to revert this major public health threat.

Fat Mass Index (FMI) as a Trustworthy Overweight and Obesity Marker in Mexican Pediatric Population

Predictive formulas to estimate body composition in children have been explored for some time, to this date, the most accurate obesity diagnostic tool is to determine fat mass. The aim of this study is to establish cutoff points that allow for a precise interpretation of nutritional status using the Fat Mass Index (FMI) in a Mexican pediatric population. A literature review using PubMed and Cochrane databases was made, searching for research articles on childhood obesity that compared BMI, FM percentage, and FMI, as well as those proposing diagnostic cutoff points. Mathematic formulas and linear regressions were then used to make a proposal on accurate cutoff points for this population. Our findings show that FM percentage is less precise than BMI and FMI in diagnosing obesity, and FMI seems to be a more complete tool for assessment as it differentiates fat and muscle mass of the total body weight. Both BMI and FMI should be considered when clinical evaluations regarding weight, with BMI complementing FMI by establishing fat-free mass. Our proposed cutoff points need to be validated in this population.

Genome-Wide Association Study of Body Mass Index and Body Fat in Mexican-Mestizo Children

BACKGROUND

Childhood obesity is a major health problem in Mexico. Obesity prevalence estimated by body mass index (BMI) is almost half than that estimated by percent body fat (%BF) in the Childhood Obesity pediatric cohort (COIPIS).

OBJECTIVE

We performed a genome-wide association study (GWAS) of BMI and %BF in 828 children from the COIPIS to identify markers of predisposition to high values for both phenotypes used for obesity classification.

METHODS

For the GWAS we used the LAT Axiom 1, Affymetrix and 2.5 million single loci from the 1000 Genomes Phase 3 imputation panel. We used a linear model, adjusted by age, sex, and Amerindian ancestry assuming an additive inheritance model.

RESULTS

Genome-wide significance (p ≤ 5.0 × 10-8) and 80% of statistical power was reached for associations of two loci in two genes (CERS3 and CYP2E1) to BMI. Also, 11 loci in six genes (ANKS1B, ARNTL2, KCNS3, LMNB1, SRGAP3, TRPC7) reached genome-wide significance for associations to %BF, though not 80% of statistical power.

DISCUSSION

None of the SNPs were previously reported as being associated to BMI or %BF. In addition, different loci were found for BMI and %BF. These results highlight the importance of gaining deeper understanding of genetic markers of predisposition to high values for the phenotypes used for obesity diagnosis.

Polymorphisms in Adipokines in Mexican Children with Obesity

The high prevalence of childhood obesity in Mexico is alarming in the health-science field. We propose to investigate the contribution of adipokines and cytokines polymorphisms and common BMI/obesity-associated loci, revealed in genome-wide association studies in Caucasian adult cohorts, with childhood obesity. This study included 773 Mexican-Mestizo children (5-15 years old) in a case-control study. The polymorphisms included were ADIPOQ (rs6444174), TNF-α (rs1800750), IL-1β (rs1143643), IL-6 (rs1524107; rs2069845), NEGR1 (rs34305371), SEC16B-RASAL2 (rs10913469), TMEM18 (rs6548238; rs7561317), GNPDA2 (rs16857402), LEP (rs2167270), MTCH2 (rs10838738), LGR4-LIN7C-BDNF (rs925946), BCDIN3D-FAIM2 (rs7138803), FTO (rs62033400), MC4R (rs11872992), MC4R (rs17782313), and KCTD15 (rs29942). No significant contribution was found with adipokines and cytokines polymorphisms in this study. Only both TMEM18 (rs6548238; rs7561317) polymorphisms were found associated with obesity (OR=0.5, P=0.008) and were in linkage disequilibrium (r2=0.87). The linear regression showed that the rs7561317 polymorphism of TMEM18 is negatively associated with obesity. This report highlights the influence of TMEM18 in Mexican-Mestizo children obesity, while adipokine and cytokine polymorphisms were not associated with it.