Relationship of body mass index to percent body fat and waist circumference among schoolchildren in Japan--the influence of gender and obesity: a population-based cross-sectional study

Evaluation of Chinese populational exposure to environmental electromagnetic field based on stochastic dosimetry and parametric human modelling

This study aimed to estimate the distribution of the whole-body averaged specific absorption rate (WBSAR) using several measurable physique parameters for Chinese adult population exposed to environmental electromagnetic fields (EMFs) of current wireless communication frequencies, and to discuss the effects of these physique parameters in the frequency-dependent dosimetric results. The physique distribution of Chinese adults was obtained from the National Physical Fitness and Health Database comprising 81,490 adult samples. The number of physique parameters used to construct the surrogate model was reduced to three via mutual information analysis. A stochastic method with 40 deterministic simulations was used to generate frequency-dependent and gender-specific surrogate models for WBSAR via polynomial chaos expansion. In the simulations, we constructed anatomically correct models conforming to the targeted physique parameters via deformable human modelling technique, which was based on deep learning from the image database including 767 Chinese adults. Thereafter, we analysed the sensitivity of the physique parameters to WBSAR by covariance-based Sobol decomposition. The results indicated that the generated models were consistent with the targeted physique parameters. The estimated dosimetric results were validated using finite-difference time-domain simulations (the error was < 6% across all the investigated frequencies for WBSAR). The novelty of the study included that it demonstrated the feasibility of estimating the individual WBSAR using a limited number of physique parameters with the aid of surrogate modelling. In addition, the population-based distribution of the WBSAR in Chinese adults was firstly presented in the manuscript. The results also indicated that the different combinations of physique parameter, dependent on genders and frequencies, significantly influenced the WBSAR, although the general conservativeness of the guidelines of the International Commission on Non-Ionizing Radiation and Protection can be confirmed in the surveyed population.

The association between obesity and problematic smartphone use among school-age children and adolescents: a cross-sectional study in Shanghai

BACKGROUND

The study aimed to investigate the association between content-based problematic smartphone use and obesity in school-age children and adolescents, including variations in the association by educational stage and sex.

METHODS

Two-stage non-probability sampling was used to recruit 8419 participants from nineteen primary schools, five middle schools, and thirteen high schools in Shanghai in December 2017. Obesity was identified by body mass index (BMI), which was obtained from the school physical examination record, while problematic smartphone use was measured by the Revised Problematic Smartphone Use Classification Scale as the independent variable.

RESULTS

The rates of obesity varied with educational stages, while problematic smartphone use increased with educational stages. Male students reported higher obesity rates (37.1%vs19.4%, P < 0.001) and greater problematic smartphone use scores (25.65 ± 10.37 vs 22.88 ± 8.94, P < 0.001) than female students. Problematic smartphone use for entertainment (smartphone users addicted to entertainment games, music, videos, novels and other applications) was positively associated to obesity status for primary school [odds ratio (OR), 1.030; 95% confidence interval (95% CI), 1.005-1.057] and high school students (OR, 1.031; 95% CI, 1.004-1.059). For female students, problematic smartphone use for entertainment was positively associated with obesity status (OR, 1.046; 95% CI, 1.018-1.075).

CONCLUSIONS

Problematic smartphone use may be associated with obesity in children and adolescents. The association differed based on the educational stage and sex, and the difference possessed dimensional specificity.

Association between Body Fat and Elevated Blood Pressure among Children and Adolescents Aged 7-17 Years: Using Dual-Energy X-ray Absorptiometry (DEXA) and Bioelectrical Impedance Analysis (BIA) from a Cross-Sectional Study in China

To investigate the associations between body fat percentage (BF%) with childhood blood pressure (BP) levels and elevated BP (EBP) risks, and further examine the validity of bioelectrical impedance analysis (BIA), we conducted a cross-sectional study of 1426 children and adolescents aged 7–17 years in Beijing, 2020. EBP, including elevated systolic BP (ESBP) and elevated diastolic BP (EDBP), was defined based on the age- and sex-specific 90th BP reference values of children and adolescents in China. BF% was measured by dual-energy X-ray absorptiometry (DEXA) and BIA devices, and was divided into four quartiles. Log-binomial models were applied to calculate odds ratios (ORs) and 95% confidence intervals (95%CI). Girls tended to have higher BF% levels than boys (p < 0.05). There was 41.0% of girls who developed EBP. High BF% was associated with increased BP levels with ORs of 0.364 (95%CI = 0.283–0.444) for SBP, 0.112 (95%CI = 0.059–0.165) for DBP, and 1.043 (95%CI = 1.027–1.059) for EBP, while the effects were more pronounced in girls and older-aged children. BIA devices agreed well with BF% assessment obtained by DEXA. High BF% might have negative effects on childhood BP. Convenient measurements of body fat might help to assess childhood obesity and potential risks of hypertension.

Comparison of Body Mass Index and fat percentage criteria classification of 7-13 year-old rural boys in South Africa

Background

The aim of this paper was to investigate whether BMI and fat percentage classification criteria, would classify a sample of 7–13 year old boys from a rural background in similar nutritional categories.

Methods

A cross-sectional study with a stratified random sampling included 601 rural boys (7–13 years old). Fat percentage criteria classification and BMI were calculated and compared. Maturity status, and age at peak height velocity (PHV) were indirectly determined. Statistical techniques included descriptive statistics, Pearson product correlation coefficients, the Kappa agreement test and the McNemar’s test. The level of statistical significance was set at p ≤ 0.05.

Results

All age groups presented with statistically significant high correlations between BMI and fat percentage, and low to medium correlations between fat percentage and maturity age (MA). Measurement of agreement between BMI and fat percentage classifications showed poor to fair agreements for all age groups, with the exception of the eight-year old group which presented a moderate agreement.

Conclusions

Classifications based on BMI and fat percentage, results in different classifications for the same population. Until further research has been done to determine the best classification for nutritional status, it is recommended that both classification methods be used for more accurate classification of nutritional status.

Different spexin level in obese vs normal weight children and its relationship with obesity related risk factors

BACKGROUND AND AIMS

Spexin (SPX) is a novel peptide recently discovered as an important regulatory adipokine in obesity and related metabolic diseases. The aim of the current study was to determine the potential role of Circulating levels of SPX in obese children and explore its relationships with obesity-related risk factors, and its potential role in preventing obesity.

METHODS AND RESULTS

Forty-five obese children and 45 normal-weight children of similar age and sex, with mean age of 13.73 (2.68) were recruited in this Study. Weight and height, blood pressure, resting metabolic rate (RMR), physical activity level, stress, anxiety and depression, appetite status, daily energy intake, pubertal stage, serum Spexin, Interleukin-10 (IL-10), IL-1β, high-sensitivity C-reactive protein (hs-CRP), fasting glucose, insulin and lipid profile, were measure during standard techniques. Median (IQR) of Spexin levels were significantly lower in obese vs. normal-weight children [120.70 (77.7) pg/mL vs.145 (186.7)pg/mL; P = 0.03]. Based on the tertiles of the serum Spexin levels, a protective independent effect was observed for the highest tertile of serum Spexin concentrations. Crude OR (CI): 0.33 (0.11-0.95), P-trend = 0.04. Model 1 OR (CI): 0.20 (0.05-0.73), P- trend = 0.01, Model 2 OR (CI): 0.22 (0.05-0.86), P -trend = 0.03. Serum Spexin concentration was significantly associated with IL-10, IL-1β, fasting Insulin and HOMA-IR (P < 0.05).

CONCLUSION

The lower circulating levels of Spexin in obese children compared to their normal-weight peers, the protective independent effect found for the highest tertile of serum Spexin, and its association with glucose metabolism and immune function observed in our study, suggest a potential role for this novel peptide in childhood obesity and its related metabolic disorders.

Influence of eating quickly and eating until full on anthropometric gains in girls: A population-based, longitudinal study

BACKGROUND

In examining childhood overweight/obesity, there is a need to consider both eating quickly and eating until full. This longitudinal study investigated the influence of eating quickly and/or eating until full on anthropometric variables and becoming overweight/obese among Japanese schoolgirls.

METHODS

Study participants were fourth-grade schoolgirls (aged 9 or 10 years) in Ina Town, Japan. Physical examinations and a questionnaire survey were performed at baseline (fourth grade) and after 3 years (seventh grade). Height, weight, and waist circumference were measured in the physical examinations, while the data on eating quickly and eating until full were collected in the questionnaire survey. Analysis of variance and analysis of covariance were used to compare the differences in each anthropometric variable between fourth and seventh grade among groups.

RESULTS

Data on 425 non-overweight/obese schoolgirls in fourth grade were analyzed. Gains in anthropometric variables (body mass index, waist circumference, and waist-to-height ratio) from fourth to seventh grade were significantly larger in the "eating quickly and eating until full" group than in the "not eating quickly and not eating until full" group. In contrast, there were no significant differences in the gains between the "eating quickly or eating until full" group and the "not eating quickly and not eating until full" group. The proportion of overweight/obese girls in seventh grade was higher in the "eating quickly and eating until full" group than in the other groups.

CONCLUSIONS

Eating quickly and eating until full had a substantial impact on excess gains in anthropometric variables among schoolgirls, suggesting that modifying these eating behaviors may help prevent non-overweight/obese girls from the excess gains. Accordingly, school health programs need to focus on not eating quickly and/or not eating until full to prevent overweight/obesity; it is necessary to emphasize "the risk of overweight/obesity associated with these eating behaviors" in schools.

Community Policies and Programs to Prevent Obesity and Child Adiposity

INTRODUCTION

Evidence regarding impact of community policies and programs (CPPs) to prevent child obesity is limited, and which combinations of strategies and components are most important is not understood. The Healthy Communities Study was an observational study to assess relationships of characteristics and intensity of CPPs with adiposity, diet, and physical activity in children, taking advantage of variation across the U.S. in community actions to prevent child obesity. The study examined the association of CPPs to prevent child obesity with measured BMI and waist circumference, hypothesizing that communities with more-comprehensive CPPs would have children with lower adiposity.

METHODS

The study included 130 communities selected by probability-based sampling or because of known CPPs targeting child obesity. Data were collected at home visits on 5,138 children during 2013-2015. CPPs were scored for multiple attributes to create a CPP intensity score. A CPP target behavior score reflected the number of distinct target behaviors addressed. Scores were standardized with the smallest observed score across communities being 0 and the largest 1. Multilevel regression analysis in 2016 adjusted for community, household, and individual characteristics.

RESULTS

Higher CPP target behavior score was significantly associated with lower BMI and waist circumference in a dose-response relationship, with magnitude for the past 3 years of CPPs of 0.843 (p=0.013) for BMI and 1.783 cm (p=0.020) for waist circumference.

CONCLUSIONS

This study provides plausible evidence that comprehensive CPPs targeting a greater number of distinct physical activity and nutrition behaviors were associated with lower child adiposity.

Lifestyle factors associated with underweight among Japanese adolescents: a cross-sectional study

Background

Because underweight in adolescents poses several health problems, it is important to prevent it in adolescence. For the prevention of underweight, it is necessary to investigate risk factors, especially lifestyles, because these can be modified. However, a limited number of studies exist regarding lifestyle factors associated with underweight among adolescents. The present study aimed to investigate the relationship between lifestyle factors and underweight among Japanese adolescents.

Methods

Study subjects comprised 2641 seventh-grade school children (age 12 or 13 years) from the town of Ina, Saitama Prefecture, Japan. Measurements of height and weight were made for each subject, while information regarding lifestyles of each subject was obtained using a self-administered questionnaire. Underweight was determined by the age- and sex-specific body mass index cut-off points. A logistic regression model was used to estimate the odds ratio (OR) and 95% confidence interval (95% CI) for underweight.

Results

Adolescents who ate slowly were more likely to be underweight than those who did not eat slowly; the OR (95% CI) was 2.78 (1.77–4.39) in boys and 2.69 (1.81–3.98) in girls. Girls who did not exercise were more likely than those who exercised to be underweight (OR: 1.64, 95% CI: 1.07–2.51).

Conclusions

The present study showed that eating slowly and exercise were associated with underweight among Japanese adolescents. These results suggest that eating speed and exercise need to be considered in school health programs for healthy body weight.

Overweight and obesity in Slovak high school students and body composition indicators: a non-randomized cross-sectional study

BACKGROUND

Physical development can be considered as an indicator of the overall health status of the youth population. Currently, it appears that the increasing trend of the prevalence of obesity among children and youths has stopped in a number of countries worldwide. Studies point to the fact that adolescence is a critical period for the development of obesity. Body mass index (BMI) seems to be an orientation parameter in the assessment of prevalence of obesity which is not sufficient for more accurate identification of at risk individuals. The purpose of this study was to evaluate association between BMI percentile zones as health-risk for being overweight and obese and body composition indicators in high-school students from the Prešov (Slovakia) region.

METHODS

A non-randomized cross-sectional study in high school students from the Prešov (Slovakia) region was conducted. The research sample consisted of 1014 participants (boys n = 466, girls n = 549). Body composition was measured using direct segmental multi-frequency bioelectrical impedance analysis (DSM-BIA). To examine the association between obesity and selected body composition indicators, Kruskal-Wallis ANOVA and Eta(2) were used. The relationship between selected body composition indicators and percentile BMI zones was determined using the Kendall tau correlation.

RESULTS

In groups with different BMI percentile zones (normal weight, overweight, obese), ANOVA showed significant differences for girls and boys (p ˂.05) with high effect size (η(2) ˂.26) in body weight, body fat mass index, body fat percentage, fat free mass index, fat-free mass percentage, visceral fat area, waist-to-hip ratio, waist circumference, protein mass and mineral mass. The highest degree of correlation among boys was between BMI values indicating overweight and obesity and fat free mass index and waist circumference, respectively (τ = .71, τ = .70, respectively). In girls, the highest correlation was found between classification of BMI percentile zones and waist circumference (t = .78).

CONCLUSION

The characteristics of body composition are very useful determinants of health and nutrition status. Our data revealed a direct association between BMI value and chosen body composition indicators. The most accurate indicator of overweight and obesity in our study appears to be waist circumference for both male and female population.

Waist circumference percentiles for Singaporean children and adolescents aged 6-17 years

AIM

Population-specific waist circumference (WC) percentiles are crucial for screening children at higher obesity-related metabolic risk. This study aimed to develop age- and gender-specific WC percentile curves for Singaporean children and adolescents.

METHODS

3029 participants (boys, 1506; girls, 1523) from different population strata of Singapore were recruited. Stature, weight and WC were measured and BMI calculated. Smoothed WC percentile curves and cut-offs for the 3rd, 5th, 10th, 25th, 50th, 75th, 85th, 90th, 95th, 97th were constructed using the Cole's LMS method.

RESULTS

WC and BMI increased with age in both sexes and boys had higher WC than girls at every age. Comparison of 50th and 90th percentiles with other populations showed distinct difference in WC curve patterns and values of Singaporean children.

CONCLUSIONS

We present the first working WC percentile curves and age- and gender-specific cut-offs of Singaporean children and adolescents. These cut-offs and curves can serve as valuable reference for screening and identify children at a higher metabolic risk, for international comparisons and to better understand secular trends in paediatric obesity.

Eating quickly is associated with waist-to-height ratio among Japanese adolescents: a cross-sectional survey

Background

Central obesity, based on waist circumference (WC), has more adverse effects on health than general obesity, determined by body mass index. To date, eating quickly has been reported to be risk factors for overweight/obesity among children, adolescents, and adults. In contrast, there are few studies on the relationship between fast eating and central obesity among adolescents, particularly in Japan, where WC is not commonly measured in junior high schools. The aim of the present study was to investigate the relationship between eating quickly and waist-to-height ratio (WHtR), an index of central obesity, among adolescents in Japan.

Methods

Study subjects were 2136 seventh-grade school children (12 or 13 years of age) from Ina town junior high schools in Japan, between 2004 and 2009. Measurements of height, weight, and WC were performed, and information about eating habits was collected using a self-administered questionnaire. A logistic regression model was used to calculate the odds ratio (OR) and 95 % confidence interval (95 % CI) for WHtR ≥ 0.5.

Results

Eating quickly significantly increased the OR for WHtR ≥ 0.5 in boys (OR: 2.05, 95 % CI: 1.31–3.23) and girls (2.09, 1.15–3.81). When compared with the “not eating quickly and not eating until full” group, the OR for WHtR ≥ 0.5 in the “eating quickly and eating until full” group was 2.67 (95 % CI: 1.50–4.73) in boys and 2.59 (1.17–5.73) in girls, whereas that in the “eating quickly and not eating until full” group or the “not eating quickly and eating until full” group was not statistically significant regardless of sex.

Conclusions

The present study showed that eating quickly was associated with WHtR ≥ 0.5, and “eating quickly and eating until full” had a substantial impact on WHtR ≥ 0.5 among adolescents. This study suggests that modifying fast eating to a slower pace may help prevent central obesity among adolescents.

Comparison of methods to measure body fat in 7-to-10-year-old children: a systematic review

OBJECTIVE

To investigate methodological aspects in body fat (BF) measurements in 7-to-10-year-old children.

STUDY DESIGN

Systematic review of the literature.

METHODS

The studies were chosen from the PubMed and Scielo databases according to a protocol that defined: inclusion criteria; a search and quality-assessment strategy; and information extraction.

RESULTS

27 studies published from 2004 to 2014 were included. The literature describes skinfold measurements and dual energy X-ray absorptiometry (DEXA) as being the reference methods most widely used in the assessment of the ability of methods to identify BF. The most commonly-used statistical analyses were the Pearson correlation coefficient, and sensitivity and specificity performance analyses. The comparison between the tested methods and the references showed that body mass index (BMI) and waist circumference (WC) are strongly correlated to BF as calculated by bioelectrical impedance or skinfolds, and that there is a moderate positive correlation with percent body fat as calculated by DEXA, air-displacement plethysmography (ADP) or isotope dilution. There was a moderate positive correlation between waist-to-height ratio (WHtR) and BF, as estimated by ADP and skinfolds. Performance studies suggest that BMI and WC are very specific but less sensitive methods.

CONCLUSIONS

The results of this systematic review show favourable evidence for the use of anthropometric indicators - above all BMI and WC- in the measurement of BF, when more accurate techniques such as DEXA and ADP are not feasible. They also demonstrate features that make them advantageous for epidemiological studies in a child population, since they are easy and safe to obtain and well tolerated by the children.

Estimation of waist and hip circumferences using body mass index in Delhi school girls (6-11 years)

Central obesity has been associated with the risk of cardiovascular and metabolic disease in children. A total of 358 Delhi school girls aged 6–11 years were measured for height, weight, waist circumference and hip circumference. The study demonstrates a linear correlation between body mass index (BMI) and waist and hip circumference and suggests an indirect method of estimating waist and hip circumferences, whose high values may be used for the diagnosis of metabolic syndrome and cardiovascular disease. Further investigations on different groups are needed to substantiate these results and attribute BMI a predictive value in the clinical setting for the risk and diagnosis of childhood obesity-related metabolic disorders.

Waist-to-height ratio is more closely associated with alanine aminotransferase levels than body mass index and waist circumference among population-based children: a cross-sectional study in Japan

BACKGROUND

An association between anthropometric measurements, including waist circumference (WC), and alanine aminotransferase (ALT) levels has been reported among adults. However, studies conducted among population-based elementary schoolchildren to date have been limited, especially in Japan, where the measurement of WC and blood collection are not usually performed in the annual health examination at elementary schools. The present study investigated the association between anthropometric measurements and ALT levels among population-based elementary schoolchildren in Japan.

METHODS

Subjects were fourth-grade schoolchildren (aged 9 or 10) from the town of Ina in Saitama Prefecture, Japan during 2004-2009. The height, weight, and WC of each subject were measured, and blood samples were drawn to measure ALT levels. Childhood overweight or obesity was defined according to the age- and sex-specific cut-off points proposed by the International Obesity Task Force. Spearman's correlation coefficients between anthropometric measurements (body mass index (BMI), WC, and waist-to-height ratio (WHtR)) and ALT levels were calculated.

RESULTS

Data from 2499 subjects (1293 boys and 1206 girls) were analyzed. BMI, WC, and WHtR were significantly positively correlated with ALT levels; the correlation coefficient of ALT levels with WHtR was higher than that with BMI and WC in boys and girls. In the analysis stratified by physique (non-overweight/obesity, overweight, or obesity), all anthropometric measurements were significantly positively correlated with ALT levels among boys, while only WHtR was significantly positively correlated with ALT levels among girls. Moreover, the correlation coefficient of ALT levels with WHtR was more pronounced than that with BMI and WC in the non-overweight/obesity group, in the overweight group, and in the obesity group for each sex.

CONCLUSIONS

The present study showed that WHtR was more closely associated with ALT levels than BMI and WC. Furthermore, only WHtR was significantly positively associated with ALT levels regardless of sex and physique. This study suggests that it is more useful to monitor WHtR than BMI and WC as a surrogate for ALT levels among population-based elementary schoolchildren.

Systematic review to identify and appraise outcome measures used to evaluate childhood obesity treatment interventions (CoOR): evidence of purpose, application, validity, reliability and sensitivity

BACKGROUND

Lack of uniformity in outcome measures used in evaluations of childhood obesity treatment interventions can impede the ability to assess effectiveness and limits comparisons across trials.

OBJECTIVE

To identify and appraise outcome measures to produce a framework of recommended measures for use in evaluations of childhood obesity treatment interventions.

DATA SOURCES

Eleven electronic databases were searched between August and December 2011, including MEDLINE; MEDLINE In-Process and Other Non-Indexed Citations; EMBASE; PsycINFO; Health Management Information Consortium (HMIC); Allied and Complementary Medicine Database (AMED); Global Health, Maternity and Infant Care (all Ovid); Cumulative Index to Nursing and Allied Health Literature (CINAHL) (EBSCOhost); Science Citation Index (SCI) [Web of Science (WoS)]; and The Cochrane Library (Wiley) - from the date of inception, with no language restrictions. This was supported by review of relevant grey literature and trial databases.

REVIEW METHODS

Two searches were conducted to identify (1) outcome measures and corresponding citations used in published childhood obesity treatment evaluations and (2) manuscripts describing the development and/or evaluation of the outcome measures used in the childhood intervention obesity evaluations. Search 1 search strategy (review of trials) was modelled on elements of a review by Luttikhuis et al. (Oude Luttikhuis H, Baur L, Jansen H, Shrewsbury VA, O'Malley C, Stolk RP, et al. Interventions for treating obesity in children. Cochrane Database Syst Rev 2009;1:CD001872). Search 2 strategy (methodology papers) was built on Terwee et al.'s search filter (Terwee CB, Jansma EP, Riphagen II, de Vet HCW. Development of a methodological PubMed search filter for finding studies on measurement properties of measurement instruments. Qual Life Res 2009;18:1115-23). Eligible papers were appraised for quality initially by the internal project team. This was followed by an external appraisal by expert collaborators in order to agree which outcome measures should be recommended for the Childhood obesity Outcomes Review (CoOR) outcome measures framework.

RESULTS

Three hundred and seventy-nine manuscripts describing 180 outcome measures met eligibility criteria. Appraisal of these resulted in the recommendation of 36 measures for the CoOR outcome measures framework. Recommended primary outcome measures were body mass index (BMI) and dual-energy X-ray absorptiometry (DXA). Experts did not advocate any self-reported measures where objective measurement was possible (e.g. physical activity). Physiological outcomes hold potential to be primary outcomes, as they are indicators of cardiovascular health, but without evidence of what constitutes a minimally importance difference they have remained as secondary outcomes (although the corresponding lack of evidence for BMI and DXA is acknowledged). No preference-based quality-of-life measures were identified that would enable economic evaluation via calculation of quality-adjusted life-years. Few measures reported evaluating responsiveness.

LIMITATIONS

Proposed recommended measures are fit for use as outcome measures within studies that evaluate childhood obesity treatment evaluations specifically. These may or may not be suitable for other study designs, and some excluded measures may be more suitable in other study designs.

CONCLUSIONS

The CoOR outcome measures framework provides clear guidance of recommended primary and secondary outcome measures. This will enhance comparability between treatment evaluations and ensure that appropriate measures are being used. Where possible, future work should focus on modification and evaluation of existing measures rather than development of tools de nova. In addition, it is recommended that a similar outcome measures framework is produced to support evaluation of adult obesity programmes.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Childhood overweight and obesity in a region of Italian immigration in Southern Brazil: a cross-sectional study

Background

The main modifiable risk factors for obesity are related to lifestyle and significantly influenced by the family, environment and culture. We aimed to estimate the prevalence of overweight/obesity and associated lifestyle factors in children from Bento Gonçalves, a southern Brazil city with strong Italian immigration influence. Italian traditional foods were locally adapted since the immigrants’ arrival in the XIX century, to include more fat and fewer vegetables, and physical activity levels have decreased.

Methods

Cross-sectional study of a population-based cluster sample with students aged 9–18 years. We assessed time spent in sedentary behaviors, hours of physical activity, food frequency and family history. All children underwent physical examination with anthropometric and blood pressure measurements. Overweight and obesity were classified according to WHO percentile curves.

Results

A total of 590 students were evaluated. Mean age was 12.45 ± 1.49 years. The prevalence of overweight and obesity was 16.3% and 8.3%, respectively. Boys were more frequently overweight and obese than girls (16.3% and 12.2% versus 16.2% and 5.5%, respectively). Vegetables and fruits were consumed less than 4 times per week in 49% and 36.8%, while soft drinks, fast food and sweets were consumed more than 4 times a week by 71%, 70.3% and 42.7%, respectively. The habit of omitting breakfast was associated with overweight (p = 0.007). The average screen time was 5.38 ± 2.88 hours/day. Overweight/obesity was present in 12.2% (n = 5), 24.8% (n = 122) and 36.8% (n = 14) children with low birth weight, normal birth weight and high birth weight respectively (p = 0.04). The prevalence of high blood pressure was higher in obese (30.6%) and overweight (21.2%) children, comparing to eutrophic children (6.8%; p < 0.001). Excess weight was more frequent among fathers (62.8%) than in mothers (46.3%), but excess weight in mothers was positively associated with excess weight in children (p 0.048).

Conclusion

The city showed high prevalence of overweight and obesity. These findings reinforce the importance of implementing prevention strategies aimed at children and their families, considering that health habits are shared and transmitted along generations.

Comparison of percentage body fat and body mass index for the prediction of inflammatory and atherogenic lipid risk profiles in elderly women

OBJECTIVE

To compare the clinical classification of the body mass index (BMI) and percentage body fat (PBF) for the prediction of inflammatory and atherogenic lipid profile risk in older women.

METHOD

Cross-sectional analytical study with 277 elderly women from a local community in the Federal District, Brazil. PBF and fat-free mass (FFM) were determined by dual energy X-ray absorptiometry. The investigated inflammatory parameters were interleukin 6 and C-reactive protein.

RESULTS

Twenty-five percent of the elderly women were classified as normal weight, 50% overweight, and 25% obese by the BMI. The obese group had higher levels of triglycerides and very low-density lipoproteins than did the normal weight group (P≤0.05) and lower levels of high-density lipoproteins (HDL) than did the overweight group (P≤0.05). According to the PBF, 49% of the elderly women were classified as eutrophic, 28% overweight, and 23% obese. In the binomial logistic regression analyses including age, FFM, and lipid profile, only FFM (odds ratio [OR]=0.809, 95% confidence interval [CI]: 0.739-0.886; P<0.0005) proved to be a predictor of reaching the eutrophic state by the BMI. When the cutoff points of PBF were used for the classification, FFM (OR=0.903, CI=0.884-0.965; P=0.003) and the total cholesterol/HDL ratio (OR=0.113, CI=0.023-0.546; P=0.007) proved to be predictors of reaching the eutrophic state.

CONCLUSION

Accurate identification of obesity, systemic inflammation, and atherogenic lipid profile is key to assessing the risk of cardiometabolic diseases. Classification based on dual energy X-ray absorptiometry measures, along with biochemical and inflammatory parameters, seems to have a great clinical importance, since it allows the lipid profile eutrophic distinction in elderly overweight women.

Temporal divergence of percent body fat and body mass index in pre-teenage children: the LOOK longitudinal study

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

The index of body mass related to stature, (body mass index, BMI, kgm(-2) ), is widely used as a proxy for percent body fat (%BF) in cross-sectional and longitudinal investigations. BMI does not distinguish between lean and fat mass and in children, the cross-sectional relationship between %BF and BMI changes with age and sex.

WHAT THIS STUDY ADDS

While BMI increases linearly with age from age 8 to 12 years in both boys and girls, %BF plateaus off between 10 and 12 years. Repeated measures in children show a systematic decrease in %BF for any given BMI from age 8 to 10 to 12 years. Because changes in BMI misrepresent changes in %BF, its use as a proxy of %BF should be avoided in longitudinal studies in this age group.

BACKGROUND

Body mass index (BMI, kgm(-2) ) is commonly used as an indicator of pediatric adiposity, but with its inability to distinguish changes in lean and fat mass, its use in longitudinal studies of children requires careful consideration.

OBJECTIVE

To investigate the suitability of BMI as a surrogate of percent body fat (%BF) in pediatric longitudinal investigations.

METHODS

In this longitudinal study, healthy Australian children (256 girls and 278 boys) were measured at ages 8.0 (standard deviation 0.3), 10.0 and 12.0 years for height, weight and percent body fat (%BF) by dual-energy X-ray absorptiometry.

RESULTS

The patterns of change in the means of %BF and BMI were different (P < 0.001). While mean BMI increased linearly from 8 to 12 years of age, %BF did not change between 10 and 12 years. Relationships between %BF and BMI in boys and girls were curvilinear and varied with age (P < 0.001) and gender (P < 0.001); any given BMI corresponding with a lower %BF as a child became older.

CONCLUSION

Considering the divergence of temporal patterns of %BF and BMI between 10 and 12 years of age, employment of BMI as a proxy for %BF in absolute or age and sex standardized forms in pediatric longitudinal investigations is problematical.

Gender-assortative waist circumference in mother-daughter and father-son pairs, and its implications. An 11-year longitudinal study in children (EarlyBird 59)

BACKGROUND/OBJECTIVES

Body mass index (BMI) is reportedly gender assortative (mother-daughter, father-son) in contemporary children. We investigated the corresponding transmission of waist circumference (WC) and its implications.

METHODS

We measured parental WC at baseline and WC, height, weight and para-umbilical skin-fold (USF) annually in their offspring from 5 to 15 years (n = 223 trios). Parents were deemed normal metabolic risk (NR) or high risk (HR) according to World Health Organization (WHO) cut-points for WC (mothers 80 cm, fathers 94 cm). The residual from WC adjusted for BMI (WC|BMI ) was used as a surrogate for excess intra-abdominal fat, and its association with insulin resistance (HOMA2-IR) was sought.

RESULTS

WC and USF were both gender assortative, while WC|BMI was not. WC was greater by 1.62 cm (P < 0.05, confidence interval [CI]: 0.09-3.16) and USF by 0.37 cm (P < 0.01, CI: 0.19-0.56) among the daughters (but not the sons) of HR compared with those of NR mothers, and by 1.32 cm (P < 0.05, CI: 0.09-2.55) and 0.18 cm (P < 0.05, CI: 0.04-0.32), respectively in the corresponding father-son (but not father-daughter) pairings. No such differences could be demonstrated for WC|BMI . A standard deviation score 1(SDS) change in WC|BMI , independent of BMI, was associated with a 7.14% change in IR in girls (P < 0.01, CI: 1.76-12.80) and 8.02% in boys (P < 0.001, CI: 2.93-13.36), but there was no relationship between IR and USF.

CONCLUSION

The relationship of offspring WC to metabolic health and to parental size is complex. Subcutaneous abdominal fat is gender assortative but harmless, while intra-abdominal fat (its surrogate in this analysis) is unrelated to parental waist circumference, but metabolically harmful.

Eating behaviors and overweight among adolescents: a population-based survey in Japan

OBJECTIVES

The aim of the present study was to investigate the relationship between eating behaviors and overweight among population-based adolescents in Japan.

METHODS

Study subjects comprised adolescents in the seventh grade (age range, 12-13 years) from Ina, a town in Saitama Prefecture, Japan, between 1999 and 2008. The height and weight of the subjects were measured, and information concerning eating behaviors (eating speed and eating until full) was obtained using a self-administered questionnaire.

RESULTS

Among boys (n = 1586), fast eating speed significantly increased the odds ratio (OR) for overweight when compared with medium eating speed, regardless of eating until full or not; moreover, a more marked increase in the OR was observed among boys eating until full (OR: 2.78, 95% confidence interval: 1.76-4.38) than among those not eating until full (2.43, 1.41-4.20). Among girls (n = 1542), fast eating speed led to a significant increase in the OR in those eating until full; however, no significant increases were observed in the OR in those eating quickly and not until full.

CONCLUSIONS

Among adolescents, fast eating speed was associated with overweight; furthermore, the combination of both fast eating speed and eating until full may have a significant effect on overweight.

Dual-energy X-ray absorptiometry prediction of adipose tissue depots in children and adolescents

BACKGROUND

The measurement of adipose tissue (AT) depots in vivo requires expensive imaging methods not accessible to most clinicians and researchers. The study aim was to derive mathematical models to predict total AT (TAT) and subdepots from total body fat derived from a dual-energy X-ray absorptiometry (DXA) scan.

METHODS

Models were developed to predict magnetic resonance imaging-derived TAT and subdepots subcutaneous AT, visceral AT, and intermuscular AT from DXA total body fat (Fat(DXA)) using cross-sectional data (time 0 (T0)) and validated results using 1 (T1) and 2 (T2) y follow-up data. Subjects were 176 multiethnic healthy children ages 5-17 y at T0. Twenty-two were measured at T1 and T2. TAT was compared with Fat(DXA).

RESULTS

At T0, TAT was greater than Fat(DXA) (12.5 ± 8.4 vs.12.0 ± 9.4 kg; P < 0.0001), with a quadratic relationship between TAT and Fat(DXA) that varied by sex. Predicted mean TATs were not different from measured TATs: T1: (9.84 ± 4.45 kg vs. 9.50 ± 4.37 kg; P = 0.11); T2: (12.94 ± 6.75 kg vs. 12.89 ± 7.09 kg; P = 0.76). The quadratic relationship was not influenced by race or age.

CONCLUSION

In general, the prediction equations for TAT and subdepots were consistent with the measured values using T1 and T2 data.

Number of siblings, birth order, and childhood overweight: a population-based cross-sectional study in Japan

Background

Although several studies have investigated the relationship between the number of siblings or birth order and childhood overweight, the results are inconsistent. In addition, little is known about the impact of having older or younger siblings on overweight among elementary schoolchildren. The present population-based study investigated the relationship of the number of siblings and birth order with childhood overweight and evaluated the impact of having younger or older siblings on childhood overweight among elementary schoolchildren in Japan.

Methods

Subjects comprised fourth-grade schoolchildren (age, 9–10 years) in Ina Town during 1999–2009. Information about subjects’ sex, age, birth weight, birth order, number of siblings, lifestyle, and parents’ age, height, and weight was collected by a self-administered questionnaire, while measurements of subjects’ height and weight were done at school. Childhood overweight was defined according to age- and sex-specific cut-off points proposed by the International Obesity Task Force. A logistic regression model was used to calculate the odds ratio (OR) and 95% confidence intervals (95% CI) of "number of siblings" or "birth order" for overweight.

Results

Data from 4026 children were analyzed. Only children (OR: 2.13, 95% CI: 1.45-3.14) and youngest children (1.56, 1.13-2.16) significantly increased ORs for overweight compared with middle children. A larger number of siblings decreased the OR for overweight (P for trend < 0.001). Although there was no statistically significant relationship between a larger number of older siblings and overweight, a larger number of younger siblings resulted in a lower OR for overweight (P for trend < 0.001).

Conclusions

Being an only or youngest child was associated with childhood overweight, and having a larger number of younger siblings was negatively associated with overweight. The present study suggests that public health interventions to prevent childhood overweight need to focus on children from these family backgrounds.

High-molecular-weight adiponectin and anthropometric variables among elementary schoolchildren: a population-based cross-sectional study in Japan

Background

Studies about the relationship between high-molecular-weight adiponectin (HMW-adn) and anthropometric variables among population-based elementary schoolchildren have been too limited, especially in Japan, where blood collection is not usually performed in the annual health examination at elementary schools. The objective of the present study was to investigate the relationship between HMW-adn and anthropometric variables (body mass index [BMI], percent body fat [%BF], waist circumference [WC], and waist-to-height ratio [WHtR]) among population-based elementary schoolchildren in Japan.

Methods

Subjects comprised all fourth-grade schoolchildren (9 or 10 years of age) in the town of Ina, Saitama Prefecture, Japan during 2005–2008 (N = 1675). After excluding 21 subjects because of refusal to participate or incomplete data, data from a total of 1654 subjects (846 boys and 808 girls) were analyzed. The height, weight, %BF, and WC of each subject were measured, while blood samples were drawn from the subjects to measure adiponectin levels (HMW-adn and total adiponectin). Childhood obesity was determined according to the age- and sex-specific cut-off points proposed by the International Obesity Task Force. Spearman’s correlation coefficients between adiponectin levels and anthropometric variables were calculated for each sex.

Results

The anthropometric variables were negatively correlated with HMW-adn in both boys and girls. Correlation coefficients of HMW-adn with anthropometric variables in the obesity group were consistently higher than those in the non-obesity group among both boys and girls. In addition, only WHtR was significantly correlated with HMW-adn regardless of sex and physique (obesity or non-obesity); the correlation coefficient was -0.386 among boys and -0.543 among girls in the obesity group, while it was -0.124 among boys and -0.081 among girls in the non-obesity group.

Conclusions

HMW-adn was negatively correlated with anthropometric variables, while the correlation coefficients of HMW-adn with anthropometric variables in the obesity group were consistently higher than those in the non-obesity group. Moreover, only WHtR was significantly associated with HMW-adn regardless of sex and physique. The results of this study suggested that it is useful to monitor WHtR as a surrogate for HMW-adn among elementary school students, especially obese children.

Secular trends in blood pressure among Japanese schoolchildren: a population-based annual survey from 1994 to 2010

Background

Monitoring secular trends in blood pressure (BP) among children is important in predicting subsequent hypertension and cardiovascular disease. We investigated secular trends in BP using data from population-based annual screenings of Japanese schoolchildren.

Methods

The participants were 10 894 children (all fourth graders between 1994 and 2010 and all seventh graders between 1997 and 2010) living in the town of Ina in Saitama Prefecture, Japan. Body height, weight, and BP were measured, after which children were classified as non-overweight, overweight, or obese. Trends in variables relative to calendar year were analyzed using regression models.

Results

Systolic BP was significantly associated with calendar year among fourth- and seventh-grade boys (−0.350 and −0.434 mm Hg/year, respectively) and fourth- and seventh-grade girls (−0.513 and −0.473 mm Hg/year, respectively) (all P < 0.001), respectively, over time. Systolic BP and calendar year were significantly negatively correlated regardless of physique or sex among all fourth graders, but not among obese seventh-grade girls. In addition, diastolic BP and calendar year did not significantly correlate among seventh-grade overweight or obese boys or obese seventh-grade girls.

Conclusions

BP decreased among fourth-grade schoolchildren in Ina during the past 17 years, regardless of sex or physique. However, BP and calendar year did not significantly correlate among obese seventh graders.

Eating behavior and childhood overweight among population-based elementary schoolchildren in Japan

This study investigated the relationship between eating behavior and childhood overweight among population-based elementary schoolchildren in Japan. Data was collected from fourth graders (9 or 10 years of age) from Ina Town, Saitama Prefecture, Japan from 1999 to 2009. Information about subjects' sex, age, and lifestyle, including eating behaviors (eating until full and chewing thoroughly), was obtained using a self-administered questionnaire, and height and weight were measured directly. Overweight was determined according to the definition established by the International Obesity Task Force. Data from 4027 subjects (2079 boys and 1948 girls) were analyzed. Chewing thoroughly was associated with a significantly decreased odds ratio (OR) for being overweight, whereas eating until full significantly increased the OR for being overweight (OR: 1.50, 95% confidence interval: 1.16-1.94) among boys. However, eating until full was not associated with a significantly increased OR for being overweight among the group that reported chewing thoroughly, whereas it was associated with a significantly increased OR for being overweight (2.02, 1.38-2.94) among boys who did not chew thoroughly. In conclusion, eating until full or not chewing thoroughly was associated with being overweight among elementary schoolchildren. Results of this study suggest that chewing thoroughly may be an avenue to explore childhood overweight prevention efforts.

Body mass index correlates with waist circumference in school aged Italian children

This study demonstrates the existence of a linear correlation between Body Mass Index (BMI) and waist circumference in Italian school aged children and suggests an indirect method (from weight and height) to estimate waist circumference, whose increase may be indicative for the diagnosis of the metabolic syndrome.

Body mass index, waist circumference, body fat, fasting blood glucose in a sample of moroccan adolescents aged 11-17 years

Objectives. The study aimed to assess the relationship between body fat and each of body mass index (BMI) and waist circumference (WC), and to test the effectiveness of fat mass (FM), percent of body fat (PBF), BMI, and WC in predicting high levels of fasting blood glucose (FBG). Methods. A total of 167 adolescents aged 11–17 years were recruited from Rabat region. BMI and WC were determined using standard equipments. FM and PBF were derived from isotope dilution technique. FBG was determined by the hexokinase method. Results. Regardless of the weight status, BMI showed a strong positive correlation with FM and PBF in both genders. WC was significantly correlated with FM in boys and girls, and with PBF in different groups of girls and boys of the study sample. However, there was no significant relationship between WC and PBF in normal weight and overweight-obese groups of boys. FBG was highly correlated with FM and PBF in girls of the study sample and in overweight-obese girls. Similar significant relationship between FBG and both BMI and WC was observed in overweight-obese girls, while there was no significant association between FBG and other variables in boys and normal-weight girls. Conclusion. BMI and WC were closely associated with FM and PBF, respectively. However, the degree of these associations depends on gender and weight status. BMI may provide a better proxy estimate of overall adiposity than WC; nevertheless, both of them would appear to be a reasonable surrogate for FM and PBF as screening tools to identify adolescents at risk of developing excess body fat and high level of FBG.