To develop an internationally acceptable definition of child overweight and obesity, specifying the measurement, the reference population, and the age and sex specific cut off points.
International survey of six large nationally representative cross sectional growth studies.
Brazil, Great Britain, Hong Kong, the Netherlands, Singapore, and the United States.
97 876 males and 94 851 females from birth to 25 years of age.
Main outcome measure
Body mass index (weight/height2).
For each of the surveys, centile curves were drawn that at age 18 years passed through the widely used cut off points of 25 and 30 kg/m2 for adult overweight and obesity. The resulting curves were averaged to provide age and sex specific cut off points from 2-18 years.
The proposed cut off points, which are less arbitrary and more internationally based than current alternatives, should help to provide internationally comparable prevalence rates of overweight and obesity in children.
Body mass index (BMI) shows several limitations as indicator of fatness. Using the International Obesity Task Force (IOTF) reference and the World Health Organization (WHO) standard 2007 on the same dataset yielded widely different rates. At higher levels, BMI and the BMI cut-offs may be help in informing a clinical judgement, but at levels near the norm additional criteria may be needed. This study compares the prevalence of overweight and obesity using IOTF and WHO-2007 references and interprets body composition by comparing measures of BMI and body fatness (fat mass index, FMI; and waist-to-height ratio, WHtR) among an adolescent population.
Methods and Results
A random sample (n = 1231) of adolescent population (12–17 years old) was interviewed. Weight, height, waist circumference, triceps and subscapular skinfolds were used to calculate BMI, FMI, and WHtR. The prevalence of overweight and obesity were 12.3% and 15.4% (WHO standards) and 18.6% and 6.1% (IOTF definition). Despite that IOTF cut-offs misclassified less often than WHO standards, BMI categories were combined with FMI and WHtR resulting in the Adiposity & Fat Distribution for adolescents (AFAD-A) classification, which identified the following groups normal-weight normal-fat (73.2%), normal-weight overfat (2.1%), overweight normal-fat (6.7%), overweight overfat (11.9%) and obesity (6.1%), and also classified overweight at risk and obese adolescents into type-I (9.5% and 1.3%, respectively) and type-II (2.3% and 4.9%, respectively) depending if they had or not abdominal fatness.
There are differences between IOTF and WHO-2007 international references and there is a misclassification when adiposity is considered. The BMI limitations, especially for overweight identification, could be reduced by adding an estimate of both adiposity (FMI) and fat distribution (WHtR). The AFAD-A classification could be useful in clinical and population health to identify overfat adolescent and those who have greater risk of developing weight-related cardiovascular diseases according to the BMI category.
To assess the prevalence of thinness among 5-10 year old school children of Nandigram, Purba Medinipur District of West Bengal, India.
A total of 596 students (323 boys and 288 girls) aged 5-10 years were included in this crosssectional study. Height and weight were measured and the body mass index (BMI) was computed. The new international BMI-based classification cut-off points proposed by Cole et al were utilized to identify thinness.
The overall (age-combined) mean BMI among boys and girls were 13.9 kg/m2 (SD = 1.4) and 13.8 kg/m2 (SD = 1.2), respectively. In general, mean BMI increased with age in both sexes. There was no significant sex difference in mean BMI. The overall (age-combined) prevalence of thinness was 62.9% and 61.6% in boys and girls, respectively.
The present study clearly indicated that the nutritional situation of these children was unsatisfactory.
Body mass index; undernutrition; thinness; IOTF cut off points; nandigram; West Bengal
The purpose of this study was to determine the prevalence of overweight and obesity and to examine the effects of actual weight status, perceived weight status and body satisfaction on self-esteem and depression in a high school population in Turkey.
A cross-sectional survey of 2101 tenth-grade Turkish adolescents aged 15–18 was conducted. Body mass index (BMI) was calculated using weight and height measures. The overweight and obesity were based on the age- and gender-spesific BMI cut-off points of the International Obesity Task Force values. Self-esteem was measured using the Rosenberg Self-Esteem Scale, and depression was measured using Children's Depression Inventory. Logistic regression analysis was used to examine relationships among the variables.
Based on BMI cut-off points, 9.0% of the students were overweight and 1.1% were obese. Logistic regression analysis indicated that (1) being male and being from a higher socio-economical level were important in the prediction of overweight based on BMI; (2) being female and being from a higher socio-economical level were important in the prediction of perceived overweight; (3) being female was important in the prediction of body dissatisfaction; (4) body dissatisfaction was related to low self-esteem and depression, perceived overweight was related only to low self-esteem but actual overweight was not related to low self-esteem and depression in adolescents.
The results of this study suggest that school-based adolescents in urban Turkey have a lower risk of overweight and obesity than adolescents in developed countries. The findings of this study suggest that psychological well-being of adolescents is more related to body satisfaction than actual and perceived weight status is.
Weight misperception is the discordance between an individual’s actual weight status and the perception of his/her weight. It is a common problem in the youth population as enumerated by many international studies. However data from Pakistan in this area is deficient.
A multi-center cross-sectional survey was carried out in undergraduate university students of Karachi between the ages of 15–24. Participants were questioned regarding their perception of being thin, normal or fat and it was compared with their Body Mass Index (BMI). Measurements of height and weight were taken for this purpose and BMI was categorized using Asian cut offs. Weight misperception was identified when the self-perceived weight (average, fat, thin) did not match the calculated BMI distribution. Chi square tests and logistic regression tests were applied to show associations of misperception and types of misperception (overestimation, underestimation) with independent variables like age, gender, type of university and faculties. P-value of <0.05 was taken as statistically significant.
42.4% of the total participants i.e. 43.3% males and 41% females misperceived their weight. Amongst those who misperceived 38.2% had overestimated and 61.8% had underestimated their weight. Greatest misperception of was observed in the overweight category (91%), specifically amongst overweight males (95%). Females of the underweight category overestimated their weight and males of the overweight category underestimated their weight. Amongst the total participants, females overestimated 8 times more than males (OR 8.054, 95% CI 5.34-12.13). Misperception increased with the age of the participants (OR 1.114, 95% CI 1.041-1.191). Odds of misperception were greater in students of private sector universities as compared to public (OR 1.861, 95% CI: 1.29-2.67). Odds of misperception were less in students of medical sciences (OR 0.693, 95% CI 0.491-0.977), engineering (OR 0.586, 95% CI 0.364-0.941) and business administration (OR 0.439, 95% CI 0.290-0.662) as compared to general faculty universities.
There was marked discrepancy between the calculated BMI and the self-perceived weight in the youth of Karachi. Better awareness campaigns need to be implemented to reverse these trends.
Weight misperception; BMI; Pakistan; Undergraduate students; Youth; Overweight; Underweight; Overestimation; Underestimation
Obesity among children and adolescents is a growing public health problem. The aim of the present paper is to identify potential determinants of obesity and risk groups among 3- to 17-year old children and adolescents to provide a basis for effective prevention strategies.
Data were collected in the German Health Interview and Examination Survey for Children and Adolescents (KiGGS), a nationally representative and comprehensive data set on health behaviour and health status of German children and adolescents. Body height and weight were measured and body mass index (BMI) was classified according to IOTF cut-off points. Statistical analyses were conducted on 13,450 non-underweight children and adolescents aged 3 to 17 years. The association between overweight, obesity and several potential determinants was analysed for this group as well as for three socio-economic status (SES) groups. A multiple logistic regression model with obesity as the dependent variable was also calculated.
The strongest association with obesity was observed for parental overweight and for low SES. Furthermore, a positive association with both overweight (including obesity) and obesity was seen for maternal smoking during pregnancy, high weight gain during pregnancy (only for mothers of normal weight), high birth weight, and high media consumption. In addition, high intakes of meat and sausages, total beverages, water and tea, total food and beverages, as well as energy-providing food and beverages were significantly associated with overweight as well as with obesity. Long sleep time was negatively associated with obesity among 3- to 10-year olds. Determinants of obesity occurred more often among children and adolescents with low SES.
Parental overweight and a low SES are major potential determinants of obesity. Families with these characteristics should be focused on in obesity prevention.
The prevalence of adolescents’ obesity and overweight has dramatically elevated in China. Obese children were likely to insulin resistance and dyslipidemia, which are risk factors of cardiovascular diseases. However there was no cut-off point of anthropometric values to predict the risk factors in Chinese adolescents. The present study was to investigate glycolipid metabolism status of adolescents in Shanghai and to explore the correlations between body mass index standard deviation score (BMI-SDS) and metabolic indices, determine the best cut-off value of BMI-SDS to predict dyslipidemia.
Fifteen schools in Shanghai’s two districts were chosen by cluster sampling and primary screening was done in children aged 9-15 years old. After screening of bodyweight and height, overweight and obese adolescents and age-matched children with normal body weight were randomly recruited in the study. Anthropometric measurements, biochemical measurements of glycolipid profiles were done. SPSS19.0 was used to analyze the data. Receiver operating characteristic (ROC) curves were made and the best cut-off values of BMI-SDS to predict dyslipidemia were determined while the Youden indices were maximum.
Five hundred and thirty-eight adolescents were enrolled in this research, among which 283 have normal bodyweight, 115 were overweight and 140 were obese. No significant differences of the ages among 3 groups were found. There were significant differences of WC-SDS (p<0.001), triacylglycerol (p<0.05), high and low density lipoprotein cholesterol (p<0.01), fasting insulin (p<0.01) and C-peptide (p<0.001) among 3 groups. Significant difference of fasting glucose was only found between normal weight and overweight group. Significant difference of total cholesterol was found between obese and normal weight group. There was no significant difference of glycated hemoglobin among 3 groups. The same tendency was found in boys but not in girls. Only HDL-C reduced and TG increased while BMI elevated in girls. The best cut-off value of BMI-SDS was 1.22 to predict dyslipidemia in boys. The BMI cut-off was 21.67 in boys.
Overweight and obese youths had reduced insulin sensitivity and high prevalence of dyslipidemia.When BMI-SDS elevated up to 1.22 and BMI was higher than 21.67 in boys, dyslipidemia may happen.
Adolescents; Children; Lipid metabolism; Obesity; Overweight; BMI-SDS; China
Parental reports are often used in large-scale surveys to assess children's body mass index (BMI). Therefore, it is important to know to what extent these parental reports are valid and whether it makes a difference if the parents measured their children's weight and height at home or whether they simply estimated these values. The aim of this study is to compare the validity of parent-reported height, weight and BMI values of preschool children (3-7 y-old), when measured at home or estimated by parents without actual measurement.
The subjects were 297 Belgian preschool children (52.9% male). Participation rate was 73%. A questionnaire including questions about height and weight of the children was completed by the parents. Nurses measured height and weight following standardised procedures. International age- and sex-specific BMI cut-off values were employed to determine categories of weight status and obesity.
On the group level, no important differences in accuracy of reported height, weight and BMI were identified between parent-measured or estimated values. However, for all 3 parameters, the correlations between parental reports and nurse measurements were higher in the group of children whose body dimensions were measured by the parents. Sensitivity for underweight and overweight/obesity were respectively 73% and 47% when parents measured their child's height and weight, and 55% and 47% when parents estimated values without measurement. Specificity for underweight and overweight/obesity were respectively 82% and 97% when parents measured the children, and 75% and 93% with parent estimations.
Diagnostic measures were more accurate when parents measured their child's weight and height at home than when those dimensions were based on parental judgements. When parent-reported data on an individual level is used, the accuracy could be improved by encouraging the parents to measure weight and height of their children at home.
BMI; weight; height; validity; children; parent reports
Background: Body Mass Index (BMI) offers a simple and reasonable measure of obesity that, with the use of the appropriate reference, can help in the early detection of children with weight problems. Our aim was to compare the two most commonly used international BMI references and the national Greek BMI reference in identifying Greek children being overweight and obese.
Methods: A group of 1557 children (820 girls and 737 boys, mean age: 11.42 ± 3.51 years) were studied. Weight and height was measured using standard methods, and BMI was calculated. Overweight and obesity were determined using the International Obesity Task Force (IOTF) standards, the Centers for Disease Control and Prevention (CDC) BMI-forage curves and the most recent Greek BMI-for-age curves.
Results: Results showed that the IOTF's cut-off limits identifies a significantly higher prevalence of overweight (22.4%) compared with both the CDC's (11.8%, p=0.03) and the Greek's (7.4%, p=0.002) cut-off limits. However, the prevalence of obesity was generally increased when it was determined using the CDC's cut-off limits (13.9%) compared to the prevalence calculated with both the IOTF's (6.5%, p=0.05) and the Greek's (6.9%, n.s.) cut off limits.
Conclusions: The use of the national Greek reference standards for BMI underestimates the true prevalence of overweight and obesity. On the contrary, both the IOTF and the CDC standards, although independently, detect an increased number of overweight and obese children and thus they should be adopted in the clinical practice for an earlier identification and a timelier intervention.
children; obesity; overweight; BMI; Greek
While much cross-sectional data is available, there have been few longitudinal investigations of patterns of electronic media use in children. Further, the possibility of a bi-directional relationship between electronic media use and body mass index in children has not been considered. This study aimed to describe longitudinal patterns of television viewing and electronic game/computer use, and investigate relationships with body mass index (BMI).
This prospective cohort study was conducted in elementary schools in Victoria, Australia. 1278 children aged 5–10 years at baseline and 8–13 years at follow-up had their BMI calculated, from measured height and weight, and transformed to z-scores based on US 2000 growth data. Weight status (non-overweight, overweight and obese) was based on international BMI cut-off points. Weekly television viewing and electronic game/computer use were reported by parents, these were summed to generate total weekly screen time. Children were classified as meeting electronic media use guidelines if their total screen time was ≤14 hrs/wk.
Electronic media use increased over the course of the study; 40% met guidelines at baseline but only 18% three years later. Television viewing and electronic game/computer use tracked moderately and total screen time was positively associated with adiposity cross-sectionally. While weaker relationships with adiposity were observed longitudinally, baseline z-BMI and weight status were positively associated with follow-up screen time and baseline screen time was positively associated with z-BMI and weight status at follow-up. Children who did not meet guidelines at baseline had significantly higher z-BMI and were more likely to be classified as overweight/obese at follow-up.
Electronic media use in Australian elementary school children is high, increases with age and tracks over time. There appears to be a bi-directional association suggesting that interventions targeting reductions in either screen time or adiposity may have a positive effect on both screen time and adiposity.
The underlying mechanisms of overweight and obesity in adolescents are still not fully understood. The aim of this study was to investigate modifiable and non-modifiable correlates of weight status among 1103 Norwegian 11-year-old adolescents in the HEalth in Adolescents (HEIA) study, including demographic factors such as gender and parental education, and behavioral factors such as intake of sugar-sweetened beverages, snacks and breakfast consumption, watching TV and playing computer games, physical activity and sedentary time.
Weight and height were measured objectively, body mass index (BMI) was calculated and International Obesity Task Force cut-offs were used to define weight status. Physical activity and sedentary time were measured by accelerometers. Other behavioral correlates and pubertal status were self-reported by questionnaires. Parental education was reported by the parents on the consent form for their child. Associations were investigated using logistic regressions.
There were gender differences in behavioral correlates of weight status but not for weight status itself. Adolescents with parents in the highest education category had a 46% reduced odds of being overweight compared to adolescents with parents in the lowest education category. Adolescents with parents with medium education had 42% lower odds of being overweight than adolescents with parents with the lowest education category. Level of parental education, breakfast consumption and moderate to vigorous physical activity were positively associated with being normal weight, and time watching TV was positively associated with being overweight for the total sample. Gender differences were detected; boys had a doubled risk of being overweight for every additional hour of watching TV per week, while for girls there was no association.
The present study showed a social gradient in weight status in 11-year-olds. Both breakfast consumption and moderate to vigorous physical activity were inversely associated with weight status. No associations were found between intake of sugar-sweetened beverages and snacks, playing computer games and weight status. Watching TV was positively associated with weight status for boys but not for girls. Interventions are needed to gain more insight into the correlates of change in weight status.
Overweight; Physical activity; Sedentary time; Parental education; Diet; Children; Adolescents
Weight-related issues such as obesity, dieting and eating disorders in adolescents are major public health problems. Moreover, undertaking a diet tends to be common among school children and the reasons for doing so are not always related to weight status. The objectives of the study were to evaluate the role of body mass index (BMI), gender and self-esteem in the adoption of a diet in middle-school Sicilian children.
The survey included middle-school children in some Sicilian provinces. Weight status was determined by sex-specific body mass index for age according to the international BMI cut-off proposed by Cole. Classic chi-square test and linear trend chi-square were used to compare percentages. Univariate and multivariate logistic regressions were computed to study the risk of dieting according to weight status (with the underweight group as the reference group), gender, self-esteem adjusted for province. Adjusted odds ratios (ORs) and 95% confidence intervals (CI) along with associated p-values were furnished.
The survey showed that 45.2% of the children were of average-weight, 6.6% were underweight, 12.6% were overweight and 2.9% were clinically obese. The missing data were up to 32.8%. Regarding dieting, 26.3% of the children stated that they had been on a diet during the last three months, 56.4% claimed they had not, and 17.2% did not answer. Age was not associated with dieting (p = 0.76). More girls than boys had undertaken a diet (31.4% versus 21.4%, p < 0.0001). Self-esteem had an influence on the choice of following a diet; in fact, 40.8%, 28.5% and 20.9% of the children with negative, normal and positive self-esteem were following a diet (trend p < 0.0001). The multivariate analysis showed that self-esteem seemed to influence more girls than boys (p = 0.06), and stratified analysis by gender indicated that it seemed more influent in girls (p = 0.0008) than in boys (p = 0.01).
In addition to the relation between dieting and BMI, our results highlight the link between dieting, gender and self-esteem. We underline the importance of interventions within the context of health education in order to improve global self-esteem and to encourage proper eating habits to prevent weight-related health problems.
The purpose of this study was to examine the association between functional movement and overweight and obesity in British children.
Data were obtained from 90, 7–10 year old children (38 boys and 52 girls). Body mass (kg) and height (m) were assessed from which body mass index (BMI) was determined and children were classified as normal weight, overweight or obese according to international cut offs. Functional movement was assessed using the functional movement screen.
Total functional movement score was significantly, negatively correlated with BMI (P = .0001). Functional movement scores were also significantly higher for normal weight children compared to obese children (P = .0001). Normal weight children performed significantly better on all individual tests within the functional movement screen compared to their obese peers (P <0.05) and significantly better than overweight children for the deep squat (P = .0001) and shoulder mobility tests (P = .04). Overweight children scored significantly better than obese in the hurdle step (P = .0001), in line lunge (P = .05), shoulder mobility (P = .04) and active straight leg raise (P = .016).
Functional movement scores were not significantly different between boys and girls (P > .05) when considered as total scores. However, girls performed significantly better than boys on the hurdle step (P = .03) and straight leg raise (P = .004) but poorer than boys on the trunk stability push-up (P = .014).
This study highlights that overweight and obesity are significantly associated with poorer functional movement in children and that girls outperform boys in functional movements.
Functional movement screen; Movement patterns; Mechanics; Weight status
Sex and individual differences in biological maturity status can influence height, weight, and body fat. Thus, the rigorous control of these variables seems necessary for estimating overweight and obesity in adolescents. The aims of this study were to estimate the prevalence of overweight and obesity and over-fatness in Azorean adolescents and to examine the contributions of chronological age, sex, estimated maturity status, and cardiorespiratory fitness (CRF) to the risk of overweight and obesity and over-fatness.
The sample comprised 1,206 youth aged 11–15 years (626 boys and 580 girls) from the Azores Islands, Portugal. Body mass, stature, and skinfolds (triceps and subscapular) were measured. Body mass index (BMI) was calculated and percent fat was predicted from skinfolds. Age- and sex-specific IOTF cut-off values of the BMI defined nutritional status. Biological maturation was estimated as present height expressed as a percentage of predicted adult (mature) stature. The CRF was analyzed from the 20-m shuttle run test.
The total prevalence rates of overweight/obesity and over-fatness were of 31% and 27%, respectively. Low CRF (unfit) and being average and advanced in maturity status were positively and significantly associated with overweight/obesity and with risk of being over-fatness in both sexes.
High prevalence rates of overweight/obesity and over-fatness were identified in Azorean youth, and low CRF and advanced biological maturation were positively associated with overweight/obesity and over-fatness in our sample of adolescents.
Aim: To use existing data on height and weight of 5 year old children, routinely recorded annually as part of the school entry medical, to monitor trends in obesity over the last 16 years in three South Wales localities.
Methods: Body mass index (BMI) and percentage of children over the cut off points for being overweight or obese proposed by the International Obesity Task Force were determined in 46 073 children who had height, weight, and sex recorded each school year (between 1986/87 and 2001/02) on the National Child Health Computer System held at the Swansea NHS Trust.
Results: With the exception of one year, the coverage for BMI measurements ranged between 87% and 99%. The accuracy of measurement and data entry was identified as suspect in some cases, and although some data entry errors could be corrected, 14% of BMI measurements were inadmissible. Logistic regression analysis of BMI trends in the remainder showed that the percentage of 5 year olds classified as overweight or obese had increased significantly over the time period and that the rate of change in girls was significantly greater than that in boys.
Conclusion: Overweight and obese children have increased in frequency in this population. The Child Health Computer System is potentially a valuable source of information on the health status of populations and should be capable of monitoring trends in obesity. However, accuracy of measurement and data entry need to be improved, and the system, to be useful on a national basis, needs to be amalgamated at a higher level than individual NHS Trusts.
The SPEEDY study was set up to quantify levels of physical activity (PA) and dietary habits and the association with potential correlates in 9–10 year old British school children. We present here the analyses of the PA, dietary and anthropometry data.
In a cross-sectional study of 2064 children (926 boys, 1138 girls) in Norfolk, England, we collected anthropometry data at school using standardised procedures. Body mass index (BMI) was used to define obesity status. PA was assessed with the Actigraph accelerometer over 7 days. A cut-off of ≥ 2000 activity counts was used to define minutes of moderate-to-vigorous PA (MVPA). Dietary habits were assessed using the Health Behaviour in School Children food questionnaire. Weight status was defined using published international cut-offs (Cole, 2000). Differences between groups were assessed using independent t-tests for continuous data and chi-squared tests for categorical data.
Valid PA data (>500 minutes per day on ≥ 3 days) was available for 1888 children. Mean (± SD) activity counts per minute among boys and girls were 716.5 ± 220.2 and 635.6 ± 210.6, respectively (p < 0.001). Boys spent an average of 84.1 ± 25.9 minutes in MVPA per day compared to 66.1 ± 20.8 among girls (p < 0.001), with an average of 69.1% of children accumulating 60 minutes each day. The proportion of children classified as overweight and obese was 15.0% and 4.1% for boys and 19.3% and 6.6% for girls, respectively (p = 0.001). Daily consumption of at least one portion of fruit and of vegetables was 56.8% and 49.9% respectively, with higher daily consumption in girls than boys and in children from higher socioeconomic backgrounds.
Results indicate that almost 70% of children meet national PA guidelines, indicating that a prevention of decline, rather than increasing physical activity levels, might be an appropriate intervention target. Promotion of daily fruit and vegetable intake in this age group is also warranted, possibly focussing on children from lower socioeconomic backgrounds.
This study aimed to examine the secular trends in body mass index (BMI), waist circumference (WC), and the prevalence of general and abdominal obesity among Chinese children and adolescents from 1993 to 2009.
Data were obtained from the China Health and Nutrition Survey conducted from 1993 to 2009. 9693 children and adolescents aged 6-17years were included in this study, with their height, weight and WC were measured. General obesity was defined using the BMI cutoffs for overweight recommended by the International Obesity Task Force, and abdominal obesity was assessed when a WC above the 90th percentile for sex and age.
Among total participants, mean BMI and WC increased significantly over the period 1993–2009: BMI increased from 17.6 to 17.8 kg/m2, and WC increased from 61.4 to 63.1 cm (both increases P <0.001). The prevalence of general obesity and abdominal obesity increased significantly over the period: general obesity (including overweight) rose from 6.1% to 13.1% and abdominal obesity from 4.9% to 11.7% (both increases P <0.001). WC and abdominal obesity increased at a relatively higher rate than BMI and general obesity. Upward trends in the prevalence of general and abdominal obesity were observed in all subgroups of sex, age and region (all increases P <0.05), except for abdominal obesity in girls aged 13–17 years old (P =0.102).
General and abdominal obesity increased significantly over the past 17 years in Chinese children.
trend; body mass index; waist circumference; obesity; children; adolescents; China
This study compares the Center for Disease Control (CDC) and International Obesity Task Force (IOTF) references in assessment of overweight and obesity among Iranian adolescents.
The data of this study was drawn from a cross sectional study of a representative sample of 1200 adolescents aged 12-17 years in Babol, northern Iran. A standard procedure was used to measure height and weight and the body mass index was calculated. Each subject was classified as overweight and obese based on IOTF cut off values of BMI and CDC references BMI percentile sets by age and sex. The kappa coefficients were estimated for the degree of agreement.
In assessment of obesity/overweight prevalence, the CDC and IOTF references produced a similar estimate by age group and sex. The maximum differences was about 1% and the kappa coefficients was 0.96 to 1 (P = 0.001). While for assessment of obesity, the CDC reference produced slightly a higher rate of obesity and the difference in prevalence between the two sets of references was ranged from 1.4% to 3.2% with kappa coefficients: 0.90 to 0.70 (P = 0.001) depending on the age group and sex and a greater difference was observed among younger age group.
The findings suggest an excellent agreement between the TOTF and CDC references in assessment of overall overweight/obesity prevalence among adolescent boys and girls. While in assessment of obesity prevalence alone the degree of agreement between the two sets of references slightly diminished. Overall, the two references are comparable and the agreement varies a little with respect to age and sex.
Adolescents; Babol; center for disease control; international obesity task force; obesity; overweight
This paper investigated the validity of self-reported height and weight of adolescents for the diagnosis of underweight, overweight and obesity and the influence of weighing behaviour on the accuracy. A total of 982 adolescents reported their height, weight, weighing behaviour and eating patterns in a questionnaire. Afterwards, their height and weight were measured and their Body Mass Index (BMI)-categories were determined using age- and gender-specific BMI cut-off points. Both girls and boys underreported their weight, whilst height was overestimated by girls and underestimated by boys. Cohen’s d indicated that these misreportings were in fact trivial. The prevalence of underweight was overestimated when using the self-reported BMI for classification, whilst the prevalence of overweight and obesity was underestimated. Gender and educational level influenced the accuracy of the adolescents’ self-reported BMI. Weighing behaviour only positively influenced the accuracy of the self-reported weight and not height or BMI. In summary, adolescents’ self-reported weight and height cannot replace measured values to determine their BMI-category, and thus the latter are highly recommended when investigating underweight, overweight and obesity in adolescents.
height; weight; body mass index; validity; adolescents; weighing behaviour
Parents are responsible not only for the genetic structure of their children, but also for passing onto them their behaviours and attitudes toward life. The aim of this study was to analyse the connection between school-age children's obesity and that of their parents as well as between child obesity and parents' educational level, as a proxy indicator of the socio-economic status (SES) of families in Tuscany.
The children sample was selected from "OKkio alla Salute 2010" (a cross sectional survey carried out by the Italian Institute of Health) and consisted of 1,751 (922 males and 855 females) 8-9 year-old school children. Weight and height were measured by ad hoc trained personnel, and Body Mass Index (BMI) categories were calculated using Cole et al.'s cut-off. Parents' weight, height and educational level were collected by a self-administered questionnaire. The educational levels were classified as high, medium and low.
The prevalence of obese children increased along the parents' BMI category: from 1.4% for underweight mothers to 30.3% for obese mothers and from 4% for under-normal-weight fathers to 23.9% for obese fathers (p < 0.001). An inverse relationship was observed between the parents' educational level and child obesity, the lowest educational level corresponding to the highest prevalence of obese children: 9.3% for mothers with a low educational level compared to 5.8% for mothers with a high educational level (p = 0.15); similarly, the corresponding prevalence for fathers was 9.5% compared to 4.5% (p = 0.03).
Parents' obesity and the cultural resources of the family, particularly the father's, seem to influence the prevalence of overweight and obesity in Tuscan children.
childhood; obesity; underweight; parents' nutritional status; educational level
The World Health Organization (WHO) is in the process of establishing a new global database on the growth of school children and adolescents. Limited national data exist from Asian children, notably those living in the Middle East and North Africa (MENA). This study aimed to generate the growth chart of a nationally representative sample of Iranian children aged 10–19 years, and to explore how well these anthropometric data match with international growth references.
In this nationwide study, the anthropometric data were recorded from Iranian students, aged 10–19 years, who were selected by multistage random cluster sampling from urban and rural areas. Prior to the analysis, outliers were excluded from the features height-for-age and body mass index (BMI)-for-age using the NCHS/WHO cut-offs. The Box-Cox power exponential (BCPE) method was used to calculate height-for-age and BMI-for-age Z-scores for our study participants. Then, children with overweight, obesity, thinness, and severe thinness were identified using the BMI-for-age z-scores. Moreover, stunted children were detected using the height-for-age z-scores. The growth curve of the Iranian children was then generated from the z-scores, smoothed by cubic S-plines.
The study population comprised 5430 school students consisting of 2312 (44%) participants aged 10–14 years , and 3118 (58%) with 15–19 years of age. Eight percent of the participants had low BMI (thinness: 6% and severe thinness: 2%), 20% had high BMI (overweight: 14% and obesity: 6%), and 7% were stunted. The prevalence rates of low and high BMI were greater in boys than in girls (P < 0.001). The mean BMI-for-age, and the average height-for-age of Iranian children aged 10–19 years were lower than the WHO 2007 and United states Centers for Disease Control and Prevention 2000 (USCDC2000) references.
The current growth curves generated from a national dataset may be included for establishing WHO global database on children’s growth. Similar to most low-and middle income populations, Iranian children aged 10–19 years are facing a double burden of weight disorders, notably under- and over- nutrition, which should be considered in public health policy-making.
Growth; Iran; Reference curve; Weight disorder
Objective. To assess the prevalence of obesity, overweight, and thinness among children in an Italian school. Methods. Five hundred ninety-five children (289 males and 306 females) were enrolled, aged between 6 and 19 years old, in Italian school in Rome. Body mass index (BMI) was calculated according to International Obesity Task Force (IOFT) cut-off points. By age criterion all participants have been classified in age classes. Results. A normal BMI was recorded in 73.6% of all cases. Obesity, overweight, and thinness prevalence was 5.9%, 9.6%, and 10.9%, respectively, without statistical differences in both genders, except the prevalence of overweight that resulted statistically significant (13.1% males versus 6.2% females, P < 0.05). Differences in the age groups have been found. About 23.4% of children between 7 to 11 years were defined obese and about 42.3% between 6 to 8 years thin grade 2, respectively. Conclusion. The study reports the low prevalence of overweight and obesity, in contrast to the unexpected thinness prevalence. The identification of specific age groups with abnormal nutritional status could be the first step to address future epidemiological investigations in order to plan strategic approach in selected age periods.
Body mass index (BMI) is a common indirect method to assess weight status among children. There is evidence that BMI data alone can underestimate overweight-related health risk and that waist circumference (WC) should also be measured. In this study we investigated the agreement between BMI and WC and BMI and the waist-height ratio (WHtR) when used to identify overweight among children.
This cross-sectional population-based study uses baseline data from 5-year-olds (n = 7703) collected by healthcare professionals for the ‘Be active, eat right’ study.
According to age-specific and sex-specific cut-off points for BMI (IOTF, 2000) and WC (Fredriks et al., 2005), the prevalence of overweight (obesity included) was 7.0% and 7.1% among boys, and 11.6% and 10.1% among girls, respectively. For the WHtR the 90th percentile was used as the cut-off point. Among boys, observed proportion of agreement between BMI and WC classification was 0.95, Cohen’s kappa 0.58 (95% CI; 0.53-0.63), and proportions of positive and negative agreement were 0.61 and 0.97, respectively. Observed proportion of agreement between BMI and WHtR classification was 0.92, Cohen’s kappa 0.46 (95% CI; 0.41-0.51), and proportions of positive and negative agreement were 0.51 and 0.95. Children identified as overweight according to WC were relatively tall, and children classified as overweight according to the WHtR only were relatively short (comparable results for girls).
There is moderate agreement between BMI and measures of WC on the presence of overweight among 5-year-olds. If BMI data and cut-offs continue to be used, then part of the group of children identified as overweight according to WC and the WHtR will be omitted. Follow-up of the children classified as overweight according to BMI only, WC only, and WHtR only, will give indications whether WC should be measured in addition to BMI or whether WC should only be measured in certain subgroups (e.g. relatively tall or short children) to identify and monitor overweight in children. This may improve early identification and prevention of overweight and overweight-related health problems in children.
Body mass index; Waist circumference; Overweight; Preschool child; Pediatrics; Prevalence
Objectives. We examined cross-sectional and longitudinal associations between obesity and emotional and behavioural problems in a nationally representative sample of young children. Methods. Data were available from 11 202 children (50% boys) participating in the UK's Millennium Cohort Study. Height and weight were measured at 3 and 5 years and children defined as obese using IOTF cut-offs for body mass index (BMI). Emotional and behavioural problems were parentally assessed using the Strengths and Difficulties Questionnaire. Adjusted linear and multinomial regression analyses were conducted separately for boys and girls. Results. At age 3, obese boys had more conduct problems, and obese girls had more prosocial behaviours, than their normal weight counterparts. At age 5, obese boys had more conduct problems, hyperactivity and inattention problems, peer relationship problems and total difficulties. Obese girls only had more peer relationship problems. Obese 3-year-olds were not at increased risk of abnormal scores; in contrast, obese 5-year-old boys were significantly more likely to have abnormal scores for conduct problems, hyperactivity and inattention problems, peer relationship problems, prosocial behaviours and total difficulties. Obesity, at age 3, was also predictive of peer relationship problems at age 5 in boys (95% CI: 0.26 [0.01, 0.52]). Conclusions. Childhood obesity is associated with emotional and behavioural problems from a very young age. Obese boys are at particular risk. Further research is required to examine effect modifiers and mediating factors in these associations. Recognition and response to these mental health problems should be a goal of pediatric obesity interventions and policies.
Children; emotional and behavioural problems; mental health; obesity; prospective relationships; Strengths and Difficulties; Questionnaire
Obesity is associated with increased morbidity and premature death. Obesity rates have increased worldwide and the WHO recommends monitoring. A steep rise in body mass index (BMI), a measure of adiposity, was detected in Greenland from 1963 to 1998. Interestingly, the BMI starting point was in the overweight range. This is not conceivable in a disease-free, physically active, pre-western hunter population.
This led us to reconsider the cut-off point for overweight among Inuit in Greenland.
Design and findings
We found 3 different approaches to defining the cut-off point of high BMI in Inuit. First, the contribution to the height by the torso compared to the legs is relatively high. This causes relatively more kilograms per centimetre of height that increases the BMI by approximately 10% compared to Caucasian whites. Second, defining the cut-off by the upper 90-percentile of BMI from height and weight in healthy young Inuit surveyed in 1963 estimated the cut-off point to be around 10% higher compared to Caucasians. Third, if similar LDL-cholesterol and triglycerides are assumed for a certain BMI in Caucasians, the corresponding BMI in Inuit in both Greenland and Canada is around 10% higher. However, genetic admixture of Greenland Inuit and Caucasian Danes will influence this difference and hamper a clear distinction with time.
Defining overweight according to the WHO cut-off of a BMI above 25 kg/m2 in Greenland Inuit may overestimate the number of individuals with elevated BMI.
BMI; cut-off point; overweight; obesity; Greenland Inuit; ethnicity; review