Pedometer-determined physical activity among obese and non-obese 8- to 12-year-old Saudi schoolboys

Physical activity levels were measured in obese and non-obese 8- to 12- year-old schoolboys (n=296). Anthropometric measures included weight, height, body mass index (BMI), triceps and subscapular skinfolds, predicted fat percentage, fat mass (FM), fat-free mass (FFM), FM index (FMI), and FFM index (FFMI). Physical activity was assessed using an electronic pedometer for three continuous weekdays. Boys were divided into active and inactive groups based on daily accumulation of pedometer counts above or below 13,000 steps. Obesity was defined as body fat content that equals or exceeds 25% of body weight. The international age- and gender-specific child BMI cut-off points were also used to define overweight and obesity. Estimated fat content for the whole sample averaged 23.3+/-9.7%. More than 37% of the boys were classified as obese. The mean step counts were about 13,489+/-5,791 steps per day (range: 335-29,169 steps). Over 71% of the boys accumulated 10,000 steps or more per day. Based on BMI standards, mean step counts for the obese group (10,602+/-4,800 steps/day) were significantly (p=0.004) lower than in the normal group (14,271+/-5,576 steps/day). Based on fat percentage, obese boys also accumulated significantly (p=0.009) lower numbers of steps per day (12,682+/-5,236) than did non-obese boys (14,915+/-5,643). Further, there were significant differences (p<0.05) between active and inactive boys in weight, BMI, triceps and subscapular skinfolds, fat percentage, FMI, and flexibility. It is concluded that the prevalence of obesity and inactivity among Saudi boys aged 8-12 years was high. Active boys exhibited significantly lower body fat percentage and BMI than inactive peers. Obese boys, on the other hand, were significantly less active than non-obese boys. Increased prevalence of obesity and physical inactivity among Saudi children is a major public health concern.     

Body mass and body fat in Hungarian schoolboys: differences between 1980-2005

The prevalence of juvenile excess weight keeps growing in the more developed world (WHO, 1998). The aim of the study was to compare the prevalence of overweight and obesity in Hungarian schoolboys in 1980 and 2005.Two independent representative data collections were performed in volunteer boys aged between 6.51 and 18.50 years in the same 90 settlements of the country in 1980 (n=13,061) and 2005 (n=13,060). Height, body mass, and five skinfolds were measured by the same investigators in both instances. Overweight and obesity were estimated by using BMI (Cole et al., 2000), respectively skinfold thicknesses (Parízková, 1961).The pair-wise differences between height means were consistently significant in the 12 age groups studied. Body mass differences were not exactly proportionate with height. The boys of 2005 had significantly more relative body fat than those of 1980. The prevalence of overweight and obesity was remarkably higher in 2005.Taller height and a part of the heavier body mass in 2005 was attributed to a positive secular growth trend. The increases in BMI and fat content are negative consequences of a markedly changed lifestyle associated with inactivity and dietary habits. Because of its public health importance the trends of childhood obesity should be closely monitored.     

Overweight and obesity in 7 to 10-year-old Hungarian boys. Short communication

Increasing prevalence of overweight and obesity is a serious social and health problem both in the economically developed and developing countries. Despite this fact the nation-wide growth studies completed in Hungary during the past 30 years had not categorised the children either by body fat content or nutritional status. The aim of the study was to estimate the prevalence of overweight and obese boys in the country at the beginning of the new millennium. Height, body mass and four skinfold thicknesses were measured in 7173 volunteer boys aged between 7 and 10 and living in various urban and rural settlements of Hungary between 2003 and 2005. Nutritional status was qualified by the BMI and relative body fat content. The significantly increasing prevalence with age of overweight and obesity ranged between 10.3 and 23.4%. The results showed the joint effects of a secular trend of growth and of a remarkably changed lifestyle. Of these the consequences of the lifestyle are the more important ones. The high and possibly further increasing prevalence of child-age overweight and obesity reminds one of the observations of Kopp and associates (5), namely that of the increased prevalence of chronic childhood diseases during the past 15 years. More intense habitual physical activity and dramatic changes in dietary habits still promise some solution. No one should reckon, however, with the efficiency of physical education at the schools with its very few classes.     

Adiposity, physical activity, and physical fitness among children from Aragón, Spain

Objective: The main purpose of this study was to determine the relationship between physical activity (PA) levels and adiposity. The secondary purpose was to assess the effect of physical fitness and living area on adiposity. Research Methods and Procedures: A cross‐sectional study was carried out in a regional representative sample of 1068 children 7 to 12 years of age. Anthropometric and physical fitness values (including BMI, aerobic capacity, strength levels, velocity assessment, and flexibility) were measured in all children. Results: The prevalence of being overweight and obese in the entire sample was 31% and 6%, respectively. No difference between urban and rural children was found. The proportion of boys who were classified as overweight and obese was similar in physically active and sedentary (non‐physically active) groups. However, physically active girls tended to show lower obesity prevalence compared with their sedentary counterparts (p = 0.06). In girls, the sum of the 6 skinfolds thickness (SSF) measurements was lower in the physically active group when compared with the non‐physically active group (p < 0.05); however, this effect was not observed in boys. Multiple regression analysis revealed that the level of physical activity (PA) had a significant effect on BMI and SSF in boys but not in girls, while maximal oxygen uptake (Vo _2max) was significantly related to adiposity in both sexes. Discussion: Regular participation in at least 2 hours per week of sports activities on top of the compulsory education program is associated with better physical fitness and lower whole body adiposity. In the children included in our study, among all physical fitness variables, Vo _2max showed the strongest relationship with BMI and fat mass assessed by means of skinfold measurements.     

Changes in anthropometrical characteristics during two years in 6 year old children

The purpose of this study was to investigate changes in anthropometrical characteristics during the last year (autumn-spring) in preschool and first year (autumn-spring) in school. Changes in anthropometrical characteristics during summer months were also studied (spring-autumn). The subjects were 130 boys and 122 girls, 6 years of age at the beginning of the investigation. The body height and mass were measured and the BMI (kg/m2) was calculated. In total, eight skinfolds, 10 girths and two bone widths were measured. In boys, the body height and mass were higher than in girls, while the skinfold thicknesses were thicker in girls. There were only very few significant differences between sexes in girth parameters. The width parameters were higher in boys. Our results indicated that there were more significant changes in skinfold thickness, girths and width parameters during winter in preschool in comparison with first year in school in boys, while there were only a very few significant changes during summer months in boys. In contrast, there were more significant changes in school in girls. The Spearman correlations between baseline and after 6, 12 and 18 months of study indicated that the tracking of body height was high in boys and girls. Body mass tracking was high in girls and moderate in boys, while BMI tracking was moderate in both groups. The tracking coefficients of skinfold thicknesses were relatively stable during the two years of study and mostly at the moderate level (r = 0.3-0.6). Tracking coefficients of girths measures were at moderate level, but lower in boys in comparison with girls. It was concluded that social changes and probably changes in the physical activity during transition from preschool to school slightly influenced the measured anthropometrical parameters.     

Validity of convenient indicators of obesity

A validation study of convenient indicators of obesity was undertaken in 540 male and female subjects, aged 7-14 yr. Four adiposity measures that have commonly accepted obesity classification points [relative weight, relative body mass index (BMI), sum of five skinfolds, and triceps skinfold] were derived from measures of height, weight, and five skinfold thickness measurements. Body density measures were converted to percentage of body fat using Lohman's (1986) age- and gender-specific regression equations. Using greater than or equal to 20% body fat for males and greater than or equal to 25% for females as the standard for obesity, the diagnostic utilities (sensitivity, specificity, overall accuracy, and positive and negative predictive values) of the four obesity indicators at their commonly used obesity cutoff points were determined. Preliminary analyses demonstrate that use of these indicators should not be considered independent of the gender of the subject or without reference to the purpose for classifying subjects as obese. Secondary analyses, in which the obesity cutoff point in each indicator was altered to obtain a minimum specificity level of 95%, demonstrated that a sum of skinfolds was better at identifying true obesity than all other indicators in both males and females. There is potential for inappropriate labeling with all convenient indicators of obesity, and thus they should be used with caution.     

Height and Adiposity among Children

Objectives : Although BMI (kilograms per meter squared) is widely used as a surrogate measure of adiposity, it is moderately associated (r ～ 0.3) with height among children. We examined whether the resulting preferential classification of taller children as overweight, based on a BMI ≥95th percentile, is appropriate. Research Methods and Procedures : We assessed the cross‐sectional relation of height among 5‐ to 18‐year‐old subjects (n = 1180) to levels of BMI, the sum of 10 skinfold thicknesses, and percentage body fat as determined by DXA. Results : The prevalence of a BMI level ≥95th percentile was substantially higher among 5‐ to 11‐year‐old subjects who were relatively tall for their age than among shorter children. Among 5‐ to 8‐year‐old boys, for example, each SD increase in height‐for‐age was associated with a 4.6‐fold increase in the prevalence of overweight (p < 0.001). Height not only was associated with BMI but also showed similar correlations with the skinfold sum and with percentage body fat; furthermore, the magnitudes of these associations decreased with age. We also found that the association between percentage body fat and BMI (r = 0.85 to 0.90) was close to the maximum correlation that can be achieved by any weight‐height index. Discussion : The use of BMI, which preferentially classifies taller young children as overweight, is appropriate because height and adiposity are correlated before the age of 12 years.     

Physical Activity as a Predictor of Body Composition in American Indian Children

Objective: To examine physical activity in second grade American Indian children as a predictor of percentage body fat 3 years later. Research Methods and Procedures: Physical activity was assessed as average vector magnitude (AVM) counts from an accelerometer in 454 second grade children as part of the Pathways study. BMI was assessed, and skinfolds and bioelectrical impedance were used to estimate fat mass, fat‐free body mass, and percentage body fat in validated prediction equations. Associations were examined using mixed models regression controlling for baseline body composition. Results: In normal‐weight children, higher AVM counts were significantly associated with decreases in percentage body fat. Among overweight children, higher AVM counts were significantly associated with increases in BMI, fat mass, and fat‐free mass but not percentage body fat. Discussion: Higher physical activity levels in second grade were associated with lower levels of percentage body fat in fifth grade in normal‐weight but not in overweight children. BMI showed no association with physical activity among normal‐weight children, and increases in BMI were associated with increasing amounts of physical activity among overweight children. These findings emphasize the importance of valid body composition measures and may indicate important differences in associations between physical activity and adiposity in normal‐weight as compared with overweight children.     

芜湖地区青少年儿童皮下脂肪及身体围度发育规律初探

分析了安徽省芜湖地区1217名城乡在校中小学生四项皮褶厚度及四项身体围度随年龄变化的规律,尤其是青春期的变化;以及营养、气候等环境因素对儿童青少年身体发育的影响。结果表明：在即将进入青春发育期时,男性四肢部皮下脂肪迅速减少;女性皮下脂肪在青春期迅速增厚;身体围度则随年龄增长而增加,在青春后期,围度保持在一定水平。     

Bright Start: Description and Main Outcomes From a Group‐Randomized Obesity Prevention Trial in American Indian Children

The aim of the Bright Start study was to develop and test the effectiveness of a school environment intervention, supplemented with family involvement, to reduce excessive weight gain by increasing physical activity and healthy eating practices among kindergarten and first‐grade American Indian children. Bright Start was a group‐randomized, school‐based trial involving 454 children attending 14 schools on the Pine Ridge Reservation in South Dakota. Children were followed from the beginning of their kindergarten year through the end of first grade. Main outcome variables were mean BMI, mean percent body fat, and prevalence of overweight/obese children. The goals of the intervention were to: increase physical activity at school to at least 60 min/day; modify school meals and snacks; and involve families in making behavioral and environmental changes at home. At baseline, 32% of boys and 25% of girls were overweight/obese. Although the intervention was not associated with statistically significant change in mean levels of BMI, BMI‐Z, skinfolds or percentage body fat, the intervention was associated with a statistically significant net decrease of 10% in the prevalence of overweight. Intervention children experienced a 13.4% incidence of overweight, whereas the control children experienced a corresponding incidence of 24.8%; a difference of ?11.4% (P = 0.033). The intervention significantly reduced parent‐reported mean child intakes of sugar‐sweetened beverages, whole milk, and chocolate milk. Changes in duration of school physical activity were not significant. Because obesity is the most daunting health challenge facing American Indian children today, more intervention research is needed to identify effective approaches.     

Comparisons of fatness indicators in Budapest children

The aim of this study was to estimate the fatness level of Budapest children and youth in different ways and to compare these estimations using a large representative sample. Eighteen body measurements were taken on 2606 healthy boys and 2471 healthy girls aged between 3 and 18 years. About 20% of this sample was measured by the Futrex 5000A near infrared (NIR) spectrophotometer to assess the body fat percent (data of 419 boys and 462 girls aged between 5 and 18 years were analysed). Triceps skinfold thickness (TSF), sum of triceps, medial calf, subscapular and suprailiac skinfold thicknesses (SFS), body fat percent estimated according to Slaughter et al. (%BF), BMI (calculated from height and weight) and body fat percent assessed by NIR-method (NIR%BF) were compared. chi 2 tests of independence show significant connections among the distributions ranged by the five fatness indicators. However, correlation coefficients and standard errors indicate that strong relationships are only among the assessments based on skinfold thicknesses (r = 0.92-0.97, SEE = 1.8-2.6%). BMI and NIR%BF assess body fatness differently compared to skinfold thicknesses: r-values are moderate and SEE-values are relatively large (r = 0.59-0.87, SEE = 1.9-4.7%). These findings can be seen in both the boys and the girls. NIR%BF comparing to %BF significantly overpredicts body fat percent in the boys and significantly underpredicts it in the girls. BMI, height and weight are not in significant correlation with NIR%BF in the boys but there are moderate correlations in the girls. Our suggestion is that more research is needed with the use of NIR-method in children and adolescents, and it is necessary to refine prediction equations taking into consideration very carefully sex sand age differences.     

Differences in physical activity between non-overweight, overweight and obese children

The purpose of the study was to find out differences in moderate to vigorous physical activity among non-overweight, overweight and obese children, and between boys and girls. The sample included 364 children (179 boys and 185 girls), aged 6.4 years (+/- 0.3 SD). Physical activity was assessed by 7-day questionnaire. Age adapted BMI was used as overweight and obesity indicator. The children were divided into non-overweight, overweight and obese groups. It was found out, that there are significant differences in non-overweight, overweight and obese children (p < 0.05). Boys were significantly (p < 0.05) less moderate to vigorous physical active than girls, especially in indoor activities. There were also significant differences (p < 0.05) in moderate to vigorous physical activity among non-overweight and obese boys and among overweight and obese boys in weekends and total weekly activity. In girls there are significant differences (p < 0.05) in non-overweight, overweight and groups in weekends and total weekly activity. It is possible to conclude, that obese boys and overweight and obese girls, are prone to less physical activity.     

Effects of 3 hours a week of physical activity on body fat and cardio-respiratory parameters in obese boys

The prevalence of overweight or fat children and adolescents has markedly increased in Hungary during the past three decades. Among the possible factors insufficient physical activity and a relative or absolute excess of calorie intake associated to it can be regarded as the most important ones. The aim of the study was to analyse the effects of a 20-week aerobic exercise on body composition and on the exercise tested cardio-respiratory functions in 10-year-old obese boys. Obesity was defined by a BMI greater than the cut-off value reported by Cole and co-workers (5) and a relative body fat content above 30% (13). Of the study group 21 volunteer children completed the program; the contrast group contained 28 obese boys. Mean calendar age was 10.03 +/- 0.26 in the study group (S) and 9.88 +/- 0.29 in the control group (C). The members of group S had two curricular physical education (PE) classes a week and three extracurricular aerobic physical activity sessions of 60 min net time in the afternoon, on Mondays (swimming and water games), Wednesdays (folk dance) and Fridays (soccer). Group C had only 2 PE classes a week. Anthropometric and spiroergometric data were collected in the middle of January and June of 2004. Relative body fat content and BMI did not increase during the observation period in contrast to the significant increase of both in the control group. Peak minute ventilation, aerobic power, oxygen pulse, and running distance (performed on a treadmill) increased in group S, and did not change in group C. The program was considered successful despite that the changes in the observed physiological and physical indicators appeared to be slight. However, the 5-month elevated level of physical activity brought about such development in the physical status of the obese subjects that might be an appropriate basis for regular training. Fortunately, the cardio-respiratory functions of the investigated boys were not affected yet by obesity, consequently the really dramatic change in their further lifestyle exclusively depends on their decision.     

达斡尔族学生皮下脂肪发育的研究

作者内蒙古莫力达瓦达斡尔族自治旗１７５９例中小学生项项皮褶厚度及体脂发育情况进行了调查研究。结果表明：（１）达斡尔族学生进入青春期后,随着年龄的增长,男性躯干部皮变厚,四肢部皮褶变薄,女性躯干、四肢部皮褶均增厚。（２）１２岁后,女性皮褶厚度显著大于男性。（３）青春发育早期,男性体脂逐渐有下降,女性于１２－１４岁体脂迅速增加。（４）总体说来,达斡尔族学生并不偏于肥胖。     

Energy intake, diet composition, energy expenditure, and body fatness of adolescents in northern Greece

Objective: The purpose of this study was to examine energy intake, energy expenditure, diet composition, and obesity of adolescents in Northern Greece. Research Methods and Procedures: Anthropometric measurements were taken for all participants. Height, weight, and skinfold thickness at two sites were measured. BMI and percentage body fat were calculated. Energy intake and macronutrient and micronutrient intakes were determined by a 3‐day weighed dietary diary. Energy expenditure was calculated based on calculated resting metabolic rate (RMR) 1 multiplied by an activity factor based on reported physical activity. Results: Thirty‐one percent of boys and 21% of girls had BMI corresponding to ≥25 kg/m² at 18 years and were classified as overweight. Both overweight boys and girls reported a lower energy intake compared with their non‐overweight counterparts when expressed as kilocalories per kilogram body weight. Overweight children had a higher negative energy balance. Both overweight and non‐overweight adolescents had higher than recommended fat intakes. Mean daily carbohydrate, protein, and fat intake, expressed as grams per kilogram body weight, of overweight adolescents were significantly lower compared with the non‐overweight adolescents. Total daily carbohydrate intake, when expressed in grams, was found to be higher for non‐overweight adolescents. Both overweight boys and girls had lower iron intakes than their non‐overweight counterparts. Overweight boys had statistically lower fiber and niacin intakes than non‐overweight boys. Both overweight and non‐overweight adolescents had lower than recommended iron intakes. Furthermore, overweight adolescents consumed more snacks (potato chips, chocolate bars, pizza, cheese pie, and cream pie), more sugar, jam, and honey, and fewer legumes, vegetables, and fruits than their non‐overweight counterparts. Discussion: Reported energy intake of overweight adolescents was lower than their non‐overweight counterparts. Regarding diet composition overweight subjects had significantly lower intakes of carbohydrates compared with non‐overweight subjects. The food consumption pattern of overweight children showed less adherence to the traditional Mediterranean diet.     

Fat distribution in lean and obese young indian women: A densitometric and anthropometric evaluation

The pattern of fat distribution in lean and obese young Indian women was studied using seven girths and ten skinfold thicknesses. Though the lean and obese subjects differed significantly with respect to their body weight and total body fat content, body girths indicated that the proportion of fat distributed between the extremities and over the trunk region was essentially similar. By comparing skinfold thicknesses, it was observed that the fat women were merely an exaggeration of the fat profile pattern of the lean women. Although the pattern of subcutaneous fat distribution was similar in lean and obese subjects, the rate of fat deposition differed on different parts of the body with increase in total adiposity.     

Moderate exercise and bright light treatment in overweight and obese individuals

Objective: Increased physical activity is important given the concern over the growing rates of obesity. The aim of this study is to conduct a controlled investigation of the effects of bright light therapy and exercise on weight loss and body composition in overweight and obese individuals. Research Methods and Procedures: Twenty‐five overweight and obese subjects were assigned to 6 weeks of moderate exercise with or without bright light treatment. Outcome measure included changes in body mass and body composition and ratings of mood, seasonality, and sleep. Results: Body weight decreased significantly with exercise in subjects in the light and non‐light treatment groups, but the change was not significantly different between the groups. Similar results were found for BMI. With exercise, body fat decreased significantly only in the light treatment group. There was a significant effect of the interaction of group by time on body fat composition, but the group by time interaction failed to reach statistical significance for body weight and BMI. Mood scores improved significantly with exercise in the light group, but no significant changes were noted regarding sleep. Discussion: This preliminary study is the first to show that addition of bright light treatment to a 6‐week moderate exercise program can alter body composition by significantly reducing body fat. The reduction in body fat mass is of particular importance, because visceral fat has been particularly implicated as a major factor in the development of the metabolic syndrome. This study is an important step toward finding ways to maximize the effects of exercise.     

Longitudinal study of body weight changes in children: who is gaining and who is losing weight

Cross-sectional studies have reported significant temporal increases in prevalence of childhood obesity in both genders and various racial groups, but recently the rise has subsided. Childhood obesity prevention trials suggest that, on average, overweight/obese children lose body weight and nonoverweight children gain weight. This investigation tested the hypothesis that overweight children lose body weight/fat and nonoverweight children gain body weight/fat using a longitudinal research design that did not include an obesity prevention program. The participants were 451 children in 4th to 6th grades at baseline. Height, weight, and body fat were measured at month 0 and month 28. Each child's BMI percentile score was calculated specific for their age, gender and height. Higher BMI percentile scores and percent body fat at baseline were associated with larger decreases in BMI and percent body fat after 28 months. The BMI percentile mean for African-American girls increased whereas BMI percentile means for white boys and girls and African-American boys were stable over the 28-month study period. Estimates of obesity and overweight prevalence were stable because incidence and remission were similar. These findings support the hypothesis that overweight children tend to lose body weight and nonoverweight children tend to gain body weight.     

Physical Fitness and Physical Activity in Obese and Nonobese Flemish Youth

Objective: To assess different aspects of physical fitness and physical activity in obese and nonobese Flemish youth. Research Methods and Procedures: A random sample of 3214 Flemish schoolchildren was selected and divided into an “obese” and “nonobese” group based on body mass index and sum of skinfolds. Physical fitness was assessed by the European physical fitness test battery. Physical activity was estimated by a modified version of the Baecke Questionnaire. Results: Obese subjects had inferior performances on all tests requiring propulsion or lifting of the body mass (standing‐broad jump, sit‐ups, bent‐arm hang, speed shuttle run, and endurance shuttle run) compared with their nonobese counterparts (p < 0.001). In contrast, the obese subjects showed greater strength on handgrip (p < 0.001). Both groups had similar levels of leisure‐time physical activity; however, nonobese boys had a higher sport index than their obese counterparts (p < 0.05). Discussion: Results of this study show that obese subjects had poorer performances on weight‐bearing tasks, but did not have lower scores on all fitness components. To encourage adherence to physical activity in obese youth, it is important that activities are tailored to their capabilities. Results suggest that weight‐bearing activities should be limited at the start of an intervention with obese participants and alternative activities that rely more on static strength used.     

Relationship between the percentage of body fat and surrogate indices of fatness in male and female Polish active and sedentary students

Background

Limited data have indicated that body mass index (BMI), waist circumference (WC), waist to hip ratio (WHR) and waist to height ratio (WHtR) of athletes and young adults provide misleading results concerning body fat content. This study was aimed at the evaluation of the relationship between different surrogate indices of fatness (BMI, WC, WHR, WHtR and body adiposity index (BAI)) with the percentage of body fat in Polish students with respect to their sex and physical activity.

Methods

A total of 272 students volunteered to participate in the study. Of these students, 177 physical education students (90 males and 87 females) were accepted as active (physical activity of 7 to 9 hours/week); and 95 students of other specializations (49 males and 46 females) were accepted as sedentary (physical activity of 1.5 hours/week). Weight, height, waist and hip circumferences were measured, and BMI, WHR, WHtR and BAI were calculated. Body fat percentage was assessed using four skinfold measurements.

Results

Classification of fatness according to the BMI and the percentage of body fat have indicated that BMI overestimates fatness in lean subjects (active men and women, sedentary men), but underestimates body fat in obese subjects (sedentary women). In all groups, BMI, WHR, WHtR and BAI were significantly correlated with the percentage of body fat (with the exception of WHR and hip circumference in active and sedentary women, respectively). However, coefficients of determination not exceeding 50% and Lin’s concordance correlation coefficients lower than 0.9 indicated no relationship between measured and calculated body fat.

Conclusion

The findings in the present study support the concept that irrespective of physical activity and sex none of the calculated indices of fatness are useful in the determination of body fat in young adults. Thus, it seems that easily calculated indices may contribute to distorted body image and unhealthy dietary habits observed in many young adults in Western countries, but also in female athletes.