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.     

Sugar‐Added Beverages and Adolescent Weight Change

Objectives : The increase in consumption of sugar‐added beverages over recent decades may be partly responsible for the obesity epidemic among U.S. adolescents. Our aim was to evaluate the relationship between BMI changes and intakes of sugar‐added beverages, milk, fruit juices, and diet soda. Research Methods and Procedures : Our prospective cohort study included >10, 000 boys and girls participating in the U.S. Growing Up Today Study. The participants were 9 to 14 years old in 1996 and completed questionnaires in 1996, 1997, and 1998. We analyzed change in BMI (kilograms per meter squared) over two 1‐year periods among children who completed annual food frequency questionnaires assessing typical past year intakes. We studied beverage intakes during the year corresponding to each BMI change, and in separate models, we studied 1‐year changes in beverage intakes, adjusting for prior year intakes. Models included all beverages simultaneously; further models adjusted for total energy intake. Results : Consumption of sugar‐added beverages was associated with small BMI gains during the corresponding year (boys: +0.03 kg/m² per daily serving, p = 0.04; girls: +0.02 kg/m², p = 0.096). In models not assuming a linear dose‐response trend, girls who drank 1 serving/d of sugar‐added beverages gained more weight (+0.068, p = 0.02) than girls drinking none, as did girls drinking 2 servings/d (+0.09, p = 0.06) or 3+ servings/d (+0.08, p = 0.06). Analyses of year‐to‐year change in beverage intakes provided generally similar findings; boys who increased consumption of sugar‐added beverages from the prior year experienced weight gain (+0.04 kg/m² per additional daily serving, p = 0.01). Children who increased intakes by 2 or more servings/d from the prior year gained weight (boys: +0.14, p = 0.01; girls +0.10, p = 0.046). Further adjusting our models for total energy intake substantially reduced the estimated effects, which were no longer significant. Discussion : Consumption of sugar‐added beverages may contribute to weight gain among adolescents, probably due to their contribution to total energy intake, because adjustment for calories greatly attenuated the estimated associations.     

Racial and ethnic differences in secular trends for childhood BMI, weight, and height

Objectives: The prevalence of childhood overweight in the United States has markedly increased over the last 30 years. We examined differences in the secular trends for BMI, weight, and height among white, black, and Mexican‐American children. Research Methods and Procedures: Analyses were based on nationally representative data collected from 2 to 17 year olds in four examinations (1971–1974 through 1999–2002). Results: Overall, black children experienced much larger secular increases in BMI, weight, and height than did white children. For example, over the 30‐year period, the prevalence of overweight increased ～3‐fold (4% to 13%) among 6‐ to 11‐year‐old white children but 5‐fold (4% to 20%) among black children. In most sex‐age groups, Mexican‐American children experienced increases in BMI and overweight that were between those experienced by blacks and whites. Race/ethnicity differences were less marked among 2 to 5 year olds, and in this age group, white children experienced the largest increase in overweight (from 4% to 9%). In 1999–2002, the prevalence of extreme BMI levels (≥99th percentile) reached 6% to 7% among black girls and Mexican‐American boys. Discussion: Because of the strong tracking of childhood BMI levels into adulthood, it is likely that the secular increases in childhood overweight will greatly increase the burden of adult disease. The further development of obesity interventions in different racial/ethnic groups should be emphasized.     

Weight Loss Surgery Eligibility According to Various BMI Criteria Among Adolescents

A BMI cutoff point at the 99th percentile for age and gender or at 40 kg/m² has been suggested for more aggressive treatment of adolescent obesity. The main objective of this study was to determine the proportion of adolescents eligible for weight loss surgery (WLS) based on various BMI cutoff points. Data was extracted from the electronic medical record database of an urban pediatric ambulatory care center over 4 years. National data were used to calculate BMI percentiles (Centers for Disease Control and Prevention (CDC), 2000). Eligibility for WLS was based on a BMI percentile criterion (≥99th percentile) or the adult WLS cutoff point (≥40 kg/m²). The sample consisted of 3,220 adolescents aged 12–17.9 years, of which 53% were female, 55% were of black race, and 17% of Hispanic ethnicity. Overall, 88 (3%) adolescents had a BMI ≥40 kg/m² and 236 (7%) had a BMI ≥99th percentile (P < 0.001). All adolescents with BMI ≥40 kg/m² had a BMI ≥99th percentile. A total of 159/2,007 (8%) of 12–14.9‐year olds had a BMI ≥99th percentile compared with 77/1,213 (6%) 15–17.9‐year olds (P = 0.10), whereas 43/2,007 (2%) of 12–14.9‐year olds had a BMI ≥40 kg/m² compared with 45/1,213 (4%) 15–17.9‐year olds (P = 0.003). In summary, a relatively large proportion of adolescents from a diverse urban population would qualify for WLS based on the percentile criterion. Fewer adolescents would be eligible based on the adult WLS criterion, and younger adolescents would be less likely to be eligible for WLS than older adolescents.     

Weight Status in Childhood as a Predictor of Becoming Overweight or Hypertensive in Early Adulthood**

Objective: To assess the extent to which weight status in childhood or adolescence predicts becoming overweight or hypertensive by young adulthood. Research Methods and Procedures: We conducted a prospective study of 314 children, who were 8 to 15 years old at baseline, and were followed up 8 to 12 years later. Weight, height, and blood pressure were measured by trained research staff. Incident overweight was defined as BMI ≥ 25 kg/m² among participants who had not been overweight as children. Results: More male subjects (48.3%) than female subjects (23.5%) became overweight or obese between their first childhood visit and the young adult follow‐up (p < 0.001). Being in the upper one half of the normal weight range (i.e., BMI between the 50th and 84th percentiles for age and gender in childhood) was a good predictor of becoming overweight as a young adult. Compared with children with a BMI <50th percentile, girls and boys between the 50th and 74th percentiles of BMI were ～5 times more likely [boys, odds ratio (OR) = 5.3, p = 0.002; girls, OR = 4.8, p = 0.07] and those with a BMI between the 75th and 84th percentiles were up to 20 times more likely (boys, OR = 4.3, p = 0.02; girls, OR = 20.2, p = 0.001) to become overweight. The incidence of high blood pressure was greater among the male subjects (12.3% vs. 1.9%). Compared with boys who had childhood BMI below the 75th percentile, boys between the 75th and 85th percentiles of BMI as children were four times more likely (OR = 3.6) and those at above the 85th percentile were five times more likely (OR = 5.1) to become hypertensive. Discussion: High normal weight status in childhood predicted becoming overweight or obese as an adult. Also, among the boys, elevated BMI in childhood predicted risk of hypertension in young adulthood.     

Reformulation of BMI and Percent Body Fat to Remove the Height Bias in 8‐year‐olds

BMI and percent body fat (%BF) are both related to height (Ht) in prepubertal children, so may misrepresent childhood adiposity, especially in tall or short children. We sought to construct replacement functions for BMI and %BF that are independent of Ht. Fat mass (FM) was measured using dual‐energy X‐ray absorptiometry, together with Ht and body mass (BM) in 746 healthy boys and girls aged 8 years (0.34 s.d.). Relationships between BM, FM, and Ht were measured and values of p and q derived such that the functions BM. Ht^?p and FM.BM^?q were unrelated to Ht. BM was not directly proportional to Ht², BMI being significantly related to Ht in both boys and girls (P < 0.001). BM was proportional to Ht³, BM. Ht^?3 being independent of Ht. Similarly, FM was not directly proportional to BM and %BF was significantly related to Ht (P < 0.001). While FM was proportional to BM², FM.BM^?1.5 was the function found to be independent of Ht. Using the 85th and 95th percentiles as the cutoffs for overweight and obesity respectively, 6.4% of the boys and 6.8% of the girls were classified differently by BMI and the Ht independent measure BM. Ht^?3. Similarly, 10.1% boys and 13.7% girls were classified differently by %BF and the Ht independent measure FM.BM^?1.5. We propose that improved diagnostic accuracy of body composition in 8‐year‐olds is provided by the BM function (BMF, BM. Ht^?3) and FM function (FMF, FM.BM^?1.5) replacing BMI and %BF, which both overestimate the adiposity of taller children and underestimate it in shorter children.     

Weight and BMI over 6 years in Korean Children: Relationships to Body Image and Weight Loss Efforts

Objective: To investigate the relationships among longitudinal weight status, body dissatisfaction, and attitude to weight loss among Korean children from the age of 7‐8 to 13‐14 years old. Research Methods and Procedures: 351 Korean school children's heights and weights were measured at the ages of 7‐8 and 13‐14 years old; at the age of 13‐14, they completed a questionnaire about body dissatisfaction and weight loss efforts. Results: At the age of 7‐8, 15.7% of children were overweight by International Obesity Task Force standards, as compared with 26.2% at the age of 13‐14. Of the 55 7‐ to 8‐year‐old overweight children, 85.5% were still overweight at the age of 13‐14 years old. Greater concerns about body image and stronger desires to be thinner were observed among stable overweight children and among those in whom there had been a rapid increase in BMI over the 6‐year study period. Girls favored thinner shapes than did boys, regardless of their weight status or BMI changes. In girls, the level of body dissatisfaction was related only to weight loss desire, regardless of weight status or changes in BMI. In boys, however, weight loss desire was related only to weight loss attempts and was independent of weight status, BMI changes, and level of body dissatisfaction. Discussion: Regardless of weight status, changes in BMI should be considered when dealing with body dissatisfaction and attitudes to weight loss in children.     

Swedish experience of two dose vaccination programme aiming at eliminating measles,mumps, and rubella.

In 1982 a two dose regimen was introduced in Sweden for the combined vaccination against measles, mumps, and rubella of children aged 18 months and 12 years. Since 1977 about half of the preschool children were vaccinated against measles annually, and since 1974 about 80% of 12 year old girls were vaccinated against rubella. During the period 1982 to 1985 90-93% of the eligible age cohorts of 18 month old children and 88-91% of the 12 year old children were immunised with the new combined vaccine. A study in 1982 of about 140 18 month old children who were nearly all seronegative before vaccination showed that 96%, 92%, and 99% seroconverted against measles, mumps, and rubella, respectively. A second study was carried out in 1983 of 247 12 year old children, of whom 11% lacked antibodies to measles, 27% to mumps, and 45% to rubella. This showed seroconversion in 82% and 80% against measles and mumps, respectively, and all children seroconverted against rubella. In the latest study in 1985 of 496 12 year olds 9% and 13% were seronegative against measles and mumps before vaccination, and 41% against rubella. Of these, 88% seroconverted to measles and 80% to mumps, and all converted to rubella when sera were tested by the haemolysis in gel method. After a neutralisation test against measles as well all children showed immunity to the disease. A low incidence of measles and declining figures for mumps and rubella were reported in 1984 to 1986. An outbreak of rubella during 1985 affected mainly boys in age cohorts in which only the girls had been vaccinated during the 1970s.     

Obesity,Fasting Plasma Insulin,and C‐Reactive Protein Levels in Healthy Children

Objective: Obesity is associated with hyperinsulinemia and increased level of C‐reactive protein in older children and adults, but little is known about these relationships in very young children. We examined these relationships in healthy 2‐ to 3‐year‐old children. Research Methods and Procedures: Analyses were performed on data from 491 healthy 2‐ to 3‐year‐old Hispanic children enrolled in a dietary study conducted in New York City, 1992 to 1995. Results: Body mass index (BMI), ponderal index, and sum of four skinfolds were highly correlated (r > 0.75) in both boys and girls. Fasting insulin and glucose levels were only modestly correlated (r = 0.37 for boys and r = 0.28 for girls; p < 0.001 for both), but essentially all of the variability in a calculated index of insulin resistance was attributable to variability in fasting insulin level. The correlations of BMI with fasting insulin level were r = 0.16 (p < 0.05) in boys and r = 0.14 (p < 0.05) in girls. In separate multivariate regression analyses adjusting for age and sex, BMI and ponderal index were associated with fasting plasma insulin level (p < 0.001 for both obesity measures). In multivariate regression analyses adjusting simultaneously for age, sex, and either BMI or ponderal index, fasting insulin level, but not these obesity measures, was associated with C‐reactive protein level. Discussion: Obesity is associated with higher fasting insulin level, and fasting insulin is associated with C‐reactive protein level, in healthy 2‐ to 3‐year‐old children.     

Lower Serum Adiponectin Levels in African‐American Boys

Objective: To examine adiponectin, an adipocyte‐secreted hormone with anti‐inflammatory and insulin‐sensitizing effects, in relation to race or gender in younger subjects. Research Methods and Procedures: The relationship of adiponectin, quantitated by radioimmunoassay, to anthropometric and metabolic factors (fasting insulin, glucose, and leptin) and reproductive hormones was examined in 46 healthy African Americans (25 girls/21 boys) and 40 whites (20 girls/20 boys) ranging in age from 12 to 21 years. Results: There was no statistical difference in BMI or in BMI percentile among the four groups. Sums of skinfolds, but not skinfold percentile, were significantly lower in boys than girls (p = 0.001 and p = 0.896, respectively), whereas there was no difference between racial groups. Leptin was significantly greater in girls (p = 0.0002). There was no difference in fasting serum glucose, insulin, or homeostasis model assessment score among any of the groups. There was a significant negative univariate relationship between serum adiponectin and both BMI and BMI percentile for the entire group (p = 0.006 and p = 0.005). In a multivariate model, BMI percentile (p = 0.005) and the interaction between race and gender (p = 0.026) were significant predictors of serum adiponectin. In this model, African‐American boys had the lowest serum adiponectin level, 37% less than white boys, who had the highest adiponectin levels. Discussion: Serum adiponectin levels are reduced in young obese subjects (African Americans and whites) and are lower in African‐American boys than white boys. A lower adiponectin level in African‐American boys may predispose this group to a greater risk of diabetes and cardiovascular disease.     

Significant sex difference in the association between C‐reactive protein concentration and anthropometry among 13‐ to 19‐year olds,but not 6‐ to 12‐year olds in Nepal

Life history theory predicts a trade‐off between immunostimulation and growth. Using a cross‐sectional study design, this study aims to test the hypothesis that C‐reactive protein (CRP) is negatively associated with height‐for‐age z‐scores (HAZ scores) and BMI‐for‐age z‐scores (BAZ scores) among 6‐ to 19‐year olds (N = 426) residing in five Nepalese communities. Dried blood spot (DBS) samples were collected and assayed for CRP using an in‐house enzyme immunoassay (EIA). Sex‐ and age‐group‐specific CRP quartiles were used to examine its association with growth in linear mixed‐effects (LME) models. A significant difference was found in the proportion of elevated CRP (>2 mg/L, equivalent to ～3.2 mg/L serum CRP) between 13‐ and 19‐year‐old boys (12%) and girls (4%). Concentrations of CRP were positively associated with HAZ score among adolescent (13–19 years) boys, which may indicate that individuals with greater energy resources have better growth and a better response to infections, thus eliminating the expected trade‐off between body maintenance (immunostimulation) and growth. Adolescent boys with low BAZ and HAZ scores had low CRP values, suggesting that those who do not have enough energy for growth cannot increase their CRP level even when infected with pathogens. Among adolescent girls a positive association was observed between CRP and BAZ scores suggesting the possible effects of chronic low‐grade inflammation due to body fat rather than infection. The association between CRP and growth was less evident among children (6–12 years) compared with adolescents, indicating that the elevated energy requirement needed for the adolescent growth spurt and puberty may play some role. Am J Phys Anthropol 154:42–51, 2014. © 2014 Wiley Periodicals, Inc.     

Trends in Childhood Obesity in Japan over the Last 25 Years from the National Nutrition Survey

Objective: To describe the 25‐year changes in BMI (measured in kilograms per meters squared) and the prevalence of obesity in Japanese children with special reference to urban‐rural differences. Research Methods and Procedures: We used the data sets from the cross‐sectional annual nationwide surveys (National Nutrition Survey, Japan) conducted from 1976 to 2000 and comprising 29, 052 boys and 27, 552 girls between 6 and 14 years of age. We carried out the trend analyses with the data on sex and age groups and on residential areas according to the size of the municipality (metropolitan areas, cities, and small towns). Results: The mean (age‐adjusted) BMI increased by +0.32 kg/m² per 10 years in boys and by +0.24 kg/m² per 10 years in girls, increases that were remarkable in small towns. The prevalence of obese boys and girls increased from 6.1% and 7.1%, respectively, in the time‐period 1976 to 1980, to 11.1% and 10.2% in 1996 to 2000. The increasing trend was most evident in 9‐ to 11‐year‐old children of both sexes living in small towns, whereas no changes were observed in girls in metropolitan areas. Discussion: Our data clearly show increasing trends in obesity prevalence in Japanese school children. Degrees of the increasing trends, however, differed across sex and age groups and residential areas, demonstrating a particular phenomenon that girls in metropolitan areas were unlikely to become obese. These epidemiological aspects indicate the priorities for intervention in population strategies to control obesity in children.     

Activity pattern, smoking habits, and somatometric variables of the Czechoslovakian population

A total of 3762 subjects of both sexes, natives of Czechoslovakia, ranging in age from 12--55 years, were examined. Both anamnestic data and selected anthropometric variables were evaluated. The proportion of non-smokers for adult males was 47--56%, and for adult females was 54--74% of the population. The proportion of subjects not engaged in any type of physical activity decreases in boys between 12 and 18 years from 28 to 16%, in girls between 12 and 15 years from 25 to 22%; from then on the trend reverses and the percentages rises up to 42% in men and 65% in women. The number of subjects participating in competitive sporting activity reaches its peak at 18 years, when 46% of boys annd 43% of girls compete, but then decreases quickly. 12 year old girls are taller and heavier than boys but at 15 years the relationship is reversed. The LBM at the age of 12 is equal in boys and girls, but from then till 18 years the increase is larger in boys. The LBM weight in adults remains steady, women attaining 77% of the value found in men. The skinfold increases with age similarly in both sexes, except for an interval between 12 and 18 years, when girls show a steeper increase. Adult women attain 121--160% of the values characteristic for men. The grip strength of the right hand equals about 50 kp in adult men and 30 kp in adult women. Within the age range followed, it remains unaffected by age.     

A factor analysis of cranial base and vault dimensions in children

Lengths within the cranial base and vault were measured in cephalometric radiographs of 220 boys and 177 girls ranging in age from 0 to 15 years; all these children are participants in The Fels Longitudinal Growth Study. The present study is based on mixed longitudinal data derived from 1640 radiographs for boys and 1260 radiographs for girls. Factor analysis was applied separately for boys and girls for each age group; i.e., 0–3, 4–6, 7–9, 10–12, and 13–15 years. For the 0–3 year age group, two factors were extracted in each sex, whereas four factors were extracted in the rest of the age groups. The factor structures are similar in the three older age groups of boys (7–9, 10–12, and 13–15 years). The first four factors for these groups are labelled, respectively: cranial vault size, posterior cranial base length, presphenoid length, and basisphenoid length. The order of the third and fourth factors is reversed in the 7–9 year olds. For girls, the factors extracted were also the same in both the 7–9 and 10–12 year age groups, even though the order of factors was different between age groups; i.e., anterior cranial base length, cranial vault size, basisphenoid length, and basioccipital length. Differential growth rates among cranial base dimensions probably cause changes in factor patterns. Obliteration of the spheno-occipital synchondrosis is suggested as the mechanism responsible for the change of factor pattern in the girls. Closure of this synchondrosis would have occurred too late to affect the patterns in boys.     

Trends in Height and BMI of 6‐Year‐Old Children during the Nutrition Transition in Chile

Objective: We analyzed trends in height and BMI and their interaction in 6‐year‐old Chilean children over the last 15 years. Research Methods and Procedures: We calculated height for age z‐score (HAZ), BMI z‐score, prevalence of obesity, underweight, and stunting from cross‐sectional national school‐based annual population surveys in 1987, 1990, 1993, 1996, 2000, and 2002. Using mixed model analysis, we determined the risk of obesity according to height over time as odds ratios (ORs) and 95% confidence interval and the potential influence of height and year of study on BMI z‐score. Results: Over the study period, height increased by 2.8 cm in boys and 2.6 cm in girls, whereas stunting declined from 5% to 2% in both. Tallness increased by ～2%, BMI z‐score increased from +0.3 to +0.65 in boys and to +0.62 in girls, and HAZ increased from ?0.47 in boys and ?0.45 in girls to 0 in 2002. Underweight declined from 4% to 3%, whereas obesity rose from 5% to ～14%. The probability of obesity among tall children was significantly greater than that for normal height children (OR, 2.3 to 3.5). The lowest obesity risk was observed between ?2 and ?1 HAZ. The OR for obesity in the stunted relative to normal height children was variable, ranging from 1.23 to 0.65, whereas it was significant and consistently positive (1.1 to 1.7) for boys and girls when it was compared with the lowest obesity risk according to height. Discussion: Tallness is significantly associated with increased obesity risk in children, while stunting is also associated, but to a lesser degree.     

Body mass effects of a physical activity and healthy food intervention in middle schools

Objective: To evaluate the effects of a 2‐year middle school physical activity and healthy food intervention, including an environmental and computer‐tailored component on BMI and BMI z‐score in boys and girls. Research Methods and Procedures: A random sample of 15 schools with seventh and eighth graders was randomly assigned to three conditions: an intervention with parental support group, an intervention‐alone group, and a control group. Weight and height were measured at the beginning and end of each school year to assess BMI and BMI z‐score. A physical activity and healthy food program was implemented over 2 school years. Results: In girls, BMI and BMI z‐score increased significantly less in the intervention with parental support group compared with the control group (p < 0.05) or the intervention‐alone group (p = 0.05). In boys, no significant positive intervention effects were found. Discussion: This was the first study evaluating the effectiveness of an intervention combining environmental changes with personal computer‐tailored feedback on BMI and BMI z‐score in middle school children. After 2 school years, BMI and BMI z‐score changed in a more positive direction in girls as a result of the intervention with parental support.     

Racial Differences in the Tracking of Childhood BMI to Adulthood

Objective: The possibility that there are racial differences in the patterns of BMI (kilograms per meter squared) change throughout life has not been examined. For example, the high prevalence of obesity among black women could result from a higher prevalence of obesity among black girls or because normal‐weight black girls experience larger BMI increases in adolescence or adulthood than do their white counterparts. Therefore, we examined the tracking of childhood BMI into adulthood in a biracial (36% black) sample. Research Methods and Procedures: Five‐ to 14‐year‐old children (2392) were followed for (mean) 17 years. Childhood overweight was defined as BMI ≥ 95th percentile, and adult obesity was defined as BMI ≥ 30 kg/m². Results: The tracking of childhood BMI differed between whites and blacks. Among overweight children, 65% of white girls vs. 84% of black girls became obese adults, and predictive values among boys were 71% (whites) vs. 82% (blacks). These racial differences reflected contrasting patterns in the rate of BMI change. Although the initial BMI of black children was not higher than that of white children, BMI increases with age were larger among black girls and overweight black boys than among their white counterparts. In contrast, relatively thin (BMI < 50th percentile) white boys were more likely to become overweight adults than were their black counterparts. Discussion: These findings emphasize the black/white differences in BMI changes with age. Because of the adult health consequences of childhood‐onset obesity, early prevention should be given additional emphasis.     

Association between television in bedroom and adiposity throughout adolescence

Objective: The objective was to determine if having a television (TV) in the bedroom is associated with physical activity (PA), TV/video viewing, and adiposity throughout adolescence. Research Methods and Procedures: Longitudinal data (September 2002 through June 2005) were analyzed of 379 initially 12‐year‐old French adolescents participating as controls in the Intervention Centered on Adolescents’ Physical activity and Sedentary behavior (ICAPS). Presence of a TV set in the bedroom (TV_bedroom) and leisure activities were obtained by questionnaire. There was annual assessment of BMI, waist circumference, and body fat by bioimpedance. Results: In boys but not girls, baseline TV_bedroom was associated with higher TV/video viewing over time [odds ratio (OR) of high TV/video = 1.87; 95% confidence interval, 1.2 to 2.8] and less no‐sport club participation (OR = 0.59; 95% confidence interval, 0.35 to 1.0). Both boys and girls with baseline TV_bedroom had lower reading time (p < 0.0001 in boys; p = 0.04 in girls), while PA did not differ according to TV_bedroom for boys or for girls. For boys only, baseline TV_bedroom was associated with higher BMI (mean BMI over time 20.5 ± 0.5 vs. 19.0 ± 0.5 kg/m²; p = 0.001), waist circumference (70.9 ± 0.9 vs. 67.2 ± 0.8 cm; p < 0.001), and body fat (15.9 ± 0.9% vs. 13.5 ± 0.9%; p < 0.001), without interaction with time. These relationships remained significant after adjustment for socioeconomic status. TV/video viewing explained 26%, 42%, and 36% of the relationships of TV_bedroom with BMI, waist circumference, and body fat, respectively, while addition of other leisure activities in the models only marginally reduced the effects. Discussion: These results suggest the importance of keeping TV out of an adolescent's bedroom from an obesity prevention perspective but show gender differences.     

Prevalence of obesity in elementary schoolchildren living in Northeast Attica, Greece

Objective: To assess the prevalence of obesity and obesity trend in schoolchildren living in Northeast Attica, Greece. Research Methods and Procedures: Mean (standard deviation) and median weight and BMI were calculated in 4131 (2054 boys and 2077 girls) 6‐ to 11‐year‐old Greek schoolchildren living in Northeast Attica between November 2003 and April 2004. Two hundred thirty‐six (95 boys, 141 girls) immigrant children also participated in the study. The secular trend for obesity was determined comparing our data with those of a similar study performed in 1994. Results: Of boys, 27.8% were overweight, and 12.3% were obese. For girls, the corresponding values were 26.5% for overweight and 9.9% for obesity. There was an increase in the prevalence of overweight and obesity in the last 10 years in both sexes. For boys, overweight increased by 4.2% and obesity by 2.9%, whereas, for girls, overweight increased by 3.8% and obesity by 1.6%. Overweight and obesity were less prevalent in the immigrant children compared with their Greek peers. For immigrant boys, overweight was 15.9% and obesity was 7.9%, and for immigrant girls, overweight was 15.2% and obesity was 8.7%. Discussion: Greek schoolchildren living in Northeast Attica present a high prevalence of overweight and obesity and a positive secular change in the prevalence of obesity.     

Cardiorespiratory fitness and sedentary activities are associated with adiposity in adolescents

Objective: To determine whether physical activity, sedentary activities, and/or cardiorespiratory fitness are related to waist circumference in adolescents, as previously reported in adults. Research Methods and Procedures: The study subjects were a representative sample of Spanish adolescents (N = 2859; 1357 boys, 1502 girls; age, 13 to 18.5 years), all of whom were involved in the AVENA (Food and Assessment of the Nutritional Status of Adolescents) study. BMI, waist circumference, pubertal maturation status, and cardiorespiratory fitness were measured in all. Leisure‐time physical activity, sedentary activities, active commuting to school, and socioeconomic status were assessed by self‐reported questionnaires. Results: No relationship was found between leisure‐time physical activity and BMI or waist circumference. In contrast, and in both boys and girls and after adjustment for confounding variables, cardiorespiratory fitness was found to be inversely associated with waist circumference and BMI, independent of sedentary activities or physical activity (p ≤ 0.001). The maximum oxygen consumption explained 13% of the variance in waist circumference in boys and 16% in girls. Sedentary activities were independently and directly related to waist circumference in both boys and girls (p ≤ 0.05) and to BMI in boys (p ≤ 0.05). Sedentary activities explained 10% of the variance in waist circumference in boys and 18% in girls. The BMI‐adjusted waist circumference was inversely correlated with cardiorespiratory fitness in overweight‐obese boys (p ≤ 0.05) and showed a trend toward significance in girls (p ≤ 0.1). Discussion: Both moderate to high levels of cardiorespiratory fitness and sedentary activities, but not physical activity, are associated with lower abdominal adiposity, as measured by waist circumference.