School-based overweight preventive intervention lowers incidence of disordered weight-control behaviors in early adolescent girls

OBJECTIVE: To determine the effect of a school-based intervention to promote healthful nutrition and physical activity on disordered weight-control behaviors (self-induced vomiting or use of laxatives or diet pills to control weight) in early adolescent girls and boys. DESIGN: Using a group-randomized, controlled-trial design, we randomly assigned middle schools to an intervention or control condition. Multivariate logistic regression analyses were used to assess the effect of the intervention on the odds of reporting a new case of disordered weight-control behaviors at follow-up, adjusting for sex, school-level prevalence of disordered weight-control behaviors at baseline, and school clusters. Students reporting these behaviors at baseline were excluded from the analyses. SETTING: Thirteen middle schools. PARTICIPANTS: At baseline, 749 girls and 702 boys in grades 6 and 7. Intervention The 5-2-1 Go! intervention (Planet Health obesity prevention curriculum plus School Health Index for Physical Activity and Healthy Eating: A Self-Assessment and Planning Guide, Middle/High School Version) was implemented during 2 school years, from November 2002 through May 2004. Main Outcome Measure Self-reported disordered weight-control behaviors in last 30 days at follow-up. RESULTS: At follow-up in girls, 3.6% (15 of 422) in control schools compared with 1.2% (4 of 327) in intervention schools reported engaging in disordered weight-control behaviors (P = .04). Multivariate analyses indicated that the odds of these behaviors in girls in intervention schools were reduced by two thirds compared with girls in control schools (odds ratio, 0.33; 95% confidence interval, 0.11-0.97). No intervention effect was observed in boys. CONCLUSIONS: Results add compelling support for the effectiveness of an interdisciplinary, school-based obesity prevention intervention to prevent disordered weight-control behaviors in early adolescent girls.     

The impact of a school-based obesity prevention trial on disordered weight-control behaviors in early adolescent girls

OBJECTIVE: To assess the impact of an obesity prevention intervention on use of self-induced vomiting/laxatives (purging) and diet pills to control weight in girls in early adolescence. DESIGN: We matched and randomly assigned 10 middle schools to an intervention or a control condition in a randomized controlled trial. Longitudinal multivariable analyses using generalized estimating equations were conducted with data from 480 girls to examine the effects of the intervention on the risk of reporting a new case of purging or diet pill use to control weight at follow-up 21 months later, while controlling for ethnicity and school matched pairs. Girls who reported purging or using diet pills at baseline were excluded from analyses. SETTING: Middle schools. PARTICIPANTS: Four hundred eighty girls in early adolescence aged 10 to 14 years (mean age, 11.5 years). INTERVENTION: The Planet Health obesity prevention program was implemented during 2 school years and was designed to promote healthful nutrition and physical activity and to reduce television viewing. OUTCOME: Reduced risk of using self-induced vomiting/laxatives or diet pills to control weight in the past 30 days. RESULTS: After the intervention, we found 14 (6.2%) of 226 girls in control schools and 7 (2.8%) of 254 girls in intervention schools reported purging or using diet pills to control their weight (P = .003). In a multivariable generalized estimating equation model, girls in intervention schools were less than half as likely to report purging or using diet pills at follow-up compared with girls in control schools (odds ratio, 0.41; 95% confidence interval, 0.22-0.75). CONCLUSION: These findings provide promising evidence that school-based interventions may effectively integrate prevention of both obesity and disordered weight-control behaviors.     

Descriptive epidemiology of small screen recreation among Australian adolescents

AIM: To describe the epidemiology of small screen recreation (SSR) that is: television, computer, video, and DVD use among school students aged 11-15 years in New South Wales, Australia. METHODS: Cross-sectional representative population survey (n=2750) of 45 primary and 48 secondary schools in rural and urban areas. Self-reported time spent in SSR was categorised according to national guidelines into less than 2 h per day (low users) or 2 or more hours per day (high users). RESULTS: Of primary and secondary school students, 53% and 72%, respectively, were high users of SSR. Boys spent significantly more time in SSR and were more likely to be high users of SSR compared with girls. For primary students, rural boys had a higher prevalence of high SSR use than urban boys (odds ratio (OR) 1.9, 95% confidence interval (CI) 1.0-3.5), while overweight girls had a higher prevalence than healthy-weight girls (OR 1.8, 95% CI 1.2-2.8). For secondary students, rural boys had a lower prevalence of high SSR use than urban boys (OR 0.5, 95% CI 0.3-0.6), and girls from high SES backgrounds had a lower prevalence than girls from low socio-economic status backgrounds (OR 0.6, 95% CI 0.3-1.0). CONCLUSION: The majority of school students in New South Wales exceed the national guidelines for SSR. Reducing the time spent in SSR among young people is one potential approach to increasing energy expenditure and reducing adiposity or maintaining a healthy weight. First steps for intervention strategies among school-age children to reduce SSR could include teaching awareness skills and self-monitoring techniques.     

Impact of a school-based interdisciplinary intervention on diet and physical activity among urban primary school children: eat well and keep moving.

OBJECTIVE: To evaluate the impact of a school-based interdisciplinary health behavior intervention on diet and physical activity among children in grades 4 and 5. DESIGN: A quasiexperimental field trial with 6 intervention and 8 matched control schools. Outcomes were assessed longitudinally using preintervention (fall 1995) and follow-up (spring 1997) student survey food frequency and activity measures and follow-up 24-hour recall measures of diet and activity. Change was also assessed using yearly repeated cross-sectional surveys of all grade 5 students from 1995 through 1997. PARTICIPANTS: Longitudinal data were collected from 479 students initially in grade 4 in Baltimore, Md, public schools; 91% were African American. Repeated 24-hour recall measures in 1997 were collected for a random subsample of 336 students. Cross-sectional survey data were collected from all grade 5 students in 1995,1996, and 1997 (n = 2103). INTERVENTION: The Eat Well and Keep Moving Program was taught by classroom teachers over 2 years in math, science, language arts, and social studies classes. Materials provided links to school food services and families and provided training and wellness programs for teachers and other staff members. Intervention materials focused on decreasing consumption of foods high in total and saturated fat and increasing fruit and vegetable intake, as well as reducing television viewing and increasing physical activity. MAIN OUTCOME MEASURES: Dietary intake and physical activity measured via repeated 24-hour recall were primary end points, with additional food frequency and activity measures. RESULTS: The 24-hour recall measures indicated that, after controlling for baseline covariates, the percentages of total energy from fat and saturated fat were reduced among students in intervention compared with control schools (-1.4%; 95% confidence interval [CI], -2.8 to -0.04; P = .04 and -0.60%; 95% CI, -1.2 to -0.01; P = .05). There was an increase in fruit and vegetable intake (0.36 servings/4184 kJ; 95% CI, 0.10-0.62; P=.01), in vitamin C intake (8.8 mg/4184 kJ; 95% CI, 2.0-16; P=.01), and in fiber consumption (0.7 g/4184 kJ; 95% CI, 0.0-1.4; P=.05). Television viewing was marginally reduced (-0.55 h/d; 95% CI, -1.04 to 0.04; P=.06). Analysis of longitudinal and repeated cross-sectional food frequency data indicated similar significant decreases in the percentages of total energy from fat and saturated fat. CONCLUSION: Evaluation of the Eat Well and Keep Moving Program indicates effectiveness in improving dietary intake of students and reducing television viewing.     

Is physical activity differentially associated with different types of sedentary pursuits?

OBJECTIVE: To determine whether there is a relationship between the time adolescents spend in physical activity and time they spend in different sedentary pursuits: watching television, playing video games, working on computers, doing homework, and reading, taking into account the effect of part-time work on students' residual time. DESIGN: Cross-sectional cohort design. PARTICIPANTS AND SETTING: Seven hundred forty-three high school students from 2 inner-city public schools and 1 private school. METHODS: Students completed a self-administered questionnaire that addressed time spent in physical activity, time spent in sedentary pursuits, musculoskeletal pain, and psychosocial issues and were also measured for height and weight.Main Outcome Measure Level of physical activity (low, moderate, high). RESULTS: There were more girls than boys in the low and moderate physical activity groups and more boys than girls in the high activity group. Ordinal logistic regression showed that increased time spent in "productive sedentary behavior" (reading or doing homework and working on computers) was associated with increased physical activity (odds ratio, 1.7; 95% confidence interval, 1.2-2.4), as was time spent working (odds ratio, 1.3; 95% confidence interval, 1.2-1.4). Time spent watching television and playing video games was not associated with decreased physical activity. CONCLUSIONS: Physical activity was not inversely associated with watching television or playing video games, but was positively associated with productive sedentary behavior and part-time work. Some students appear capable of managing their time better than others. Future studies should explore the ability of students to manage their time and also determine what characteristics are conducive to better time management.     

Effects of reducing television viewing on children's requests for toys: a randomized controlled trial.

Previous attempts to reduce the effects of television advertising on children's purchase requests have had little success. Therefore, we tested the effects of a classroom intervention to reduce television, videotape, and video game use on children's toy purchase requests, in a school-based randomized controlled trial. Third- and fourth-grade children (mean age, 8.9 years) in two sociodemographically and scholastically matched public elementary schools were eligible to participate. Children in one randomly selected elementary school received an 18-lesson, 6-month classroom curriculum to reduce television, videotape, and video game use. In both schools, in September (before intervention) and April (after intervention) of a single school year, children and parents reported children's prior week's purchase requests for toys seen on television. After intervention, children in the intervention school were significantly less likely to report toy purchase requests than children in the control school, with adjusting for baseline purchase requests, gender, and age (odds ratio, 0.29; 95% confidence interval, 0.12-0.69). Among intervention school children, reductions in self-reported purchase requests were also associated with reductions in television viewing. There was no significant difference between schools in parent reports of children's requests for toy purchases. These findings suggest that reducing television viewing is a promising approach to reducing the influences of advertising on children's behavior.     

Television watching and soft drink consumption: associations with obesity in 11- to 13-year-old schoolchildren

OBJECTIVES: To determine the prevalence of obesity among sixth- and seventh-grade students in a school-based setting, and to identify lifestyle parameters associated with obesity. METHODS: Sixth- and seventh-grade students (n = 385, 186 boys and 199 girls) from 3 schools participated in a school-based screening study, and 319 completed a short questionnaire. Height and weight were measured, and body fat as a percentage of body weight was obtained using a Tanita bioelectrical impedance scale. RESULTS: Overall, 35.3% of students had a body mass index (BMI; calculated as the weight in kilograms divided by the height in meters squared) at or above the 85th percentile, and half these students (17.4%) had a BMI at or above the 95th percentile. Rates were higher among Latino and lower among Asian than non-Hispanic white students. Significant associations were found between BMI and hours of television watched per evening and daily soft drink consumption. The mean (SE) BMI z score for those watching less than 2 hours per night (0.34 [0.09]) was lower than for those watching 2 or more hours per night (0.82 [0.08]; P<.001). The mean (SE) BMI z score for those consuming less than 3 soft drinks per day (0.51 [0.07]) was lower than for those consuming 3 or more soft drinks per day (1.02 [0.13]; P =.003). Latino students watched more television (2.4 hours per night) than did non-Hispanic white or Asian students (1.3 hours per night; P<.001 for each) and consumed more soft drinks (1.6 per day) than non-Hispanic white students (1.1 per day; P =.004) or Asian students (0.7 per day; P<.001). CONCLUSIONS: Time spent watching television and the number of soft drinks consumed were significantly associated with obesity. Latinos spent more time watching television and consumed more soft drinks than did non-Hispanic white or Asian students. These findings will be beneficial in developing preventive measures for these children.     

Parental weight status as a moderator of the relationship between television viewing and childhood overweight

OBJECTIVE: To examine whether and to what extent the relationship between television viewing and children's weight status differs according to parental weight status. DESIGN: Population-level survey including in-home and telephone interview components. SETTING: United States. PARTICIPANTS: Representative sample of children aged 6 to 19 years in 2002 (n = 1483). MAIN EXPOSURE: Hours of television viewing. MAIN OUTCOME MEASURES: Child weight status (normal weight, at risk for overweight, overweight) as defined by current Centers for Disease Control and Prevention standards. RESULTS: Parental obesity increased the risk of child overweight for all of the children except boys aged 6 to 9 years. There were significant interactions between television viewing hours and parental obesity among boys aged 14 to 19 years and girls aged 10 to 13 years. For these 2 groups, the odds of overweight status increased with viewing hours for children with at least 1 obese parent but not at all for children of normal-weight parents. CONCLUSIONS: Results indicate that when parental obesity is taken into account, television viewing hours do not significantly relate to increased odds of childhood overweight, and parental body mass index may serve to moderate the relationship between television viewing and child weight status among adolescents (but not among younger children). Further examination of the moderating effect of parental body mass index on the relationship between television viewing and child weight status is warranted.     

An intervention to reduce television viewing by preschool children

BACKGROUND: Television viewing has been associated with increased violence in play and higher rates of obesity. Although there are interventions to reduce television viewing by school-aged children, there are none for younger children. OBJECTIVE: To develop and evaluate an intervention to reduce television viewing by preschool children. DESIGN: Randomized controlled trial conducted in 16 preschool and/or day care centers in rural upstate New York. PATIENTS: Children aged 2.6 through 5.5 years. INTERVENTION: Children attending intervention centers received a 7-session program designed to reduce television viewing as part of a health promotion curriculum, whereas children attending the control centers received a safety and injury prevention program. OUTCOME MEASUREMENTS: Change in parent-reported child television/video viewing and measured growth variables. RESULTS: Before the intervention, the intervention and control groups viewed 11.9 and 14.0 h/wk of television/videos, respectively. Afterward, children in the intervention group decreased their television/video viewing 3.1 h/wk, whereas children in the control group increased their viewing by 1.6 h/wk, for an adjusted difference between the groups of -4.7 h/wk (95% confidence interval, -8.4 to -1.0 h/wk; P =.02). The percentage of children watching television/videos more than 2 h/d also decreased significantly from 33% to 18% among the intervention group, compared with an increase of 41% to 47% among the control group, for a difference of -21.5% (95% confidence interval, -42.5% to -0.5%; P =.046). There were no statistically significant differences in children's growth between groups. CONCLUSIONS: This study is the first to show that a preschool-based intervention can lead to reductions in young children's television/video viewing. Further research is needed to determine the long-term effects associated with reductions in young children's television viewing.     

Television viewing and risk of sexual initiation by young adolescents

OBJECTIVE: To determine if television viewing is associated with the risk of initiating sexual intercourse in young adolescents. DESIGN: Secondary analysis of data obtained from 1994 through 1996. SETTING: The National Longitudinal Study of Adolescent Health. PARTICIPANTS: The 4808 students younger than 16 years who had not initiated intercourse before baseline interview. EXPOSURES: Primary exposure was self-reported daily television watching, categorized as low (< 2 hours) or high (> or =2 hours) use. Secondary exposure was parental regulation of television programming watched. MAIN OUTCOME MEASURE: Odds ratio for initiating intercourse by 1-year follow-up, adjusted for potential confounders. RESULTS: At baseline, 2414 (48.8%) subjects watched television 2 or more hours per day. By 1-year follow-up, 791 (15.6%) subjects had initiated intercourse. Sexual initiation was associated with high television use (adjusted odds ratio, 1.35; 95% confidence interval, 1.01-1.79) and lack of parental regulation of television programming (adjusted odds ratio, 1.35; 95% confidence interval, 1.01-1.80). Most subjects (73.8%) reported strong parental disapproval of sex; their overall rate of initiation was 12.5%, and their risk was independently associated with high television use (adjusted odds ratio, 1.72; 95% confidence interval, 1.24-2.40) and lack of parental regulation of television programming (adjusted odds ratio, 1.35; 95% confidence interval, 1.01-1.81). Among adolescents who did not report strong parental disapproval, the rate of sexual initiation was higher (24.1%) but unrelated to television use. CONCLUSION: Among young adolescents who reported strong parental disapproval of sex, watching television 2 or more hours per day and lack of parental regulation of television programming were each associated with increased risk of initiating sexual intercourse within a year.     

Overweight, obesity, weight-related concerns and behaviours in Hong Kong Chinese children and adolescents

Aim: To study the prevalence of overweight and obesity, and weight-related concerns and behaviours among overweight, obese and non-overweight children and adolescents. Methods: We carried out a cross-sectional survey of all Chinese students in primary schools in the Central and Western District of Hong Kong in March 2002. Thirty-one of 32 schools participated, and 5402 boys and 5371 girls aged 8 to 15 y who completed a standardized questionnaire were included. We used the International Obesity Task Force definition (IOTF reference) to define overweight and obesity. Results: The prevalence (95% CI) of overweight was 16.4% (15.7-17.1%) (19.9% in boys, 12.9% in girls), and that of obesity was 7.7% (7.2-8.2%) (10.3% in boys and 5.1% in girls). The combined prevalence of overweight and obesity was similar to that based on the local reference. Overweight children had more concerns about their weight than obese children. They were more likely than obese children to feel fat, wish to be lighter, diet and exercise to lose weight. Although obese children were heavier, they did not make more effort to lose weight than overweight children.

Conclusions: The differences in weight-related concerns and behaviours among overweight, obese and non-overweight children suggested good validity of the IOTF reference and the self-reported data. The differences between overweight and obese children suggested that the two groups had different psychological states and that they needed different weight management programmes and other intervention strategies.     

Association between peer relationship problems and childhood overweight/obesity

Aims:  To assess the association between peer relationship problems and childhood overweight and obesity.
Methods:  Data on 4718 preschool children were obtained at the obligatory school entry health examination in Bavaria. Parentally reported peer relationship problems ('normal', 'borderline' or 'abnormal') were assessed from the Strengths and Difficulties Questionnaire. Overweight and obesity were defined according to age- and gender-specific BMI cut-off points. Multivariate logistic regression analysis was performed to control potential confounders.
Results:  The prevalence of overweight and obesity was higher among children with 'borderline' or 'abnormal' peer relationship problems compared to 'normal' children. The association of 'abnormal' peer relationship problems was still significant in the final logistic regression model for girls [odds ratio (OR) for overweight 2.0; 95% confidence interval (CI): 1.4–3.0; OR for obesity 2.6; 95% CI: 1.3–5.0]. Among boys the adjusted odds ratio were lower and no longer significant.
Conclusion:  The significantly increased prevalence of overweight and obesity among preschool children with peer relationship problems could not be explained by confounding. It seems evident that there is a relevant co-morbidity of peer relationship problems and obesity in pre-school children pointing to the need of interventions focusing on both physical as well as psychosocial health.     

Overweight and obesity trends from 1974 to 2003 in English children: what is the role of socioeconomic factors?

AIMS: To examine the childhood overweight and obesity prevalence trends between 1974 and 2003 and to assess whether these trends relate to parental social class and household income. METHODS: A school based and a general population health survey: the National Study of Health and Growth in 1974, 1984, and 1994, and the Health Survey for England, yearly from 1996 to 2003. Participants were 14,587 white boys and 14,014 white girls aged 5-10 years. Overweight and obesity prevalence were calculated using UK specific as well as international body mass index (kg/m2) cut-offs. Socioeconomic status was measured using the Registrar General's social class; household income (1997 onwards only) was adjusted for household size. RESULTS: The prevalence of obesity (UK specific definition) in boys increased from 1.2% in 1984 to 3.4% in 1996-97 and 6.0% in 2002-03. In girls, obesity increased from 1.8% in 1984 to 4.5% in 1996-97 and 6.6% in 2002-03. Obesity prevalence has been increasing at accelerating rates in the more recent years. Children from manual social classes had marginally higher odds (OR 1.14, 95% CI 0.98 to 1.33) and children from higher income households had lower odds (OR 0.74, 95% CI 0.61 to 0.89) to be obese than their peers from non-manual class, and lower income households, respectively. CONCLUSION: Childhood obesity is increasing rapidly into the 2000s in England and these increases are more marked among children from lower socioeconomic strata. There is an urgent need for action to prevent further increase in obesity among children.     

Short-term effects of school-based weight gain prevention among adolescents

OBJECTIVE: To determine whether a multicomponent health promotion intervention for Dutch adolescents would be successful in influencing body composition and aerobic fitness. DESIGN: Randomized controlled trial. SETTING: Ten intervention and 8 control prevocational secondary schools. PARTICIPANTS: A total of 978 adolescents (mean age, 12.7 years). INTERVENTION: An interdisciplinary multicomponent intervention program with an adapted curriculum for 11 biology and physical education lessons and environmental change options, including additional lessons on physical education and advice on the school canteen selection. MAIN OUTCOME MEASURES: Body height and weight, hip and waist circumference, 4 skinfold thickness measurements, and aerobic fitness. RESULTS: Multilevel analyses showed significant differences in changes after the 8-month intervention period in favor of the intervention group with regard to hip circumference (mean difference, 0.53 cm; 95% confidence interval, 0.07 to 0.98) and sum of skinfolds among girls (mean difference, -2.31 mm; 95% confidence interval, -4.34 to -0.28). In boys, the intervention resulted in a significant difference in waist circumference (mean difference, -0.57 cm; 95% confidence interval, -1.10 to -0.05). No significant intervention effects were found related to aerobic fitness. CONCLUSIONS: The multicomponent Dutch Obesity Intervention in Teenagers program positively influenced several measures of body composition among both girls and boys. Our results indicate that secondary prevocational school curriculum changes may contribute to excessive weight gain prevention among adolescents.     

Television viewing associates with delayed language development

AIM: To identify impact of television viewing on language development. METHODS: The case-control study included 56 new patients with language delay and 110 normal children, aged 15-48 months. Language delay was diagnosed by reviewing language milestones and Denver-II. Television viewing variables and child/parental characteristics between both groups were interviewed. The data were analyzed by ANOVA and chi-square test. Adjusted odds ratios and 95% confidence intervals were calculated from multivariate logistic regression model. RESULTS: Forty-six boys and 10 girls; mean [+/-SD] age, 2.11+/-0.47 years of the case group and 59 boys and 51 girls; mean [+/-SD] age, 2.23+/-0.80 years of the control group were enrolled. Children who had language delay usually started watching television earlier at age 7.22+/-5.52 months vs. 11.92+/-5.86 months, p-value<0.001 and also spent more time watching television than normal children (3.05+/-1.90 h/day vs. 1.85+/-1.18 h/day; p-value<0.001). Children who started watching television at<12 months of age and watched television>2 h/day were approximately six times more likely to have language delays. CONCLUSIONS: There is a relationship between early onset and high frequency of TV viewing and language delay.     

Associations of Passive and Mentally Active Screen Time With Perceived School Performance of 197,439 Adolescents Across 38 Countries

ObjectiveTo examine the associations of passive (ie, television) and active (ie, electronic games, computer use) screen time (ST) with perceived school performance of adolescents across gender.MethodsData were from the 2014 Health Behaviour in School-aged Children survey conducted across 38 European countries and Canada. Perceived school performance was assessed using an item and dichotomized as high (good/very good) versus the remainder (average/below-average as reference). Participants reported hours per day of time spent watching television, playing electronic games, and using a computer in their free time. Multilevel logistic regression was used to estimate the associations.ResultsA total of 197,439 adolescents (average age 13.6 [standard deviation 1.63] years; 51% girls) were analyzed. Multivariable modeling showed that engaging in >2 h/d of ST was progressively and adversely associated with high performance in both boys and girls. Adolescents reporting >4 h/d of television time (≤1 h/d as reference) had 32% lower odds in boys (odds ratio [OR] 0.68; 95% confidence interval [CI]: 0.65–0.71) and 39% lower odds in girls (OR 0.61; 95% CI, 0.58–0.65) of reporting high performance. Playing electronic games for >4 h/d was associated with high performance with odds being 38% lower in boys (OR 0.62; 95% CI, 0.59–0.66) and 45% lower in girls (OR 0.55; 95% CI, 0.52–0.57). Sex differences in the estimates were mixed.ConclusionsHigh screen use, whether active or passive, was adversely associated with perceived high school performance, with association estimates being slightly stronger in girls than boys, and for mentally active than passive screen use. Discouraging high levels of screen use of any type could be beneficial to school performance.     

Randomised controlled trial adapting US school obesity prevention to England.

OBJECTIVES: To determine whether a school obesity prevention project developed in the United States can be adapted for use in England. METHODS: A pilot cluster randomised controlled trial and interviews with teachers were carried out in 19 primary schools in South West England. Participants included 679 children in year 5 (age 9-10). Baseline and follow-up assessments were completed for 323 children (screen viewing) and 472 children (body mass index). Sixteen lessons on healthy eating, physical activity and reducing TV viewing were taught over 5 months by teachers. Main outcome measures were hours of screen activities, body mass index, mode of transport to school and teachers' views of the intervention. RESULTS: Children from intervention schools spent less time on screen-viewing activities after the intervention but these differences were imprecisely estimated: mean difference in minutes spent on screen viewing at the end of the intervention (intervention schools minus control schools) adjusted for baseline levels and clustering within schools was -11.6 (95% CI -42.7 to 19.4) for a week day and was -15.4 (95% CI -57.5 to 26.8) for a Saturday. There was no difference in mean body mass index or the odds of obesity. CONCLUSIONS: It is feasible to transfer this US school-based intervention to UK schools, and it may be effective in reducing the time children spend on screen-based activities. The study has provided information for a full-scale trial, which would require 50 schools ( approximately 1250 pupils) to detect effects on screen viewing and body mass index over 2 years of follow-up.     

Overweight and obesity prevalence in children and adolescents from a private school in Recife

OBJECTIVES: To determine the prevalence of overweight and obesity in students from a private school in Recife; compare the prevalence rates of overweight and obesity in boys and girls and in different age groups (children and adolescents) and verify the correlation between body mass index and triceps skinfold thickness in this population. METHODS: Cross-sectional study with 762 students (332 children and 430 adolescents) from a middle/upper class school in Recife, in 1999. Overweight was defined as body mass index equal or above the 85th percentile for age and gender. Obesity was defined as body mass index and triceps skinfold thickness equal or above the 85th percentile. RESULTS: The prevalence rates were 26.2% (95%CI = 23 to 29%) for overweight, and 8.5% (CI95% = 6.5 to 10.5%) for obesity. Overweight was more prevalent among children (34.3%) than among adolescents (20.0%) (P<0.001). Obesity was more frequent among children (14.2%) than among adolescents (4.2%) (P<0.001). The prevalence of overweight in boys (34.6%) was higher than in girls (20.6%) (P<0.001). The prevalence of obesity was also higher in boys (14.7%) than in girls (4.4%) (P<0.001). The correlation coefficient between body mass index and triceps skinfold thickness was equal to 0.64 (95%CI = 0.60 to 0.68). CONCLUSIONS: The prevalence of overweight in our study population was as high as that found in industrialized countries; obesity, however, was less frequent.     

Television watching, energy intake, and obesity in US children: results from the third National Health and Nutrition Examination Survey, 1988-1994

OBJECTIVES: To examine the relationship between television watching, energy intake, physical activity, and obesity status in US boys and girls, aged 8 to 16 years. METHODS: We used a nationally representative cross-sectional survey with an in-person interview and a medical examination, which included measurements of height and weight, daily hours of television watching, weekly participation in physical activity, and a dietary interview. Between 1988 and 1994, the Third National Health and Nutrition Examination Survey collected data on 4069 children. Mexican Americans and non-Hispanic blacks were oversampled to produce reliable estimates for these groups. RESULTS: The prevalence of obesity is lowest among children watching 1 or fewer hours of television a day, and highest among those watching 4 or more hours of television a day. Girls engaged in less physical activity and consumed fewer joules per day than boys. A higher percentage of non-Hispanic white boys reported participating in physical activity 5 or more times per week than any other race/ethnic and sex group. Television watching was positively associated with obesity among girls, even after controlling for age, race/ethnicity, family income, weekly physical activity, and energy intake. CONCLUSIONS: As the prevalence of overweight increases, the need to reduce sedentary behaviors and to promote a more active lifestyle becomes essential. Clinicians and public health interventionists should encourage active lifestyles to balance the energy intake of children.     

Sex disparity and perception of obesity/overweight by parents and grandparents

OBJECTIVE:

To explore the factors associated with the sex disparity showing a greater prevalence of obesity/overweight in boys compared with girls in Chinese school children.

METHODS:

Sampled students and their parents were asked to complete a questionnaire. Perceptions of weight status by the parents, grandparents and children themselves were collected. A logistic regression analysis was used.

RESULTS:

The sampled students included 327 obese/overweight students and 1078 students with normal body mass index (BMI). The crude OR of obesity/overweight for boys compared with girls was 1.57 (95% CI 1.22 to 2.01). The increased risk of childhood obesity/overweight for boys remained after adjustment for prenatal and infant factors, daily habits and family situation, but disappeared after adjustment for perception of weight status (OR 1.27 [95% CI 0.93 to 1.67]). There were differences in underestimation of children’s weight status between boys and girls by their parents and grandparents (OR 1.33 [95% CI 1.08 to 1.64] and OR 1.42 [95% CI 1.15 to 1.75], respectively).

CONCLUSIONS:

Misconceptions about a child’s weight status were prevalent among parents and grandparents, and boys’ weight status was more frequently underestimated than girls. The disparity of underestimating weight according to sex may partially contribute to the difference in the prevalence of obesity/overweight between boys and girls among Chinese school children.