Low sleep and low socioeconomic status predict high body mass index: a 4-year longitudinal study of Australian schoolchildren.

OBJECTIVE: The objective of this study was to examine the longitudinal relationships between body mass index (BMI), sleep duration and socioeconomic status (SES) in a 4-year cohort of 939 children aged 7-12 years. METHODS: Children and their mothers completed an annual questionnaire to assess usual weekday sleep and wake times, amount of sleep, physical activity, parental education and school SES. 93% of children were enrolled (939/1010) and retention was 88%, 83% and 81% in consecutive years. Height and weight were measured annually. RESULTS: BMI increased with decreasing amount of sleep and less sleep predicted greater International Obesity Task Force measures of obesity and overweight. In all 4 years, after controlling for baseline BMI, low SES was a significant predictor of high BMI. Children in the upper tertile of sleep in year 1 had a 2.3 kg lower weight gain (standard error [SE]: 0.5) between years 1 and 4 (P < 0.0001) than children in the lower tertile of sleep and a 0.45 kg m(-2) lower increase in BMI (SE: 0.15) (P = 0.004). The difference between children with consistently low and high sleep duration over 4 years was 1 BMI point. Those with the lowest BMI were the children with both high SES and high sleep duration. PA was not associated with BMI. CONCLUSIONS: Both low SES and short sleep duration predict obesity risk in children after controlling for baseline BMI and this trend becomes stronger as children enter adolescence. Obesity prevention should include a sleep promotion component and this may be more beneficial to children of low SES and/or socially disadvantaged backgrounds.

Association between socioeconomic status, weight, age and gender, and the body image and weight control practices of 6- to 19-year-old children and adolescents.

The aim of the study was to examine the effect of socioeconomic status (SES), age, weight and gender on the body image and weight control practices of children and adolescents, and to investigate whether health education about weight issues should target low socioeconomic groups. The study participants were a randomly selected group of school children who completed a questionnaire, and had their height and weight measured. Participants (n = 1131) were aged 6-19 years from 12 schools in New South Wales. SES, age, gender, body weight, body image, skipping breakfast, physical self-esteem, attempts to lose or gain weight, and dietary and weight control advice received from others were examined. Log-linear, chi 2 and MANOVA analyses were used to determine interactions between variables. Low SES children were more likely to be overweight, to skip breakfast, to perceive themselves as 'too thin', to be trying to gain weight and less likely to receive dietary or weight control advice. Physical self-esteem was lowest among overweight girls of middle/upper SES and greatest among boys of low SES, despite the latter being more likely to be overweight. Being overweight does not appear to adversely affect the physical self-esteem of children of low SES, particularly boys. Health educators should examine these issues with young people to help make health education and nutrition education most relevant and appropriate.

Body mass index, menarche, and perception of dieting among peripubertal adolescent females.

OBJECTIVE: To examine perceptions of dieting among pre and postmenarchial female school students. METHOD: All 51 female students of mean (SD) age 12.6 (0.6) years from a state school volunteered to complete a questionnaire about general health, eating and weight control behaviors, and menstrual status. Height and weight were measured. Focus groups using structured questions and discussion were used to elicit responses about the meaning of dieting and its association with menarche. RESULTS: Postmenarchial females were significantly more likely than the same age premenarchial students to have increased their body mass index (BMI), to clearly articulate the meaning of dieting, to report trying to lose weight, and to use diet and exercise to lose weight. Premenarchial females did not have a clear perception of dieting. Premenarchial females who reported trying to lose weight equated dieting with healthy eating and did not include losing weight or the behaviors and feeling associated with the concept of dieting unless their BMI had increased and menarche was imminent. DISCUSSION: The concept of dieting that may result in weight loss and the behaviors and feelings associated with dieting did not develop until menarche and is likely to be associated with the rapid increase in height, weight, and body fat that precedes menarche. Educational interventions aimed at preventing eating disorders among premenarchial adolescents may therefore be inappropriate, ineffective, and potentially dangerous.

Knowledge, beliefs, attitudes, and behaviors related to weight control, eating disorders, and body image in Australian trainee home economics and physical education teachers.

OBJECTIVE: To examine the knowledge, beliefs, and attitudes about weight control and eating disorders among trainee home economics and physical education teachers and to assess their body image and weight control practices. The association between actual body weight and body image was also examined. DESIGN: Survey research was undertaken using a self-report questionnaire. Height and weight were measured. SUBJECTS/SETTINGS: Trainee home economics and physical education teachers (N = 216, 96% participation rate) in their last month of training at three major state teacher training universities completed a questionnaire during their regular class times. MAIN OUTCOME MEASURES: Advice teachers give to overweight adolescents knowledge and beliefs about eating disorders, body image, desired weight, food habits, dieting, body appearance ratings, weight control practices, and diagnosed and self-reported eating disorders. STATISTICAL ANALYSIS PERFORMED: Descriptive statistics, chi square, and analyses of variance compare gender and Body Mass Index differences. RESULTS: Males (85%) and females (87%) advised young overweight adolescents to diet to lose weight. Twenty percent of females and 13% of males regularly skipped breakfast. The advise given showed a lack of specific nutrition education about weight control, adolescent nutritional needs, and fad diets. Participants held misconceptions about eating disorders, and a range of 14% to 72% answered these questions incorrectly. Fourteen percent of females self-reported that they currently had an eating disorder, but only 6% had received treatment. Some females used potentially dangerous methods of weight loss, including 19% who abused laxatives and 10% who induced vomiting. IMPLICATIONS: Trainee home economics and physical education teachers need specific nutrition information and training about eating disorders, weight control, and suitable advice for overweight students. The female trainee teachers in our study had a poor body image and disordered eating similar to other young women in Western countries, and this should be taken into account by teacher training institutions.

Improving the body image, eating attitudes, and behaviors of young male and female adolescents: a new educational approach that focuses on self-esteem.

OBJECTIVE: This study examines the effect of an interactive, school-based, self-esteem education program on the body image and eating attitudes and behaviors of young male and female adolescents following the program and after 12 months. METHOD: All 470 eligible students (63% female) aged 11-14 years volunteered to participate. The intervention group students participated in the program, whereas the control group students received their scheduled personal development and health class. RESULTS: The program significantly improved the body satisfaction of the intervention students and significantly changed aspects of their self-esteem; social acceptance, physical appearance, and athletic ability became less important for the intervention students and more important for control students. Female intervention students rated their physical appearance as perceived by others significantly higher than control students and allowed their body weight to increase appropriately by preventing the age increase in weight-losing behaviors of the control students. One year after the intervention, body image and attitude changes were still present. These findings also held for the 116 students (63% females) with low self-esteem and higher anxiety, who were considered at risk for the development of eating disorders. These students also had significantly lower drive for thinness and greater body satisfaction following the intervention and the decreased importance of physical appearance to their self-esteem was present at 12 months. Control at-risk students significantly decreased their body weight, whereas the weight of the intervention at-risk students significantly increased. The intervention program was effective, safe, having no effect on measures of students' anxiety or depression, and was rated highly by students. DISCUSSION: This is the first controlled educational intervention to successfully improve body image and to produce long-term changes in the attitudes and self-image of young adolescents. This new approach to prevent the development of eating disorders by improving self-esteem may be effective, particularly if reinforced by teachers and family.

Association between self-concept and body weight, gender, and pubertal development among male and female adolescents.

This study examined the effects and interactions of gender, pubertal status, and body weight on the self-concept of 462 young adolescent Australian students from two different schools. All students enrolled in Years 7 and 8 completed the Self-Perception Profile for Adolescents, which includes several self-concept subscales and ratings of the importance of each subscale. The self-concept subscales ranked as most important by male and female students were Close Friendship, Scholastic Competence, and Job Competence. Females rated their ability to form close friendships significantly higher and of greater importance than did males. Standard body weight was related to students' Physical Appearance subscale scores, with higher weight students having lower self-concept, and postmenarcheal females having the poorest opinion of their physical appearance. Higher body weight males had lower scores on Athletic Competence, Job Competence, and Behavioral Conduct than did other males. Overweight females and normal weight males considered athletic competence to be more important than did other students. Pubertal status was related to students' scores on Athletic Competence, with postpubertal males who were not overweight scoring highest, and on Physical Appearance, with postmenarcheal females having the lowest opinion of their appearance. The mean self-concept score was significantly related to students' standard body weight, and there was an interaction between gender and puberty, with postpubertal males having the highest and postmenarcheal females the lowest self-concept score. The discrepancy score suggested that females felt they had failed to meet their ideal self-concept significantly more than did males. The results suggest that school programs should be implemented to provide exercise and job skill training suitable for all students, especially those who are overweight. These programs, while taking into account students' pubertal status, should aim to improve self-image without resulting in feelings of failure.

Onset of disordered eating attitudes and behaviors in early adolescence: interplay of pubertal status, gender, weight, and age.

The interplay of puberty, gender, weight, and age in regard to body image and disordered eating behaviors and attitudes was investigated in a sample of early adolescents. It was found that, after menarche, females had increased personal expectations and were dissatisfied with weight/shape changes. They wanted to reduce their weight and between-meal eating (which was associated with increased feelings of inadequacy, loss of control, and decreased self-esteem). Young postmenarcheal females who were higher achievers and had higher trait anxiety were more likely to have lower weight. Young males at puberty desired to build up their bodies, believing that appearance was important to their sexual appeal. They were also more willing to form close relationships. Postpubertal males felt most in control of their lives, had the highest self-esteem, and were more trusting of their body cues. Overall, high achieving, more anxious postmenarcheal females were at greatest risk for eating disturbances. These results indicate that the interaction of pubertal status and gender must be considered when developing intervention programs.