Association between distorted body image and changes in weight status among normal weight preadolescents in Japan: a population-based cohort study

The Association of Body Image Self-Discrepancy With Female Gender, Calorie-Restricted Diet, and Psychological Symptoms Among Healthy Junior High School Students in Japan

Background: Body image self-discrepancy reflects a preference for weight loss regardless of normal body size and is a distorted cognition that may be a precursor to eating disorders. The aim of this study was to investigate factors associated with body image self-discrepancy among healthy junior high school students in Japan.

Method: This cross-sectional study was conducted at one junior high school in Saitama, Japan, in December 2016. After excluding obese participants (defined as 20% above their ideal weight), 304 students (mean age, 13.9years; n=181 girls, 59.5%) who fell into underweight (n=22, 7.2%) and normal weight categories were selected. Body image self-discrepancy was measured using the Contour Drawing Rating Scale which includes eight separate figures representing body sizes. We then calculated the difference by subtracting ideal from current body sizes and defined body image self-discrepancy if the difference >1.

Results: Girls constituted 92% (n=49) of the 53 students with body image self-discrepancy. In all students, multivariable stepwise models demonstrated that female gender (OR, 6.92, 95% CI: 2.33–20.51), a calorie-restricted diet (OR, 5.18, 95% CI: 2.22–12.05), and psychological symptoms (OR, 1.47, 95% CI: 1.15–1.87) were significantly associated with an increased risk of body image self-discrepancy. Specifically for girls, an increased risk of body image self-discrepancy was associated with calorie-restricted suppers and psychological symptoms.

Conclusion: Body image self-discrepancy among healthy adolescents in Japan was found to be closely linked to being a girl, having a calorie-restricted diet, and having psychological symptoms.

Five-year change in body mass index category of childhood and the establishment of an obesity prediction model

The prevalence of childhood obesity in China has recently become increasingly severe, and intervention measures are needed to stop its growth. Currently, there is a lack of assessment and prediction methods for childhood obesity. We develop a predictive model that uses currently measured predictors [gender, age, urban/rural, height and body mass index (BMI)] to quantify children’s probabilities of belonging to one of four BMI category 5 years later and identify the high-risk group for possible intervention. A total of 88,980 students underwent a routine standard physical examination and were reexamined 5 years later to complete the study. The full model shows that boys, urban residence and height have positive effects and that age has a negative effect on transition to the overweight or obese category along with significant BMI effects. Our model correctly predicts BMI categories 5 years later for 70% of the students. From 2018 to 2023, the prevalence of obesity in rural boys and girls is expected to increase by 4% and 2%, respectively, while that in urban boys and girls is expected to remain unchanged. Predictive models help us assess the severity of childhood obesity and take targeted interventions and treatments to prevent it.

Body Weight Misperception and Weight Disorders among Chinese Children and Adolescents: A Latent Class Analysis

Body misperception plays an important role in the development of weight and dietary disorders among children and adolescents. A school-based health promotion program (2014-2015) was conducted to promote the school health education and improve the teenagers' physical health among Chinese children and adolescents. Based on this program, we intended to examine weight status and weight misperception among Chinese children and adolescents and to explore the relationship between weight misperception and lifestyle behaviors. A total of 10 708 Chinese children and adolescents in 3rd and 7th grade from Shandong and Qinghai province participated in the program. The participants' dietary and activity patterns were clustered by latent class analysis (LCA). Logistic regression analysis was undertaken to explore the relationship between weight perception and demographic factors or dietary and activity patterns. Given the gender-specific difference of children and adolescents, analyses were separately conducted among boys and girls. The total prevalence of weight misperception was 44.50%. Boys, especially those in higher grade and living in wealthier district, were more likely to misperceive body weight. Girls were more likely to overestimate their weight (26.10%) while boys tended to underestimate the weight (28.32%). Three latent dietary and activity patterns including obesogenic pattern, malnourished pattern and healthy pattern were derived. The participants who had weight misperception were more likely to choose unhealthy dietary and exercise activities. The high prevalence of weight misperception was closely related to the unhealthy weight pattern and unhealthy dietary or exercise patterns. Our research found that most children and adolescents failed to perceive their weight correctly and boys tended to underestimate their weight while girls were subjected to overestimation. So, comprehensive intervention programs should focus on improving self-weight awareness, and appropriate guidance should be made to lead the adolescents to more healthy weight pattern.

Incidence of childhood overweight and obesity and its association with weight-related attitudes and behaviors in China: a national longitudinal study

BACKGROUND

Childhood obesity is a major public health challenge. We aimed to investigate the incidence of overweight/obesity among Chinese children; and prospectively examine the associations of weight-change intention with risk of overweight/obesity and behavioral changes in initially normal-weight children.

METHODS

A national sample of 21,796 children aged 6-17 years were investigated in September 2013 and followed up nine months later, of which 19,887 (91%) were normal weight and 1909 (9%) were underweight at baseline. Weight and height were objectively measured. Weight perception, weight-change intention, weight control practices, weight-related behaviors, and demographic information were obtained by questionnaires.

RESULTS

Among children with underweight or normal-weight, the cumulative incidence of overweight/obesity was 2.77% (95% CI 2.55-2.99). Among normal-weight children, those who overestimated their weight had higher baseline BMI z-scores and an increased relative risk (RR) of overweight/obesity (RR 1.51, 95% CI 1.15-1.99). Children who misperceived themselves as underweight or overweight had stronger weight-change intention than their counterparts. However, children with weight-change intention did not develop greater changes in dietary intakes, physical activities, or sedentary behaviors than those without intention. There was no significant association between weight-change intention and incidence after adjusting for BMI z-scores at baseline. Self-reported improving diet, increasing physical activity, and dieting were associated with certain actual behavioral improvements and smaller increase in BMI z-score, but not associated with decreased risk of overweight/obesity.

CONCLUSION

The 9-months cumulative incidence of overweight/obesity was 2.77% among Chinese children. Weight-change intention was not associated with incidence of overweight/obesity in normal-weight children, regardless of their weight perception. More importantly, children's weight-change intention was insufficient in achieving desirable behavioral changes. Future overweight and obesity prevention programs should directly target on promoting children's actual behavioral changes.