Comparison of overweight, weight perception, and weight-related practices among high school students in three large Chinese cities and two large U.S. cities

Global Prevalence of Adolescent Use of Nonprescription Weight-Loss Products: A Systematic Review and Meta-Analysis

Importance

Use of nonprescribed weight-loss products in adolescents is a public health concern that is associated with negative physical and psychological consequences. However, the prevalence of nonprescribed weight-loss product use in adolescents is unknown.

Objective

To determine the global prevalence of nonprescription weight-loss product use in children and adolescents.

Data Sources

Four databases, including MEDLINE, PsycINFO, CINAHL (Cumulative Index of Nursing and Allied Health), and EMBASE, were searched for quantitative studies that reported prevalence data on use of nonprescription weight-loss products with no restrictions on publication date. The search was performed December 1, 2020, and updated March 6, 2023.

Study Selection

Studies were included in the meta-analysis if they reported the prevalence of weight-loss product use, were published in English, and included individuals 18 years or younger.

Data Extraction and Synthesis

Data extraction was completed by 2 independent reviewers. Data analysis determined the overall pooled proportion of weight-loss product use in total and during the past week, past 30 days, past year, or lifetime. Inverse variance heterogeneity effect models were used.

Main Outcomes and Measures

The main outcome measure was the prevalence of nonprescription weight-loss product use in adolescents for all included studies and over the past week, past month, past year, or lifetime. Subgroup analysis included separation of groups by sex, specific weight-loss product types, geographical location, and study publication time.

Results

A total of 90 articles (604 552 unique participants) were included in the meta-analysis. Of these, 50 studies (56%) were from North America. The reported prevalence of weight-loss product use in adolescents was 5.5% (96% CI, 5.5%-5.6%) overall. When identifying use of weight-loss products in the general population, prevalence was 2.0% (95% CI, 1.9%-2.1%) in the past week, 4.4% (95% CI, 4.3%-4.5%) in the past month, 6.2% (95% CI, 6.1%-6.3%) in the past year, and 8.9% (95% CI, 8.6%-9.2%) in their lifetime. Use of weight-loss products was higher among girls than boys.

Conclusions and Relevance

This meta-analysis found that use of weight-loss products occurs at high levels in adolescents, especially girls. These findings suggest that, given the ineffectiveness of these products for weight loss coupled with their harmful long-term health consequences, interventions are required to reduce use of weight-loss products in this group.

The Influence of a School Social Network Intervention on Adolescent's Health Behaviors: A Gender-Specific Agent-Based Model

Introduction

Adolescence is a crucial stage for health behavior development, which is associated with health in adulthood. School closures caused by the coronavirus disease 2019 (COVID-19) pandemic have exposed adolescents to an increased risk of obesity due to a lack of physical activity. Although social network interventions provide an effective approach for promoting health-related behavior, current practices neglect gender differences in adolescent behavioral patterns and emotional preferences. The aim of this study was to examine the effectiveness of centrality-based methods integrated with of gender contexts in a social network intervention to improve adolescent's health behavior.

Methods

We developed an agent-based model (ABM) that supports the small-world characteristics of adolescent social networks. Health-related data for junior middle school students (n = 234, 48% girls) were collected in November 2018, 2019 and 2020 in Tianjin, China. We simulated multiple network-based interventions with different criteria for influential agents (i.e., betweenness centrality, closeness centrality, eigenvector centrality, and PageRank) and a random condition. The rules for generating peer influence and accelerating behavioral changes were based on the diffusion of innovations theory, with gender specifications.

Results

After the school closures, there was a significant increase in the prevalence of overweight and obesity among adolescents, with a greater increase in girls than in boys (+8.85% vs. +1.65%, p < 0.001). Simulations showed that centrality-based network interventions were more effective than the random condition (average 6.17% per tick vs. 5.22% per tick, p < 0.05), with a higher efficiency in girls than boys (average 3.68% vs. 2.99% per tick, p < 0.05). PageRank outperformed other centrality conditions at the population level (6.37% per tick, p < 0.05). In girls, betweenness centrality was the best method (3.85% per tick, p < 0.05), while in boys, PageRank still had the greatest efficiency (3.21% per tick, p < 0.05).

Conclusions

We found evidence for gender differences in the negative impact of COVID-19-related school closures and the potential for centrality-based social network interventions to affect adolescent health behavior. Therefore, we emphasize the importance of gender-specific targeting strategies to further promote health-related school programs in the post-pandemic era.

Intention to lose weight and use of electronic cigarettes among adolescents

Electronic cigarette use among American adolescents is a major public health concern given the negative health consequences of nicotine in youth. Recent literature has shown that weight control may be one motivation for use in this population. This study examined associations between intention to lose weight and e-cigarette use among adolescents having overweight or obesity from an ethnically diverse sample of Texas youth by gender. We performed a cross-sectional analysis of a state representative sample of 9056 eighth and eleventh grade students from the 2015-2016 Texas School Physical Activity and Nutrition (Texas SPAN) study. Validated survey items assessed weight intentions and e-cigarette use. Staff collected anthropometric measures. Logistic regression analysis was conducted to assess the relationship between e-cigarette use and weight intentions with gender interaction, adjusting for grade, race/ethnicity, economic status, weight-behaviors and stratified by BMI class. More than half (50.9%) of the weighted sample were Hispanic and 12.5% were Non-Hispanic Black; 8.5% used e-cigarettes; and 50.0% intended to lose weight. Of the 40.2% of the sample having overweight or obesity, 82.9% intended to lose weight. Among respondents with obesity, use of e-cigarettes was significantly higher among males intending to lose weight than among females intending to lose weight (12% versus 6%, p = 0.007). These findings contrast with previous research suggesting that e-cigarette use in females is more likely to be motivated by an intent to lose weight. The ethnic diversity of the Texas SPAN population may explain this discrepancy.

Clustering of unhealthy lifestyle behaviours and associations with perceived and actual weight status among primary school children in China: A nationally representative cross-sectional study

Few studies have focused on clustering of unhealthy lifestyle behaviours among primary school children and potential associations with perceived and actual weight status. An index was constructed from adding up 13 unhealthy behaviours measured by survey responses. Multilevel linear regressions were used to analyse associations between child personal characteristics, perceived and actual weight status with the unhealthy lifestyle index among 11,157 children in primary schools across China. Parental and area factors were also taken into account, including education, weight status, physical activity, urban/rural and area socioeconomic circumstances. The unhealthy lifestyle index normally distributed, with 84.5% of children reporting between 2 and 6 unhealthy behaviours. Boys reported more unhealthy behaviours compared with girls (coefficient 0.32, 95%CI 0.26 to 0.37) and children in urban areas had fewer unhealthy behaviours than their rural counterparts (-0.29, 95%CI -0.56 to -0.03). An interaction revealed stronger 'protective' effects of living in cities for girls than boys, which were not explained by differences in child overweight/obesity. More unhealthy behaviours were characteristic of children in more affluent areas, and of those born to mothers and/or fathers with lower educational attainment. Children who perceived themselves as overweight or underweight both scored higher on the unhealthy lifestyle index. Unhealthy behaviours that could increase the risk of childhood obesity are common among Chinese primary school children, particularly among boys in cities, those in more affluent areas and with parents with lower education. There was no effect of actual weight status on number of unhealthy behaviours. Perceived, but not actual weight status, was also a significant correlate of unhealthy behaviours. Clustering of unhealthy lifestyle behaviours that could increase the risk of childhood obesity are common among Chinese primary school children, particularly among boys in cities, those in more affluent areas and with parents with lower education. Perceived, but not actual weight status, was also a significant correlate of unhealthy lifestyle. This has important implications for public health because understanding clustering of unhealthy lifestyle behaviours can be used to assist in the development of targeted obesity prevention initiatives.

Relationship between body weight perception and weight-related behaviours

Objectives

This study aimed to examine the prevalence of weight misperception and to explore the association of weight perception with physical activity and dietary intake.

Methods

A population-based, nationally representative cross-sectional survey was conducted of 920 Thai adolescents aged 13 to 24 years. Respondents were selected using stratified multistage sampling. Respondents who agreed to participate were asked to complete the Youth Risk Behavior Questionnaire.

Results

Females were more likely than males to misperceive themselves as overweight (21.8% vs. 11.7%), whereas males were more likely than females to misperceive themselves as underweight (12.3% vs. 3.4%). Males were more likely than females to report a high intake of vegetables (45.7% vs. 38.0%), milk (39.1% vs. 38.0%), 100% fruit juice (20.9% vs. 17.7%) and soda or pop (38.5% vs. 20.6%). Males were also more likely than females to report vigorous physical activity of more than 60 minutes per day (38.1% vs. 21.3%) and vigorous exercise to strengthen or tone muscles (37.3% vs. 13.2%).

Conclusions

Gender differences in dietary intake and physical activity were identified. However, there were no significant differences in dietary intake and physical activity between adolescents who correctly perceived themselves as overweight and those who misperceived themselves as overweight.

The Relationship Between Body Image Concerns and Weight-Related Behaviours of Adolescents and Emerging Adults: A Systematic Review

This systematic review investigates evidence on the association between body image concerns and weight-related behaviours of adolescents and emerging adults. It includes peer-reviewed journal articles reporting research involving body image concerns and weight-related behaviours of adolescents and emerging adults, published between 2005–2017, and located through systematic searches from four databases. This review includes studies from 11 countries or regions: United States (n = 13), Asia (n = 9), Europe (n = 8), Middle East (n = 3), South America (Brazil; n = 3), Canada (n = 3), Australia (n = 1), New Zealand (n = 1), Trinidad (n = 1), Turkey (n = 1) and Seychelles (n = 1); 24 different countries (n = 1); three Asian countries and the United States (n = 1). Out of 46 studies included in this review, 45 studies reported a positive association between body image concerns and weight-related behaviours. Adolescents and emerging adults who misperceived their weight engaged in weight-related behaviours. Higher body dissatisfaction had a significant association in the development of eating disorders and extreme weight-loss behaviours. Body image concerns play a significant role in adolescents and emerging adults engaging in weight-related behaviours. Experimental research designs are required to determine the causality of this association. Evidence strongly suggests policy makers and public health practitioners contemplate strategies to promote positive body image and healthy weight-related behaviours among adolescents and emerging adults.

A systematic review of the relationship between weight status perceptions and weight loss attempts, strategies, behaviours and outcomes

It is commonly assumed that a person identifying that they are 'overweight' is an important prerequisite to successful weight management. However, there has been no systematic evaluation of evidence supporting this proposition. The aim of the present research was to systematically review evidence on the relationship between perceived overweight and (i) weight loss attempts, (ii) weight control strategies (healthy and unhealthy), (iii) weight-related behaviours (physical activity and eating habits), (iv) disordered eating and (v) weight change. We synthesized evidence from 78 eligible studies and evaluated evidence linking perceived overweight with outcome variables separately according to the gender, age and objective weight status of study participants. Results indicated that perceived overweight was associated with an increased likelihood of attempting weight loss and with healthy and unhealthy weight control strategies in some participant groups. However, perceived overweight was not reliably associated with physical activity or healthy eating and was associated with greater disordered eating in some groups. Rather than being associated with improved weight management, there was consistent evidence that perceived overweight was predictive of increased weight gain over time. Individuals who perceive their weight status as overweight are more likely to report attempting weight loss but over time gain more weight.

Body weight perception and body weight control behaviors in adolescents

OBJECTIVE

To investigate the association between the perception of body weight (as above or below the desired) and behaviors for body weight control in adolescents.

METHODS

This was a cross-sectional study that included 1051 adolescents (aged 15-19 years) who were high school students attending public schools. The authors collected information on the perception of body weight (dependent variable), weight control behaviors (initiative to change the weight, physical exercise, eating less or cutting calories, fasting for 24h, taking medications, vomiting, or taking laxatives), and measured body weight and height to calculate the body mass index and then classify the weight status. Associations were tested by multinomial logistic regression analysis.

RESULTS

Adolescents of both sexes who perceived their body weight as below the expected weight took more initiatives to gain weight, and those who perceived themselves as overweight made more efforts to lose weight. In adolescents who perceived themselves as overweight, the behavior of not taking medication was associated with the outcome only in boys (Odds Ratio=8.12), whereas in girls, an association was observed with the variables eating less, cutting calories, or avoiding fatty foods aiming to lose or avoid increasing body weight (Odds Ratio=3.39). Adolescents of both sexes who practiced exercises were more likely to perceive themselves as overweight (male Odds Ratio=2.00; Odds Ratio=1.93 female).

CONCLUSION

The perception of the body weight as above and below one's expected weight was associated with weight control behaviors, which were more likely to result in initiatives to lose and gain weight, respectively.

Weight perception and its association with socio-demographic and health-related factors among Korean adolescents

BACKGROUND

Adolescence is a time of rapid growth with dramatic changes in physical appearance. The body image established at this time could affect their physical and mental health throughout their entire life. However, adolescents sometimes perceive themselves as underweight or overweight irrespective of actual weight status. The purpose of the present study was to examine the extent of weight misperception for Korean adolescents, to explore socio-demographic factors associated with weight misperception, and to examine gender-specific differences in the relationships between weight misperception and health-related factors.

METHODS

We selected data on 3321 adolescents aged 12-18 years from the five-year Korea Health and Nutrition Examination Survey (KNHANES) datasets (2007-2011). Self-perceived weight status was compared with measured weight status by cross-tabulation. The generalized logit model was used to explore the socio-demographic factors associated with weight misperception, and separate logistic regression models were fitted to examine gender-specific differences in the relationships between weight misperception and health-related factors.

RESULTS

Overall, 25.8 % of boys (overestimation 17.1 %; underestimation 8.6 %) and 29.3 % of girls (overestimation 24.0 %; underestimation 5.3 %) misclassified their weight status according to the objective standards. Weight overestimation was particularly prominent among underweight girls. Weight misperception was associated with socio-demographic factors such as gender, age, BMI, place of residence, and maternal education level. Weight overestimation and underestimation in boys and weight overestimation in girls were significantly related to inappropriate weight control practice. However, weight underestimation in girls seems to be negatively linked to inappropriate weight control practice.

CONCLUSIONS

Based on the results of the present study, comprehensive intervention programs for adolescents and their parents could be devised to raise self-awareness of their weight status, to overcome weight misperception, and to prevent obesity and its related health risks.

Diet-related determinants of childhood obesity in urban settings: a comparison between Shanghai and New York

Over the past three decades, both Shanghai and New York City (NYC), have experienced dramatic rises in childhood obesity rates. Given the role that obesity plays in the aetiology of chronic diseases such as diabetes and heart disease, the elevated rates are a major concern. Despite differences in governance systems and cultures, Shanghai and NYC have experienced rapid industrialization, a growing population and a rise in income inequality. The prevalence of childhood obesity in Shanghai and NYC is greater than their respective national rate. However, the trajectory and development of this epidemic has differed between the cities. The distribution of obesity by race and ethnicity, socio-economic status, sex, and age differs markedly between the two cities. To reduce prevalence and inequities within this complex epidemic requires an understanding of the dynamic changes in living conditions among social groups in each city and the behaviours that are influenced by such changes. By comparing changes in the influences on dietary behaviours, such as food distribution, pricing, gender values, and media and marketing, this highlights opportunities for Shanghai, NYC, and other world cities with high or rising rates of childhood obesity to inform future program and policy initiatives. It reiterates the importance of a comprehensive and multilevel approach that includes action at the individual, family, community, municipal, national, and global levels.

Cultural trends and eating disorders

PURPOSE OF REVIEW

Culture has long been recognized as significant to the cause and expression of eating disorders. We reviewed the recent literature about recent trends in the occurrence of eating disorders in different cultures.

RECENT FINDINGS

While historically, eating disorders were conceptualized as primarily afflicting Caucasian adolescent or young adult women within high-income, industrialized Western Europe and North America, eating disorders are increasingly documented in diverse countries and cultures worldwide. This study highlights recent trends that reflect the changing landscape of culture and eating disorders: stabilization of the incidence of anorexia nervosa and possibly lower incidence rates of bulimia nervosa in Caucasian North American and Northern European groups; increasing rates of eating disorders in Asia; increasing rates of eating disorders in the Arab region; and increasing rates of binge eating and bulimia nervosa in Hispanic and Black American minority groups in North America.

SUMMARY

The changing face of eating disorders calls for a new conceptualization of culture in both the emergence and spread of eating disorders across the globe.

Weight misperception and health risk behaviors in youth: the 2011 US YRBS

OBJECTIVES

To evaluate dose-response associations between misperceived weight and 32 health risk behaviors in a nationally representative sample of US adolescents.

METHODS

Participants included 13,864 US high school students in the 2011 Youth Risk Behavior Survey. Comparing the degree of agreement between perceived and reported actual weight, weight misperception was determined as 5 categories. Multivariable-adjusted logistic regression analyses evaluated associations of weight misperception with 32 health risk behaviors.

RESULTS

Both underestimated and overestimated weight were statistically significantly associated with all 32 health risk behaviors in a dose-response manner after adjustment for age, sex and race/ethnicity, where greater weight misperception was associated with higher engagement in health risk behaviors.

CONCLUSIONS

Understanding potential impacts of weight misperception on health risk behaviors could improve interventions that encourage healthy weight perception and attainment for adolescents.

Prevalence and sociodemographic trends of weight misperception in Korean adolescents

BACKGROUND

Rapid physical and emotional growth occurs during youth. Adolescence is one of the most important periods for adapting to body change and establishing an ideal body image. Body change is an important and sensitive concern for adolescents, and the values and self-conception established at this time affect various aspects of the entire life. This study aimed to investigate the prevalence and trends of weight misperception among adolescents in Korea.

METHODS

We analyzed raw data from the 2011 Korea Youth Risk Behaviour Web-based Survey-VII (KYRBWS-VII), in which 73,474 adolescents from the middle-school first grade to the high-school third grade (aged 12-18) participated. For the multivariate logistic regression model, the dependent variable was existence of misperception (yes/no) and independent variables were sociodemographic factors.

RESULTS

We found that the prevalence of weight misperception was 49.3% (overestimation, 23.7%; underestimation, 25.6%). Among male students, 65.0% underestimated their weight, whereas 62.2% of female students overestimated their weight. Multivariate logistic regression analysis revealed that gender (OR = 1.254; 95% CI = 1.214-1.294; p < 0.001) and socioeconomic status (OR = 1.173; 95% CI = 1.121-1.228; p < 0.001) were significantly associated with weight misperception. Compared with overweight/obese adolescents, adolescents whose BMI-based body weight was underweight or normal showed 2.386-times higher (OR = 2.386; 95% CI = 2.045-2.783, p < 0.001) and 32.804-times higher (OR = 32.804; 95% CI = 29.829-36.077, p < 0.001) body shape misperception, respectively.

CONCLUSIONS

An effective obesity intervention program for adolescents must reflect and monitor body shape perception as well as BMI, and should include subjects who overestimate as well as underestimate their weight.

Inaccurate weight perception is associated with extreme weight-management practices in U.S. high school students

OBJECTIVE

The objective of the present study was to examine whether adolescents' weight perception accuracy (WPA) was associated with extreme weight-management practices (EWPs) in differing body mass index (BMI) categories.

METHODS

WPA, overassessment, and underassessment were determined by comparing self-reported BMI and weight perception among U.S. high school students in the 2009 National Youth Risk Behavior Survey. BMI was classified as follows: underweight (<5th percentile), healthy weight (5th to <85th), overweight (≥85th to <95th), and obese (≥95th). WPA was considered inaccurate if BMI and weight perception were discordant. Overassessors thought they were heavier than they were (among underweight/healthy groups); underassessors thought they were lighter than they were (among healthy/overweight/obese groups). EWPs included ≥1 of fasting, use of diet pills, or purging/laxative use. Logit models were fitted for different BMI sex strata.

RESULTS

In the final sample of 14,722 US high school students with complete data, 20.2%, 85.7%, 5.8%, and 80.9% of those who were underweight, healthy weight, overweight, and obese, inaccurately assessed their weight, respectively. In turn, 11.4% and 17.6% of accurate and inaccurate assessors engaged in EWPs, respectively. After adjustment, underweight girls who overassessed their weight had 12.6 times higher odds of EWPs (95% confidence interval 3.4-46.6). Moreover, there were elevated odds of EWPs among healthy weight students who overassessed their weight.

CONCLUSIONS

Overassessing healthy weight students and underweight girls had higher odds of ≥1 EWPs, likely related to an unhealthy desire to lose weight. The present study demonstrates a need to further educate clinicians on WPA and its relation to EWPs even among those of healthy weight who may be seen as not at risk.

Physical Activity Research in Hong Kong From 1987 to 2012

A comprehensive understanding of research on the physical activity (PA) of Hong Kong youth is necessary to develop specific and effective intervention strategies. This review summarizes existing evidence in studies on PA among the Hong Kong youth. An electronic literature search was conducted using MEDLINE, SPORTDiscus, ERIC, and HighWire database. Forty-five studies published from 1987 to 2012 were included in this review. The findings are presented in five categories, namely, health benefits of PA, participation in PA, assessment of PA, correlates of PA, and interventions to promote PA. The results indicate that PA among the youth in Hong Kong has attracted concern in the past decade. Specifically, extensive studies focused on the areas of health benefits of PA, participation in PA, and correlates of PA. Research into context-specific correlates of PA and tailored PA promotion programs for the Hong Kong youth is warranted in the future.

Language spoken at home and parental birthplace moderate the association of race/ethnicity and distorted weight perception

Distorted weight perception (DWP), specifically overestimating weight status, is common in adolescents and may lead to eating disorders. The authors examined the role of acculturation proxies as effect modifiers of the relationship between race/ethnicity and DWP in a diverse adolescent population. Analysis of the 2005 California Health Interview Survey showed that of 2955 adolescents with underweight or healthy weight status, 10.6% reported DWP. Latino adolescents had increased odds of DWP compared with white adolescents (adjusted odds ratio [aOR] = 3.02; 95% confidence interval [CI] = 2.00, 4.57). Latinos who spoke English and other language(s) at home (aOR = 3.38; 95% CI = 2.11, 5.41) and Latino (aOR = 5.00; 95% CI = 2.34, 10.72) and Asian (aOR = 3.10, 95% CI = 1.15, 8.35) adolescents who spoke no English at home had increased odds of DWP compared with white, English-only speakers. Latino adolescents had increased odds (aOR = 3.98, 95% CI = 2.45, 6.47) of DWP if neither parent was US born. Assessing acculturation proxies may help identify adolescents at risk of DWP.

Unhealthy weight-control behaviours, dieting and weight status: a cross-cultural comparison between North American and Spanish adolescents

The aim of the current study was to examine and compare dieting and unhealthy weight-control behaviours (UWCB) in population-based samples in two large urban areas in Spain (Barcelona) and in the USA (Twin Cities of Minneapolis and St. Paul, Minnesota). Additionally, use of UWCB across weight categories was explored in both samples. Participants included 1501 adolescents from Barcelona (48% girls, 52% boys) and 2793 adolescents from the Twin Cities (53% girls, 47% boys). The main outcome measures were dieting, UWCB (less extreme and extreme) and weight status. Although dieting and UWCB were prevalent in both samples, particularly among girls, the prevalence was higher in the US sample. In both countries, the report of dieting and use of UWCB was highest among overweight and obese youth. Prevention interventions that address the broad spectrum of eating and weight-related problems should be warranted in light of the high prevalence and co-occurrence of overweight and unhealthy weight-related behaviours.