Adolescent obesity: towards evidence-based policy and environmental solutions

Association between eating rate and childhood overweight/obesity: a systematic review and meta-analysis

Many studies have reported the relationship between eating rate and childhood overweight/obesity, while results remain inconclusive. The present study was done to estimate the association between eating rate and childhood overweight/obesity through a systematic review of prevalence studies. Relevant studies were searched by two independent researchers in databases including PubMed, Embase, Cochrane Library, and Web of Science, and data were collected from relevant studies published through June 2023 using predefined inclusion/exclusion criteria. A summary estimate was calculated using a random-effect model, and subgroup analysis was performed to explore sources of heterogeneity. Data from 16 published studies were eligible for inclusion. Fast eating was associated with a higher risk of overweight/obesity compared with a medium eating rate (OR = 1.80; 95% CI: 1.49, 2.18), and slow eating showed a declined overweight/obesity risk among children and adolescents (OR = 0.65; 95% CI: 0.52, 0.81). Subgroup analysis performed according to age showed that in all age groups, eating fast was positively correlated with overweight/obesity, while eating slowly was negatively associated with overweight/obesity. According to our study, eating rate was closely related to childhood overweight/obesity, and eating fast was associated with an increased likelihood of being overweight/obesity. In the future, it will be necessary to understand the factors that influence fast eating and develop methods to slow down the eating rate in children and adolescents.

Insights from Multiple Stakeholders Regarding Adolescent Obesity in China: An Exploratory Qualitative Study

With a significant increase in the obesity epidemic in China, addressing adolescent obesity should be highlighted as a priority. The current qualitative study aims to explore the perspectives of key stakeholders regarding adolescent obesity, providing guidance for developing effective obesity interventions for Chinese adolescents. A total of 12 focus group discussions were convened with a range of representative stakeholders including adolescents (n = 37), parents (n = 28), and school staff (n = 21) from sample schools. Semi-structured topic guides were used for data collection. All data were transcribed verbatim and analyzed thematically. From multiple stakeholder perspectives, we finally identified 3 overarching themes (Understanding adolescent obesity, Key healthy lifestyles, and Barriers to obesity prevention practices) and 8 sub-themes. While participants had mixed perceptions of status and prevalence of adolescent obesity, all acknowledged the serious health consequences associated with it. As significant modifiable risk factors, unhealthy diet and physical activity were identified to be prevalent among Chinese teenagers and lead to excessive weight gain. However, a variety of individual, environmental and sociocultural factors hindered the implementation of healthy lifestyles, affecting adolescent obesity prevention and control. Given adolescent obesity is a complex, multifactorial and multilevel public issue, comprehensive lifestyle interventions are recommended that synergistically engage multiple stakeholders across key communities to fight the ongoing obesity epidemic.

Obesity, inflammation, and depression in adolescents

Background

The prevalence of depression and obesity among adolescents has markedly increased over the last few decades. A bidirectional relationship has been proposed between depression and obesity in adolescence, but it remains poorly understood. Inflammation is a phenomenon that has been implicated in both disorders. Thus, a cross-sectional study was designed to investigate inflammation as a factor in the association between obesity and depression. The goal of this study is to better understand the interplay between these two disorders.

Methods

The study sample consisted of female and male, black and white adolescents aged 15-18 years. Participants were diagnosed with major depressive disorder (MDD) according to the Diagnostic and Statistical Manual of Mental Disorders-5. Depression severity was determined using the Quick Inventory of Depressive Symptomatology (QIDS). Participants completed the Childhood Trust Events Survey (CTES) and received an Early Life Stress (ELS) score based on the survey results. Those with a score of ≥4 were placed in the ELS group and those with a score ≤ 3 were placed in the non-ELS group. Anthropometric measures and a Dual Energy X-ray Absorptiometry (DEXA) scan were performed for body composition. Blood samples were collected to measure inflammatory factors.

Results

Adolescents with MDD (n = 47) had significantly elevated body mass index (BMI) percentiles compared to the controls (n = 47) (77.11 ± 3.58 vs. 59.63 ± 4.40), and increased adiposity measures, including total fat (p = 0.016), trunk fat (p = 0.016), and trunk/total fat ratio (p = 0.021). Levels of C-reactive protein, tumor necrosis factor-alpha, interleukin-6, leptin, and adiponectin varied significantly between the MDD and control groups, however, significance was not retained when BMI percentile and ELS score were controlled. There was a significant and positive relationship between QIDS and multiple measures of adiposity such as BMI percentile, visceral abdominal tissue, and trunk/total ratio. Depression severity was best predicted by ELS score, visceral adipose tissue, and adiponectin level.

Conclusion

Adolescents with MDD had increased levels of inflammatory factors and many measures of adiposity. Thus, the treatment of adolescent depression should include a focus on managing body composition and reducing chronic inflammation to potentially improve treatment outcomes.

Self-reported eating speed is associated with overweight among Chinese schoolchildren: a cross-sectional survey

PURPOSE

This study aimed to examine the association between eating speed and overweight in Chinese schoolchildren.

METHODS

In all, 664 schoolchildren (10-12 years) from three primary schools participated in this study in China. Their height and body weight were measured. Information about eating speed and other lifestyle behaviors were collected using a self-administered questionnaire. Multivariable logistic regression model was used to estimate the odds ratio (OR) and 95% confidence interval (95% CI) for overweight.

RESULTS

Data from 629 students were analyzed. 26.2% of participants reported they were eating fast. The prevalence of overweight (including obesity) was 22.9%, and the mean of sleep duration was 9.69 (SD = 0.63) hours (Table 1). In the multiple linear regression analysis, slower eating speed was independently associated with lower BMI (B = - 0.70, 95% CI - 1.26 to - 0.14) and TG (B = - 0.16, 95% CI - 0.28 to - 0.04). In addition, participants who ate fast were more likely to be overweight (OR 1.81, 95% CI 1.19-2.75) after adjusting for potential confounding factors.

CONCLUSIONS

This study indicates that eating fast is associated with overweight among Chinese school children.

LEVEL OF EVIDENCE

Cross-section descriptive study, Level V.

Regional Adolescent Obesity and Overweight Status in Korea from 2018-2019: Comparison between Two Data Sources

Difference in the regional adolescent obesity level may cause a notable health inequality between regions since it significantly affects adulthood health status. This study examined 2018 and 2019 regional obesity and overweight status of adolescents aged 12 to 18 by comparing two cross sectional population-based data sources, the Korea Youth Risk Behavior Web-based Survey (KYRBS) and the National Student Health Examination (NSHE). Prevalence was estimated by calculating weighted percentages and 95% confidence intervals. Correlations in the relative rankings of each municipality were determined by computing Spearman correlation coefficients (r_s), and prevalence discrepancies between the data sources were visualized by simple correlation graphs. The geographical distributions of adolescent obesity and overweight status showed no perfect concordances between the data sources regardless of sexes and survey years. For adolescent obesity status, there were significant difference between the least and the most obese regions and r_s levels were fair to good with p-values less than 0.05, but the correlation graphs indicated body mass index (BMI) underreporting in the KYRBS. For adolescent overweight status, no significant similarities were defined between the data. These results can be used as a basis for the establishment of related policies.

Dinner-to-bed time is independently associated with overweight/obesity in Chinese school-aged children

PURPOSE

Little is known about the association between dinner-to-bed time and obesity. Thus, this study was aimed to assess the relationships between dinner-to-bed and overweight/obesity in Chinese school-aged children in Ningbo, China.

METHODS

Data of this study were based on 1667 schoolchildren (14-15 years) from 14 primary schools participated in this study in China. Anthropometric measurement of height, body weight and waist circumference (WC) was performed. Information about meal duration and other lifestyle behaviors was collected using a self-administered questionnaire. Multivariable logistic regression model was performed to assess the association between dinner-to-bed time and overweight/obesity. Restricted cubic spline regression was drawn to evaluate the shape of the relation between dinner-bed-time and the odds of overweight.

RESULTS

Among the study participants, the prevalence of overweight was 17.6%, and the mean of dinner-to-bed time was 4.26 (0.93) h. In the logistic regression analysis, participants who had dinner-to-bed time less than 3 h or 3.01 ~ ≦ 4.00 h are more likely to be overweight (OR = 1.94, 95% CI 1.10-3.42; OR = 1.65, 95% CI 1.03-2.65, respectively) or characterised by abdominal obesity (OR = 3.03, 95% CI 1.86-4.95; OR = 2.61, 95% CI 1.73-3.92, respectively) compared with dinner-to-bed time more than 5 h. In addition, long dinner-to-bed time was associated with lower risks of overweight (OR = 0.83, 95% CI 0.70-0.97) and abdominal obesity (OR = 0.63, 95% CI 0.54-0.73). The cubic spline regression analysis showed that the association between dinner-to-bed time and overweight/abdominal obesity seems to be a linear.

CONCLUSIONS

This study indicates that short dinner-to-bed time is associated with an increased likelihood of being overweight or characterised by abdominal obesity among Chinese school-aged children.

LEVEL OF EVIDENCE

Level V; cross-section descriptive study.

School Gardening Activities Aimed at Obesity Prevention Improve Body Mass Index and Waist Circumference Parameters in School-Aged Children: A Systematic Review and Meta-Analysis

Background: Childhood obesity, due to its increasing prevalence, is one of the most challenging problems in public health and prevention. Recent strategies have been implemented to tackle this trend, including school gardening projects. This systematic review analyzes the main elements of school gardening with a specific meta-analysis about its impact on anthropometric parameters. Materials and Methods: We searched studies in PubMed, EMBASE, and Cochrane Library on school gardening projects carried out until February 2019 and addressed to children aged 6 to 13 years. Results: Thirty-three studies passed the screening selection. Outcomes analyzed were fruits and vegetables consumption/knowledge, nutritional attitudes and behavior, anthropometric outcomes (i.e., BMI, waist circumference-WC) and other outcomes (i.e., blood pressure, science achievement, and physical activity). We performed descriptive analyses of these outcomes and found a general benefit from school gardening projects. We subsequently performed a meta-analysis on anthropometric outcomes, highlighting a significant reduction of both BMI percentile (%) (-1.37%) and WC (-1.30 cm). Conclusions: Although more high-quality studies are needed on this topic, along with a greater homogeneity of anthropometric measurements, the results of our article show a modest but positive impact of school gardening projects on anthropometric measures and more generally on children's health.

Body Weight Concern and Belief among Adolescent Egyptian Girls

BACKGROUND

Body weight concern and belief in adolescent females are of great importance. They are the keys to successful dietary interventions including dietary habits' modifications to practice a healthy diet. This critical phase of transition from childhood to adulthood is the most sensitive stage of behavioural rectification.

AIM

This study was conducted with the aim to figure out the prevalence of body image dissatisfaction and the association of body image satisfaction and believe with body mass index in adolescent girls aged 16-18 years.

MATERIAL AND METHODS

Two hundred and three Egyptian adolescent females were enrolled in this cross-sectional study. Their mean age was (17.4 ± 0.64) years old. Self-administered questionnaires about the students' body satisfaction and weight belief were answered by the candidates. Their body mass index was calculated. Also, sociodemographic data were collected. Data were analysed using SPSS software version 16.0. Chi-square test was conducted for the variables.

RESULTS

Sixty-eight percent of the students were within normal weight, 3.3% were underweight, while 18.2% and 10.5% were overweight and obese respectively. Body dissatisfaction was prevalent among 37.4%. The prevalence of body dissatisfaction was higher in both obese and underweight candidates reaching (93.8% and 80%) respectively. This reflects students' awareness of their body shape.

CONCLUSION

More than one-third of adolescent females were dissatisfied with their body image. The subjective belief about self-body image matched the objective Body Mass Index measurements.

Analysis of Factors Affecting the Body Mass Index in a National Sample of Iranian Children and Adolescents: Bootstrapping Regression

Background

This study aims to evaluate the effect of some factors, including birth weight, sex, age, waist circumference, family history of obesity, as well as some lifestyle factors as frequency of breakfast days and physical activity, on the body mass index among a nationally representative sample of Iranian children and adolescents by using bootstrapping regression.

Materials and Methods

This study was conducted as the third survey of a school-based surveillance system (CASPIAN-III study). Total participants were 5570 school students, aged 10-18 years, selected by multistage random cluster sampling from urban and rural areas of 27 provinces of Iran. Multiple linear regressions was used to evaluate the effect of various factors on obesity, but in our data the assumptions of this model violated, and possible solutions were not appropriate, therefore the bootstrapping regression based on the observations and errors resampling approaches was used as an alternative.

Results

The tests of significance showed that the effects of sex, age, waist circumference, family history obesity and frequency of breakfast days were clearly significant (P < 0.001). The effect of vigorous level of physical activity was significant in comparison to mild physical activity (P = 0.01). In comparison to low birth weight, medium and high birth weight had significant effect on obesity.

Conclusions

Bootstrap method is preferable in linear regression because of some theoretical properties like having any distributional assumptions on the residuals and hence allows for inference even if the errors do not follow normal distribution or constant error variance.

Eating quickly is associated with waist-to-height ratio among Japanese adolescents: a cross-sectional survey

Background

Central obesity, based on waist circumference (WC), has more adverse effects on health than general obesity, determined by body mass index. To date, eating quickly has been reported to be risk factors for overweight/obesity among children, adolescents, and adults. In contrast, there are few studies on the relationship between fast eating and central obesity among adolescents, particularly in Japan, where WC is not commonly measured in junior high schools. The aim of the present study was to investigate the relationship between eating quickly and waist-to-height ratio (WHtR), an index of central obesity, among adolescents in Japan.

Methods

Study subjects were 2136 seventh-grade school children (12 or 13 years of age) from Ina town junior high schools in Japan, between 2004 and 2009. Measurements of height, weight, and WC were performed, and information about eating habits was collected using a self-administered questionnaire. A logistic regression model was used to calculate the odds ratio (OR) and 95 % confidence interval (95 % CI) for WHtR ≥ 0.5.

Results

Eating quickly significantly increased the OR for WHtR ≥ 0.5 in boys (OR: 2.05, 95 % CI: 1.31–3.23) and girls (2.09, 1.15–3.81). When compared with the “not eating quickly and not eating until full” group, the OR for WHtR ≥ 0.5 in the “eating quickly and eating until full” group was 2.67 (95 % CI: 1.50–4.73) in boys and 2.59 (1.17–5.73) in girls, whereas that in the “eating quickly and not eating until full” group or the “not eating quickly and eating until full” group was not statistically significant regardless of sex.

Conclusions

The present study showed that eating quickly was associated with WHtR ≥ 0.5, and “eating quickly and eating until full” had a substantial impact on WHtR ≥ 0.5 among adolescents. This study suggests that modifying fast eating to a slower pace may help prevent central obesity among adolescents.

Size misperception among overweight and obese families

BACKGROUND

Perception of body size is a key factor driving health behavior. Mothers directly influence children's nutritional and exercise behaviors. Mothers of ethnic minority groups and lower socioeconomic status are less likely to correctly identify young children as overweight or obese. Little evaluation has been done of the inverse--the child's perception of the mother's weight.

OBJECTIVE

To determine awareness of weight status among mother-child dyads (n = 506).

DESIGN

Cross-sectional study conducted in an outpatient pediatric dental clinic of Columbia University Medical Center, New York, NY.

PARTICIPANTS

Primarily Hispanic (82.2 %) mothers (n = 253), 38.8 ± 7.5 years of age, and children (n = 253), 10.5 ± 1.4 years of age, responding to a questionnaire adapted from the validated Behavioral Risk Factor Surveillance System.

MAIN MEASURES

Anthropometric measures-including height, weight, and waist circumference-and awareness of self-size and size of other generation were obtained.

KEY RESULTS

71.4 % of obese adults and 35.1 % of overweight adults underestimated size, vs. 8.6 % of normal-weight (NW) adults (both p < 0.001). Among overweight and obese children, 86.3 % and 62.3 % underestimated their size, vs. 14.9 % NW children (both p < 0.001). Among mothers with overweight children, 80.0 % underestimated their child's weight, vs. 7.1 % of mothers with NW children (p < 0.001); 23.1 % of mothers with obese children also underestimated their child's weight (p < 0.01). Among children with obese mothers, only 13.0 % correctly classified the adult's size, vs. 76.5 % with NW mothers (p < 0.001). Among obese mothers, 20.8 % classified overweight body size as ideal, vs. 1.2 % among NW mothers (p < 0.001).

CONCLUSION

Overweight/obese adults and children frequently underestimate their size. Adults misjudge overweight/obese children as being of normal weight, and children of obese mothers often underestimate the adult's size. Failure to recognize overweight/obesity status among adults and children can lead to prolonged exposure to obesity-related comorbidities.

Effect of changes to the school food environment on eating behaviours and/or body weight in children: a systematic review

Previous school obesity-prevention reviews have included multi-component interventions. Here, we aimed to review the evidence for the effect of isolated food environment interventions on both eating behaviours (including food purchasing) and/or body weight. Five electronic databases were searched (last updated 30 November 2013). Of the 1,002 unique papers identified, 55 reported on school food environment changes, based on a review of titles and abstracts. Thirty-seven further papers were excluded, for not meeting the inclusion criteria. The final selection consisted of 18 papers (14 United States, 4 United Kingdom). Two studies had a body mass index (BMI) outcome, 14 assessed purchasing or eating behaviours and two studies assessed both weight and behaviour. Seventeen of 18 papers reported a positive outcome on either BMI (or change in BMI) or the healthfulness of food sold or consumed. Two studies were rated as strong quality and 11 as weak. Only three studies included a control group. A school environment supportive of healthy eating is essential to combat heavy marketing of unhealthy food. Modification of the school food environment (including high-level policy changes at state or national level) can have a positive impact on eating behaviours. A need exists, however, for further high-quality studies.

Leadership skills are associated with health behaviours among Canadian children

Life skills development is a core area for action in the Ottawa Charter for Health Promotion. The role of life skills in influencing health behaviours among children has received little attention in research. The purpose of this cross-sectional study was to investigate the relationship between self-leadership, as a model of life skills, and diet quality, physical activity, sleep duration and body weight. A provincially representative sample of 2328 grade 5 students (aged 10-11 years) was surveyed in Alberta, Canada. Self-leadership skills were assessed based on student responses indicating frequency of performing various leadership traits. Diet quality was based on responses to the Harvard Youth/Adolescent Food Frequency Questionnaire and physical activity on responses to the Physical Activity Questionnaire for Children. Sleep duration was assessed based on parent survey responses, and body mass index determined based on measured height and weight. Random effects regression models with children nested within schools were used to determine the associations. Higher self-leadership was associated with better diet quality (P < 0.01) and more physical activity (P < 0.01). Although not statistically significant, higher self-leadership was suggestive of healthier body weight status (OR = 0.91, 95% CI = 0.66, 1.27). No association of self-leadership with sleep duration was found. The incorporation of leadership skill development may enhance the effectiveness of school-based health promotion programs. This study reinforces the importance of leadership skill promotion in the promotion of healthy eating and active living, which may help curb the obesity epidemic in the short term, and prevention of chronic diseases and mounting healthcare costs in the long term.

Children's executive function and high-calorie, low-nutrient food intake: mediating effects of child-perceived adult fast food intake

OBJECTIVE

This study tested the relationships among child executive function (EF), child-perceived parent fast food intake, and child self-reported subsequent consumption of high-calorie, low-nutrient (HCLN) food.

DESIGN

One year and 6-month longitudinal observation from a larger randomized controlled trial.

SETTING

Southern California elementary schools.

PARTICIPANTS

Fourth- and fifth-grade children (N = 1,005) participating in the Pathways to Health obesity prevention program.

RESULTS

Child EF problems were associated with higher concurrent HCLN intake (B = 0.29, SE = 0.10, p < .001) and had a significant indirect effect through higher perceived frequency of parent fast food intake (indirect effect = 0.17, 95% confidence interval [CI] = [0.11, 0.25], p < .001). Longitudinally, child EF problems did not significantly predict higher HCLN intake a year and a half later (B = 0.01, SE = 0.10, p = .92, n = 848) but did have a significant indirect effect through higher perceived parent fast food intake (indirect effect = 0.05, 95% CI = [0.02, 0.10], p < .001).

CONCLUSIONS

Children's EF difficulties may increase their perception of parent concurrent fast food intake, contributing to their own unhealthy food intake. However, EF problems may not directly affect HCLN intake across time, except when problems are associated with child perception of more frequent parent consumption of convenience foods. Future research is needed to investigate the possibility that helping children perceive and understand role models' convenience food consumption may improve child dietary consumption patterns.

Adolescent and young adult health in the United States in the past decade: little improvement and young adults remain worse off than adolescents

Adolescence and young adulthood are unique developmental periods that present opportunities and challenges for improving health. Health at this age can affect health throughout the lifespan. This review has two aims: (1) to examine trends in key indicators in outcomes, behaviors, and health care over the past decade for U.S. adolescents and young adults; and (2) to compare U.S. adolescents and young adults on these indicators. The review also assesses sociodemographic differences in trends and current indicators. Guided by our aims, previous reviews, and national priorities, the present review identified 21 sources of nationally representative data to examine trends in 53 areas and comparisons of adolescents and young adults in 42 areas. Most health and health care indicators have changed little over the past decade. Encouraging exceptions were found for adolescents and young adults in unintentional injury, assault, and tobacco use, and, for adolescents, in sexual/reproductive health. Trends in violence and chronic disease and related behaviors were mixed. Review of current indicators demonstrates that young adulthood continues to entail greater risk and worse outcomes than adolescence. Young adults fared worse on about two-thirds of the indicators examined. Differences among sociodemographic subgroups persisted for both trends and current indicators.

The impact of a population-level school food and nutrition policy on dietary intake and body weights of Canadian children

OBJECTIVE

The objective of this study is to assess population-level trends in children's dietary intake and weight status before and after the implementation of a provincial school nutrition policy in the province of Nova Scotia, Canada.

METHOD

Self-reported dietary behavior and nutrient intake and measured body mass index were collected as part of a population-level study with grade 5 students in 2003 (n=5215) and 2011 (5508), prior to and following implementation of the policy. We applied random effects regression methods to assess the effect of the policy on dietary and health outcomes.

RESULTS

In 2011, students reported consuming more milk products, while there was no difference in mean consumption of vegetables and fruits in adjusted models. Adjusted regression analysis revealed a statistically significant decrease in sugar-sweetened beverage consumption. Despite significant temporal decreases in dietary energy intake and increases in diet quality, prevalence rates of overweight and obesity continued to increase.

CONCLUSION

This population-level intervention research suggests a positive influence of school nutrition policies on diet quality, energy intake and healthy beverage consumption, and that more action beyond schools is needed to curb the increases in the prevalence of childhood obesity.

Residency and racial/ethnic differences in weight status and lifestyle behaviors among US youth

PURPOSE

Elevated risk for obesity is found in rural environments and in some minority populations. It is unclear whether living in rural or nonmetropolitan areas and being a minority compound the risk of obesity beyond that of either factor acting alone. Our purpose was to examine adolescent obesity in light of the potential concomitant influences of race/ethnicity, residency, and obesity-related lifestyle behaviors.

METHODS

We assessed obesity prevalence, physical activity, consumption of fatty snack foods, and screen time in 8,363 US adolescents based on variation in race/ethnicity and residency. Descriptive, bivariate, and multivariate statistics were used to: (1) calculate race- and residency-based rates of obesity and obesity-related lifestyle behaviors and (2) generate race- and residency-based obesity odds ratios as a function of those same behaviors.

FINDINGS

The results indicated that nonmetropolitan black youth had the highest risk of obesity (26%), rate of consuming fatty snack foods on more than 2 days/week (86%), and rate of spending more than 2 hours/day in screen time (91%) compared to white metropolitan youth. Compared to their metropolitan counterparts, black nonmetropolitan youth had greater odds of being obese if they exercised less than daily (1.71 times), ate fatty snack foods on more than 2 days/week (1.65 times), or spent more than 2 hours/day in screen time (1.64 times).

CONCLUSIONS

Race/ethnicity and residency may have a compounding effect on the risk of obesity. Prevention and intervention must be viewed in a socioecological framework that recognizes the importance of culture and community on obesity-related behaviors.

Cognitive Behavioral Treatment for Recurrent Binge Eating in Adolescent Girls: A Pilot Trial

There is a need for treatment interventions to address the high prevalence of disordered eating throughout adolescence and early adulthood. We developed an adolescent-specific manualized CBT protocol to treat female adolescents with recurrent binge eating and tested its efficacy in a small, pilot randomized controlled trial. We present lessons learned in recruiting adolescents, a description of our treatment approach, acceptability of the treatment for teens and parents, as well as results from the pilot trial. Participants in the CBT group had significantly fewer posttreatment eating binges than those in a treatment as usual/delayed treatment (TAU-DT) control group; 100% of CBT participants were abstinent at follow-up. Our results provide preliminary support for the efficacy of this adolescent adaptation of evidence-based CBT for recurrent binge eating. The large, robust effect size estimate observed for the main outcome (NNT=2) places this among the larger effects observed for any mental health intervention.

Genetic variations in the serotoninergic system contribute to body-mass index in Chinese adolescents

OBJECTIVE

Obesity has become a worldwide health problem in the past decades. Human and animal studies have implicated serotonin in appetite regulation, and behavior genetic studies have shown that body mass index (BMI) has a strong genetic component. However, the roles of genes related to the serotoninergic (5-hydroxytryptamine,5-HT) system in obesity/BMI are not well understood, especially in Chinese subjects.

SUBJECTS AND DESIGN

With a sample of 478 healthy Chinese volunteers, this study investigated the relation between BMI and genetic variations of the serotoninergic system as characterized by 136 representative polymorphisms. We used a system-level approach to identify SNPs associated with BMI, then estimated their overall contribution to BMI by multiple regression and verified it by permutation.

RESULTS

We identified 12 SNPs that made statistically significant contributions to BMI. After controlling for gender and age, four of these SNPs accounted for 7.7% additional variance of BMI. Permutation analysis showed that the probability of obtaining these findings by chance was low (p = 0.015, permuted for 1000 times).

CONCLUSION

These results showed that genetic variations in the serotoninergic system made a moderate contribution to individual differences in BMI among a healthy Chinese sample, suggesting that a similar approach can be used to study obesity.

Eating behaviors and overweight among adolescents: a population-based survey in Japan

OBJECTIVES

The aim of the present study was to investigate the relationship between eating behaviors and overweight among population-based adolescents in Japan.

METHODS

Study subjects comprised adolescents in the seventh grade (age range, 12-13 years) from Ina, a town in Saitama Prefecture, Japan, between 1999 and 2008. The height and weight of the subjects were measured, and information concerning eating behaviors (eating speed and eating until full) was obtained using a self-administered questionnaire.

RESULTS

Among boys (n = 1586), fast eating speed significantly increased the odds ratio (OR) for overweight when compared with medium eating speed, regardless of eating until full or not; moreover, a more marked increase in the OR was observed among boys eating until full (OR: 2.78, 95% confidence interval: 1.76-4.38) than among those not eating until full (2.43, 1.41-4.20). Among girls (n = 1542), fast eating speed led to a significant increase in the OR in those eating until full; however, no significant increases were observed in the OR in those eating quickly and not until full.

CONCLUSIONS

Among adolescents, fast eating speed was associated with overweight; furthermore, the combination of both fast eating speed and eating until full may have a significant effect on overweight.

Projections of type 1 and type 2 diabetes burden in the U.S. population aged <20 years through 2050: dynamic modeling of incidence, mortality, and population growth

OBJECTIVE

To forecast the number of U.S. individuals aged <20 years with type 1 diabetes mellitus (T1DM) or type 2 diabetes mellitus (T2DM) through 2050, accounting for changing demography and diabetes incidence.

RESEARCH DESIGN AND METHODS

We used Markov modeling framework to generate yearly forecasts of the number of individuals in each of three states (diabetes, no diabetes, and death). We used 2001 prevalence and 2002 incidence of T1DM and T2DM from the SEARCH for Diabetes in Youth study and U.S. Census Bureau population demographic projections. Two scenarios were considered for T1DM and T2DM incidence: 1) constant incidence over time; 2) for T1DM yearly percentage increases of 3.5, 2.2, 1.8, and 2.1% by age-groups 0-4 years, 5-9 years, 10-14 years, and 15-19 years, respectively, and for T2DM a yearly 2.3% increase across all ages.

RESULTS

Under scenario 1, the projected number of youth with T1DM rises from 166,018 to 203,382 and with T2DM from 20,203 to 30,111, respectively, in 2010 and 2050. Under scenario 2, the number of youth with T1DM nearly triples from 179,388 in 2010 to 587,488 in 2050 (prevalence 2.13/1,000 and 5.20/1,000 [+144% increase]), with the greatest increase in youth of minority racial/ethnic groups. The number of youth with T2DM almost quadruples from 22,820 in 2010 to 84,131 in 2050; prevalence increases from 0.27/1,000 to 0.75/1,000 (+178% increase).

CONCLUSIONS

A linear increase in diabetes incidence could result in a substantial increase in the number of youth with T1DM and T2DM over the next 40 years, especially those of minority race/ethnicity.

The new threat of digital marketing

Because of their avid use of new media and their increased spending power, children and teens have become primary targets of a new "media and marketing ecosystem." The digital marketplace is undergoing rapid innovation as new technologies and software applications continue to reshape the media landscape and user behaviors. The advertising industry, in many instances led by food and beverage marketers, is purposefully exploiting the special relationship that youth have with new media, as online marketing campaigns create unprecedented intimacies between adolescents and the brands and products that now literally surround them.

Trends in body mass index in adolescence and young adulthood in the United States: 1959-2002

PURPOSE

This study examined trends in body mass index (BMI) during the transition from adolescence to young adulthood by gender and race, using national data from the United States spanning for >40 years from 1959 and 2002. Although past research has investigated BMI trends separately in childhood/adolescence and adulthood, this study uniquely focused on the transition to adulthood (12-26 years) to identify the emergence of the obesity epidemic during this critical life-stage.

METHODS

Longitudinal and cross-sectional data were obtained from four nationally representative surveys: National Health and Nutrition Examination Survey, National Longitudinal Study of Adolescent Health, National Health Interview Survey, and National Longitudinal Surveys of Youth (NLSY79 and NLSY97). The analysis tracked age trends in BMI by time, which allowed for the examination of how BMI changed during the transition to adulthood and whether the patterns of change varied by period. Data best suited for trend analysis were identified. Age trends in BMI by gender and race were graphed and regression analysis was used to test for significant differences in the trends using the National Health and Nutrition Examination Survey and National Longitudinal Study of Adolescent Health.

RESULTS

BMI increased sharply in the adolescent ages, beginning in the 1990s and among young adults around 2000. This age pattern of BMI increase was more dramatic among females and blacks, particularly black females.

CONCLUSIONS

BMI increased during the transition to adulthood and these increases have grown larger over time. Obesity prevention efforts should focus on this high-risk transition period, particularly among minority populations.

Barriers to optimizing investments in the built environment to reduce youth obesity: policy-maker perspectives

OBJECTIVE

To identify factors which limit the ability of local governments to make appropriate investments in the built environment to promote youth health and reduce obesity outcomes in Atlantic Canada.

METHOD

Policy-makers and professionals participated in focus groups to discuss the receptiveness of local governments to introducing health considerations into decision-making. Seven facilitated focus groups involved 44 participants from Atlantic Canada. Thematic discourse analysis of the meeting transcripts identified systemic barriers to creating a built environment that fosters health for youth aged 12-15 years.

RESULTS

Participants consistently identified four categories of barriers. Financial barriers limit the capacities of local government to build, maintain and operate appropriate facilities. Legacy issues mean that communities inherit a built environment designed to facilitate car use, with inadequate zoning authority to control fast food outlets, and without the means to determine where schools are built or how they are used. Governance barriers derive from government departments with distinct and competing mandates, with a professional structure that privileges engineering, and with funding programs that encourage competition between municipalities. Cultural factors and values affect outcomes: people have adapted to car-oriented living; poverty reduces options for many families; parental fears limit children's mobility; youth receive limited priority in built environment investments.

CONCLUSION

Participants indicated that health issues have increasing profile within local government, making this an opportune time to discuss strategies for optimizing investments in the built environment. The focus group method can foster mutual learning among professionals within government in ways that could advance health promotion.

Translating epidemiology into policy to prevent childhood obesity: the case for promoting physical activity in school settings

Childhood obesity is a serious public health problem resulting from energy imbalance (when the intake of energy is greater than the amount of energy expended through physical activity). Numerous health authorities have identified policy interventions as promising strategies for creating population-wide improvements in physical activity. This case study focuses on energy expenditure through physical activity (with a particular emphasis on school-based physical education [PE]). Policy-relevant evidence for promoting physical activity in youth may take numerous forms, including epidemiologic data and other supporting evidence (e.g., qualitative data). The implementation and evaluation of school PE interventions leads to a set of lessons related to epidemiology and evidence-based policy. These include the need to: (i) enhance the focus on external validity, (ii) develop more policy-relevant evidence on the basis of "natural experiments," (iii) understand that policy making is political, (iv) better articulate the factors that influence policy dissemination, (v) understand the real-world constraints when implementing policy in school environments, and (vi) build transdisciplinary teams for policy progress. The issues described in this case study provide leverage points for practitioners, policy makers, and researchers as they seek to translate epidemiology to policy.

The influence of a high intensity physical activity intervention on a selection of health related outcomes: an ecological approach

Background

Cardiovascular disease (CVD) is the main cause of mortality throughout the world. With accumulating evidence suggesting that CVD has its origins in childhood, it is unsurprising that research into obesity prevalence within school aged youth is burgeoning.

Within this study our primary objective will be to examine whether high intensity interval training (HIT) improves the CVD risk profile of secondary school aged adolescents. Our secondary objective will be to identify the prevalence of CVD risk factors and examine factors associated with these in adolescents aged 15 - 18 years.

Method/Design

A South Lanarkshire school of low socioeconomic status (SES) was selected to participate in the study intervention. Participants from secondary 5 (15 - 17 years) and 6 (16 - 18 years) will be recruited for this study. Participants from secondary 6 will be randomly assigned to Group A (HIT) or Group B (moderate-vigorous) and will perform each protocol three times weekly. The secondary 5 participants will act as the control group. Data collection will take place during the Physical Education (PE) lessons and on school premises and will include: anthropometrical variables (height, weight, waist and hip circumferences, skinfold thickness at two sites), physiological responses (blood pressure, aerobic fitness, heart rate (HR) response, vertical jump performance, 10-metre (m) sprint, 50-m sprint and 505-agility test), diet (self-reported seven-day food diary), physical activity (Physical Activity Questionnaire for Adolescents (PAQ-A)) and blood tests (fasting glucose, insulin, total cholesterol (TC), high-density lipoprotein (HDL), high-sensitivity C-reactive protein (hs-CRP), fibrinogen (Fg), interleukin-6 (IL-6), adiponectin (high molecular weight), triglyceride and plasminogen activator inhibitor-1 (PAI-1). An environmental audit of the secondary school and the health related quality of life (HRQOL) of the participants will also be measured. Finally, all exercise sessions will be video recorded and rate of perceived exertion (RPE) and mood states will also be taken after each exercise session.

Discussion

Our study may be able to demonstrate a time efficient means of reducing CVD risk factors in adolescents.

Trial Registration

NCT01027156