Annual incidence and prevalence of obesity in childhood and young adulthood based on a 30-year longitudinal population-based cohort study in Korea: the Kangwha study

Prevalence and trends in obesity and severe obesity in Korean children and adolescents, 2007-2020: A population-based study

BACKGROUND

The age-adjusted prevalence of child and adolescent obesity has been stabilized in the Korean population, although severe obesity has increased with adverse health effects. In this study, we detailed the prevalence of and trends in overweight, obesity, and severe obesity in Korean children and adolescents by age group and sex from a nationally representative sample, using a new, 2017 age- and sex-specific reference for body mass index.

METHODS

We collected Korea National Health and Nutrition Examination Survey data from the years 2007-2020. A total of 23,595 subjects (11,210 females) aged 2-18 years were included in this study. We calculated the recent prevalence of overweight and obesity, including severe obesity, by weighted data from 2019 and 2020.

RESULTS

The prevalence of overweight and obesity (class II and class III obesity) was 23.5% and 14.2% (2.5% and 0.5%), respectively. Males showed a higher prevalence of overweight and obesity. Adolescents aged 13-15 years showed the highest prevalence of severe obesity. A positive linear trend was significant for overweight (p = 0.025), class I obesity (p < 0.001), and class II obesity (p = 0.002) for both sexes and all ages combined. However, the trend of obesity prevalence was different in each subgroup. Comparing pre- and post- COVID-19 pandemic, obesity prevalence seemed to increase, but not significantly.

CONCLUSIONS

Despite previous reports that obesity in children and adolescents has remained stable, we found that the prevalence of overweight, obesity, and severe obesity has increased in Korean children and adolescents. The effects of COVID-19 on this trend require further evaluation.

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.

The Interactions of Media Use, Obesity, and Suboptimal Health Status: A Nationwide Time-Trend Study in China

Obesity and suboptimal health status (SHS) have been global public health concerns in recent decades. A growing number of works have explored the relationships between media use and obesity, as well as SHS. This study aimed to examine the time trend of the associations between media use (including traditional media and new media) and obesity, as well as SHS. The data were derived from three national random samples of the Chinese General Social Survey (CGSS), which was separately conducted in 2013, 2015, and 2017. In total, 34,468 respondents were included in this study, consisting of 16,624 males and 17,844 females, and the average age was 49.95 years old (SD = 16.72). It found that broadcast use and television use were positively associated with obesity and showed an increasing trend over time. Cellphone use emerged as a risk factor for obesity in 2017 and showed an increasing trend. By contrast, newspaper use, television use, and internet use were negatively associated with SHS, and television use showed a decreasing trend in the association with SHS, while internet and newspaper use showed an increasing trend. In conclusion, media use was positively associated with obesity while negatively associated with SHS. It showed a decreasing trend in the associations between traditional media use and obesity, while revealing an increasing trend in the associations between new media use and obesity, as well as SHS. The practical implications of the findings are discussed.