Time spent on social media use and BMI z-score: A cross-sectional explanatory pathway analysis of 10798 14-year-old boys and girls

[The mediating role of social media addiction and sleep quality in the association between social media usage and depressive symptoms in university students]

Increase in time spent on social media and its association with depressive symptoms, especially among young adults, has generated the need to understand how this association occurs in order to support the development of policies to reduce harm and complications. In view of this fact, this study aimed to assess the mediating effect of social media addiction and sleep quality on the association between time spent on social media and depressive symptoms in Brazilian university students. This is a cross-sectional study conducted with 2,823 university students, who provided information regarding time spent on social media, social media addiction, depressive symptoms and sleep quality. The mediation analysis, adjusted for confounding factors, was performed using the PROCESS macro for SPSS to obtain the total (c), direct (c'), and indirect effects (EI1, EI2, and EI3). The results identified an association between time spent on social media and depressive symptoms, mediated by social media addiction (EI1 = 20%) and sleep quality (EI1 = 40%). These findings help expand knowledge about the mechanisms that mutually influence the relationship between time spent on social media and depressive symptoms, supporting the adoption of strategies to reduce harm resulting from excessive social media use.

United States Long-Term Trends in Adult BMI (1959-2018): Unraveling the Roots of the Obesity Epidemic

The escalating rates of obesity since the 1950s poses a critical public health challenge across all age groups in the United States. While numerous studies have examined cross-sectional disparities across racial, ethnic, and socioeconomic groups, there has been limited research on long-term trends. To address this gap, we analyzed average adult body mass index (BMI) trends from 1959 to 2018, using data from the National Health and Nutrition Examination Survey (NHANES) and the National Health Examination Survey (NHES). Employing time series analysis, we evaluated BMI trends across income, education, and race/ethnicity. The results revealed a consistent upward trajectory in average BMI across all groups over the six-decade period, with no significant differences by income or education levels among high school graduates. However, individuals with less than a high school education displayed a more gradual increase in BMI. Racial disparities were also evident, with Black adults showing higher BMI growth rates compared to White adults, while Hispanic and other racial groups experienced slower increases. These findings underscore the need for systemic interventions to address the ongoing obesity epidemic, emphasizing the importance of research to identify trends over time and a system-thinking approach to inform effective population-level interventions and policy decisions.