麻豆传媒

Adolescents with low body mass and overweight or obesity had increased psychosomatic symptoms compared to peers with healthy weight, according to multi-country, cross-sectional study.

An analysis of more than 1 million adolescents in Europe and North America revealed significantly higher psychosomatic symptoms among individuals with low body mass (unstandardized β 0.14, 95% CI 0.08-0.19) as well as those with overweight (unstandardized β 0.27, 95% CI 0.24-0.30) or obesity (unstandardized β 0.62, 95% CI 0.56-0.67) compared with individuals with healthy weight, after accounting for confounders, Shanquan Chen, PhD, of the London School of Hygiene & Tropical Medicine in England, and co-authors reported.

Notably, individuals with underweight had significantly fewer psychosomatic symptoms compared with healthy individuals (unstandardized β -0.18, 95% CI -0.22 to -0.15), the authors reported in .

"Our study revealed a U-shaped association between adolescent BMI and mental health, which was consistent across sex and grades and became stronger over time. These insights emphasize the need for targeted interventions addressing body image and mental health, and call for further research into underlying mechanisms," they concluded.

Previous studies have also found a similar U-shaped association between BMI and mental health in both adolescents and adults, the researchers said.

When compared to the first year of survey data (2002), psychosomatic concerns among adolescents increased significantly in each subsequent year the survey was conducted: 2006 (unstandardized β 0.19), 2010 (unstandardized β 0.14), 2014 (unstandardized β 0.48), and 2018 (unstandardized β 0.82).

Similarly, psychosomatic concerns were also significantly greater in middle school (unstandardized β 1.15) and in high school (unstandardized β 2.12) than in primary school.

In addition, girls reported significantly higher psychosomatic concerns than boys (unstandardized β 2.27, 95% CI 2.25-2.30).

"The increasing mental health issues associated with the same BMI z score values over time, particularly in recent years, highlight a growing sensitivity among adolescents about body weight," the authors wrote.

They suggested that the widespread adoption of social media and digital influence could be a factor contributing to this development, in part because adolescents are increasingly exposed to idealized body images which could increase self-consciousness about appearance and weight. "[S]ocietal stigma around having overweight or obesity could increase stress, anxiety, and depression in adolescents," they explained.

"These findings highlight the need to consider various influences on adolescent mental health, including social and environmental factors, not just BMI z scores metrics," they added.

The associations across different years, sex, and grades indicate a broad relevance to overall adolescent mental health, they said. Findings could help "inform public health and school programs, emphasizing correcting body image misconceptions, encouraging healthy weight, and creating supportive peer environments."

To conduct the analysis, the authors collected survey data from the Health Behavior in School-Aged Children survey in Europe and North America for 1,036,869 adolescents ages 11 to 15 years. Surveys were collected every 4 years beginning in 2002 and ending in 2018. Data was analyzed from October 2022 to March 2023. Survey participants had a mean age of 13.55 years and roughly half were girls (50.9%).

Mental health symptoms were measured using an eight-item instrument for psychological concerns that totaled to a score from 0 to 32, with a higher score representing higher psychosomatic issues.

BMI z scores standardized for age and sex and were used to group participants: low body mass (BMI z score ≤-2), underweight (BMI z score -1.99 to -1), healthy weight (BMI z score -0.99 to 0.99), overweight (BMI z score 1 to 1.99), and obese (BMI z score ≥2).

The authors used a multilevel generalized additive model to analyze the data, and they adjusted for several confounders, including sex, living with parents, academic pressure, the experience of being bullied, screen time, and physical activity.

The study had several limitations, including using the BMI z-score as the only measure could have resulted in inaccurate classification of weight status, due to differences in muscle mass or fat distribution in adolescents. They also noted that the study could not establish a causal relationship due to its cross-sectional design.

In addition, they noted that measuring mental health using psychosomatic concerns did not represent all mental health manifestations in youth, such as sleep quality. Similarly, the analysis didn't assess confounders, like dietary habits or a family history of mental health, the authors explained.

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