AUTHOR=Schrijvers Karen , Cosma Alina , Potrebny Thomas , Thorsteinsson Einar , Catunda Carolina , Reiss Franziska , Hulbert Sabina , Kostičová Michaela , Melkumova Marina , Bersia Michela , Klanšček Helena Jeriček , Gaspar Tania , Dierckens Maxim TITLE=Three Decades of Adolescent Health: Unveiling Global Trends Across 41 Countries in Psychological and Somatic Complaints (1994–2022) JOURNAL=International Journal of Public Health VOLUME=69 YEAR=2024 URL=https://www.ssph-journal.org/journals/international-journal-of-public-health/articles/10.3389/ijph.2024.1607774 DOI=10.3389/ijph.2024.1607774 ISSN=1661-8564 ABSTRACT=Objectives

This study examined (non-)monotonic time trends in psychological and somatic complaints among adolescents, along with gender differences.

Methods

Repeated cross-sectional Health Behaviour in School-aged Children (HBSC) data from 1994 to 2022 covering 15-year-old adolescents from 41 countries (N = 470,797) were analysed. Three polynomial logistic regression models (linear, quadratic, cubic) were tested for best fit, including separate analyses by gender and health complaints dimension.

Results

Time trend patterns varied by gender and health complaints dimension. Increases were found in 82.3% of cases (linear 25%, quadratic U-shaped 28.7%, cubic 28.7%), while 14% showed no clear trend, and 3.7% decreased. Boys typically showed linear increases or no clear trend over time, whereas girls generally showed cubic or U-shaped trends. Psychological complaints often displayed U-shaped or cubic patterns, whereas somatic complaints mostly showed linear increases.

Conclusion

Psychological and somatic complaints demonstrated diverse time trend patterns across countries, with non-monotonic patterns (U-shaped and cubic) frequently observed alongside linear increases. These findings highlight the complexity of changes within countries over three decades, suggesting that linear modelling may not effectively capture this heterogeneity.