# Associations of dietary patterns and screen time with depressive symptoms among adolescents in Shandong Province, China

## TL;DR

This study finds that poor diets and high screen time are linked to higher rates of depressive symptoms in Chinese adolescents.

## Contribution

The study identifies specific dietary patterns and screen time thresholds that are associated with increased risk of depressive symptoms in adolescents.

## Key findings

- Processed dietary patterns are associated with a 62% higher risk of depressive symptoms compared to balanced diets.
- Screen time ≥ 2 hours per day increases depressive symptom risk by 46% compared to less than 2 hours.
- Processed diets combined with high screen time show the highest risk (234% increased odds) of depressive symptoms.

## Abstract

Understanding the interplay among dietary patterns, screen time, and depressive symptoms among adolescents is crucial for the development of effective prevention strategies. This study aimed to explore the associations between dietary patterns, screen time, and their combined effects on depressive symptoms among high school students in Shandong Province, China.

Utilizing the Database of Youth Health (DYH) from the China Population Health Science Data Center in 2020, demographic characteristics, food intake frequencies, and screen time information were collected from 8,276 high school students aged 12–20 years in Shandong Province, China. Principal component analysis was employed to identify distinct dietary patterns, and logistic regression analysis was used to assess the associations of dietary patterns and screen time single and co-exposure with depressive symptoms.

The prevalence of depressive symptoms among adolescents in Shandong Province stood at 18.9%. Principal component analysis identified three main dietary patterns: balanced dietary patterns, high-protein dietary patterns, and processed dietary patterns. In comparison to students who maintained balanced dietary patterns, those who followed processed dietary patterns demonstrated a higher risk of depressive symptoms, exhibiting odds ratios (ORs) and 95% confidence intervals (CIs) of 1.62 (1.40–1.88). Additionally, adolescents whose screen time ≥ 2 h/d faced a greater risk of depressive symptoms than those whose screen time was < 2 h/d (OR = 1.46, 95% CI 1.25–1.70). Adolescents in high-protein dietary patterns with screen time ≥ 2 h/d, processed dietary patterns with screen time < 2 h/d, and processed dietary patterns with screen time ≥ 2 h/d all showed elevated risks of depressive symptoms. The respective ORs (95% CIs) for these groups were 1.71 (1.27–2.31), 1.60 (1.36–1.89), and 2.34 (1.86–2.94).

Our findings demonstrate that co-exposure to high-protein dietary patterns and screen time ≥ 2 h/d is significantly associated with increased risk of depressive symptoms in adolescents. Notably, processed dietary patterns exhibit a more pronounced association, demonstrating heightened depressive symptom risks even when combined with either shorter (< 2 h/d) or longer (≥ 2 h/d) screen time durations.

The online version contains supplementary material available at 10.1186/s12889-025-25976-z.