Screen exposure before age two and developmental outcomes in early childhood: a national cross-sectional study in China

The relationship between screen exposure and early childhood development requires further investigation, especially regarding the age at screen onset, daily screen duration, and potential gender-specific vulnerabilities. This study explored the associations between screen exposure before the age of two and domain-specific developmental outcomes, with particular emphasis on to age of onset, daily exposure duration, and gender differences. This cross-sectional study was conducted as part of the China National Nutrition and Health Systematic Survey for Children Aged 0–17 Years (CNHSC, 2019–2021). A total of 4617 children under the age of two were included. Parents reported their children’s screen exposure history, and developmental outcomes were assessed using the China Development Scale for Children (CDSC, WS/T580-2017). Propensity score matching was applied to minimize potential confounding and selection bias. Three-level linear mixed-effects models were used to assess associations with age at onset, daily screen time, and gender interactions. Among participants (49.7% boys, 50.1% rural), 15.4% had screen exposure. Screen exposure was significantly associated with a lower overall developmental score (mean difference: -2.58; 95% CI, -4.27 to -0.90), with the most pronounced negative associations in language (β=-4.54, 95% CI: -6.86 to -2.23), fine motor (β=-2.81, 95% CI: -5.19 to -0.43), adaptability (β=-2.34, 95% CI: -4.64 to -0.03), and social behavior (β=-3.01, 95% CI: -5.45 to -0.57) domains. The age at screen onset was not significantly associated with DQ scores. However, longer daily screen time was consistently linked to lower DQ scores, with the strongest associations observed in language (β=-3.70, 95% CI: -5.55 to -1.86), fine motor (β=-3.03, 95% CI: -4.65 to -1.41), and overall development (β=-2.43, 95% CI: -3.52 to -1.33). A significant gender interaction indicated that the negative relationship between screen time and DQ scores was attenuated in girls, particularly for fine motor, social behavior, and overall development. Screen exposure before the age of two was associated with poorer developmental outcomes, particularly in the language, social behavior, and fine motor domains. Limiting daily screen time emerged as a crucial factor associated with better developmental scores. Additionally, girls exhibited a weaker association between screen time and lower scores compared to boys. These findings highlight the importance of public health recommendations focused on reducing daily screen use and addressing gender differences.