Supplementary file 1_Screen exposure patterns and their associations with obesity and sleep among preschool children in a resource-limited city in eastern China: a multicenter cross-sectional study protocol.docx

Excessive screen exposure will be defined as average daily screen time >1 h/day, with ≤1 h/day used as the reference category. Overweight/obesity will be the primary outcome. Survey-weighted Poisson regression with a log link and robust variance estimation will be used to estimate prevalence ratios and 95% confidence intervals for the primary association, accounting for the stratified multistage cluster sampling design and survey weights.

Associations between screen exposure and individual sleep-related indicators will be examined separately as secondary analyses using survey-weighted ordinal logistic regression models.</p>Discussion<p>This study will provide context-specific epidemiological evidence on screen exposure patterns among preschool children in a resource-limited setting in eastern China. By examining multidimensional screen-use behaviors and their association with overweight/obesity, while also assessing sleep-related indicators as secondary outcomes, the study may inform future health promotion strategies and provide a basis for longitudinal research on screen exposure and child health.</p>Clinical trial registration<p>chictr.org.cn; identifier ChiCTR2600126288.</p>