Joint association of physical activity and screen exposure with subsequent suspected developmental coordination disorder in preschool children: a nationwide population-based study

Background Developmental coordination disorder (DCD) is a common neurodevelopmental condition in preschoolers. Physical activity (PA) and screen exposure are two highly prevalent and modifiable daily behaviors in early childhood, but evidence regarding their joint association with DCD is limited. This study aimed to investigate the joint associations of PA and screen exposure time (SET) with subsequent suspected DCD in Chinese preschoolers. Methods This study used data from a nationally representative, stratified cluster survey covering 551 cities across China. Motor coordination was assessed by the Little Developmental Coordination Disorder Questionnaire (LDCDQ), and suspected DCD was defined according to age- and sex-specific cut-off values. Parent-reported data was used to calculate total daily physical activity (TDPA), moderate-to-vigorous physical activity (MVPA), and daily SET over the previous 12 months. The interactions between PA and SET were examined on both additive and multiplicative scale. Multilevel logistic regression models were employed to explore the association of PA and SET with suspected DCD. Results The study included 129,278 preschoolers, among whom 19,969 (15.4%) were suspected DCD. Compared with children in the normal TDPA & SET < 1 h group, the group of low TDPA & SET > 4 h exhibited highest odds of subsequent suspected DCD (aOR = 2.29, 95% CI: 2.02–2.60) when adjusting for covariates; while compared with the normal MVPA & SET < 1 h, those with normal MVPA & SET > 4 h exhibited highest odds of suspected DCD (aOR = 1.96, 95% CI: 1.78–2.15). Analysis of interaction on additive scale (RERI = -0.22, 95% CI: -0.31 to -0.13) and multiplicative scale (aOR = 0.87, 95% CI: 0.80–0.94) indicated that a significantly negative interaction was observed between low MVPA and SET at 1–4 h/day using normal MVPA & SET < 1 h as the reference. Stratified analyses revealed that: (1) low TDPA was a risk factor for suspected DCD at SET ≤ 4 h, whereas low MVPA appeared protective; and (2) across all PA strata, SET ≥ 1 h was significantly associated with the risk of suspected DCD. Conclusions Insufficient TDPA, higher MVPA, and excessive SET were associated with a higher risk of subsequent suspected DCD among Chinese preschoolers. A protective interaction was observed between low MVPA and moderate screen exposure (1–4 h/day).