Objective Residential injury is a leading cause of morbidity and mortality in US children. Rates and types of injury vary by child age but little is known about injury risk based on child cognitive and motor abilities. The objective of this study was to determine whether cognitive or motor development in young children is associated with residential injury.

Methods We employed data from Health Outcomes and Measures of the Environment (HOME) Study. Parent report of medically attended injury was obtained at regular intervals from 0 to 42 months. Child development was assessed at 12, 24 and 36 months using Bayley Scales of Infant and Toddler Development, 2nd edition, which generates both mental developmental index (MDI) and a psychomotor developmental index (PDI). Injury risk was modelled using multivariable logistic regression as function of child's MDI or PDI. Effects of MDI and PDI on injury risk were examined separately and jointly, adjusting for important covariates.

Results Children with cognitive delay (MDI <77) were at significantly higher risk of injury than children without cognitive delay (OR=3.7, 95% CI 1.4 to 10.5, p=0.012). There was no significant association of PDI with injury. There was, however, significant interaction of MDI and PDI (p=0.02); children with cognitive delay but normal motor development were at significantly higher risk of injury than children with normal cognitive and motor development (OR=9.6, 95% CI 2.6 to 35.8, p=0.001).

Conclusions Children with cognitive delays, especially those with normal motor development, are at elevated risk for residential injuries. Injury prevention efforts should target children with developmental delays.

Clinical trials number NCT00129324; post-results.