Risk Factors at Birth Predictive of Subsequent Injury Among Japanese Preschool Children: A Nationwide 5-Year Cohort Study.

Objective: To identify risk factors at birth that are predictive of subsequent injury among pre-school children. Methods: Retrospective analysis of population-based birth cohort data from the "Longitudinal Survey of Babies Born in the 21st Century" was performed from 2001 through 2007 in Japan (n = 47,015). The cumulative incidence and the total number of hospitalizations or examinations conducted at medical facilities for injury among children from birth up to the age of 5 years were calculated. To identify risk factors at birth that are predictive of injury, multivariate analysis of data for hospitalization or admission because of injury during a 5-year period (age, 0-5 years) was performed using the total number of hospital examinations as the dependent variable. Results: The cumulative incidence (95% confidence interval) of hospital examinations for injury over the 5-year period was 34.8% (34.2%-35.4%) for boys and 27.6% (27.0%-28.2%) for girls. The predictive risk factors at birth we identified for injury among preschool children were sex (boys), heavy birth weight, late birth order, no cohabitation with the grandfather or grandmother, father's long working hours, mother's high education level, and strong intensity of parenting anxiety. Conclusion: Based on the results of this study, we identified a number of predictive factors for injury in children. To reduce the risk of injury in the juvenile population as a whole, it is important to pursue a high-risk or population approach by focusing on the predictive factors we have identified.