Effects of Increasing Child Restraint Use in Reducing Occupant Injuries Among Children Aged 0–5 Years in Japan

Abstract

Objectives: In Japan, child restraint use among preschool children started to increase before compulsory child restraint use for children aged 0–5 years was introduced by legislation in April 2000. This study determined the effects of increased child restraint use in reducing motor vehicle occupant injuries among children aged 0–5 years.Methods: We obtained monthly police data of child vehicle occupant injuries from 1990 to 2009. We calculated monthly ratios of morbidity rates per population of children aged 0–5 years to those of children aged 6–9 years. Time trends of the morbidity rate ratios were analyzed using a joinpoint regression model to determine whether there were trend changes in child occupant injuries and when they occurred if there were trend changes.Results: The morbidity rate ratios showed a slightly increasing trend of 0.03% per month (95% confidence interval [CI], −0.02% to 0.09%) until the change-point in December 1997 (95% CI, July 1996 to January 1999), which then changed to a decreasing trend of −0.14% per month (95% CI, −0.16 to −0.11), with an overall trend change of −0.17% (95% CI, −0.23 to −0.11). No change-point was identified in or around April 2000 when compulsory restraint use was introduced.Conclusions: The present study used comparative indicators relative to age groups that were not covered by the legislation and showed that a decreasing trend of occupant morbidity among children aged 0–5 years started before the introduction of compulsory restraint use. This change probably reflects the prelegislative voluntary increase in child restraint use.