Pediatric motor vehicle related injuries in the Navajo Nation: the impact of the 1988 child occupant restraint laws.

BACKGROUND Navajo motor vehicle mortality is the highest among the 12 Indian Health Service (IHS) administrative areas. In July 1988, the Navajo Nation enacted a primary enforcement safety belt use and a child restraint law. OBJECTIVE Assess the impact of the laws on the rate and severity of pediatric (0-19 years) motor vehicle injury resulting in hospitalizations in the Navajo Nation. METHODS Hospitalizations associated with motor vehicle related injury discharges were identified by International Classification of Diseases, 9th revision, CM E codes, 810-825 (.0,.1) from the Navajo IHS hospital discharge database. Age specific rates for the period before the law, 1983-88, were compared with those after enactment and enforcement, 1991-95. Severity of injury, measured by the abbreviated injury scale (AIS) score and new injury severity score (NISS), was determined with ICDMAP-90 software. Wilcoxon rank sum and chi(2) tests were used for analysis. RESULTS Discharge rates (SE) for motor vehicle injury (per 100 000) decreased significantly in all age groups: 0-4 years (62 (7) to 28 (4)), 5-11 years (55.3 (6) to 26 (4)), and 15-19 years (139 (14) to 68 (7)); p=0.0001. In children 0-4 years, the median AIS score decreased from 1.5 (1,3) (25th, 75th centile) to 1 (1,2), p=0.06, and the median NISS decreased from 3.5 (1,9) to 2 (1,5), p=0.07. The proportion of children with NISS scores >4 decreased significantly for the 0-4 year age group (p=0.03). CONCLUSIONS Concurrent with enactment of the Navajo Nation occupant and child restraint laws there was a reduction in the rate of motor vehicle related hospital discharges for children. Severity of injury declined in very young Navajo children. The effect of enactment and enforcement of this Native American child occupant restraint law may serve as an example of an effective injury control effort directed at Native American children.