Effectiveness of Booster Seats Compared With No Restraint or Seat Belt Alone for Crash Injury Prevention


  • This study was supported, in part, by funding from Zhejiang University, Hangzhou, China, and the National Institute of Biomedical Imaging and Bioengineering of the National Institutes of Health, Bethesda, MD (grant R01EB006552-01A1). The opinions expressed herein represent those of the authors and not necessarily those of Zhejiang University, the NIH, or any other organizations with which the authors are affiliated. No funding bodies had any role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
  • Dr. Allison has, anticipates, or has had financial interests with the Frontiers Foundation; Vivus, Inc; Kraft Foods; University of Wisconsin; University of Arizona; Paul, Weiss, Wharton & Garrison LLP; and Sage Publications. All other authors have no conflict of interest in relation to the present study.



The objective was to evaluate the effectiveness of belt-positioning booster seats, compared with no restraint use and with seat belt use only, during motor vehicle crashes among U.S. children.


This was a retrospective matched cohort study with data from the 1998 through 2009 National Automotive Sampling System (NASS) Crashworthiness Data System (CDS). The study sample consisted of children aged 0 to 10 years who were not seated in the front seat of the vehicle. We used Cox proportional hazards models to estimate the risk of overall, fatal, and regional body injury.


Children using seat belts in belt-positioning booster seats experienced less overall injury (Injury Severity Score [ISS] > 0, adjusted risk ratio [RR] = 0.73, 95% confidence interval [CI] = 0.55 to 0.96; Abbreviated Injury Scale [AIS] score of 2 or higher, adjusted RR = 0.30, 95% CI = 0.16 to 0.58; ISS > 8, adjusted RR = 0.19, 95% CI = 0.06 to 0.56), and less injury in most body regions except the neck (adjusted RR = 4.79, 95% CI = 1.43 to 16.00) than did children with no restraint use. Children using seat belts in belt-positioning booster seats had an equal risk of injury but higher risks of neck (adjusted RR = 1.86, 95% CI = 1.02 to 3.40) and thorax (adjusted RR = 2.86, 95% CI = 1.33 to 6.15) injury than did children restrained by seat belts only.


Children using belt-positioning booster seats appear to experience a higher risk of AIS > 0 injury to the neck and thorax than do children using seat belts only. Future research should examine whether the observed increase in neck and thorax injuries can be attributed to improper use of booster seats.


Efectividad de los Asientos Elevadores en Comparación con Ninguna Restricción o con Sólo el Cinturón de Seguridad para la Prevención de la Lesión por Colisión


El objetivo fue evaluar la efectividad de las sillas elevadoras con cinturones de seguridad en comparación con el uso de sólo el cinturón de seguridad durante las colisiones de vehículos a motor en los niños de Estados Unidos.


Estudio de cohorte retrospectivo que utilizó los datos del National Automotive Sampling System Crashworthiness Data System de 1998 a 2009. La muestra del estudio consistió en niños de 0 a 10 años de edad que no estaban sentados en el asiento delantero del vehículo. Se usaron modelos de Cox para estimar el riesgo de lesión global, fatal y regional del cuerpo.


Los niños que usaron cinturones de seguridad en sillas elevadoras con cinturón experimentaron menos lesiones globales (Injury Severity Score [ISS] > 0, razón de riesgo ajustado [RR] = 0,73, intervalo de confianza [IC] 95% = 0,55 a 0,96; Abbreviated Injury Scale [AIS] score de 2 o mayor [AIS 2+ ], RR ajustado = 0,30, IC95% = 0,16 a 0,58; ISS>8, RR ajustado = 0,19, IC 95% = 0,06 a 0,56), y menos lesiones en la mayoría de las regiones del cuerpo excepto en el cuello (RR ajustado= 4,79, IC 95% = 1,43 a 16,00) que los niños que no usaron restricciones. Los niños que usaron cinturones de seguridad en sillas elevadoras con cinturón tuvieron un riesgo igual de lesión pero mayores riesgos de lesión del cuello (RR ajustada=1,86, IC 95% = 1,02 a 3,40) y del tórax (RR ajustada=2,86, IC 95% = 1,33 a 6,15) que los niños que usaron restricciones con sólo cinturones de seguridad.


Los niños que usan sillas elevadoras con cinturón parecen experimentar un mayor riesgo de lesión AIS1+  para el cuello y el tórax que los niños que usan solo cinturón de seguridad. Futuras investigaciones deberán investigar si el incremento de lesiones de cuello y tórax observadas pueden ser atribuidas al uso inapropiado de los asientos elevadores.