Study examines state-level factors contributing to variation in MVC-related pediatric mortality

Unintentional injury is the leading cause of pediatric death in the U.S. and motor vehicle crashes (MVCs) are the most common cause of injury. A new paper published in the Journal of Pediatrics by researchers at Center for Surgery and Public Health (CSPH) at Brigham and Women's Hospital (BWH) and UT Southwestern Medical Center in Dallas, is the first to examine state-level factors contributing to variation in pediatric mortality in motor vehicle crashes and to identify trends across states.

On average across all states, researchers found that 20 percent of children involved in a fatal crash were unrestrained or inappropriately restrained at the time of the crash. Thirteen percent were inappropriately seated in the front seat, and nearly 9 percent of drivers transporting a child passenger were under the influence of alcohol. The study's authors estimate that a 10 percent absolute improvement in child restraint use--decreasing the average number of unrestrained or inappropriately restrained children from 20 percent to 10 percent nationally--would avert approximately 232 pediatric deaths per year, or more than 1,100 over five years. These findings highlight the importance of child restraint use and reinforce guidelines on child restraints published by the American Academy of Pediatrics (AAP) in 2011.

"In order to prevent children from being killed in motor vehicle crashes, we must understand the effects of state-level regulations, their implementation, and enforcement," said Lindsey Wolf, MD, MPH, general surgery resident at BWH, research fellow at CSPH and lead author of the study. "Since laws governing child traffic safety are made at the state level, we formulated a study design that would produce state-by-state geographic results, which could easily be utilized by policy makers aiming to reduce pediatric mortality and save children's lives in their states."

The authors found substantial state-level variation, and concluded overall that the percentage of children who were unrestrained or inappropriately restrained was a leading predictor of mortality. The percentage of children involved in a fatal crash who were unrestrained or inappropriately restrained varied from 2 percent in New Hampshire to 38 percent in Mississippi.

Crashes were most likely to occur on state highways (35 percent) and on roads classified as rural by the Federal Highway Authority (62 percent). Characteristics of the crashes also varied: the percentage of those that occurred on a rural road varied from 17 percent in Massachusetts and Rhode Island to 100 percent in Maine and Vermont; the percentage of those that occurred on state highways varied from 11 percent in Iowa to 84 percent in Hawaii; and the percentage of those that occurred on a road with a speed limit 65 to 80 miles per hour varied from 0 percent in Hawaii, Maine, and Rhode Island to 80 percent in Wyoming.

The number of fatal crashes over 2010-2014 ranged from 18 in Rhode Island to 2,017 in Texas, while the number of deaths ranged from 3 in Rhode Island to 346 in Texas. Age-adjusted, mean MVC-related pediatric mortality per 100,000 children varied from 0.25 in Massachusetts to 3.23 in Mississippi. The percentage of children that died of those involved in a fatal crash varied from 8 percent in New Hampshire to 30 percent in Nebraska.

The first-of-its-kind analysis included data from 18,116 children, ages 15 and younger, riding in a passenger vehicle involved in a fatal crash occurring from 2010-2014, as reported in the Fatality Analysis Reporting System (FARS) dataset. FARS is a nationwide census providing publicly-available data on fatalities associated with MVCs, compiled from various documents in each state, including police accident reports, death certificates, state vehicle registration files, medical examiner reports, state driver licensing files, state highway department data, emergency medical service reports and vital statistics. These data were used in conjunction with annual U.S. Census data to create population size estimates by age, state and region, and the percentage of households with a vehicle, in examining two outcomes: state-based, age-adjusted, mean MVC-related pediatric mortality per 100,000 children; and percentage of children involved in a fatal crash who died ("fatal crashes" were defined as crashes that occurred on a public road and resulted in at least one death, adult or pediatric, within 30 days). Both of these outcomes were calculated by region (Midwest, Northeast, South, West) and nationally.

An extensive list of factors potentially affecting MVC-related pediatric mortality were examined, including restraint use, road type, vehicle type, speed limit, red light camera policy and more. In order to understand the effects of individual factors on the desired outcomes, the study's authors leveraged an ecological study design, first employing multivariable linear regression to identify state characteristics associated with each outcome.

"The American Academy of Pediatrics has issued clear guidelines regarding child restraints and other factors in order to save children's lives in the event of motor vehicle crashes, and many states have implemented them in part, but no state has implemented them fully," said Faisal Qureshi, MD, MBA, associate professor of surgery at UT Southwestern Medical Center, and senior author of the study. "The significant state-level variation evident in our findings emphasizes the need for close collaboration between the injury prevention community and those enacting and enforcing legislation, and suggests the potential for a federal intervention in the area of child traffic safety."

The authors note that further research is required to understand how factors like vehicle type, roadway characteristics, speed limits, and red light camera use may contribute to the overall risk of death.