Motor Vehicle–Related Deaths — United States, 2005 and 2009

Bethany A. West, MPH

Rebecca B. Naumann, MSPH

National Center for Injury Prevention and Control, CDC

Corresponding author: Bethany A. West, MPH, Division of Unintentional Injury Prevention, National Center for Injury Prevention and Control, CDC. Telephone: 770-488-0602; E-mail: bwest2@cdc.gov.

Introduction

Motor vehicle crashes are a leading cause of death for children, teenagers, and young adults in the United States (1). In 2009, approximately 36,000 persons were killed in motor vehicle crashes, and racial/ethnic minorities were affected disproportionally (1,2). Approximately 4.3% of all American Indian/Alaska Native (AI/AN) deaths and 3.3% of all Hispanic deaths were attributed to crashes, whereas crashes were the cause of death for <1.7% of blacks, whites, and Asian/Pacific Islanders (A/PI) (1).

The motor vehicle–related death rate analysis and discussion that follows is part of the second CDC Health Disparities and Inequalities Report (CHDIR). The 2011 CHDIR (3) was the first CDC report to take a broad view of disparities across a wide range of diseases, behavioral risk factors, environmental exposures, social determinants, and health care access. The topic presented in this report is based on criteria that are described in the CHDIR Introduction (4). The report that follows provides more current information to what was presented in the 2011 CHDIR (2). The purposes of this motor vehicle–related death report are to discuss and raise awareness of differences in the characteristics of persons who die from motor vehicle–related crashes and to prompt actions to reduce disparities.

Methods

To assess disparities in motor vehicle–related death rates by race/ethnicity and sex, CDC analyzed data from the National Vital Statistics System (NVSS). NVSS does not collect data on other variables such as education and income. Race/ethnicity was divided into five mutually exclusive categories: non-Hispanic whites, non-Hispanic blacks, non-Hispanic AI/ANs, non-Hispanic A/PIs, and Hispanics of all races.

Bridged-race postcensal population estimates from the U.S. Census Bureau were used to calculate death rates. Death rates and corresponding 95% confidence intervals were calculated and age-adjusted to the 2000 standard U.S. population. Absolute and relative differences in rates were calculated by sex and race/ethnicity. Disparities were measured as the deviations from a "referent" category rate. The absolute difference was measured as the simple difference between a population subgroup estimate and the estimate for its respective reference group. The relative difference, a percentage, was calculated by dividing the difference by the value in the referent category and multiplying by 100. Differences between age-adjusted death rates in 2005 and 2009 were compared using the z statistic based on a normal approximation, and p values ≤0.05 were considered statistically significant.

Results

The overall motor vehicle–related age-adjusted death rate was 11.7 deaths per 100,000 population in 2009 (Table 1). The death rate for males was 2.5 times that for females (16.8 vs. 6.8). In 2009, AI/ANs consistently had the highest motor vehicle–related death rates among both males and females (Table). Among males, the AI/AN death rate (33.6) was approximately 2–5 times the rates of other races/ethnicities. Black males had the second-highest death rate (18.5), followed by whites (17.3), Hispanics (14.7), and A/PIs (6.3). Among females, the AI/AN motor vehicle–related death rate (17.3) was approximately 2-4 times the rates of other races/ethnicities. White females had the second-highest death rate (7.1), followed by blacks (6.4), Hispanics (5.7), and A/PIs (4.0).

Between 2005 and 2009, age-adjusted death rates showed statistically significant declines by sex among all race/ethnicities with the exception of AI/AN women (Table). The greatest decrease in rates for males occurred among AI/AN, from a death rate of 42.7 per 100,000 population in 2005 to 33.6 in 2009 (absolute rate change: -9.1). Among females, the greatest decrease occurred among whites, from a death rate of 9.4 in 2005 to 7.1 in 2009 (absolute rate change: -2.3).

Discussion

Evidence-based strategies to reduce overall motor vehicle–related deaths and injuries include primary seat belt laws (i.e., legislation allowing police to stop a vehicle solely for a safety belt violation), age- and size-appropriate child safety seat and booster seat use laws, focused child restraint distribution plus education programs, ignition interlock devices (i.e., devices that disable a vehicle's ignition after detection of alcohol in the driver's breath), sobriety checkpoints, minimum drinking age laws (21 years), and 0.08 g/dL blood alcohol concentration laws (5). Tailoring these strategies to the unique cultures of different racial/ethnic groups can help reduce disparities in motor vehicle–related mortality (6,7).

To address the disparities in motor vehicle–related death and injury among AI/AN, CDC funded four American Indian tribes during 2004–2009 to tailor, implement, and evaluate evidence-based interventions to reduce motor vehicle–related injury and death in their communities. These pilot programs were successful at increasing seat belt use, increasing child safety seat use, and decreasing motor vehicle crashes (6,7). Across the four pilot programs, relative increases in drivers' observed seat belt use ranged from a 38% increase to a 315% increase and child safety seat use increases ranged from a 45% increase to an 85% increase in use. Declines in motor vehicle crashes ranged from a 29% decrease to a 36% decrease in the number of motor vehicle crashes and the number of motor vehicle crashes in which someone was injured, respectively. As a result, CDC has expanded the tribal programs and is funding eight new tribes during 2010–2014.

Limitations

The findings in this report are subject to at least one limitation. Because NVSS data are extracted from death certificates and not self-reported, some racial misclassification is likely, particularly for AI/AN (8).

Conclusion

Despite the recent declines in motor vehicle–related death rates noted in this report, the need remains for increased use of evidence-based strategies to reduce disparities. More translational research is warranted on the scalability of interventions that have successfully been tailored to communities of different racial/ethnic and cultural backgrounds.

References

1. CDC. Web-based Injury Statistics Query and Reporting System (WISQARS) [Online database]. Atlanta, GA: US Department of Health and Human Services, CDC, National Center for Injury Prevention and Control; 2010. Available at http://www.cdc.gov/injury/wisqars/index.html.
2. CDC. Motor vehicle-related deaths—United States, 2003-2007. In: CDC health disparities and inequalities report—United States, 2011. MMWR 2011;60(Suppl; January 14, 2011):52-55.
3. CDC. CDC health disparities and inequalities report—United States, 2011. MMWR 2011;60 (Suppl; January 14, 2011).
4. CDC. Introduction: CDC health disparities and inequalities report-United States, 2013. MMWR 2013;62(No. Suppl 3).
5. Task Force on Community Preventive Services. Motor vehicle–related injury prevention. Atlanta, GA: Task Force on Community Preventive Services; 2010. Available at http://www.thecommunityguide.org/mvoi/index.html.
6. Reede C, Piontkowski S, Tsatoke G. Using evidence-based strategies to reduce motor vehicle injuries on the San Carlos Apache Reservation. IHS Primary Care Provider 2007;32:209–12.
7. Letourneau RJ, Crump CD, Thunder N, Voss R. Increasing occupant restraint use among Ho-Chunk Nation members: tailoring evidence-based strategies to local context. IHS Primary Care Provider 2009;34:212–7.
8. US Department of Health and Human Services; Westat. Data on health and well-being of American Indians, Alaska Natives, and other Native Americans: data catalog. December 2006. Available at http://aspe.hhs.gov/hsp/06/Catalog-AI-AN-NA/index.htm.