Motor Vehicle Crash Deaths - United States and 28 Other High-Income Countries, 2015 and 2019.

Motor vehicle crashes are preventable, yet they continue to be a leading cause of death in the United States. An average of 36,791 crash deaths occurred each year (101 deaths each day) during 2015-2019 in the United States. To measure progress in reducing motor vehicle crash deaths, CDC calculated population-based, distance-based, and vehicle-based death rates in 2015 and 2019, as well as average rates and average percent changes from 2015 to 2019, for the United States and 28 other high-income countries for which data were available. In 2019, the population-based death rate in the United States (11.1 per 100,000 population; 36,355 deaths) was the highest among the 29 high-income countries and was 2.3 times the average rate of the 28 other high-income countries (4.8). The 2019 U.S. distance-based death rate (1.11 per 100 million vehicle miles traveled) was higher than the average rate among 20 other high-income countries (0.92), and the 2019 U.S. vehicle-based death rate (1.21 per 10,000 registered vehicles) was higher than the average rate among 27 other high-income countries (0.78). The population-based death rate in the United States increased 0.1% from 2015 to 2019, whereas the average change among 27 other high-income countries was -10.4%. Widespread implementation of proven strategies and the Safe System approach, which accounts for human error and works to protect everyone on the road, (1) can help reduce motor vehicle crash deaths in the United States.

COVID-19 Trends Among Persons Aged 0-24 Years - United States, March 1-December 12, 2020.

Coronavirus disease 2019 (COVID-19) case and electronic laboratory data reported to CDC were analyzed to describe demographic characteristics, underlying health conditions, and clinical outcomes, as well as trends in laboratory-confirmed COVID-19 incidence and testing volume among U.S. children, adolescents, and young adults (persons aged 0-24 years). This analysis provides a critical update and expansion of previously published data, to include trends after fall school reopenings, and adds preschool-aged children (0-4 years) and college-aged young adults (18-24 years) (1). Among children, adolescents, and young adults, weekly incidence (cases per 100,000 persons) increased with age and was highest during the final week of the review period (the week of December 6) among all age groups. Time trends in weekly reported incidence for children and adolescents aged 0-17 years tracked consistently with trends observed among adults since June, with both incidence and positive test results tending to increase since September after summer declines. Reported incidence and positive test results among children aged 0-10 years were consistently lower than those in older age groups. To reduce community transmission, which will support schools in operating more safely for in-person learning, communities and schools should fully implement and strictly adhere to recommended mitigation strategies, especially universal and proper masking, to reduce COVID-19 incidence.

Guidance for Implementing COVID-19 Prevention Strategies in the Context of Varying Community Transmission Levels and Vaccination Coverage.

COVID-19 vaccination remains the most effective means to achieve control of the pandemic. In the United States, COVID-19 cases and deaths have markedly declined since their peak in early January 2021, due in part to increased vaccination coverage (1). However, during June 19-July 23, 2021, COVID-19 cases increased approximately 300% nationally, followed by increases in hospitalizations and deaths, driven by the highly transmissible B.1.617.2 (Delta) variant* of SARS-CoV-2, the virus that causes COVID-19. Available data indicate that the vaccines authorized in the United States (Pfizer-BioNTech, Moderna, and Janssen [Johnson & Johnson]) offer high levels of protection against severe illness and death from infection with the Delta variant and other currently circulating variants of the virus (2). Despite widespread availability, vaccine uptake has slowed nationally with wide variation in coverage by state (range = 33.9%-67.2%) and by county (range = 8.8%-89.0%).† Unvaccinated persons, as well as persons with certain immunocompromising conditions (3), remain at substantial risk for infection, severe illness, and death, especially in areas where the level of SARS-CoV-2 community transmission is high. The Delta variant is more than two times as transmissible as the original strains circulating at the start of the pandemic and is causing large, rapid increases in infections, which could compromise the capacity of some local and regional health care systems to provide medical care for the communities they serve. Until vaccination coverage is high and community transmission is low, public health practitioners, as well as schools, businesses, and institutions (organizations) need to regularly assess the need for prevention strategies to avoid stressing health care capacity and imperiling adequate care for both COVID-19 and other non-COVID-19 conditions. CDC recommends five critical factors be considered to inform local decision-making: 1) level of SARS-CoV-2 community transmission; 2) health system capacity; 3) COVID-19 vaccination coverage; 4) capacity for early detection of increases in COVID-19 cases; and 5) populations at increased risk for severe outcomes from COVID-19. Among strategies to prevent COVID-19, CDC recommends all unvaccinated persons wear masks in public indoor settings. Based on emerging evidence on the Delta variant (2), CDC also recommends that fully vaccinated persons wear masks in public indoor settings in areas of substantial or high transmission. Fully vaccinated persons might consider wearing a mask in public indoor settings, regardless of transmission level, if they or someone in their household is immunocompromised or is at increased risk for severe disease, or if someone in their household is unvaccinated (including children aged <12 years who are currently ineligible for vaccination).

Implementation of Hospital Practices Supportive of Breastfeeding in the Context of COVID-19 - United States, July 15-August 20, 2020.

Breastfeeding has health benefits for both infants and mothers and is recommended by numerous health and medical organizations*,† (1). The birth hospitalization is a critical period for establishing breastfeeding; however, some hospital practices, particularly related to mother-newborn contact, have given rise to concern about the potential for mother-to-newborn transmission of SARS-CoV-2, the virus that causes coronavirus disease 2019 (COVID-19) (2). CDC conducted a COVID-19 survey (July 15-August 20, 2020) among 1,344 hospitals that completed the 2018 Maternity Practices in Infant Nutrition and Care (mPINC) survey to assess current practices and breastfeeding support while in the hospital. Among mothers with suspected or confirmed COVID-19, 14.0% of hospitals discouraged and 6.5% prohibited skin-to-skin care; 37.8% discouraged and 5.3% prohibited rooming-in; 20.1% discouraged direct breastfeeding but allowed it if the mother chose; and 12.7% did not support direct breastfeeding, but encouraged feeding of expressed breast milk. In response to the pandemic, 17.9% of hospitals reported reduced in-person lactation support, and 72.9% reported discharging mothers and their newborns <48 hours after birth. Some of the infection prevention and control (IPC) practices that hospitals were implementing conflicted with evidence-based care to support breastfeeding. Mothers who are separated from their newborn or not feeding directly at the breast might need additional postdischarge breastfeeding support. In addition, the American Academy of Pediatrics (AAP) recommends that newborns discharged before 48 hours receive prompt follow-up with a pediatric health care provider.

Summary of Guidance for Public Health Strategies to Address High Levels of Community Transmission of SARS-CoV-2 and Related Deaths, December 2020.

In the 10 months since the first confirmed case of coronavirus disease 2019 (COVID-19) was reported in the United States on January 20, 2020 (1), approximately 13.8 million cases and 272,525 deaths have been reported in the United States. On October 30, the number of new cases reported in the United States in a single day exceeded 100,000 for the first time, and by December 2 had reached a daily high of 196,227.* With colder weather, more time spent indoors, the ongoing U.S. holiday season, and silent spread of disease, with approximately 50% of transmission from asymptomatic persons (2), the United States has entered a phase of high-level transmission where a multipronged approach to implementing all evidence-based public health strategies at both the individual and community levels is essential. This summary guidance highlights critical evidence-based CDC recommendations and sustainable strategies to reduce COVID-19 transmission. These strategies include 1) universal face mask use, 2) maintaining physical distance from other persons and limiting in-person contacts, 3) avoiding nonessential indoor spaces and crowded outdoor spaces, 4) increasing testing to rapidly identify and isolate infected persons, 5) promptly identifying, quarantining, and testing close contacts of persons with known COVID-19, 6) safeguarding persons most at risk for severe illness or death from infection with SARS-CoV-2, the virus that causes COVID-19, 7) protecting essential workers with provision of adequate personal protective equipment and safe work practices, 8) postponing travel, 9) increasing room air ventilation and enhancing hand hygiene and environmental disinfection, and 10) achieving widespread availability and high community coverage with effective COVID-19 vaccines. In combination, these strategies can reduce SARS-CoV-2 transmission, long-term sequelae or disability, and death, and mitigate the pandemic's economic impact. Consistent implementation of these strategies improves health equity, preserves health care capacity, maintains the function of essential businesses, and supports the availability of in-person instruction for kindergarten through grade 12 schools and preschool. Individual persons, households, and communities should take these actions now to reduce SARS-CoV-2 transmission from its current high level. These actions will provide a bridge to a future with wide availability and high community coverage of effective vaccines, when safe return to more everyday activities in a range of settings will be possible.

Driving Under the Influence of Marijuana and Illicit Drugs Among Persons Aged ≥16 Years - United States, 2018.

In the United States, driving while impaired is illegal. Nonetheless, an estimated 10,511 alcohol-impaired driving deaths occurred in 2018.* The contribution of marijuana and other illicit drugs to these and other impaired driving deaths remains unknown. Data from the Substance Abuse and Mental Health Services Administration's National Survey on Drug Use and Health (NSDUH) indicated that in the United States during 2014, 12.4% of all persons aged 16-25 years reported driving under the influence of alcohol, and 3.2% reported driving under the influence of marijuana (1). The impairing effects of alcohol are well established, but less is known about the effects of illicit substances or other psychoactive drugs (e.g., marijuana, cocaine, methamphetamines, and opioids, including heroin). This report provides the most recent national estimates of self-reported driving under the influence of marijuana and illicit drugs among persons aged ≥16 years, using 2018 public-use data from NSDUH. Prevalences of driving under the influence of marijuana and illicit drugs other than marijuana were assessed for persons aged ≥16 years by age group, sex, and race/ethnicity. During 2018, 12 million (4.7%) U.S. residents reported driving under the influence of marijuana in the past 12 months; 2.3 million (0.9%) reported driving under the influence of illicit drugs other than marijuana. Driving under the influence was more prevalent among males and among persons aged 16-34 years. Effective measures that deter driving under the influence of drugs are limited (2). Development, evaluation, and further implementation of strategies to prevent alcohol-impaired,† drug-impaired, and polysubstance-impaired driving, coupled with standardized testing of impaired drivers and drivers involved in fatal crashes, could advance understanding of drug- and polysubstance-impaired driving and support prevention efforts.

Vital Signs: Motor Vehicle Injury Prevention - United States and 19 Comparison Countries.

BACKGROUND: Each year >32,000 deaths and 2 million nonfatal injuries occur on U.S. roads. METHODS: CDC analyzed 2000 and 2013 data compiled by the World Health Organization and the Organisation for Economic Co-operation and Development (OECD) to determine the number and rate of motor vehicle crash deaths in the United States and 19 other high-income OECD countries and analyzed estimated seat belt use and the percentage of deaths that involved alcohol-impaired driving or speeding, by country. RESULTS: In 2013, the United States motor vehicle crash death rate of 10.3 per 100,000 population had decreased 31% from the rate in 2000; among the 19 comparison countries, the rate had declined an average of 56% during this time. Among all 20 countries, the United States had the highest rate of crash deaths per 100,000 population (10.3); the highest rate of crash deaths per 10,000 registered vehicles (1.24), and the fifth highest rate of motor vehicle crash deaths per 100 million vehicle miles traveled (1.10). Among countries for which information on national seat belt use was available, the United States ranked 18th out of 20 for front seat use, and 13th out of 18 for rear seat use. Among 19 countries, the United States reported the second highest percentage of motor vehicle crash deaths involving alcohol-impaired driving (31%), and among 15, had the eighth highest percentage of crash deaths that involved speeding (29%). CONCLUSIONS AND COMMENTS: Motor vehicle injuries are predictable and preventable. Lower death rates in other high-income countries, as well as a high prevalence of risk factors in the United States, suggest that the United States can make more progress in reducing crash deaths. With a projected increase in U.S. crash deaths in 2015, the time is right to reassess U.S. progress and set new goals. By implementing effective strategies, including those that increase seat belt use and reduce alcohol-impaired driving and speeding, the United States can prevent thousands of motor vehicle crash-related injuries and deaths and hundreds of millions of dollars in direct medical costs every year.

Comprehensive review of sleep-related sudden unexpected infant deaths and their investigations: Florida 2008.

To describe 2008 Florida sleep-related sudden unexpected infant deaths (SUIDs) by describing (a) percentage distribution of medical examiner (ME) cause-of-death determinations; (b) mortality rates by maternal and infant characteristics; (c) prevalence of selected suffocation or sudden infant death syndrome (SIDS) risk and protective factors; (d) frequency of selected scene investigation and autopsy components (including extent of missing data); and (e) percentage with public health program contact. In this population-based study, we identified sleep-related SUIDs occurring among Florida residents from the 2008-linked Florida infant death and birth certificates. Information about the circumstances of death was abstracted from ME, law enforcement, and hospital records. We used frequencies and percentages to describe characteristics of sleep-related SUID cases. Of 215 sleep-related SUID cases, MEs identified 47.9% as accidental suffocation and strangulation in bed, 35.4% as unknown or undetermined cause, and 16.7% as SIDS. Sleep-related SUID most frequently occurred in an adult bed (n = 108; 50.2%). At death, 82.4% of sleep-related SUIDs had ≥1 suffocation or SIDS risk factor with 54.4% infants sharing a sleep surface, 38.1% placed nonsupine, 24.2% placed on a pillow, and 10.2% having head covering. Missing data frequently resulted from incomplete scene investigation and autopsy components. SUID contributed to ≥1 in seven Florida infant deaths in 2008. Approximately 80% of sleep-related SUIDs were reported among infants placed in unsafe sleeping environments. Effective interventions are needed to promote safe sleep among caregivers of Florida infants. These interventions must reach infant caregivers at highest risk and change unsafe sleep practices. The substantial percentage of missing investigation data reinforces the need for standardized reporting.

Pediatricians' self-reported knowledge, attitudes, and practices about child passenger safety.

OBJECTIVE: To evaluate pediatricians' self-reported knowledge, attitudes, and dissemination practices regarding the new American Academy of Pediatrics' (AAP) child passenger safety (CPS) policy recommendations. STUDY DESIGN: A cross-sectional survey was distributed to pediatric primary care physicians via AAP e-mail distribution lists. Knowledge, attitudes, and practices related to current AAP CPS recommendations and the revised policy statement were ascertained. RESULTS: There were 718 respondents from 3497 physicians with active e-mail addresses, resulting in a 20.5% response rate, of which 533 were eligible based on the initial survey question. All 6 CPS knowledge and scenario-based items were answered correctly by 52.9% of the sample; these respondents were identified as the "high knowledge" group. Pediatricians with high knowledge were more likely to be female (P < .001), to have completed a pediatrics residency (vs medicine-pediatrics) (P = .03), and have a child between 4 and 7 years of age (P = .001). CPS information was distributed more frequently at routine health visits for patients 0-2 years of age vs those 4-12 years of age. Those with high knowledge were less likely to report several specific barriers to dissemination of CPS information, more likely to allot adequate time and discuss CPS with parents, and had greater confidence for topics related to all CPS topics. CONCLUSIONS: Although CPS knowledge is generally high among respondents, gaps in knowledge still exist. Knowledge is associated with attitudes, practices, barriers, and facilitators of CPS guideline dissemination. These results identify opportunities to increase knowledge and implement strategies to routinely disseminate CPS information in the primary care setting.

Vital signs: restraint use and motor vehicle occupant death rates among children aged 0-12 years - United States, 2002-2011.

BACKGROUND: Motor vehicle crashes are a leading cause of death among children in the United States. Age- and size-appropriate child restraint use is the most effective method for reducing these deaths. METHODS: CDC analyzed 2002­2011 data from the Fatality Analysis Reporting System to determine the number and rate of motor-vehicle occupant deaths, and the proportion of unrestrained child deaths among children aged <1 year, 1­3 years , 4­7 years, 8­12 years, and for all children aged 0­12 years. Age group­specific death rates and proportions of unrestrained child motor vehicle deaths for 2009­2010 were further stratified by race/ethnicity. RESULTS: Motor vehicle occupant death rates for children declined significantly from 2002 to 2011. However, one third (33%) of children who died in 2011 were unrestrained. Compared with white children for 2009­2010, black children had significantly higher death rates, and black and Hispanic children both had significantly higher proportions of unrestrained child deaths. CONCLUSIONS: Motor vehicle occupant deaths among children in the United States have declined in the past decade, but more deaths could be prevented if restraints were always used. IMPLICATIONS FOR PUBLIC HEALTH: Effective interventions, including child passenger restraint laws (with child safety seat/ booster seat coverage through at least age 8 years) and child safety seat distribution plus education programs, can increase restraint use and reduce child motor vehicle deaths.

Injury during pregnancy and nervous system birth defects: Texas, 1999 to 2003.

BACKGROUND: Case reports and series have suggested an association between injury during pregnancy and several nervous system and nervous system-related adverse fetal/neonatal outcomes. This study's purpose is to further determine if there is an association between injury during pregnancy and nervous system birth defects in infancy. METHODS: Through a case-control study, the association between injury during pregnancy and nervous system birth defects was tested using the Texas Birth Defects Registry (1999-2003). Semiautomated probabilistic bias analysis was used to correct for systematic error from misclassification of injury during pregnancy. RESULTS: Of the 59,750 infants eligible for this study, 4144 (6.94%) were diagnosed with a nervous system birth defect and 315 (0.53%) of the infants' mothers were injured during pregnancy. Among these 315 women, 25 (7.94%) delivered an infant with a subsequent nervous system birth defect. The adjusted odds ratio for the association between injury during pregnancy and nervous system birth defects among all study infants was 1.00; 95% confidence interval, 0.63-1.56 and 2.44; 95% confidence interval, 1.08-5.53 among breech presentation infants. Probabilistic bias analysis supported these findings. CONCLUSION: No association between injury during pregnancy and nervous system birth defects was identified. Further exploration into the association among breech presentation infants is warranted.

Dengue outbreak in Key West, Florida, USA, 2009.

After 3 dengue cases were acquired in Key West, Florida, we conducted a serosurvey to determine the scope of the outbreak. Thirteen residents showed recent infection (infection rate 5%; 90% CI 2%-8%), demonstrating the reemergence of dengue in Florida. Increased awareness of dengue among health care providers is needed.

Obesity, assisted reproductive technology, and early preterm birth--Florida, 2004-2006.

Florida resident birth certificates for 2004-2006 were linked to the Centers for Disease Control and Prevention's National ART Surveillance System and were used to investigate 1) whether the association of assisted reproductive technology (ART) with preterm birth varies by prepregnancy body mass index and 2) whether the association varies by plurality. Preterm birth was defined as early preterm birth (gestation <34 weeks) and late preterm birth (gestation 34-36 weeks). Descriptive statistics and multinomial logistic regression were used to explore maternal and infant differences by ART status and plurality. Of 581,403 women included in the study, 24.0% were overweight, 18.6% were obese, 7.3% had late preterm birth, 2.6% had early preterm birth, and 0.67% conceived through ART. Among singleton births, ART was associated with increased early preterm birth risk among underweight (odds ratio (OR) = 2.94, 95% confidence interval (CI): 1.27, 6.81), overweight (OR = 1.75, 95% CI: 1.12, 2.72), and obese (OR = 2.37, 95% CI: 1.51, 3.71) women. Among twins, ART was significantly associated with increased risk among overweight (OR = 1.61, 95% CI: 1.12, 2.32) and obese (OR = 1.85, 95% CI: 1.18, 2.90) women. Differences in the associations between ART and early preterm birth by body mass index and plurality warrant further investigation.

Reasons for the increasing Hispanic infant mortality rate: Florida, 2004-2007.

Assess whether the 55% increase in Florida's Hispanic infant mortality rate (HIMR) during 2004-2007 was real or artifactual. Using linked data from Florida resident live births and infant deaths for 2004-2007, we calculated traditional (infant Hispanic ethnicity from death certificates and maternal Hispanic ethnicity from birth certificates) and nontraditional (infant and maternal Hispanic ethnicity from birth certificate maternal ethnicity) HIMRs. We assessed trends in HIMRs (per 1,000 live births) using Chi-square statistics. We tested agreement in Hispanic ethnicity after implementation of a revised 2005 death certificate by using kappa statistics and used logistic regression to test the associations of infant mortality risk factors. Hispanic was defined as being of Mexican, Puerto Rican, Cuban, Central/South American, or other/unknown Hispanic origin. During 2004-2007 traditional HIMR increased 55%, from 4.0 to 6.2 (Chi-square, P < 0.001) and nontraditional HIMR increased 20%, from 4.5 to 5.4 (Chi-square, P = 0.03). During 2004-2005, agreement in Hispanic ethnicity did not change with use of the revised certificate (kappa = 0.70 in 2004; kappa = 0.76 in 2005). Birth weight was the most significant risk factor for trends in Hispanic infant mortality (OR = 1.33, 95% CI = 1.10-1.61). Differences in Hispanic reporting on revised death certificates likely accounted for the majority of traditional HIMR increase, indicating a primarily artifactual increase. Reasons for the 20% increase in nontraditional HIMR during 2004-2007 should be further explored through other individual and community factors. Use of nontraditional HIMRs, which use a consistent source of Hispanic classification, should be considered.

Unintentional injury deaths in children and youth, 2010-2019.

BACKGROUND: Unintentional injuries are the leading cause of death for children and youth aged 1-19 in the United States. The purpose of this report is to describe how unintentional injury death rates among children and youth aged 0-19 years have changed during 2010-2019. METHOD: CDC analyzed 2010-2019 data from the National Vital Statistics System (NVSS) to determine two-year average annual number and rate of unintentional injury deaths for children and youth aged 0-19 years by sex, age group, race/ethnicity, mechanism, county urbanization level, and state. RESULTS: From 2010-2011 to 2018-2019, unintentional injury death rates decreased 11% overall-representing over 1,100 fewer annual deaths. However, rates increased among some groups-including an increase in deaths due to suffocation among infants (20%) and increases in motor-vehicle traffic deaths among Black children (9%) and poisoning deaths among Black (37%) and Hispanic (50%) children. In 2018-2019, rates were higher for males than females (11.3 vs. 6.6 per 100,000 population), children aged < 1 and 15-19 years (31.9 and 16.8 per 100,000) than other age groups, among American Indian or Alaska Native (AIAN) and Blacks than Whites (19.4 and 12.4 vs. 9.0 per 100,000), motor-vehicle traffic (MVT) than other causes of injury (4.0 per 100,000), and rates increased as rurality increased (6.8 most urban [large central metro] vs. 17.8 most rural [non-core/non-metro] per 100,000). From 2010-2011 to 2018-2019, 49 states plus DC had stable or decreasing unintentional injury death rates; death rates increased only in California (8%)-driven by poisoning deaths. Conclusion and Practical Application: While the overall injury death rates improved, certain subgroups and their caregivers can benefit from focused prevention strategies, including infants and Black, Hispanic, and AIAN children. Focusing effective strategies to reduce suffocation, MVT, and poisoning deaths among those at disproportionate risk could further reduce unintentional injury deaths among children and youth in the next decade.

Descriptive epidemiology of birth trauma in the United States in 2003.

The rate of birth trauma in the US has been reported to range between 0.2 and 37 birth traumas per 1000 births. Because of the minimal number of population-based studies and the inconsistencies among the published birth trauma rates, the rate of birth trauma in the US remains unclear. This is a cross-sectional study that was conducted using 890 582 in-hospital birth discharges from the 2003 Healthcare Cost and Utilization Project Kids' Inpatient Database. A neonate was defined as having birth trauma if their hospital discharge record contained an International Classification of Diseases, Ninth Revision, Clinical Modification diagnosis code from 767.0 to 767.9. Weighted data were used to calculate rates for all birth traumas and specific types of birth traumas, and rates and odds ratios by demographic, hospital and clinical variables. Weighted data represented a national estimate of 3 920 787 in-hospital births. Birth trauma was estimated to occur in 29 per 1000 births. The three most frequently diagnosed birth traumas were injuries to the scalp, other injuries to the skeleton and fracture of the clavicle. Significant univariable predictors for birth trauma included male gender, Asian or Pacific Islander race, living in urban or wealthy areas, being born in Western, urban and/or teaching hospital, a co-diagnosis of high birthweight, instrument delivery, malpresentation and other complications during labour and delivery. Birth trauma risk factors including those identified in this study may be useful to consider during labour and delivery. In conclusion, additional research is necessary to identify ways to reduce birth trauma and subsequent infant morbidity and mortality.

Transportation Risk Behaviors Among High School Students - Youth Risk Behavior Survey, United States, 2019.

Motor-vehicle crashes are a leading cause of death and nonfatal injury among U.S. adolescents, resulting in approximately 2,500 deaths and 300,000 nonfatal injuries each year. Risk for motor-vehicle crashes and resulting injuries and deaths varies, depending on such behaviors as seat belt use or impaired or distracted driving. Improved understanding of adolescents' transportation risk behaviors can guide prevention efforts. Therefore, data from the 2019 Youth Risk Behavior Survey were analyzed to determine prevalence of transportation risk behaviors, including not always wearing a seat belt, riding with a driver who had been drinking alcohol (riding with a drinking driver), driving after drinking alcohol, and texting or e-mailing while driving. Differences by student characteristics (age, sex, race/ethnicity, academic grades in school, and sexual identity) were calculated. Multivariable analyses controlling for student characteristics examined associations between risk behaviors. Approximately 43.1% of U.S. high school students did not always wear a seat belt and 16.7% rode with a drinking driver during the 30 days before the survey. Approximately 59.9% of students had driven a car during the 30 days before the survey. Among students who drove, 5.4% had driven after drinking alcohol and 39.0% had texted or e-mailed while driving. Prevalence of not always wearing a seat belt was higher among students who were younger, black, or had lower grades. Riding with a drinking driver was higher among Hispanic students or students with lower grades. Driving after drinking alcohol was higher among students who were older, male, Hispanic, or had lower grades. Texting while driving was higher among older students or white students. Few differences existed by sexual identity. Multivariable analyses revealed that students engaging in one transportation risk behavior were more likely to engage in other transportation risk behaviors. Traffic safety and public health professionals can use these findings to reduce transportation risk behaviors by selecting, implementing, and contextualizing the most appropriate and effective strategies for specific populations and for the environment.

The association between county-level injury rates and racial segregation revisited: a multilevel analysis.

OBJECTIVES: We investigated whether within-county racial segregation was associated with increased odds of violent injury beyond individual risk. METHODS: In a cross-sectional study, data on 75 310 patients admitted with an injury to Pennsylvania hospitals from 1997 to 1999 were analyzed to determine the association between county-level racial segregation and violent injury. We used multilevel analysis to adjust for individual- and county-level factors. Principal components analysis allowed us to separate the effect of segregation from other county-level variables. RESULTS: After adjustment, greater segregation was associated with increased odds of violent injury among Whites (odds ratio [OR] = 1.20; 95% confidence interval [CI] = 1.11, 1.30) and non-Whites (OR = 1.45; 95% CI = 1.28, 1.64). The association was stronger for non-Whites. CONCLUSIONS: Our results suggested that living in a county with high levels of racial segregation was associated with increased odds of violence not explained by an individual's own risk. These findings represent an important step in understanding the nature of observed links between race and violence. Future work should develop prevention strategies that simultaneously target community and individual risks.

Alcohol and marijuana use among young injured drivers in Arizona, 2008-2014.

OBJECTIVE: We examined alcohol and marijuana use among injured drivers aged 16-20 years evaluated at Arizona level 1 trauma centers during 2008-2014. METHODS: Using data from the Arizona State Trauma Registry, we conducted a descriptive analysis of blood alcohol concentration (BAC) and qualitative test results (positive or negative) for delta-9-tetrahydrocannabinol (THC) by year of age, sex, race, ethnicity, injury severity, seat belt use, motorcycle helmet use, and type of vehicle driven. To explore compliance with Arizona's motorcycle helmet law requiring helmet use for riders <18 years old, we examined helmet use by age. RESULTS: Data on 5,069 injured young drivers were analyzed; the annual number of injured drivers declined by 41% during the 7-year study period. Among the 76% (n = 3,849) of drivers with BAC results, 19% tested positive, indicating that at least 15% of all drivers had positive BACs. Eighty-two percent of the BAC-positive drivers had BACs ≥0.08 g/dL, the illegal threshold for drivers aged ≥21 years. Among the 49% (n = 2,476) of drivers with THC results, 30% tested positive, indicating that at least 14% of all drivers were THC-positive. American Indians and blacks had the highest proportion of THC-tested drivers with positive THC results (38%). In addition, 28% of tested American Indians had positive results for both substances, more than twice the proportion seen in all other race or ethnic groups. Crude prevalence ratios suggested that drivers who tested positive for alcohol or THC were less likely than those who tested negative to wear a helmet or seat belt, further increasing their injury risk. Helmet use among motorcyclists was lower among 16- and 17-year-old riders compared to 18- to 20-year-olds, despite Arizona's motorcycle helmet law requiring riders aged <18 years to wear a helmet. CONCLUSIONS: About 1 in 4 injured drivers aged 16-20 years tested positive for alcohol, THC, or both substances. Most drivers with positive BACs were legally intoxicated (BAC ≥0.08 g/dL). All substance-using young drivers in this study were candidates for substance abuse screening and possible referral to treatment. Broader enforcement of existing laws targeting underage access to alcohol and alcohol-impaired driving could further reduce injuries among young Arizona drivers. To further reduce crash-related injuries and fatalities among all road users, the state could consider implementing a primary enforcement seat belt law and a universal motorcycle helmet law.

Marijuana and alcohol use among injured drivers evaluated at level I trauma centers in Arizona, 2008-2014.

BACKGROUND: We examined marijuana and alcohol use trends among drivers aged ≥16 years evaluated at Level I trauma centers before and after Arizona legalized medical marijuana in April 2011. METHODS: We conducted interrupted time series (ITS) analysis of urine drug screens for marijuana metabolites and blood alcohol concentration (BAC) data from the 2008-2014 Arizona State Trauma Registry. RESULTS: Among 30,083 injured drivers, 14,710 had marijuana test results, and 2590 were positive for marijuana; of these, 1087 (42%) also tested positive for alcohol. Among 23,186 drivers with BAC results, 5266 exceeded the legal limit for their age. Compared with prelaw trends (models if law had not been enacted), postlaw models showed small but significant annual increases in the proportions of drivers testing positive for either substance. By the end of 2014, the proportion of drivers testing positive for marijuana was 9.6% versus a projected 5.6% if the law had not been enacted, and the proportion of drivers with illegal BACs was 15.7% versus a projected 8.2%. When ITS was restricted to only substance-tested drivers, no significant differences were detected. CONCLUSIONS: Despite the small annual postlaw increases in the proportion of marijuana-positive drivers compared with the prelaw trend, alcohol-impaired driving remains a more prevalent threat to road safety in Arizona.