INTRODUCTION:The aim of this study was to assess the early effects of Utah's 0.05 g/dL blood alcohol concentration per se law-passed in 2017 and enacted in 2018-on crash fatalities by comparing Utah with its 6 contiguous states. METHODS:Using data from the Fatality Analysis Reporting System, the authors conducted a difference-in-differences analysis comparing prelaw (2016) and postlaw (2019) outcomes, crash fatalities across 5 blood alcohol concentration levels (<0.01, ≥0.01, ≥0.05, ≥0.08, and ≥0.15 g/dL) between Utah and contiguous states. Eleven-year trends (2013-2023) in crash fatalities per 100 million vehicle miles traveled were displayed. Data were analyzed in 2025 using SAS, Version 9.4, for data preparation and statistical analyses. RESULTS:Utah experienced significantly larger reductions in crash fatalities than contiguous states, with difference-in-differences estimates ranging from -0.67 to -1.17 (all p<0.05). The largest decrease was observed for crashes involving drivers with blood alcohol concentration ≥0.01 (difference-in-differences = -1.17, 95% CI= -1.88 to -0.46). For nonalcohol-related crashes (blood alcohol concentration <0.01), both Utah and adjoining states experienced decreases, but the differences were not statistically significant for fatalities (p=0.96). CONCLUSIONS:Utah's 0.05 blood alcohol concentration law was associated with meaningful decreases in alcohol-related crash fatalities, strengthening the evidence supporting the public health importance of evidence-based policy and strongly supporting broader adoption of 0.05 blood alcohol concentration limits nationwide.

OBJECTIVE:In the U.S., motor vehicle crashes are the leading cause of death for adolescents ages 15 - 18, and alcohol use increases the risk of crashes. There is a need for greater clarity regarding the factors most effective for behavior change in preventing teen driving after drinking. Given the centrality of teen-parent relationships in influencing teen behavior, understanding the relational dynamics in this context is vital to prevention. To inform the development of more effective prevention programs for teens and parents, this study examines teen drivers' and parents of teen drivers' perspectives on drinking and driving behaviors, prevention, and parental involvement. METHODS:Surveys and focus groups were conducted among 41 teens (ages 15 - 18) and 27 parents (of teens ages 15 - 18) residing in 11 cities in Orange County, California. Participants completed an online survey assessing demographic information, driving behaviors, family relationships, physical and mental health, and substance use history. Participants then attended a one-hour in-person focus group, held separately for teens (5 focus groups; 7-13 participants per group) and parents (4 focus groups; 5-8 participants per group). During these sessions, participants engaged in open discussions about imagined scenarios involving riding with or driving while impaired, as well as imaginal scenarios designed to explore perspectives, decision-making, and prevention strategies. Focus group transcripts were coded by a multidisciplinary team using a deductive approach to explore and summarize themes. RESULTS:Teens reported varying experiences with alcohol, yet overall described a strong safety orientation, awareness of consequences, openness to parental limits, and interest in having explicit safety conversations related to driving after drinking. Although teens differed in their preferences for the timing and duration of these discussions, most expressed a desire for genuine parental understanding. Parents similarly described differing perceptions of teen alcohol use, with some expressing trust in their teens not using alcohol and others acknowledging alcohol use as common and driving after drinking as a notable concern. Parenting approaches regarding drinking ranged from expectations of strict alcohol abstinence from their teens to more permissive practices, including permitting supervised and social drinking. Parents reported a preference that their teens first turn to them for support and, when necessary, seek help from other trusted, practical sources, including family, friends, or rideshare services. CONCLUSIONS:Findings emphasized the need for proactive prevention strategies targeting driving after drinking. Teens suggested that prevention efforts should collaboratively engage both teens and parents to improve safety outcomes. Parents highlighted that comprehensive prevention efforts should extend beyond the home to multiple contexts and be adaptable to diverse family structures. These study findings present directions for future research, prevention activities, and programs.

Introduction To assess early effects of Utah’s .05 g/dL blood alcohol concentration (BAC) per se law—passed in 2017 and enacted in 2018—on crash fatalities by comparing Utah with its six contiguous states. Methods Using data from the Fatality Analysis Reporting System, we conducted a difference-in-differences (DID) analysis comparing pre-law (2016) and post-law (2019) outcomes, crash fatalities, across five BAC levels (<.01, ≥.01, ≥.05, ≥.08, and ≥.15 g/dL) between Utah and contiguous states. Eleven-year trends (2013–23) in crash fatalities per 100 million vehicle miles traveled were displayed. Data were analyzed in 2025 using SAS version 9.4 for data preparation and statistical analyses. Results Utah experienced significantly larger reductions in crash fatalities than contiguous states, with DID estimates ranging from –0.67 to –1.17 (all p<.05). The largest decrease was observed for crashes involving drivers with BAC≥.01 (DID = –1.17, 95%CI: –1.88 to –0.46). For non-alcohol-related crashes (BAC<.01), both Utah and adjoining states experienced decreases, but the differences were not statistically significant for fatalities (p=.96). Conclusions Utah’s .05 BAC law was associated with meaningful decreases in alcohol-involved crash fatalities, strengthening the evidence supporting the public health importance of evidence-based policy and strongly support broader adoption of .05 BAC limits nationwide.

Emerging adults are disproportionately at risk for substance misuse and assault injury. Assault-injured emerging adults with substance misuse have increased risk of morbidity and mortality compared to those without and often receive care in the Emergency Department (ED). This manuscript describes the development of a protocol for a pilot randomized trial of an adapted brief behavioral intervention, the Brief Negotiation Interview (BNI), for use among assault-injured emerging adults with alcohol and/or cannabis misuse presenting to the ED. First, we will perform a mixed methods study of assault-injured emerging adults with alcohol and/or cannabis misuse to elicit the shared psychosocial risk factors that contribute to both alcohol and/or cannabis misuse in the context of assault injury. We will then use these data to adapt the BNI for use among assault-injured emerging adults with alcohol and/or cannabis misuse. We will evaluate the feasibility and acceptability of the adapted BNI in a randomized trial in the ED setting (N = 50). This pilot study is a critical initial step in developing an effective brief behavioral intervention for reducing alcohol and cannabis use among assault-injured emerging adults. Trial Registration Number NCT07070414.

Objectives:To examine changes in alcohol-involved traffic crash rates among young drivers in California during and following the COVID-19 pandemic. Methods:We conducted a cross-sectional study of alcohol-involved crashes among drivers aged 15-24 using data from the University of California, Berkeley Transportation Injury Mapping System (2016-2024). The primary exposure was COVID-19 policy period (pre-, during-, and post-pandemic). Annual crash rates per 100,000 population were calculated, and Poisson regression models estimated rate ratios (RRs) comparing COVID-19 periods, stratified by county, age, and sex, with subgroup interactions. Results:Of 56,019 crashes analyzed, 68.7% involved males and 58.5% Hispanic drivers. Alcohol-involved crash rates rose 19.98% after COVID onset, then declined to 114.63 per 100,000 in 2024 from 126.24 in 2016. Post-COVID rates were significantly higher among Hispanic youth (RR = 1.29; 95% confidence interval: 1.21-1.37), with the largest increase between ages 20 and 21. Conclusions:Alcohol-involved crashes among young drivers initially rose after COVID-19 and later steadily declined. However, Hispanic youth experienced a sustained rise compared to pre-COVID levels, indicating the need for ongoing monitoring and focused interventions.

OBJECTIVE:This study examined the change in alcohol crash fatalities among 21-24y/o drivers in Utah in comparison to its contiguous states before (2016) and after (2019) Utah enacted its.05g/dL blood alcohol concentration (BAC) per se law in 2018. METHODS:Data from the Fatality Analysis Reporting System (FARS) were used. A difference-in-differences (DID) analysis was conducted to compare pre-law (2016) with post-law (2019) crash fatalities across four BAC levels (≥.01, ≥.05, ≥.08, and ≥.15g/dL) between Utah and contiguous states for 21-24y/o drivers involved in alcohol-impaired driving fatal crashes. We also present 11-year trends (2013-23) in alcohol-related crash fatalities per 100 million vehicle miles traveled (VMT) for 21-24y/o drivers. RESULTS:Of the 820 21-24y/o drivers involved in fatal crashes in Utah and six contiguous states, 371 (45.2%) were alcohol involved. Across 2013-2023, Utah consistently showed lower alcohol-related crash fatality per 100 million VMT across BAC thresholds compared to contiguous states. Following implementation of the.05 BAC law, Utah experienced notable post-policy declines over the 2016-2019 period, particularly among highly impaired drivers. DID models showed statistically significant reductions in crash fatalities for drivers with BAC ≥ .15 in Utah compared to contiguous states (p < .001), while effects at lower BAC levels were directionally protective but not statistically significant. CONCLUSIONS:Utah's.05 BAC law was associated with a significant reduction in the most severe alcohol-impaired crashes among young adult drivers, supporting lower BAC limits as an effective population-level injury prevention strategy for this known vulnerable population.

BACKGROUND:This study examined the association between readiness to change and reductions in unhealthy alcohol use among Latino adults in the emergency department (ED) who used the Automated Bilingual Computerized Alcohol Screening Intervention (AB-CASI), a digital behavioral health intervention tool. METHODS:The study included 310 self-identified US Latino ED patients with unhealthy drinking. The primary independent variable was baseline readiness to reduce alcohol consumption. Outcomes included binge drinking episodes in the past 28 days and average weekly drinks, assessed at baseline and 1-, 6-, and 12-month follow-ups. Alcohol severity was measured via the Alcohol Use Disorders Identification Test scores, with gender and language preference (English vs Spanish) as covariates. Generalized linear mixed models in SAS accounted for within-subject variability across time points for analysis. RESULTS:Binge drinking ratios comparing those "more ready" to cut down to those "less ready" were 0.61 at 1 month [95% confidence interval (CI): 0.42, 0.90; P = .013], 0.46 at 6 months (95% CI: 0.31, 0.69; P < .0001), and 0.61 at 12 months (95% CI: 0.41, 0.89; P = .011). Weekly drinks ratios were 0.60 at 1 month (95% CI: 0.40, 0.90; P = .001), 0.45 at 6 months (95% CI: 0.29, 0.71; P < .0001), and 0.63 at 12 months (95% CI: 0.41, 0.97; P = .006). CONCLUSION:In the original AB-CASI clinical trial, Latino ED patients more ready to reduce alcohol intake showed significant decreases in drinking after the intervention. This highlights the importance of readiness-to-change models in alcohol interventions for vulnerable ED populations. AB-CASI's bilingual, culturally sensitive design effectively promotes behavioral health, supporting both English- and Spanish-speaking patients in reducing unhealthy drinking behaviors.

OBJECTIVE:The purpose of this study was to investigate factors contributing to the decline in the number of passengers riding with alcohol-impaired drivers involved in fatal crashes since 1982 and to examine the impact of simulated interventions on this group through 2050. METHOD:Historical data were obtained from the Fatality Analysis Reporting System. We applied linear regression to analyze changes in the average numbers of passengers per alcohol-impaired young driver involved in fatal crashes between 1982 and 2020 by age and sex. We also extended our existing system dynamics simulation model developed to examine driving-while-impaired (DWI) behaviors of U.S. male and female drivers ages 15 to 24 and explored riding-with-an-impaired-driver (RWI) behaviors and corresponding interventions. We conducted sensitivity analyses to examine the likely trajectories of alcohol-impaired drivers' passengers in fatal crashes across multiple scenarios through 2050. RESULTS:Our findings show that the decline in passengers of alcohol-impaired drivers in fatal crashes primarily stems from a decrease in the number of impaired drivers rather than a change in the average number of passengers per impaired driver. The simulation model replicated historical trends from 1982 to 2020, and the sensitivity analyses show that the policies reducing DWI trips also decrease RWI trips. CONCLUSIONS:Wide adoption of a comprehensive strategy combining increased enforcement, an alcohol truth campaign, the provision of alternative transportation, and the enactment of a new DWI restrictive law could significantly reduce the number of passengers in fatal crashes involving alcohol-impaired drivers while minimizing possible unintended consequences.

Alcohol-impaired driving is a formidable public health problem in the United States, claiming the lives of 37 individuals daily in alcohol-related crashes. Alcohol-impaired driving is affected by a multitude of interconnected factors, coupled with long delays between stakeholders’ actions and their impacts, which not only complicate policy-making but also increase the likelihood of unintended consequences. We developed a system dynamics simulation model of drinking and driving behaviors among adolescents and young adults. This was achieved through group model building sessions with a team of multidisciplinary subject matter experts, and a focused literature review. The model was calibrated with data series from multiple sources and replicated the historical trends for male and female individuals aged 15 to 24 from 1982 to 2020. We simulated the model under different scenarios to examine the impact of a wide range of interventions on alcohol-related crash fatalities. We found that interventions vary in terms of their effectiveness in reducing alcohol-related crash fatalities. In addition, although some interventions reduce alcohol-related crash fatalities, some may increase the number of drinkers who drive after drinking. Based on insights from simulation experiments, we combined three interventions and found that the combined strategy may reduce alcohol-related crash fatalities significantly without increasing the number of alcohol-impaired drivers on US roads. Nevertheless, related fatalities plateau over time despite the combined interventions, underscoring the need for new interventions for a sustained decline in alcohol-related crash deaths beyond a few decades. Finally, through model calibration we estimated time delays between actions and their consequences in the system which provide insights for policymakers and activists when designing strategies to reduce alcohol-related crash fatalities.

ObjectiveDistracted driving is a primary contributor to for motor vehicle crashes, the leading cause for injuries and fatalities for youth. Although attention and working memory clearly underlie driving abilities, few studies explore these functions on the brain-level under the cognitive load of driving. To understand the load driving has on auditory attention processing, we examined the differences in dynamic brain response to auditory stimuli during LOAD (while driving in a high-fidelity driving simulator) and No-LOAD conditions (seated in simulator, parked on the side of the road).MethodsTwenty-seven young adult drivers (18-27 y/o; 15 = women) completed a Selective Auditory Attention Task during both a LOAD (driving) and No-LOAD condition in a 1/2 cab miniSim (R) high-fidelity driving simulator. During the task, participants responded by pressing the volume control button on the steering wheel when a target tone was presented to a target ear. Electroencephalography-recorded event-related brain responses to the target tones were evaluated through alpha and theta oscillations for two response windows (early: 150-330ms; late: 350-540ms).ResultsDuring an early time window, we observed a significant interaction between attended/unattended and LOAD/No-LOAD theta power in the right frontal cortical region (F(1, 24)= 5.4, p=.03, partial eta 2=.18). During the later window, we observed a significant interaction between attended/unattended and LOAD/No-LOAD alpha response in the posterior cortical region (F(1, 24)=11.81, p=.002, partial eta 2=.15) and in the right temporal cortical region during the window (F(1, 24)=4.3, p=.05, partial eta 2=.33).ConclusionsOur data provide insight into the demand that driving has on cognitive faculties and how dual task engagement may draw resources away from driving. We suggest future research directly incorporate vehicle control abilities into study design to understand how brain-based measures relate to driving behaviors.

Purpose: The purpose of this study was to examine the association between individual-level mindfulness and a range of risky driving behaviors among U.S. adolescents. Methods: We conducted a survey of a nationally representative sample of 16–19-year-olds, recruited from the National Opinion Research Center AmeriSpeak panel, a probability-based sample. Participants completed the Mindful Attention Awareness Scale. Risky driving measures were adapted from the Youth Risk Behavior Survey. Spline regression analysis was performed to identify the threshold where mindfulness scores significantly changed driving behaviors. Results: After adjusting for age, gender, and race, adolescents reporting higher mindfulness scores were significantly less likely to engage on all risky driving behaviors and significantly less likely to have been involved in a crash. Spline regression analysis indicated that a mindfulness score of 75 corresponded to the minimum marginal probability change averaged across the outcomes of interest. Discussion: This paper describes a previously unknown association between mindfulness and risky driving in a vulnerable population which is at higher risk of injury and death from motor vehicle crashes. The strength of the associations across a range of behaviors suggests mindfulness could be a general protective factor for adolescents’ driving behaviors and suggests that mindfulness training may be a promising safety intervention for adolescents. A mindfulness score of 75 could be a potential target for mindfulness training interventions aiming to reduce risky driving behaviors and crashes among teenage drivers.Abbreviations: ADHD, Attention Deficit Hyperactivity Disorder; CI, Confidence Interval; MAAS, Mindful Attention Awareness Scale; NORC, University of Chicago’s National Opinion Research Center; YRBS, Youth Risk Behavior Survey.

OBJECTIVE:To contextually examine facilitators of young driver decisions to ride with an impaired driver (RWI) or drive while impaired (DWI). METHODS:Data were from the NIH's NEXT Generation Health Study (NEXT), a 7-year longitudinal nationally representative study with a U.S. probability cohort of 10th graders starting in 2009-2010. Using a multistage sequential explanatory mixed methods approach, we conducted latent class analysis (n = 2,783) to identify RWI/DWI trajectories from adolescence to young adulthood (Stage-1). We then conducted in-depth qualitative interviews with purposively sampled young adults (N = 105, 26.30 ± 0.43 y/o) from four identified RWI/DWI trajectory classes (Stage-2): 31 Abstainers (consistently low probability), 33 Escalators (low-to-high probability), 14 Decliners (high-to-low probability), and 27 Persisters (consistently high probability). In Stage-2, the qualitative interview guide was informed by Stage-1 findings and Ecodevelopmental Theory. Using directed content analysis, we applied inductive and deductive theory-grounded codes to interview transcripts. With data immersion, reflexivity, and team dialogue, we derived themes from the code, "Facilitators of RWI and/or DWI". Demographics and validated measures of resiliency, health-related quality of life, Timeline Follow Back for alcohol and marijuana, and recent engagement in RWI/DWI were collected during the interviews. RESULTS:Based on the interview transcripts, five themes emerged around RWI/DWI facilitators during and after high school: (1) beliefs about alcohol/drug effects; (2) trust of others; (3) trust of self; (4) parental disapproval; and (5) transportation factors. Participants who RWI confidently placed their trust in their assessment of the driver's impairment and their own in the context of close relationships. Those who DWI described desire to maintain simple/easy vehicle access while avoiding tickets/towing. The joint display of the quantitative and qualitative data is presented. CONCLUSIONS:Notable misperceptions exist about how alcohol/drugs impact driving in the RWI/DWI context, particularly regarding the subtle signs of impairment. Youth commonly relied on their own assessment of impairment before driving themselves or riding with a potentially impaired driver, sometimes to avoid parental disapproval. Some engage in RWI/DWI to avoid discord with parents. DWI may relate to needing easy/immediate vehicle access. Pragmatic remedy considerations could include educating youth and young drivers about impairment, enhancing safe public transportation, and expanding ride-share programing.

In 2021, there were 11.7 million licensed young drivers in the U.S. This is 1.5 million fewer young drivers compared to 2007. The phenomenon of delay in driving licensure among teens has notable implications for opportunities positioning them for life success when transitioning into emerging adulthood and in later life.

Introduction : Prior work has found incongruencies in injury information reported by crash and hospital records. However, no work has focused on child passengers. The objective of this study was to compare crash scene and hospital-reported injury information for crash-involved child passengers. This study also explored injury location and severity by child age and restraint type. Methods : Utilizing linked New Jersey data from 2017 through 2019, the authors identified crash-involved child passengers <13 years old and their injuries in crash and hospital reports. Then, they characterized the congruency of injury frequency, severity, and location, as well as the frequency of injuries by child age and restraint type. Analyses were conducted from December 2023 through February 2024. Results : Of 84,060 crash-involved child passengers, crash reports documented 7,858 (9%) children with at least “possible” injuries, while 2,577 (3%) had at least one injury in hospital events. Crash report and hospital data were incongruent for both body region of injury and injury severity. The proportion of children injured increased as children's ages increased and as restraint type progressed. Conclusions : Crash reports overestimated the number of injured child passengers and misrepresented injury severity and locations. Child restraint systems mitigated a child's injury risk. Importantly, injury information documented on crash reports currently informs the allocation of traffic safety resources. These results highlight the importance of improving these reports’ accuracy and underscore calls to link administrative datasets for public health efforts.

Purpose: Driving after drinking is a preventable threat to public health. We examined the prospective association of adolescent-reported parental monitoring knowledge (PMK) with recurrent driving after drinking in emerging adulthood. Methods: We analyzed six annual rounds (1-4, 6,11) of the National Longitudinal Survey of Youth 1997 with a sample of 5,261 participants. PMK variables were created to recategorize parental monitoring measures by age of the youth. Recurrent driving after drinking was measured in 2002 and 2007 and dichotomized. Unadjusted and adjusted binary logistic regressions analyzed the association of PMK at ages 14,15,16, and 17 with recurrent drinking after driving in 2002 (ages 18-23) and 2007 (ages 22-28). Adjusted models included age, sex, race, household income, and education. Results: Mother 's PMK from ages 14 to 17 was inversely associated with recurrent driving after drinking in 2002 (adjusted odds ratios [AORs]: 0.89 [ p = .003, age 14], 0.93 [marginal p = .062, age 15], 0.88 [ p = .0003, age 16], 0.88 [ p = .0003, age 17]). By 2007, the only signi ficant association between mother 's PMK and recurrent driving after drinking was for age 16 (AOR: 0.95, p = .017). For father 's PMK, signi ficant inverse associations were only found for ages 16 and 17 with 2002 recurrent driving after drinking (AORs: 0.93, p = .025 and .88, p = .0005) and age 15 (AOR: 0.95, p = .021) with 2007 recurrent driving after drinking. Discussion: Adolescent perceived PMK appears to offer protection against recurrent driving after drinking in emerging adulthood. This protective effect appears to wane as youth reach their midtwenties. (c) 2024 Society for Adolescent Health and Medicine. All rights reserved.

BACKGROUND:A recent study shows four trajectories of riding with an impaired driver (RWI) and driving while impaired (DWI) from adolescence to emerging adulthood. We examined prospective associations of adolescent RWI/DWI trajectory class with early adulthood RWI/DWI behavior. METHODS:Data were from the NEXT Generation Health Study (NEXT), a nationally representative longitudinal study (N = 2783) beginning with a 10th-grade cohort completing 7 annual assessment waves (W1-W7) between 2010 and 2016 and a later follow-up mixed methods study. Four RWI and DWI trajectories derived from a recently published latent class analysis study (RWI (last 12 months); DWI (last 30 days) dichotomized as ≥ once vs. none) were used: Abstainer, Escalator, Decliner, and Persister. In the follow-up examination, a purposive subsample (N = 105, 26.3 ± 0.5 y/o, Female 50.5%) of NEXT participants were selected by trajectory (31 Abstainers, 33 Escalators, 14 Decliners, and 27 Persisters) for in-depth interviews 4 years after NEXT. In interviews, self-reported RWI events (number of times) related to alcohol (Alc-RWI) or marijuana (MJ-RWI) use in the last 12 months, and DWI events (number of times) related to alcohol (Alc-DWI) & marijuana (MJ-DWI) use in January 2020 (pre-COVID pandemic) were collected using structured surveys. General linear models were used to examine associations of adolescents' RWI/DWI trajectories with early adulthood RWI/DWI behavior, controlling for sex, health status, education attainment, and work hours. RESULTS:The mean number (SD) of Alc-RWI and MJ-RWI events reported by Escalators (3.83(2.48), 2.43(2.77)) and Persisters (3.83(2.43), 3.57(2.54)) were higher (p≤0.05) than Abstainers (0.82(1.42), 0.77(2.04)) and Decliners (1.81 (2.69), 1.38 (2.04)). Similarly, Escalators (1.61 (2.28), 1.88(2.69)) and Persisters (1.96(2.08), 1.93(2.48)) reported more Alc-DWI and MJ-DWI events than Abstainers (0.18 (0.53), 0.42(1.38)) and Decliners (0.00 (0.00), 0.08(0.28)). Linear regression models indicated membership in Escalator and Persister classes compared to Abstainer class was associated (p≤0.01) with higher engagement in RWI/DWI in early adulthood. CONCLUSION:Adolescents with escalating and persistent high RWI/DWI may continue these health risking behaviors into their mid-twenties. Decliners during the transition maintained low RWI/DWI into their mid-twenties. Taken together, these findings suggest that earlier reduction may have long-term effects. Our findings can be used to inform the precision tailoring of prevention efforts aimed at effectively reducing alcohol/drug impairment crash injuries and related deaths among those in early adulthood.

Background: Although inequality in traumatic brain injury (TBI) by individual socioeconomic status (SES) exists, interventions to modify individual SES are difficult. However, as interventions for area-based SES can affect the individual SES, monitoring or public health intervention can be planned. We analyzed the effect of area-based SES on hospitalization for TBI and revealed yearly inequality trends to provide a basis for health intervention.Methods: We included patients who were hospitalized due to intracranial injuries (ICIs) between 2008 and 2015 as a measure of severe TBI with data provided by the Korea National Hospital Discharge Survey. Area-based SES was synthesized using the 2010 census data. We assessed inequalities in ICI-related hospitalization rates using the relative index of inequality and the slope index of inequality for the periods 2008-2009, 2010-2011, 2012-2013, and 2014-2015. We analyzed the trends of these indices for the observation period by age and sex.Results: The overall relative indices of inequality for each 2-year period were 1.82 (95% confidence interval, 1.5-2.3), 1.97 (1.6-2.5), 2.01 (1.6-2.5), and 2.01 (1.6-2.5), respectively. The overall slope indices of inequality in each period were 38.74 (23.5-54.0), 36.75 (21.7-51.8), 35.65 (20.7-50.6), and 43.11 (27.6-58.6), respectively. The relative indices of inequality showed a linear trend for men (P = 0.006), which was most evident in the >= 65-year age group.Conclusion: Inequality in hospitalization for ICIs by area-based SES tended to increase during the observation period. Practical preventive interventions and input in healthcare resources for populations with low area-based SES are likely needed.