Correlates of axonal content in healthy adult span: Age, sex, myelin, and metabolic health.

As the emerging treatments that target grey matter pathology in Alzheimer's Disease have limited effectiveness, there is a critical need to identify new neural targets for treatments. White matter's (WM) metabolic vulnerability makes it a promising candidate for new interventions. This study examined the age and sex differences in estimates of axonal content, as well the associations of with highly prevalent modifiable health risk factors such as metabolic syndrome and adiposity. We estimated intra-axonal volume fraction (ICVF) using the Neurite Orientation Dispersion and Density Imaging (NODDI) in a sample of 89 cognitively and neurologically healthy adults (20-79 years). We showed that ICVF correlated positively with age and estimates of myelin content. The ICVF was also lower in women than men, across all ages, which difference was accounted for by intracranial volume. Finally, we found no association of metabolic risk or adiposity scores with the current estimates of ICVF. In addition, the previously observed adiposity-myelin associations (Burzynska et al., 2023) were independent of ICVF. Although our findings confirm the vulnerability of axons to aging, they suggest that metabolic dysfunction may selectively affect myelin content, at least in cognitively and neurologically healthy adults with low metabolic risk, and when using the specific MRI techniques. Future studies need to revisit our findings using larger samples and different MRI approaches, and identify modifiable factors that accelerate axonal deterioration as well as mechanisms linking peripheral metabolism with the health of myelin.

A hidden Markov modeling approach combining objective measure of activity and subjective measure of self-reported sleep to estimate the sleep-wake cycle.

Characterizing the sleep-wake cycle in adolescents is an important prerequisite to better understand the association of abnormal sleep patterns with subsequent clinical and behavioral outcomes. The aim of this research was to develop hidden Markov models (HMM) that incorporate both objective (actigraphy) and subjective (sleep log) measures to estimate the sleep-wake cycle using data from the NEXT longitudinal study, a large population-based cohort study. The model was estimated with a negative binomial distribution for the activity counts (1-minute epochs) to account for overdispersion relative to a Poisson process. Furthermore, self-reported measures were dichotomized (for each one-minute interval) and subject to misclassification. We assumed that the unobserved sleep-wake cycle follows a two-state Markov chain with transitional probabilities varying according to a circadian rhythm. Maximum-likelihood estimation using a backward-forward algorithm was applied to fit the longitudinal data on a subject by subject basis. The algorithm was used to reconstruct the sleep-wake cycle from sequences of self-reported sleep and activity data. Furthermore, we conduct simulations to examine the properties of this approach under different observational patterns including both complete and partially observed measurements on each individual.

Shared and distinct parental influences on teen impaired driving in rural and suburban contexts: A mixed methods study of young drivers.

OBJECTIVE: To explore shared and distinct parental influences on rural and suburban adolescents' riding with an impaired driver (RWI) and driving while impaired (DWI) behaviors during high school. METHODS: Participants in the NEXT Generation Health Study (NEXT) were classified into four RWI/DWI trajectory classes (i.e., Abstainer, Escalator, Decliner, Persister) which described patterns of RWI/DWI from high school to emerging adulthood. A follow-up, in-depth, qualitative interview was conducted with a purposeful selection of participants from each trajectory class between March and September 2020. Guided by Ecodevelopmental Theory, the interview included questions which explored parent-teen influences on driving and RWI/DWI. RESULTS: Imposition of a curfew was a shared parental influence in rural and suburban contexts. Unique to the rural context, parent modeling of RWI/DWI was described as normative and occurring since childhood. CONCLUSIONS: Prevention interventions targeting parent RWI/DWI may reduce their children's risk for RWI/DWI among rural adolescents.

Longitudinal perspectives of riding with a cannabis-impaired driver.

OBJECTIVE: To explore decisions and perceptions of engaging in riding with a cannabis-impaired driver (RWI) during high school and young adulthood to build context around RWI-cannabis events. METHODS: Participants were sampled from the NEXT Generation Health Study (NEXT), a 7-year national cohort study of adolescent health behaviors. Four RWI and driving while impaired (DWI) trajectories classes (i.e., Abstainer, Escalator, Decliner, Persister) were previously derived.A theoretical model based on ecological systems theory guidedin-depth semi-structured interviews to includecomplex, social-developmental and environmental multi-level factors affectingpersonal experiences with RWI-cannabis during high school, after high school, and during young adulthood. Participants (n = 105) were purposively selected from each trajectory class for follow-up, in-depth, qualitative interviews. All interviews were conducted via Zoom between March and September 2020. RESULTS: Two unique themes emerged as facilitators of RWI-cannabis: "Driving Context" and "Trust in Driver". "Legal Concerns" and "Concerns with Safety Emerge with Age" were themes that described deterrents to RWI-cannabis. CONCLUSIONS: Current data suggest that youth RWI-cannabis occurs during daytime hours and while driving to everyday activities. Youth report legal concerns as a potential deterrent to RWI-cannabis in high school and concerns for safety emerge in young adulthood. The multifaceted nature of RWI-cannabis among young drivers identifies potential complexities for programming designed to reduce RWI/DWI-cannabis.

Motivational Profile as a Predictor of Physical Activity Among US Adults During the Early Months of the COVID-19 Pandemic: A Daily Diary Study.

This study used a daily diary approach to examine associations between day-level physical activity (PA) behavior, PA-specific motivational profile, and days since the COVID-19 national emergency declaration during the early months (April-June 2020) of the pandemic. A total of 468 US adults (Mage = 34.8 y, 79% female) participated in a 28-day smartphone-based daily diary study assessing PA. A baseline survey assessed PA and motivation for PA using the Behavioral Regulation in Exercise Questionnaire. Multilevel linear regression models examined the main effects and interactions of motivational profile and time (days since the US March 13, 2020, COVID-19 national emergency declaration) on daily PA minutes. Latent profile analysis identified 4 distinct motivational profiles for PA among this sample: profile 1: high amotivation (n = 100, 21%); profile 2: low controlled motivation (n = 55, 12%); profile 3: high external regulation (n = 47, 10%); and profile 4: moderate autonomous motivation (n = 266, 57%). After controlling for baseline PA, there were significant interactions between profile and time on daily PA (-0.21, P < .01). Profile 2 showed greater decreases in daily PA minutes over time than profile 1 (b = -0.29, P < .01). Profiles 3 and 4 did not indicate significant decreases in PA compared with profile 1 (b = 0.14, P = .31 and b = -0.16, P = .05, respectively). Contrary to previous research, individuals with lower controlled or moderate autonomous motivation demonstrated the largest decreases in PA over time, whereas individuals with higher amotivation or external regulation demonstrated smaller decreases over time. These findings suggest that external motivation may have provided short-term protection against declines in PA observed during early months of the COVID-19 pandemic.

The combined effect of motivational interviewing and wearable fitness trackers on motivation and physical activity in inactive adults: A randomized controlled trial.

Despite overwhelming adoption of wearable fitness trackers (WFT), it is unclear if they affect physical activity (PA) engagement or PA motivation. We hypothesized that combining a WFT with an effective intervention, motivational interviewing (MI), would positively influence both motivation and PA. A 12-week randomized controlled trial was conducted in 40 adults who did not meet PA recommendations. The four conditions were: a PA education (Educational control, n = 10), a WFT (WFT, n = 10), bi-weekly MI sessions (MI, n = 10), or both interventions (WFT+, n = 10). Motivation and PA were measured through an online survey and actigraphy pre- and post-intervention. Both the WFT+ and MI groups improved autonomous forms and decreased controlled forms of motivation. They also had higher basic psychological needs scores when compared to the Education group post-intervention. We detected no changes in PA. High autonomous motivation at baseline predicted higher post-intervention PA in the WFT+ group but predicted lower post-intervention PA in the WFT group. Results suggests that MI alone or with a WFT can improve basic psychological needs and autonomous forms of motivation for PA, but not PA participation. Individual differences in motivation at baseline may moderate the effect of a WFT on PA. This study was registered at clinicaltrials.gov (NCT490014).

Effects of a community gardening intervention on diet, physical activity, and anthropometry outcomes in the USA (CAPS): an observer-blind, randomised controlled trial.

BACKGROUND: Unhealthy diet, physical inactivity, and social disconnection are important modifiable risk factors for non-communicable and other chronic diseases, which might be alleviated through nature-based community interventions. We tested whether a community gardening intervention could reduce these common health risks in an adult population that is diverse in terms of age, ethnicity, and socioeconomic status. METHODS: In this observer-blind, randomised, controlled trial, we recruited individuals who were on Denver Urban Garden waiting lists for community gardens in Denver and Aurora (CO, USA), aged 18 years or older, and had not gardened in the past 2 years. Participants were randomly assigned (1:1), using a randomised block design in block sizes of two, four, or six, to receive a community garden plot (intervention group) or remain on a waiting list and not garden (control group). Researchers were masked to group allocation. Primary outcomes were diet, physical activity, and anthropometry; secondary outcomes were perceived stress and anxiety. During spring (April to early June, before randomisation; timepoint 1 [T1]), autumn (late August to October; timepoint 2 [T2]), and winter (January to March, after the intervention; timepoint 3 [T3]), participants completed three diet recalls, 7-day accelerometry, surveys, and anthropometry. Analyses were done using the intention-to-treat principle (ie, including all participants randomly assigned to groups, and assessed as randomised). We used mixed models to test time-by-intervention hypotheses at an α level of 0·04, with T2 and T3 intervention effects at an α level of 0·005 (99·5% CI). Due to potential effects of the COVID-19 pandemic on outcomes, we excluded all participant data collected after Feb 1, 2020. This study is registered with ClinicalTrials.gov, NCT03089177, and data collection is now complete. FINDINGS: Between Jan 1, 2017, and June 15, 2019, 493 adults were screened and 291 completed baseline measures and were randomly assigned to the intervention (n=145) or control (n=146) groups. Mean age was 41·5 years (SD 13·5), 238 (82%) of 291 participants were female, 52 (18%) were male, 99 (34%) identified as Hispanic, and 191 (66%) identified as non-Hispanic. 237 (81%) completed measurements before the beginning of the COVID-19 pandemic. One (<1%) participant in the intervention group had an adverse allergic event in the garden. Significant time-by-intervention effects were observed for fibre intake (p=0·034), with mean between-group difference (intervention minus control) at T2 of 1·41 g per day (99·5% CI -2·09 to 4·92), and for moderate-to-vigorous physical activity (p=0·012), with mean between-group difference of 5·80 min per day (99·5% CI -4·44 to 16·05). We found no significant time-by-intervention interactions for combined fruit and vegetable intake, Healthy Eating Index (measured using Healthy Eating Index-2010), sedentary time, BMI, and waist circumference (all p>0·04). Difference score models showed greater reductions between T1 and T2 in perceived stress and anxiety among participants in the intervention group than among those in the control group. INTERPRETATION: Community gardening can provide a nature-based solution, accessible to a diverse population including new gardeners, to improve wellbeing and important behavioural risk factors for non-communicable and chronic diseases. FUNDING: American Cancer Society, University of Colorado Cancer Centre, University of Colorado Boulder, National Institutes of Health, US Department of Agriculture National Institute of Food and Agriculture, Michigan AgBioResearch Hatch projects.

Metabolic syndrome and adiposity: Risk factors for decreased myelin in cognitively healthy adults.

Metabolic syndrome (MetS) is a cluster of conditions that affects ∼25% of the global population, including excess adiposity, hyperglycemia, dyslipidemia, and elevated blood pressure. MetS is one of major risk factors not only for chronic diseases, but also for dementia and cognitive dysfunction, although the underlying mechanisms remain poorly understood. White matter is of particular interest in the context of MetS due to the metabolic vulnerability of myelin maintenance, and the accumulating evidence for the importance of the white matter in the pathophysiology of dementia. Therefore, we investigated the associations of MetS risk score and adiposity (combined body mass index and waist circumference) with myelin water fraction measured with myelin water imaging. In 90 cognitively and neurologically healthy adults (20-79 years), we found that both high MetS risk score and adiposity were correlated with lower myelin water fraction in late-myelinating prefrontal and associative fibers, controlling for age, sex, race, ethnicity, education and income. Our findings call for randomized clinical trials to establish causality between MetS, adiposity, and myelin content, and to explore the potential of weight loss and visceral adiposity reduction as means to support maintenance of myelin integrity throughout adulthood, which could open new avenues for prevention or treatment of cognitive decline and dementia.

Trends and characteristics of Tai Chi and Qi Gong use among U.S. adults: Results from the 2007-2017 National Health Interview Survey.

OBJECTIVE: To provide updated information about the prevalence, patterns, and predicting factors of Tai Chi and Qigong (TCQ) use among U.S. adults to better inform the future directions of TCQ application and research. METHODS: Using 2007, 2012, and 2017 National Health Interview Survey, we examined the trends and characteristics of TCQ use by descriptive analysis, Wald F chi-square test, and multivariable logistic regression models among U.S. adults (n = 85,360), adjusting for the complex sampling design. RESULTS: The prevalence use of TCQ among U.S. adults use was 1.17% in 2007, 1.27% in 2012, and 1.70% in 2017, which presents a 64% increase from 2007 to 2017 (p < 0.0001). Correlates of TCQ use are older adults (≥ 65 years old), Asians, having higher education levels, having lower income, and being more physically active (p < 0.001). The greater prevalence of TCQ use in 2017 than in 2012 occurred in some vulnerable demographic subgroups, including older adults, people with income less than $35,000/year, and those who were physically inactive. Those with delayed access to the conventional medical care system (e.g., had difficulty getting through on phone; couldn't get an appointment soon enough; had to wait too long to see doctor;)were also more likely to use TCQ (p < 0.001). CONCLUSIONS: The use of TCQ has significantly increased among U.S. adults from 2007 to 2017. Given that the greatest increases in use of TCQ were among older adults, females, low-income individuals, and people who were physically inactive, TCQ may serve as age-appropriate, cost-effective, mind-body exercises for these groups of populations to help ameliorate health disparities.

Comparisons of physical activity, sitting time, and substance use among college students before and during the COVID-19 pandemic.

Objective: To compare physical activity (PA), sitting time, and substance use pre-COVID-19 and during COVID-19 pandemic among US college students. Participants: 484 students from a large Western university (20.6 ± 1.4 years, 80.0% female) were recruited. Methods: Self-reported online surveys were completed in June-August 2020. T-tests and non-parametric analyses were conducted for continuous and ordinal variables respectively. Results: Vigorous PA, moderate PA, and light PA decreased significantly by 32%, 27%, and 21% and sitting time increased significantly by 49% from pre-COVID-19 to during COVID-19 pandemic. Wine consumption was less during COVID-19 than pre-COVID-19 among female, non-first-generation, and White students. Sleep aids use was more frequent during COVID-19 than pre-COVID-19 pandemic among non-first-generation and White students. Conclusion: COVID-19 pandemic may influence college students' health behaviors including physical activity patterns, sitting time, and substance use. Effective health promotion and coping strategies should be widely available to college students during times of change and uncertainty.

What determines the success of states in reducing alcohol related crash fatalities? A longitudinal analysis of alcohol related crashes in the U.S. from 1985 to 2019.

In the United States, nearly 28 people die in alcohol-related motor vehicle crashes every day (1 fatality every 52 min). Over decades, states have enacted multiple laws to reduce such fatalities. From 1982 to 2019, the proportion of drivers in fatal crashes with a blood alcohol concentration (BAC) above 0.01 g/dl declined from 41% to 22%. States vary in terms of their success in reducing alcohol-related crash fatalities. The purpose of this study was to examine factors associated with changes in fatalities related to alcohol-impaired driving at the state level. We created a panel dataset of 50 states from 1985 to 2019 by merging different data sources and used fixed-effect linear regression models to analyze the data. Our two outcome variables were the ratio of drivers in fatal crashes with BAC ≥ 0.01 g/dl to those with BAC = 0.00, and the ratio of those with BAC ≥ 0.08 g/dl to those with BAC < 0.08 g/dl. Our independent variables included four laws (0.08 g/dl BAC per se law, administrative license revocation law, minimum legal drinking age law, and zero tolerance law), number of arrests due to impaired driving, alcohol consumption per capita, unemployment rate, and vehicle miles traveled. We found that the 0.08 g/dl per se law was significantly associated with lower alcohol-related crash fatalities while alcohol consumption per capita was significantly and positively associated with crash-related fatalities. Arrests due to driving under the influence (DUI) and crash fatalities were nonlinearly correlated. In addition, interaction of DUI arrests and two laws (0.08 g/dl BAC per se law, and zero tolerance) were significantly associated with lower crash-related fatalities. Our findings suggest that states which have more restrictive laws and enforce them are more likely to significantly reduce alcohol-related crash fatalities.

Association of perceived stress with changes in physical activity and sitting time before and during COVID-19 pandemic among college students.

OBJECTIVE: To examine the association of perceived stress [PS] with physical activity [PA] and sitting time [ST], before and during COVID-19 among US college students. Participants: 592 students from a large Western university (19.08 ± 4.62 years, 76.69% female, 79.39% White) were recruited. Methods: Self-reported online survey was completed in June-December 2020. Analysis included paired T-tests for continuous variables, Pearson Correlation the relationship between PSS, PA, and sitting time before and during COVID-19, and linear mixed models examined the association of outcome variables with PSS, time, and PSS × time. Results. Vigorous, moderate, and light PA decreased by 40%, 35% and 19%, sitting time increased by 52%, and PSS increase by 42% from before to during COVID-19. Conclusions: The perceived stress during COVID-19 may have influenced physical activity and sitting time. Effective health promotion programs and coping strategies are needed to protect college students as campuses reopen during COVID.

Trajectories and Outcomes of Adolescents that Ride With an Impaired Driver/Drive While Impaired.

Introduction: For young drivers, independent transportation has been noted to offer them opportunities that can be beneficial as they enter early adulthood. However, those that choose to engage in riding with an impaired driver (RWI) and drive while impaired (DWI) over time can face negative consequences reducing such opportunities. This study examined the prospective association of identified longitudinal trajectory classes among adolescents that RWI and DWI with their later health, education, and employment in emerging adulthood. Methods: We analyzed all seven annual assessments (Waves, W1-W7) of the NEXT Generation Health Study, a nationally representative longitudinal study starting with 10th grade (2009-2010 school year). Using all seven waves, trajectory classes were identified by latent class analysis with RWI (last 12 months) and DWI (last 30 days) dichotomized as ≥once = 1 vs. none = 0. Results: Four RWI trajectories and four DWI trajectories were identified: abstainer, escalator, decliner, and persister. For RWI and DWI trajectories respectively, 45.0% (N=647) and 76.2% (N=1,657) were abstainers, 15.6% (N=226) and 14.2% (N=337) were escalators, 25.0% (N=352) and 5.4% (N=99) were decliners, and 14.4% (N=197) and 3.8% (N=83) persisters. RWI trajectories were associated with W7 health status (χ2=13,20, p<.01) and education attainment (χ2=18.37, p<.01). Adolescent RWI abstainers reported better later health status than RWI escalators, decliners, and persisters; and decliners reported less favorable later education attainment than abstainers, escalators, and persisters. DWI trajectories showed no association with health status, education attainment, or employment. Conclusions: Our findings suggest the importance of later health outcomes of adolescent RWI. The mixed findings point to the need for more detailed understanding of contextual and time-dependent trajectory outcomes among adolescents engaging in RWI and DWI.

Is Delayed Driving Licensure Associated With Emerging Adult Health, Education, and Employment?

PURPOSE: Driving licensure remains a major developmental milestone for adolescents as they become more independent to access important health, education, and employment opportunities. Today, more teens are delaying driving licensure than before. We investigated associations of delayed licensure with health, education, and employment 4 years after high school. METHODS: We analyzed data from all seven annual assessments (W1-W7) of the NEXT Generation Health Study, a nationally representative cohort survey starting at 10th grade (W1, 2009-2010). The independent variable was delaying driving licensure (DDL [delaying ≥1 year] vs. No-DDL), defined as participants receiving driver licensure ≥1 year after the initial legal eligibility time until W7. Outcome variables were self-reported health, education, and employment at W7. Covariates included sex, race/ethnicity, family affluence, parental education, and urbanicity. Multinomial logistic regressions were conducted considering complex survey features. RESULTS: No-DDL versus DDL was associated with a higher likelihood of (1) excellent (adjusted odds ratio [AOR] = 2.06, p < .001), good (AOR = 1.74, p < .001), and fair (AOR = 1.34, p = .008) health compared with poor health; (2) completing a 4-year college or graduate school [AOR = 2.71, p < .001] and tech/community college [AOR = 1.92, p = .004] compared with high school or less; and (3) working ≥30 hours/week (AOR = 7.63, p = .011) and working <30 hours/week (AOR = 1.54, p = .016) compared with not working. DISCUSSION: Among emerging adults, no delay in driving licensure was associated with better self-reported health, higher education, and more working hours four years after leaving high school. Although earlier driving licensure increases driving exposure and risk, avoiding DDL appears to provide advantages for health, education, and employment during early adulthood.

Longitudinal associations of emerging adults' drinking trajectories with their behavior, health, education and work outcomes 1, 4, and 9 years later.

BACKGROUND: To characterize emerging adults' drinking trajectories and their prospective association with later behavior, health, education, and work outcomes in later young adulthood. METHODS: This study used a selected cohort (N = 1622) from rounds 3-10 (aged 18-25), 11 (aged 26), 14 (aged 29), and 17 (aged 34) of the US National Longitudinal Survey of Youth 1997. Latent class growth modeling was used to identify trajectories of drinking (days ≥1 drink in the last 30 days) during emerging adulthood (aged 18-25) using data from rounds 3-10. Multinomial and linear regressions compared identified trajectory classes to outcomes measured 1, 4, and 9 years later. Covariates included sex, race, and urbanicity. RESULTS: Six drinking trajectories were identified: Abstainers (28.42%), Moderate Increasers (24.78%), Light Experimenters (11.96%), Heavy Experimenters (9.86%), Escalators (17.26%), and Heavy Users (7.71%). Compared to abstainers, emerging adults in other classes had significantly (p < .05 to.001) higher odds of binge drinking, smoking, and marijuana use at later rounds. Compared to abstainers, escalators had significantly higher education and income later. No significant difference in physical or mental health was found. CONCLUSION: Drinking behaviors formed during emerging adulthood continue into later lifetime periods in adulthood. The experimenters shifted their drinking behaviors to greater smoking and marijuana use, while heavy users supplemented their drinking behavior. Interventions in emerging adulthood (particularly ages 19-21), the period when individuals are becoming more independent but malleable, may mitigate adverse effects of alcohol overuse and improve later life behaviors and career outcomes.

Mapping the complex causal mechanisms of drinking and driving behaviors among adolescents and young adults.

BACKGROUND: The proportion of motor vehicle crash fatalities involving alcohol-impaired drivers declined substantially between 1982 and 1997, but progress stopped after 1997. The systemic complexity of alcohol-impaired driving contributes to the persistence of this problem. This study aims to identify and map key feedback mechanisms that affect alcohol-impaired driving among adolescents and young adults in the U.S. METHODS: We apply the system dynamics approach to the problem of alcohol-impaired driving and bring a feedback perspective for understanding drivers and inhibitors of the problem. The causal loop diagram (i.e., map of dynamic hypotheses about the structure of the system producing observed behaviors over time) developed in this study is based on the output of two group model building sessions conducted with multidisciplinary subject-matter experts bolstered with extensive literature review. RESULTS: The causal loop diagram depicts diverse influences on youth impaired driving including parents, peers, policies, law enforcement, and the alcohol industry. Embedded in these feedback loops are the physical flow of youth between the categories of abstainers, drinkers who do not drive after drinking, and drinkers who drive after drinking. We identify key inertial factors, discuss how delay and feedback processes affect observed behaviors over time, and suggest strategies to reduce youth impaired driving. CONCLUSION: This review presents the first causal loop diagram of alcohol-impaired driving among adolescents and it is a vital first step toward quantitative simulation modeling of the problem. Through continued research, this model could provide a powerful tool for understanding the systemic complexity of impaired driving among adolescents, and identifying effective prevention practices and policies to reduce youth impaired driving.

A study of self-reported personal cannabis use and state legal status and associations with engagement in and perceptions of cannabis-impaired driving.

Objective: The objectives of the current study were to (1) characterize predictors of perceived risk of driving within 2 h of cannabis use and driving after cannabis use in a sample of adults who have used cannabis in the past year and (2) determine whether the influence of these predictors vary by state legalizations status.Methods: Data for this study were from online surveys. Study participants from Colorado, Iowa, and Illinois were included if they reported being between 25 and 40 years old and had a history of cannabis use. Outcome variables included (1) days of cannabis use per month, (2) reported driving within 2 h of cannabis use (vs. not driving within 2 h as reference), (3) proportion of driving after cannabis use days per month (days of driving a car within 2 h of cannabis use per month/days of cannabis use per month), and (4) perception of safety of driving after cannabis use. Potential predictors included age of first use of cannabis, gender, education status, and state of residence. The SAS GLMSELECT Procedure was used for the analysis.Results: Increased age of first use of cannabis was associated with decreased days of cannabis use per month (B = -0.51 days/month per year), a reduction in the proportion of driving after cannabis use days per month (B = -0.02 per month), and decreased perception of safety of driving after cannabis use (B = -0.06 per year). Female gender was also associated with less use (B = -2.3 days per month), a lower proportion of driving following use (B = -0.06 days driving/days used), and decreased perception of safety (B = -0.29). In addition, residents of Colorado reported using the most days, had the highest likelihood of driving within 2 h of use, and had the most positive perceptions of being able to safely drive after cannabis use.Conclusions: The delay in onset of cannabis use may mitigate its use among adults and driving after cannabis use. This has important implications for driver safety. Intervention programs for reducing cannabis's effects on driving should focus on individuals with early onset of use, male drivers, and drivers in states where cannabis for adult recreational use is legalized.

Alcohol-related deaths among young passengers: An analysis of national alcohol-related fatal crashes.

INTRODUCTION: There is consensus that riding with an impaired driver (RWI) constitutes a major threat to public health. The aim of this study was to characterize the factors contributing to the motor-vehicle deaths of 15-20 year-old (y/o) passengers that RWI with a peer. METHOD: Secondary analyses of the 2010-2018 Fatality Analysis Reporting System. 5,673 passengers aged 15-20 y/o killed while riding in passenger cars with a driver aged 21 or older, 3,542 of these drivers also aged 15-20 y/o. Analyses were conducted between October 2019 and December 2020. RESULTS: Sixty-three percent of the young passengers were killed while riding with a driver 15-20 y/o. Of these drivers, 26.8% had a blood alcohol concentration (BAC) >0.00 g/dL and 77.1% had a BAC ≥0.08 g/dL. Compared with those occurring during the day on weekdays, fatalities of young passengers who RWI with a peer driver with a BAC ≥ 0.08 g/dL often occurred on weekend nights (OR = 8.2) and weekday nights (OR = 5.2), and when the passenger and driver were both male (OR = 1.8). Race/ethnicity was not a significant contributor to RWI fatalities. CONCLUSIONS: Most 15-20 y/o RWI fatalities occurred on weekends, at night, when the driver was a young peer with a high BAC, and the passenger and driver were male. The high prevalence of fatalities in these high-risk situations suggests that young driver-passenger dynamics may contribute to alcohol-related fatalities. Practical Applications: To curb RWI fatalities among underage passengers, countermeasures should focus not only on underage drinking drivers and riders, but also on drinking drivers of all ages. Prevention should increase focus on situations in which both the young passenger and young driver are males.

Simulated and self-reported driving among young adults with and without prenatal cocaine exposure.

Objective: This exploratory study aimed to examine associations between executive function and simulated and self-reported driving behavior among young adults with and without a history of prenatal cocaine exposure (PCE).Methods: Young adult drivers with PCE (n = 38) and with no drug exposure (NDE; n = 25) were recruited from an ongoing longitudinal birth cohort study assessing effects of PCE on development (Mean age = 23.7; 60.3% male; 61.9% with a valid U.S. driver's license, 38.1% report independent driving without a license). Participants completed executive function tasks (i.e., the Stop Signal Task and Groton Maze Learning Task) and self-reported driving measures (i.e., Checkpoints Risky Driving Scale (C-RDS)) outside the cab. Average stop signal reaction time(s) measured inhibitory control, number of exploratory errors measured visuo-spatial working memory, and the total C-RDS score measured self-reported risky driving. Participants completed a high-fidelity driving simulation scenario in a miniSim™ ½ cab National Advanced Driving Simulator (NADS) that yielded indicators of driving performance shown in previous research to correlate with inhibitory control (e.g., average speed, standard deviation lane position (SDLP)) and working memory (minimum headway time, lane departures). Multivariate linear regression models tested whether PCE status, licensure status and executive function measures were associated with simulated driving measures or C-RDS, controlling for sex.Results: Multivariate regression models demonstrated inhibitory control, working memory and PCE group status was not significantly associated with driving outcomes. Licensure was significantly associated with total lane departures (ß = -0.66, SE = 0.19; p < 0.01) and C-RDS (ß = 5.86, SE = 1.4; p ≤ 0.001).Conclusions: This exploratory study suggests that young adults with PCE have similar neurocognitive performance and driving behaviors as their non-drug exposed (NDE) peers. These findings add to the growing literature demonstrating that the effect of PCE on cognitive functions in childhood may not persist to young adulthood. Further research with similar groups of young drivers in a naturalistic driving context (i.e., instrumented vehicles) is needed to more definitively translate and confirm our findings.