Age group differences in collision risk

Impacts of medical and non-medical cannabis on the health of older adults: Findings from a scoping review of the literature

BACKGROUND

Cannabis legalization has enabled increased consumption in older adults. Age-related mental, physical, and physiological changes may lead to differences in effects of cannabis in older adults compared to younger individuals.

OBJECTIVE

To perform a scoping review to map the evidence regarding the health effects of cannabis use for medical and non-medical purposes in older adults.

METHODS

Electronic databases (MEDLINE, Embase, PsycINFO, Cochrane Library) were searched for systematic reviews (SRs), randomized controlled trials (RCTs) and non-randomized/observational studies (NRSs) assessing the health effects and associations of cannabis use (medical or non-medical) in adults ≥ 50 years of age. Included studies met age-related inclusion criteria or involved a priori identified health conditions common among older adults. Records were screened using a liberal accelerated approach and data charting was performed independently by two reviewers. Descriptive summaries, structured tables, effect direction plots and bubble plots were used to synthesize study findings.

FINDINGS

From 31,393 citations, 133 publications describing 134 unique studies (26 SRs, 36 RCTs, 72 NRSs) were included. Medical cannabis had inconsistent therapeutic effects in specific patient conditions (e.g., end-stage cancer, dementia), with a number of studies suggesting possible benefits while others found no benefit. For medical cannabis, harmful associations outnumbered beneficial, and RCTs reported more negative effects than NRSs. Cannabis use was associated with greater frequencies of depression, anxiety, cognitive impairment, substance use and problematic substance use, accidents/injuries, and acute healthcare use. Studies often were small, did not consistently assess harms, and did not adjust for confounding.

DISCUSSION

The effects of medical cannabis are inconsistent within specific patient conditions. For older adults, generally, the available evidence suggests cannabis use may be associated with greater frequencies of mental health issues, substance use, and acute healthcare use, and the benefit-to-risk ratio is unclear. Studies with a balanced assessment of benefits and harms may guide appropriate public health messaging to balance the marketing pressures of cannabis to older adults.

Overestimation of self-reported driving exposure: Results from the SHRP2 Naturalistic Driving Study

OBJECTIVES

The accuracy of self-reported driving exposure has questioned the validity of using self-reported mileage to inform research questions. Studies examining the accuracy of self-reported driving exposure compared to objective measures find low validity, with drivers overestimating and underestimating driving distance. The aims of the current study were to (1) examine the discrepancy between self-reported annual mileage and driving exposure the following year and (2) investigate whether these differences depended on age and annual mileage.

METHODS

Two estimates of drivers' self-reported annual mileage collected during vehicle installation (obtained via prestudy questionnaires) and approximated annual mileage driven (based upon Global Positioning System data) were acquired from 3,323 participants who participated in the Strategic Highway Research Program 2 (SHRP2) Naturalistic Driving Study.

RESULTS

A Wilcoxon signed rank test showed that there was a significant difference between self-reported and annual driving exposure during participation in SHRP 2, with the majority of self-reported responses overestimating annual mileage the following year, irrespective of whether an ordinal or ratio variable was examined. Over 15% of participants provided self-reported responses with over 100% deviation, which were exclusive to participants underestimating annual mileage. Further, deviations in reporting differed between participants who had low, medium, and high exposure, as well as between participants in different age groups.

CONCLUSIONS

These findings indicate that although self-reported annual mileage is heavily relied on for research, such estimates of driving distance may be an overestimate of current or future mileage and can influence the validity of prior research that has utilized estimates of driving exposure.

The prevalence and correlates of texting while driving among a population-based sample of Ontario students

OBJECTIVE

Texting while driving (TWD) has a deleterious impact on driving performance and may pose a significant challenge to traffic safety. This challenge may be particularly relevant for young and inexperienced drivers. This study examined the prevalence and risk factors of writing text messages or emails while driving during the past 12 months.

METHOD

This study analyzed a subpopulation of 1,133 licensed students 16 years of age or older from the 2013 Ontario Student Drug Use Survey (OSDUHS), a population-based survey of students in Ontario, Canada.

RESULTS

Our results indicate that 36% of licensed drivers reported writing a text message while driving during the past 12 months; of those who did, 56% reported doing so 4 or more times. Graduated licensing was the strongest factor predicting TWD. Compared to students with the more restrictive G1 license, students with a G2 or full license were 9.4 times more likely to report TWD after controlling for the effect of all other factors. Older students, white students, and students attending school in urban centers were more likely to report TWD, and the amount of time spent on social media sites, being a passenger with a driver using substances, and past-year collisions were also significantly associated with TWD. Gender differences and participation in driver education training were not associated with TWD.

CONCLUSIONS

This research demonstrates that TWD is an extremely common behavior among licensed student drivers in Ontario, particularly among those who have passed the first stage of graduated licensing. TWD is associated with other risky driving behaviors and outcomes, and the findings from this study underscore the need to better understand the harms associated with this behavior.

Driving and riding under the influence of recent marijuana use: Risk factors among a racially diverse sample of young adults

Driving (DUIM) and riding (RUIM) with a driver under the influence of marijuana increases crash risk. This study assessed risk factors for DUIM and RUIM among ethnically diverse young adults. Randomly selected individuals were surveyed. Multivariable regression was used to assess risk factors associated with DUIM and RUIM. Participants (N = 335, response rate = 34.9%) were 33.7% White non-Hispanic. Reported DUIM and RUIM was not statistically significant by race/ethnicity. Frequency of marijuana use was significantly associated with greater risk of DUIM. Peer marijuana use was associated with greater risk of RUIM. Public health efforts to target social norms around marijuana-impaired driving are warranted.

Self-reported driving under the influence of alcohol and cannabis among Ontario students: Associations with graduated licensing, risk taking, and substance abuse

OBJECTIVE

This article describes the patterns of self-reported driving under the influence of alcohol (DUIA) and driving under the influence of cannabis (DUIC) among licensed Ontario students in 2009 and examines their associations with graduated licensing, risk taking, and substance use problems for understanding DUIA and DUIC behaviors. Ontario's graduated licensing system requires new drivers to hold a G1 license for a minimum of 8 months and a G2 license for a minimum of 12 months before a full and unrestricted G license can be obtained. Among other restrictions, G1 drivers must maintain a 0 blood alcohol content (BAC), have an experienced driver in the passenger seat, not drive on any high-speed expressways, and not drive between the hours of midnight and 5 a.m. A G2 license is more similar to a G license, with fewer restrictions.

METHOD

This study analyzed data from the 2009 Ontario Student Drug Use and Health Survey (OSDUHS). The OSDUHS is a biennial population-based survey of students (grades 7 to 12) in Ontario, Canada.

RESULTS

The results showed that 16.3% of licensed students in Ontario reported DUIC and 11.5% reported DUIA during the past year. After controlling for the effect of age, type of license emerged as a robust predictor for both DUIA and DUIC behavior, because students with a G2 and full license were significantly more likely to report DUIA and DUIC than drivers with a G1 license. Multivariate analyses suggested that risk-seeking behaviors were more important for understanding DUIA behavior than for DUIC behavior. Elevated problem indicators for alcohol and for cannabis were associated with DUIA and DUIC, respectively.

CONCLUSIONS

Though much attention has been paid to drinking and driving among adolescents, this research shows that more Ontario students now report driving after cannabis use than after drinking alcohol. The results identify important correlates of both behaviors that may be useful for prevention purposes.

Marijuana-using drivers, alcohol-using drivers, and their passengers: prevalence and risk factors among underage college students

IMPORTANCE

Driving after marijuana use increases the risk of a motor vehicle crash. Understanding this behavior among young drivers and how it may differ from alcohol-related driving behaviors could inform prevention efforts.

OBJECTIVE

To describe the prevalence, sex differences, and risk factors associated with underage college students' driving after using marijuana, driving after drinking alcohol, or riding with a driver using these substances.

DESIGN, SETTING, AND PARTICIPANTS

Cross-sectional telephone survey of a random sample of 315 first-year college students (aged 18-20 years) from 2 large public universities, who were participating in an ongoing longitudinal study. At recruitment, 52.8% of eligible individuals consented to participate; retention was 93.2% one year later when data for this report were collected.

MAIN OUTCOMES AND MEASURES

Self-reported past-28-day driving after marijuana use, riding with a marijuana-using driver, driving after alcohol use, and riding with an alcohol-using driver.

RESULTS

In the prior month, 20.3% of students had used marijuana. Among marijuana-using students, 43.9% of male and 8.7% of female students drove after using marijuana (P < .001), and 51.2% of male and 34.8% of female students rode as a passenger with a marijuana-using driver (P = .21). Most students (65.1%) drank alcohol, and among this group 12.0% of male students and 2.7% of female students drove after drinking (P = .01), with 20.7% and 11.5% (P = .07), respectively, reporting riding with an alcohol-using driver. Controlling for demographics and substance use behaviors, driving after substance use was associated with at least a 2-fold increase in risk of being a passenger with another user; the reverse was also true. A 1% increase in the reported percentage of friends using marijuana was associated with a 2% increased risk of riding with a marijuana-using driver (95% CI, 1.01-1.03). Among students using any substances, past-28-day use of only marijuana was associated with a 6.24-fold increased risk of driving after substance use compared with using only alcohol (95% CI, 1.89-21.17).

CONCLUSIONS AND RELEVANCE

Driving and riding after marijuana use is common among underage, marijuana-using college students. This is concerning given recent legislation that may increase marijuana availability.