Occurrence of postpartum manic or mixed episodes in women with bipolar I disorder: A systematic review and meta-analysis.

OBJECTIVE: Accurate information on the frequency and prevalence of manic or mixed episodes is important for therapeutic, prognostic, and safety concerns. We aimed to estimate the risk of relapse of manic and mixed episodes after delivery in women with bipolar I disorder or schizoaffective disorder-bipolar type. METHODS: Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, a comprehensive literature search in PubMed, PsycINFO, Embase, and Cochrane databases was carried out on November 17, 2022, using the terms ((bipolar disorder) OR (manic depressive illness)) AND (mania)) AND (postpartum)) AND (recurrence)) AND (relapse). The search was updated on March 29, 2023. Case studies and qualitative analyses were excluded. Twelve studies reporting on 3595 deliveries in 2183 women were included in the quantitative analysis. RESULTS: The overall pooled estimate of postpartum relapse risk was 39% (95% CI = 29, 49; Q(11) = 211.08, p < 0.001; I2 = 96.31%). Among those who had a relapse, the pooled estimate of risk for manic and mixed episodes was 38% (95% CI = 28, 50; Q(11) = 101.17, p < 0.001; I2 = 91.06%). Using data from the nine studies that reported the percentage of medication use during pregnancy, we estimated a meta-regression model with the percent medication use as a continuous explanatory variable. The estimated prevalence of relapse was 58.1% (95% CI, 9.6 to 39.3 to 76.8) for studies with no medication use and 25.9% (95% CI, 10.5-41.3) for studies with 100% medication use. The difference between the two prevalence estimates was statistically significant, z = -2.099, p = 0.0359. CONCLUSIONS: Our findings suggest an overall pooled estimate of postpartum relapse risk of 39%, while the pooled estimate of risk for manic and mixed episodes was 38%. These findings highlight the need to educate patients with bipolar I disorder, and their healthcare professionals about the high risk of relapse of manic or mixed episodes after delivery.

Older Drivers Reduced Engagement in Distracting Behaviors Over a Six-Year Period: Findings From the Candrive Longitudinal Study.

OBJECTIVES: Baltes and Baltes' "selective optimization with compensation" model is pertinent to driving but evidence about the use of compensation using longitudinal designs is scarce. Therefore, we sought to determine if older drivers reduced their engagement in distracting behaviors while driving, over a 6-year period. METHODS: We used data captured over several annual assessments from a cohort of 583 drivers aged 70 and older to determine if their engagement in 12 distracting behaviors (e.g., listening to the radio, talking with passengers) declined over time. We adjusted our multivariable model for several potential confounders of the association between our outcome variable and time. RESULTS: Overall, and after adjustment for potential confounders, the participants reduced their engagement in distracting behaviors over the study period (odds ratio [OR] = 0.96, 95% confidence interval [CI] = 0.95-0.97). Baseline age was negatively associated with engagement in distracting behaviors (OR = 0.95, 95% CI = 0.94-0.96). Men engaged in more distracting behaviors than women (OR = 1.15, 95% CI = 1.03-1.27), as did participants living in the largest urban centers compared to participants living in the smallest areas (OR = 1.21, 95% CI = 1.04-1.41). The number of kilometers driven per year (for every 10,000 km) was positively associated with the proportion of distracting behaviors drivers engaged in (OR = 1.13, 95% CI = 1.08-1.19). DISCUSSION: Drivers in our cohort reduced their engagement in distracting behaviors over the study period. This suggests that older drivers adjust their driving over time, which aligns with age-related theories and models about compensation.

The association between diabetes and safe driving: A systematic search and review of the literature and cross-reference with the current guidelines.

AIMS: We conducted this review to characterize the quality of evidence about associations between diabetes and safe driving and to evaluate how these findings are reflected within current guidelines available to support clinicians and their patients with diabetes. METHODS: The first stage entailed a systematic search and review of the literature. Evidence surrounding harms associated with diabetes and driving was identified, screened, extracted and appraised for quality utilizing the Newcastle Ottawa Scales (NOS). Next, relevant guidelines regarding driving and diabetes were sourced and summarized. Finally, the identified guidelines were cross-referenced with the results of the systematic search and review. RESULTS: The systematic search yielded 12,461 unique citations; 52 met the criteria for appraisal. Fourteen studies were rated as 'high', two as 'medium' and 36 as 'low'. Studies with ratings of 'high' or 'medium' were extracted, revealing a body of inconsistent methods and findings. These results, cross-referenced with the guidelines, suggest a lack of agreement and a limited evidence base to justify recommendations. CONCLUSIONS: The results presented emphasize the need for a better understanding of the impacts of diabetes on safe driving to inform evidence-based guidelines.

Personality Is Associated with Driving Avoidance in the Canadian Longitudinal Study on Aging (CLSA).

As individuals age and become aware of changes in their driving capabilities, they are more likely to self-regulate their driving by avoiding certain driving situations (i.e., night driving, rush hour traffic, etc.). In this paper, we sought to examine the correlates of situational driving avoidance with a particular emphasis on the roles of personality traits, gender, and cognition within a large sample of mid-life and older adults from the Canadian Longitudinal Study on Aging (CLSA). Our findings show that women of older ages tend to report more driving avoidance and that personality traits, specifically extraversion, emotional stability, and openness to experience, may reduce driving avoidance. A negative association was also found between cognition and driving avoidance, such that individuals with higher cognition reported less driving avoidance.

Distraction impairs drivers of all ages: A cross-sectional analysis of fatal crashes in the United States.

Objective: The objective of this study was to examine the association between distracted driving and crash responsibility across the whole age span after adjusting for several driver characteristics and the potential influence of alcohol and drugs.Methods: Using data from the Fatality Analysis Reporting System for the years 2010 to 2019, we estimated the association between distracted driving and crash responsibility in drivers (of passenger-type vehicles) aged 20 and older, with a confirmed blood alcohol concentration of zero, and who tested negative for drugs (n = 33,513). We operationalized crash responsibility as having one or more unsafe driving action (UDA) recorded.Results: In total, slightly under 9% of the drivers examined were coded as distracted. The most common UDA among distracted drivers was a failure to yield right of way (23.4% vs. 14.2% for non-distracted drivers). Driving distracted was associated with higher odds of an UDA for drivers of all ages (overall OR = 1.46, 95% CI = 1.24, 1.73).Conclusions: Distracted driving affects drivers of all ages. Given that distracted driving is highly preventable, we must increase our prevention efforts.

Psychological Resources and Driving Status: A Study of Current and Former Drivers 55 Years of Age and Older.

Psychological resources can help individuals adjust to changes associated with aging. In this study, we examined the effect of demographic, health, and psychological resource variables in explaining driving status among adults 55 years and older. A convenience sample of 222 adults between the ages of 55 and 91 years (mean = 72.20 years) completed questionnaires that included measures of driving status, self-rated health, and psychological resources (e.g., life control, life purpose, and locus of control). Multiple logistic regression models that controlled for confounders were constructed with driver status (i.e., current driver or former driver) as the outcome. Former drivers were older, reported being in poorer health, and reported more depression symptoms. After controlling for age and health, current drivers reported higher levels of life control and life purpose and a more internal locus of control. Results highlight the importance of considering psychological resources when examining driving cessation.

The Validity of Three New Driving Simulator Scenarios: Detecting Differences in Driving Performance by Difficulty and Driver Gender and Age.

OBJECTIVE: We explored the convergent and discriminant validity of three driving simulation scenarios by comparing behaviors across gender and age groups, considering what we know about on-road driving. BACKGROUND: Driving simulators offer a number of benefits, yet their use in real-world driver assessment is rare. More evidence is needed to support their use. METHOD: A total of 104 participants completed a series of increasingly difficult driving simulation scenarios. Linear mixed models were estimated to determine if behaviors changed with increasing difficulty and whether outcomes varied by age and gender, thereby demonstrating convergent and discriminant validity, respectively. RESULTS: Drivers adapted velocity, steering, acceleration, and gap acceptance according to difficulty, and the degree of adaptation differed by gender and age for some outcomes. For example, in a construction zone scenario, drivers reduced their mean velocities as congestion increased; males drove an average of 2.30 km/hr faster than females, and older participants drove more slowly than young (5.26 km/hr) and middle-aged drivers (6.59 km/hr). There was also an interaction between age and difficulty; older drivers did not reduce their velocities with increased difficulty. CONCLUSION: This study provides further support for the ability of driving simulators to elicit behaviors similar to those seen in on-road driving and to differentiate between groups, suggesting that simulators could serve a supportive role in fitness-to-drive evaluations. APPLICATION: Simulators have the potential to support driver assessment. However, this depends on the development of valid scenarios to benchmark safe driving behavior, and thereby identify deviations from safe driving behavior. The information gained through simulation may supplement other forms of assessment and possibly eliminate the need for on-road testing in some situations.

Cataract Formation and Low-Dose Radiation Exposure from Head Computed Tomography (CT) Scans in Ontario, Canada, 1994-2015.

Ionizing radiation exposure to the lens of the eye is a known cause of cataractogenesis. Administrative data from the Ontario Health Insurance Program was used to examine the association between low-dose radiation exposure from head CT scans and cataract extraction surgery for 16 million Ontarians over a 22-year period (1994-2015). Subjects were grouped based on the number of head CT scans they received, and a Cox proportional hazards analysis was used to determine if there was a correlation with cataract surgery. Covariates included in the analysis were age, sex, diabetes, hypertension and prior history of intraocular surgery. To account for the potentially long latency period between radiation exposure and cataract formation, the data were analyzed incorporating a 5- and 10-year lag between head CT scan exposure and cataract surgery. Both the 5- and 10-year lagged models followed a similar trend, where only the first three head CT scans significantly increased the risk of cataract surgery by 3-8%. Individuals receiving four or more head CT scans did not have an increased cataract risk and in several cases the risk was reduced. Overall, no positive dose-response relationship was seen between the number of head CT scans received and the risk of cataract surgery. Due to the nature of the data extracted from medical records, several uncertainties exist in the analysis related to dosimetry, ultraviolet light exposure and smoking status. Nonetheless, these results do not support an association between ionizing radiation from repeated head CT scans and cataract formation.

Measuring the impact of driving status: The Centre for Research on Safe Driving-Impact of Driving Status on Quality of Life (CRSD-IDSQoL) tool.

BACKGROUND.: Driving an automobile is often considered an activity of daily living and is crucial to quality of life for many individuals. Following driving cessation, quality of life may become compromised. PURPOSE.: The Centre for Research on Safe Driving-Impact of Driving Status on Quality of Life (CRSD-IDSQoL) was designed to measure various elements of quality of life and how those elements are affected by driving status. METHOD.: The CRSD-IDSQoL was cross-sectionally administered to a convenience sample of 114 individuals (mean age 65.8 years). Exploratory factor analysis was used to examine the factor structure. FINDINGS.: The results supported three factors. Following adjustments for conceptual fit, Cronbach's alphas for the Community Mobility, Emotional, and Resources and Safety domains were .82, .84, and .74, respectively. Community Mobility was positively associated with distance driven per week. IMPLICATIONS.: The CRSD-IDSQoL may be a useful tool to study quality-of-life impacts of driving cessation. Further evaluation of the tool is warranted.

Age modifies the association between driver's body mass index and death following motor vehicle crashes.

OBJECTIVE: We explored the association between body mass index (BMI) and the odds of a driver being fatally injured in a motor vehicle crash (MVC) after controlling for driver, crash, and vehicle factors known to independently contribute to injury severity. We hypothesized that BMI would be related to risk of fatal injury after controlling for other risk factors but that BMI would also interact with age. METHOD: We analyzed crashes involving 2 passenger type vehicles (1998-2015) from the Fatality Analysis Reporting System using binary logistic regression (with generalized estimating equations) to compute odds ratios and 95% confidence intervals of fatality by BMI status. RESULTS: Our results indicate that BMI status confers varying levels of risk at different ages. For example, a very low BMI of 18 increased the odds of fatality (relative to BMI = 21.75) more at age 85 (adjusted odds ratio [aOR] = 1.17, 95% confidence interval [CI], 1.09, 1.26) than at age 25 (aOR = 1.03, 95% CI, 1.01, 1.06). Similarly, a very high BMI of 42.5 increased the odds of fatality (relative to BMI = 21.75) more at age 85 (aOR = 2.17, 95% CI, 1.64, 2.87) than at age 25 (aOR = 1.33, 95% CI, 1.21, 1.45). Conversely, a moderate BMI of 27.5 was protective for drivers aged 85 (aOR = 0.94, 95% CI, 0.88, 0.99) but had no effect for drivers aged 25 (aOR = 1.00, 95% CI, 0.98, 1.02). We also found that a higher BMI was associated with higher odds of wearing a seat belt improperly or not wearing one at all. CONCLUSION: The relationship between BMI and fatality risk needs to be considered by policymakers, public health officials, and vehicle manufacturers to ensure that vehicles are safe for all occupants regardless of their weight, size, or shape.

Physical and mental health inequalities among aging lesbian, gay, and bisexual Canadians: cross-sectional results from the Canadian Longitudinal Study on Aging (CLSA).

OBJECTIVE: International estimates suggest the presence of health inequalities among older sexual minorities (i.e., individuals who identify as lesbian, gay, or bisexual and are 65 years old or above). In this study, we investigated the presence of health inequalities among aging lesbian and bisexual females, as well as aging gay and bisexual males in Canada. METHODS: We used baseline data from the Canadian Longitudinal Study on Aging (CLSA) Tracking and Comprehensive cohorts to cross-sectionally compare self-reported physical and mental health indicators by sex and sexual orientation. Within our analysis sample of 51,208 Canadians 45 years old and over, 2% (n = 1057) of respondents identified as lesbian, gay, or bisexual. RESULTS: Compared to heterosexual female peers, lesbian and bisexual females had greater odds of heavy drinking (AOR = 1.8, 95% CI = 1.3-2.4) and being a former smoker (AOR = 1.5, 95% CI = 1.2-1.9). Gay and bisexual males had greater odds of reporting a diagnosis of cancer (AOR = 1.5, 95% CI = 1.0-1.9) and currently smoking (AOR = 1.5, 95% CI = 1.1-2.0), compared to heterosexual males. Female and male sexual minorities had greater odds of reporting mood disorders (including depression) and anxiety disorders relative to heterosexual peers of the same sex. CONCLUSION: These findings highlight the importance of considering both sex and sexual orientation when developing approaches to support the physical and mental health of a diverse aging population in Canada.

The combined effects of on-road and simulator training with feedback on older drivers' on-road performance: Evidence from a randomized controlled trial.

OBJECTIVE: A number of training programs that seek to improve driving performance among older drivers are available accompanied by a growing interest in their effectiveness. The purpose of the present investigation was to examine the combined effect of (1) basic in-class training (BT); (2) on-road training with individualized feedback (OR); and (3) training on a driving simulator (S). METHODS: Using a randomized controlled trial study design, 78 older drivers were randomly assigned to one of 3 groups (BT, BT + OR, or BT + OR + S). All participants completed a pre- and postintervention on-road driving evaluation on a standardized route. The driving evaluations were recorded using video and Global Positioning System (GPS) equipment and were scored by a blind assessor. RESULTS: The results indicated a significant reduction of approximately 30% in overall number of driving errors/omissions among participants in the BT + OR and the BT + OR + S groups in comparison to participants in the BT group. CONCLUSIONS: This study adds to the mounting evidence demonstrating the effectiveness of individualized driver training in improving safe driving among older adults.

Using Serial Trichotomization With Common Cognitive Tests to Screen for Fitness to Drive.

OBJECTIVE: The aim of this study was to illustrate the use of serial trichotomization with five common tests of cognition to achieve greater precision in screening for fitness to drive. METHOD: We collected data (using the Montreal Cognitive Assessment, Motor-Free Visual Perception Test, Clock-Drawing Test, Trail Making Test Part A and B [Trails B], and an on-road driving test) from 83 people referred for a driving evaluation. We identified cutpoints for 100% sensitivity and specificity for each test; the driving test was the gold standard. Using serial trichotomization, we classified drivers as either "Pass," "Fail," or "Indeterminate." RESULTS: Trails B had the best sensitivity and specificity (66.3% of participants correctly classified). After applying serial trichotomization, we correctly identified the driving test outcome for 78.3% of participants. CONCLUSION: A screening strategy using serial trichotomization of multiple test results may reduce uncertainty about fitness to drive.

Community-randomised controlled trial embedded in the Anishinaabek Cervical Cancer Screening Study: human papillomavirus self-sampling versus Papanicolaou cytology.

OBJECTIVES: The incidence of cervical cancer is up to 20-fold higher among First Nations women in Canada than the general population, probably due to lower participation in screening. Offering human papillomavirus (HPV) self-sampling in place of Papanicolaou (Pap) testing may eventually increase screening participation and reduce cervical cancer rates in this population. DESIGN: A community-randomised controlled screening trial. SETTING: First Nations communities in Northwest Ontario, Canada. PARTICIPANTS: Women aged between 25 and 69, living in Robinson Superior Treaty First Nations. The community was the unit of randomisation. INTERVENTIONS: Women were asked to complete a questionnaire and have screening by HPV self-sampling (arm A) or Pap testing (arm B). PRIMARY OUTCOME MEASURES: The number of women who participated in cervical screening. RANDOMISATION: Community clusters were randomised to include approximately equivalent numbers of women in each arm. RESULTS: 6 communities were randomised to arm A and 5 to arm B. One community withdrew, leaving 5 communities in each group (834 eligible women). Participation was <25%. Using clustered intention-to-treat (ITT) analysis, initial and cumulative averaged uptakes in arm A were 1.4-fold (20% vs 14.3%, p=0.628) and 1.3-fold (20.6% vs 16%, p=0.694) higher compared to arm B, respectively. Corresponding per protocol (PP) analysis indicates 2.2-fold (22.9% vs 10.6%, p=0.305) and 1.6-fold (22.9% vs 14.1%, p=0.448) higher uptakes in arm A compared to arm B. Screening uptake varied between communities (range 0-62.1%). Among women who completed a questionnaire (18.3% in arm A, 21.7% in arm B), the screening uptake was 1.8-fold (ITT; p=0.1132) or 3-fold (PP; p<0.01) higher in arm A versus arm B. CONCLUSIONS: Pap and HPV self-sampling were compared in a marginalised, Canadian population. Results indicated a preference for self-sampling. More research on how to reach underscreened Indigenous women is necessary. TRIAL REGISTRATION NUMBER: ISRCTN84617261.

Visual-cognitive tools used to determine fitness-to-drive may reflect normal aging.

BACKGROUND: Scores on many visual-cognitive tools are proposed as indicators of fitness-to-drive. A purported feature of some tools and one believed to be important is that they are 'age-independent'. Specifically, scores are not correlated with age and poor scores represent a pathological process rather than normal aging. Yet, we know that several cognitive abilities are associated with age. One potential reason for the apparent age-independence of some tools is that focusing on older drivers leads to 'range restriction', a statistical issue that reduces the magnitude of correlations when values for one variable are restricted to a smaller range than naturally occurs. Hence, the purpose of this study was to investigate whether age is correlated with scores on visual-cognitive tests when we examine the full age range. METHODS: We recruited 114 drivers aged 18 to 89 years (mean: 42.30 ± 26.50 years). Participants completed several visual-cognitive tools often used to examine fitness-to-drive (Trail Making Tests A and B, Attention Network Test and 'useful field of view'). RESULTS: Correlations between age and test scores for drivers 65 years and older only ranged from 0.03 to 0.48. With the whole age range, correlations ranged from 0.56 to 0.84. We also compared ordinary Pearson correlations among visual-cognitive tests scores to the corresponding partial correlations after removing the effect of age. Whereas ordinary Pearson correlations ranged from 0.40 to 0.69, partial correlations ranged from 0.01 to 0.30. CONCLUSION: Test scores may reflect age-associated normal biological changes. These results have implications for predicting fitness-to-drive among older drivers and suggest caution in using these scores.

Self-rated confidence and on-road driving performance among older adults: Autoévaluation de la confiance et de la performance au volant chez les personnes âgées.

BACKGROUND.: Driver confidence can be measured through concepts such as driving frequency, situational avoidance, and self-perceptions. However, it is not clear how well confidence aligns with actual driving performance. PURPOSE.: We examined the relationship between subjective measures of confidence in driving ability and on-road performance. METHOD.: We report findings from two studies. The first compared scores from the Older and Wiser Driver Questionnaire to an on-road driving evaluation. The second looked at the Day and Night Driving Comfort Scales and Driving Habits and Intentions Questionnaire in relation to an on-road driving evaluation. FINDINGS.: No measures of confidence in driving ability were related to on-road driving performance. IMPLICATIONS.: Confidence in driving ability bears little relationship to on-road performance. Future research should examine approaches to foster a better match between self-assessments and actual abilities among drivers.

Developing emergency department physician shift schedules optimized to meet patient demand.

OBJECTIVES: 1) To assess temporal patterns in historical patient arrival rates in an emergency department (ED) to determine the appropriate number of shift schedules in an acute care area and a fast-track clinic and 2) to determine whether physician scheduling can be improved by aligning physician productivity with patient arrivals using an optimization planning model. METHODS: Historical data were statistically analyzed to determine whether the number of patients arriving at the ED varied by weekday, weekend, or holiday weekend. Poisson-based generalized additive models were used to develop models of patient arrival rate throughout the day. A mathematical programming model was used to produce an optimal ED shift schedule for the estimated patient arrival rates. We compared the current physician schedule to three other scheduling scenarios: 1) a revised schedule produced by the planning model, 2) the revised schedule with an additional acute care physician, and 3) the revised schedule with an additional fast-track clinic physician. RESULTS: Statistical modelling found that patient arrival rates were different for acute care versus fast-track clinics; the patterns in arrivals followed essentially the same daily pattern in the acute care area; and arrival patterns differed on weekdays versus weekends in the fast-track clinic. The planning model reduced the unmet patient demand (i.e., the average number of patients arriving at the ED beyond the average physician productivity) by 19%, 39%, and 69% for the three scenarios examined. CONCLUSIONS: The planning model improved the shift schedules by aligning physician productivity with patient arrivals at the ED.

Immunogenicity and efficacy of flagellin-envelope fusion dengue vaccines in mice and monkeys.

The envelope (E) protein of flaviviruses includes three domains, EI, EII, and EIII, and is the major protective antigen. Because EIII is rich in type-specific and subcomplex-specific neutralizing epitopes and is easy to express, it is particularly attractive as a recombinant vaccine antigen. VaxInnate has developed a vaccine platform that genetically links vaccine antigens to bacterial flagellin, a Toll-like receptor 5 ligand. Here we report that tetravalent dengue vaccines (TDVs) consisting of four constructs, each containing two copies of EIII fused to flagellin (R3.2x format), elicited robust and long-lived neutralizing antibodies (geometric mean titers of 200 to 3,000), as measured with a 50% focus reduction neutralization test (FRNT50). In an immunogenicity study, rhesus macaques (n = 2) immunized subcutaneously with 10 µg or 90 µg of TDV three or four times, at 4- to 6-week intervals, developed neutralizing antibodies to four dengue virus (DENV) serotypes (mean post-dose 3 FRNT50 titers of 102 to 601). In an efficacy study, rhesus macaques (n = 4) were immunized intramuscularly with 16 µg or 48 µg of TDV or a placebo control three times, at 1-month intervals. The animals that received 48-µg doses of TDV developed neutralizing antibodies against the four serotypes (geometric mean titers of 49 to 258) and exhibited reduced viremia after DENV-2 challenge, with a group mean viremia duration of 1.25 days and 2 of 4 animals being completely protected, compared to the placebo-treated animals, which all developed viremia, with a mean duration of 4 days. In conclusion, flagellin-EIII fusion vaccines are immunogenic and partially protective in a nonhuman primate model.

The combined effects of alcohol and cannabis on driving: Impact on crash risk.

BACKGROUND/OBJECTIVES: Driving under the influence of alcohol or cannabis alone is associated with increased crash risk. This study explores the combined influence of low levels of alcohol (BAC≤0.08) and cannabis on crash risk. MATERIALS AND METHODS: Drivers aged 20 years or older who had been tested for both drugs and alcohol after involvement in a fatal crash in the United States (1991-2008) were examined using a case-control design. Cases were drivers with at least one potentially unsafe driving action (UDA) recorded in relation to the crash (e.g., weaving); controls had none recorded. We examined the prevalence of driving under the influence of alcohol, cannabis, and both agents, for drivers involved in a fatal crash. Adjusted odds ratios of committing an UDA for alcohol alone, THC alone, and their combined effect were computed via logistic regression and adjusted for a number of potential confounders. RESULTS: Over the past two decades, the prevalence of THC and alcohol in car drivers involved in a fatal crash has increased approximately five-fold from below 2% in 1991 to above 10% in 2008. Each 0.01 BAC unit increased the odds of an UDA by approximately 9-11%. Drivers who were positive for THC alone had 16% increased odds of an UDA. When alcohol and THC were combined the odds of an UDA increased by approximately 8-10% for each 0.01 BAC unit increase over alcohol or THC alone. CONCLUSION: Drivers positive for both agents had greater odds of making an error than drivers positive for either alcohol or cannabis only. Further research is needed to better examine the interaction between cannabis concentration levels, alcohol, and driving. This research would support enforcement agencies and public health educators by highlighting the combined effect of cannabis at low BAC levels.