Mark Asbridge

Acute cannabis consumption and motor vehicle collision risk: systematic review of observational studies and meta-analysis

Objective To determine whether the acute consumption of cannabis (cannabinoids) by drivers increases the risk of a motor vehicle collision. Design Systematic review of observational studies, with meta-analysis. Data sources We did electronic searches in 19 databases, unrestricted by year or language of publication. We also did manual searches of reference lists, conducted a search for unpublished studies, and reviewed the personal libraries of the research team. Review methods We included observational epidemiology studies of motor vehicle collisions with an appropriate control group, and selected studies that measured recent cannabis use in drivers by toxicological analysis of whole blood or self report. We excluded experimental or simulator studies. Two independent reviewers assessed risk of bias in each selected study, with consensus, using the Newcastle-Ottawa scale. Risk estimates were combined using random effects models. Results We selected nine studies in the review and meta-analysis. Driving under the influence of cannabis was associated with a significantly increased risk of motor vehicle collisions compared with unimpaired driving (odds ratio 1.92 (95% confidence interval 1.35 to 2.73); P=0.0003); we noted heterogeneity among the individual study effects (I2=81). Collision risk estimates were higher in case-control studies (2.79 (1.23 to 6.33); P=0.01) and studies of fatal collisions (2.10 (1.31 to 3.36); P=0.002) than in culpability studies (1.65 (1.11 to 2.46); P=0.07) and studies of non-fatal collisions (1.74 (0.88 to 3.46); P=0.11). Conclusions Acute cannabis consumption is associated with an increased risk of a motor vehicle crash, especially for fatal collisions. This information could be used as the basis for campaigns against drug impaired driving, developing regional or national policies to control acute drug use while driving, and raising public awareness.

Diet Quality and Academic Performance

BACKGROUND Although the effects of nutrition on health and school performance are often cited, few research studies have examined the effect of diet quality on the academic performance of children. This study examines the association between overall diet quality and academic performance. METHODS In 2003, 5200 grade 5 students in Nova Scotia, Canada, and their parents were surveyed as part of the Childrens Lifestyle and School-performance Study. Information on dietary intake, height, and weight and sociodemographic variables were linked to results of a provincial standardized literacy assessment. Diet Quality Index-International was used to summarize overall diet quality. Multilevel regression methods were used to examine the association between indicators of diet quality and academic performance while adjusting for gender and socioeconomic characteristics of parents and residential neighborhoods. RESULTS Across various indicators of diet quality, an association with academic performance was observed. Students with decreased overall diet quality were significantly more likely to perform poorly on the assessment. Girls performed better than boys as did children from socioeconomically advantaged families. Children attending better schools and living in wealthy neighborhoods also performed better. CONCLUSIONS These findings demonstrate an association between diet quality and academic performance and identify specific dietary factors that contribute to this association. Additionally, this research supports the broader implementation and investment in effective school nutrition programs that have the potential to improve student access to healthy food choices, diet quality, academic performance, and, over the long term, health.

An emerging adolescent health risk: caffeinated energy drink consumption patterns among high school students.

OBJECTIVE To examine the prevalence, patterns, and correlates of energy drink use among adolescents, and determine whether more frequent use of energy drinks is associated with poorer health and behavioral outcomes. METHODS Data were from a 2012 cross-sectional survey of 8210 students in grades 7, 9, 10 and 12 attending public schools in Atlantic Canada. Multinomial logistic regression analysis was used to examine correlates of energy drink use patterns, including substance use, sensation seeking, risk of depression, and socioeconomic status. RESULTS Nearly two-thirds of survey respondents (62%) reported consuming energy drinks at least once in the previous year, with about 20% reporting use once or more per month. Sensation seeking, depression, and substance use were all higher among energy drink users relative to non-users, and in higher frequency users relative to lower frequency users. CONCLUSIONS The prevalence of energy drink consumption among high school students was high. The association of energy drinks with other potential negative health and behavioral outcomes suggests that use of these products may represent a marker for other activities that may negatively affect adolescent development, health and well-being.

Prevalence and Correlates of Traumatic Brain Injuries Among Adolescents

Traumatic brain injury (TBI) among adolescents has been identified as an important health priority. However, studies of TBI among adolescents in large representative samples are lacking.This information is important to the planning and evaluation of injury prevention efforts, particularly because even minor TBI may have important adverse consequences. We describe the prevalence of TBI, the mechanisms of injury, and adverse correlates in a large representative sample of adolescents living in Ontario, Canada. Language: en

Our favourite melodies: musical consumption and teenage lifestyles.

The present study explores the determinants and lifestyle correletes of musical preferences among a large sample of high school students in Toronto, Ontario. Our work is informed by theory and research on cultural stratification and adolescent subcultures. In terms of cultural stratification, we engage with Bourdieus (1984) and Petersons (1996) conceptualizations of elite taste, while subcultural theory encourages us to focus upon more dissenting tastes and to explore connections between musical tastes and peer group activity. Our findings suggest that racial and ethnic identity, school experiences and cultural capital are significant sources of variation in musical tastes that loosely correspond to existing typologies; they also confirm what has often been inferred - that musical tastes and peer group cultural practices are closely linked. Our findings are then discussed in the light of current debates about the nature and dimensions of listening audiences for music.

Suicidality, bullying and other conduct and mental health correlates of traumatic brain injury in adolescents

Objective Our knowledge on the adverse correlates of traumatic brain injuries (TBI), including non-hospitalized cases, among adolescents is limited to case studies. We report lifetime TBI and adverse mental health and conduct behaviours associated with TBI among adolescents from a population-based sample in Ontario. Method and Findings Data were derived from 4,685 surveys administered to adolescents in grades 7 through 12 as part of the 2011 population-based cross-sectional Ontario Student Drug Use and Health Survey (OSDUHS). Lifetime TBI was defined as head injury that resulted in being unconscious for at least 5 minutes or being retained in the hospital for at least one night, and was reported by 19.5% (95%CI:17.3,21.9) of students. When holding constant sex, grade, and complex sample design, students with TBI had significantly greater odds of reporting elevated psychological distress (AOR = 1.52), attempting suicide (AOR = 3.39), seeking counselling through a crisis help-line (AOR = 2.10), and being prescribed medication for anxiety, depression, or both (AOR = 2.45). Moreover, students with TBI had higher odds of being victimized through bullying at school (AOR = 1.70), being cyber-bullied (AOR = 2.05), and being threatened with a weapon at school (AOR = 2.90), compared with students who did not report TBI. Students with TBI also had higher odds of victimizing others and engaging in numerous violent as well as nonviolent conduct behaviours. Conclusions Significant associations between TBI and adverse internalizing and externalizing behaviours were found in this large population-based study of adolescents. Those who reported lifetime TBI were at a high risk for experiencing mental and physical health harms in the past year than peers who never had a head injury. Primary physicians should be vigilant and screen for potential mental heath and behavioural harms in adolescent patients with TBI. Efforts to prevent TBI during adolescence and intervene at an early stage may reduce injuries and comorbid problems in this age group.

Alcohol and driving factors in collision risk.

In this study we examine the effect of several alcohol-related measures on self-reported collision involvement within the previous 12 months while controlling for demographic and driving exposure factors based on a large representative sample of adults in Ontario. Data are based on the 2002-2006 Centre for Addiction and Mental Health Monitor, an ongoing cross-sectional telephone survey of Ontario adults aged 18 and older (n=8542). Three logistic regressions of self-reported collision involvement in the past 12 months were implemented, each consisting of 3 steps: (1) demographic factors and driving exposure entered, (2) driving after drinking within the last 12 months entered, and (3) one of three alcohol-related measures (AUDIT subscales of alcohol consumption, dependence and problems) entered. In each step, measures from the preceding step were included in order to control for those variables. In Step 1, age (OR=0.989), region overall, Central East region (OR=0.71), West region (OR=0.67), and North region (OR=0.67), income overall and those who did not state income (OR=0.64), marital status overall and those married or living common law (OR=0.60), and number of kilometers driven in a typical week (OR=1.00) were found to be significant predictors of collision involvement. The analyses revealed that driving after drinking was a significant predictor of collision involvement in Step 2 (OR=1.51) and each of the Step 3 models (ORs=1.52, 1.37, 1.34). The AUDIT Consumption subscale was not a significant factor in collision risk. Both the AUDIT Dependence and AUDIT Problems subscales were significantly related to collision risk (ORs=1.13 and 1.10, respectively). These findings suggest that alcohol, in addition to its effects on collision risk through its acute impairment of driving skills, may also affect collision risk through processes involved when individuals develop alcohol problems or alcohol dependence.

Bodychecking rules and concussion in elite hockey.

Athletes participating in contact sports such as ice hockey are exposed to a high risk of suffering a concussion. We determined whether recent rule changes regulating contact to the head introduced in 2010–11 and 2011–12 have been effective in reducing the incidence of concussion in the National Hockey League (NHL). A league with a longstanding ban on hits contacting the head, the Ontario Hockey League (OHL), was also studied. A retrospective study of NHL and OHL games for the 2009–10 to 2011–12 seasons was performed using official game records and team injury reports in addition to other media sources. Concussion incidence over the 3 seasons analyzed was 5.23 per 100 NHL regular season games and 5.05 per 100 OHL regular season games (IRR 1.04; 95% CI 1.01, 1.50). When injuries described as concussion-like or suspicious of concussion were included, incidences rose to 8.8 and 7.1 per 100 games respectively (IRR 1.23; 95% CI 0.81, 1.32). The number of NHL concussions or suspected concussions was lower in 2009–10 than in 2010–11 (IRR 0.61; 95% CI 0.45, 0.83), but did not increase from 2010–11 to 2011–12 (IRR 1.05; 95% CI 0.80, 1.38). 64.2% of NHL concussions were caused by bodychecking, and only 28.4% of concussions and 36.8% of suspected concussions were caused by illegal incidents. We conclude that rules regulating bodychecking to the head did not reduce the number of players suffering concussions during NHL regular season play and that further changes or stricter enforcement of existing rules may be required to minimize the risk of players suffering these injuries.

Longitudinal associations of cannabis and illicit drug use with depression, suicidal ideation and suicidal attempts among Nova Scotia high school students

OBJECTIVE To examine associations of cannabis and other illicit drug use with depression, suicidal ideation and suicidal attempts over a two year period during adolescence. METHODS Nine hundred and seventy-six school students in four high schools in northern Nova Scotia, Canada, were surveyed in grade 10 and followed up in grade 12. Assessments of past 30 day cannabis and illicit drug use as well as mental health variables (risk of depression, suicidal ideation and suicide attempts) were obtained at baseline (2000 and 2001) and follow-up two years later (2002 and 2003). Generalized estimating equations modelled depression, suicidal ideation and attempts among illicit drug users and non-users. RESULTS Illicit drug use with or without cannabis use was significantly associated with higher odds of depression, suicidal ideation and suicide attempt. Heavy cannabis use alone predicted depression but not suicidal ideation or attempt. CONCLUSIONS Illicit drug use, with and without accompanying cannabis use, among high school students increases the risk of depression, suicidal ideation and suicidal attempts. Heavy cannabis use alone predicts depression but not suicidal ideation or attempts.

Self-Reported Collision Risk Associated With Cannabis Use and Driving After Cannabis Use Among Ontario Adults

Objective: This study examined the effects of cannabis use and driving after cannabis use on self-reported collision involvement within the previous 12 months while controlling for demographics, driving exposure, binge drinking, and driving after drinking based on a large representative sample of adults in Ontario. Methods: Data are based on the CAMH Monitor, an ongoing cross-sectional telephone survey of Ontario adults aged 18 and older, conducted by the Centre for Addiction and Mental Health. Data on drivers who reported driving at least one kilometer per week and who responded to the collision item from 2002 to 2007 were merged into one data set (n = 8481). Logistic regression analysis of self-reported collision risk posed by cannabis use (lifetime and past 12 months), driving after cannabis use (past 12 months), and driving after drinking among drinkers (past 12 months) was implemented, controlling for the effects of gender, age, region, income, education, marital status, kilometers driven in a typical week, and consuming five or more drinks of alcohol on one occasion (past 12 months). Due to list-wise deletion of cases the logistic regression sample was reduced (n = 6907). Results: Several demographic factors were found to be significantly associated with self-reported collision involvement. The logistic regression model revealed that age, region, income, marital status, and number of kilometers driven in a typical week, were all significantly related to collision involvement, after adjusting for other factors. Respondents who reported having driven after cannabis use within the past 12 months had increased risk of collision involvement (odds ratio [OR] = 1.84) compared to those who never drove after using cannabis, a greater risk than that associated with having reported driving after drinking within the past 12 months (OR = 1.34). Conclusion: Further investigation of the impact of driving after cannabis use on collision risk and factors that may modify that relationship is warranted.