Jodi M. Gatley

Alcohol- or drug-use disorders and motor vehicle accident mortality: A retrospective cohort study

A large body of research has linked alcohol consumption and motor vehicle accidents (MVAs), but far fewer studies have estimated the risk of MVA fatality among drug users. Our study addresses this gap. We identified cohorts of individuals hospitalized in California from 1990 to 2005 with ICD-9 diagnoses of methamphetamine- (n=74,170), alcohol- (n=592,406), opioids- (n=68,066), cannabis- (n=47,048), cocaine- (n=48,949), or polydrug-related disorders (n=411,175), and these groups were followed for up to 16 years. Age-, sex-, and race-adjusted standardized mortality rates (SMRs) for deaths due to MVAs were generated in relation to the California general population. Standardized MVA mortality ratios were elevated across all drug cohorts: alcohol (4.5, 95% CI, 4.1-4.9), cocaine (3.8, 95% CI, 2.3-5.3), opioids (2.8, 95% CI, 2.1-3.5), methamphetamine (2.6, 95% CI, 2-3.1), cannabis (2.3, 95% CI, 1.5-3.2) and polydrug (2.6, 95% CI, 2.4-2.9). Males and females had similar MVA SMRs. Our large, population-based study found elevated risk of MVA mortality across all cohorts of individuals with alcohol- or drug-use disorders. Given that illicit drug users are often unaware of or misperceive the impacts of drug use on safe driving, it may be important for health-service or public-health interventions to address such biases and improve road safety.

Effects of the minimum legal drinking age on alcohol-related health service use in hospital settings in Ontario: A regression-discontinuity approach

OBJECTIVES We assessed the impact of the minimum legal drinking age (MLDA) on hospital-based treatment for alcohol-related conditions or events in Ontario, Canada. METHODS We conducted regression-discontinuity analyses to examine MLDA effects with respect to diagnosed alcohol-related conditions. Data were derived from administrative records detailing inpatient and emergency department events in Ontario from April 2002 to March 2007. RESULTS Relative to youths slightly younger than the MLDA, youths just older than the MLDA exhibited increases in inpatient and emergency department events associated with alcohol-use disorders (10.8%; P = .048), assaults (7.9%; P < .001), and suicides related to alcohol (51.8%; P = .01). Among young men who had recently crossed the MLDA threshold, there was a 2.0% increase (P = .01) in hospitalizations for injuries. CONCLUSIONS Young adults gaining legal access to alcohol incur increases in hospital-based care for a range of serious alcohol-related conditions. Our regression-discontinuity approach can be used in future studies to assess the effects of the MLDA across different settings, and our estimates can be used to inform cost-benefit analyses across MLDA scenarios.

Impacts of the minimum legal drinking age legislation on in‐patient morbidity in Canada, 1997–2007: a regression‐discontinuity approach

AIMS To provide novel, population-based estimates of the influence of minimum legal drinking age (MLDA) legislation on target in-patient hospital events in Canada. DESIGN Regression-discontinuity analyses on rates of Canadian in-patient admissions. SETTING All in-patient hospitalizations in Canada (except Québec) between 1 April 1997 and 31 March 2007. PARTICIPANTS Individuals aged 15-22 years admitted to hospital. MEASUREMENTS International Classification of Diseases-9/10 codes for alcohol-use disorders/poisoning, injury, suicide, assault and motor vehicle accidents were considered as target morbidity conditions. FINDINGS Compared with the baseline hospitalization rate just prior to the MLDA, admissions at the MLDA rose significantly (P ≤ 0.001) for alcohol-use disorders/poisoning for males (17.3%) and females (21.1%), as well as for suicide events for the combined sample (9.6%, P = 0.029). Among males, there was a significant 4.4% increase (P = 0.001) in a broad class of injuries, including a 9.2% jump (P = 0.020) in admissions for motor vehicle accidents compared with the baseline hospitalization rate just prior to the MLDA. CONCLUSION Removal of minimum legal drinking age restrictions is associated with significant population-level increases in hospital admissions among young adults in Canada for alcohol-use disorders/poisoning, as well as for other serious injuries, especially among males. Current international minimum legal drinking age policy discussions should account for the impact of the minimum legal drinking age on severe morbidity outcomes.

Impacts of drinking-age laws on mortality in Canada, 1980–2009

BACKGROUND Given the recent international debates about the effectiveness and appropriate age setpoints for legislated minimum legal drinking ages (MLDAs), the current study estimates the impact of Canadian MLDAs on mortality among young adults. Currently, the MLDA is 18 years in Alberta, Manitoba and Québec, and 19 years in the rest of Canada. METHODS Using a regression-discontinuity approach, we estimated the impacts of the MLDAs on mortality from 1980 to 2009 among 16- to 22-year-olds in Canada. RESULTS In provinces with an MLDA of 18 years, young men slightly older than the MLDA had significant and abrupt increases in all-cause mortality (14.2%, p=0.002), primarily due to deaths from a broad class of injuries [excluding motor vehicle accidents (MVAs)] (16.2%, p=0.008), as well as fatalities due to MVAs (12.7%, p=0.038). In provinces/territories with an MLDA of 19 years, significant jumps appeared immediately after the MLDA among males in all-cause mortality (7.2%, p=0.003), including injuries from external causes (10.4%, p<0.001) and MVAs (15.3%, p<0.001). Among females, there were some increases in mortality following the MLDA, but these jumps were statistically non-significant. CONCLUSIONS Canadian drinking-age legislation has a powerful impact on youth mortality. Given that removal of MLDA restrictions was associated with sharp upturns in fatalities among young men, the MLDA likely reduces population-level mortality among male youth under the constraints of drinking-age legislation. Alcohol-control policies should target the transition across the MLDA as a pronounced period of mortality risk, especially among males.

Impacts of the Minimum Legal Drinking Age on Motor Vehicle Collisions in Québec, 2000−2012

BACKGROUND International debates are occurring about the effectiveness of minimum legal drinking age laws. Most minimum legal drinking age evaluation studies have focused on motor vehicle collision outcomes, but this literature is primarily based on naturalistic experiments involving legislation changes in the U.S. in the mid-1980s. Few studies have provided up-to-date estimates of the impacts of Canadian drinking age laws on motor vehicle collisions to inform current policy discussions. PURPOSE To estimate the impacts of minimum legal drinking age legislation on motor vehicle collisions occurring in 2000-2012 in Québec, a province with a minimum legal drinking age of 18 years. METHODS Using Québec Ministry of Transportation records of police-reported motor vehicle collisions in 2000-2012, regression-discontinuity analyses were employed to assess the impacts of the minimum legal drinking age on motor vehicle collisions. All data were analyzed in 2013. RESULTS Relative to individuals slightly younger than the minimum legal drinking age, male and female drivers just older than the minimum legal drinking age had a significant and abrupt increase of approximately 6% (men, 6.3%, p=0.003; women, 5.9%, p=0.047) in population-level motor vehicle collisions, as well as a significant 11.1% (p=0.001) rise in nighttime motor vehicle collisions (a proxy for alcohol-related collisions). CONCLUSIONS Drinking-age laws continue to be an integral component of contemporary alcohol-control and driving-related policies designed to limit motor vehicle collisions among youth. In addition, the regression-discontinuity approach can guide future work to estimate potential minimum legal drinking age impacts on other health outcomes.

Hazardous birthday drinking among young people: population‐based impacts on emergency department and in‐patient hospital admissions

BACKGROUND AND AIMS There is growing concern about the possible adverse health impacts of binge drinking during birthday celebrations among adolescents and young adults. We estimate the impacts of birthday alcohol use on adolescent and young adult in-patient/emergency department (ED) hospital admissions. DESIGN We employed Autoregressive Integrated Moving Average (ARIMA) intervention analysis to assess whether the rate of ICD-10 alcohol-use-disorder (AUD) events per 1000 in-patient/ED admissions increased significantly during birthday weeks. SETTING All in-patient/ED admissions in Ontario, Canada from 1 April 2002 to 31 March 2007. PARTICIPANTS Individuals aged 12-30 years. MEASUREMENTS AUD events per 1000 in-patient/ED admissions by age in weeks. FINDINGS Multiple increases were found. The largest occurred during the birthday week of 19 years of age, the beginning of the minimum legal drinking age (MLDA) in Ontario: AUD admission rates increased (spiked) by 38.30 per 1000 total admissions [95% confidence interval (CI) = 34.66-41.94] among males (a 114.3% increase over baseline), and by 28.13 (95% CI = 25.56-30.70) among females (a 164.0% increase). Among both genders, the second largest birthday-week spikes occurred during ages 20-22 years, followed by somewhat lower but still pronounced birthday-week spikes during ages 23-26 years and 30 years (all these spikes: P < 0.05). Birthday-week spikes occurred as early as age 16 years for males and 14 years for females (both spikes: P < 0.05). CONCLUSIONS There appears to be an increase in alcohol-related adverse events from drinking around the time of ones birthday among young adults in Canada.

Assessing the impacts of Saskatchewan's minimum alcohol pricing regulations on alcohol‐related crime

INTRODUCTION Saskatchewans introduction in April 2010 of minimum prices graded by alcohol strength led to an average minimum price increase of 9.1% per Canadian standard drink (=13.45 g ethanol). This increase was shown to be associated with reduced consumption and switching to lower alcohol content beverages. Police also informally reported marked reductions in night-time alcohol-related crime. OBJECTIVES This study aims to assess the impacts of changes to Saskatchewans minimum alcohol-pricing regulations between 2008 and 2012 on selected crime events often related to alcohol use. METHODS Data were obtained from Canadas Uniform Crime Reporting Survey. Auto-regressive integrated moving average time series models were used to test immediate and lagged associations between minimum price increases and rates of night-time and police identified alcohol-related crimes. Controls were included for simultaneous crime rates in the neighbouring province of Alberta, economic variables, linear trend, seasonality and autoregressive and/or moving-average effects. RESULTS The introduction of increased minimum-alcohol prices was associated with an abrupt decrease in night-time alcohol-related traffic offences for men (-8.0%, P < 0.001), but not women. No significant immediate changes were observed for non-alcohol-related driving offences, disorderly conduct or violence. Significant monthly lagged effects were observed for violent offences (-19.7% at month 4 to -18.2% at month 6), which broadly corresponded to lagged effects in on-premise alcohol sales. DISCUSSION Increased minimum alcohol prices may contribute to reductions in alcohol-related traffic-related and violent crimes perpetrated by men. Observed lagged effects for violent incidents may be due to a delay in bars passing on increased prices to their customers, perhaps because of inventory stockpiling. [Stockwell T, Zhao J, Sherk A, Callaghan RC, Macdonald S, Gatley J. Assessing the impacts of Saskatchewans minimum alcohol pricing regulations on alcohol-related crime. Drug Alcohol Rev 2017;36:492-501].

Release from drinking-age restrictions is associated with increases in alcohol-related motor vehicle collisions among young drivers in Canada

BACKGROUND Alcohol-related motor vehicle collisions (MVCs) are a key concern in current international debates about the effectiveness of minimum legal drinking age (MLDA) laws, but the majority of this literature is based on natural experiments involving MLDA changes occurring 2-4 decades ago. METHODS A regression-discontinuity approach was used to estimate the relation between Canadian drinking-age laws and population-based alcohol-related MVCs (n=50,233) among drivers aged 15-23years in Canada. RESULTS In comparison to male drivers slightly younger than the MLDA, those just older had immediate and abrupt increases in alcohol-related MVCs of 40.6% (95% CI 25.1%-56.6%; P<0.001) in Ontario; 90.2% (95% CI 7.3%-171.2%; P=0.033) in Manitoba; 21.6% (95% CI 8.5%-35.0%; P=0.001) in British Columbia; and 27.3% (95% CI 10.9%-44.5%; P=0.001) in Alberta; but also an unexpected significant decrease in the Northwest Territories of -102.2% (95% CI -120.7%-74.9%; P<0.001). For females, release from MLDA restrictions was associated with increases in alcohol-related MVCs in Ontario [34.2% (95% CI 0.9%-68.0%; P=0.044)] and Alberta [82.2% (95% CI 41.1%-125.1%; P<0.001)]. Nationally, in comparison to male drivers slightly younger than the legislated MLDA, male drivers just older had significant increases immediately following the MLDA in alcohol-related severe MVCs [27.0% (95% CI 12.6%-41.7%, P<0.001)] and alcohol-related fatal MVCs [53.4% (95% CI 2.4%-102.9%, P=0.04)]. CONCLUSIONS Release from Canadian drinking-age restrictions appears to be associated with immediate increases in alcohol-related fatal and non-fatal MVCs, especially among male drivers.

The prominence of smoking-related mortality among individuals with alcohol- or drug-use disorders

INTRODUCTION AND AIMS Even though individuals with substance-use disorders have a high prevalence of tobacco smoking, surprisingly little is known about smoking-related mortality in these populations. The current retrospective cohort study aims to address this gap. DESIGN AND METHODS The study sample included cohorts of individuals hospitalised in California between 1990 and 2005 with alcohol- (n = 509 422), cocaine- (n = 35 276), opioid- (n = 53 172), marijuana- (n = 15 995) or methamphetamine-use (n = 36 717) disorders. Death records were linked to inpatient data. Age-, race- and sex-adjusted standardised mortality ratios (SMR) were generated for 19 smoking-related causes of death. RESULTS Smoking-related conditions comprised 49% (79 188/163 191) of total deaths in the alcohol, 40% (1412/3570) in the cocaine, 39% (4285/11 091) in the opioid, 42% (554/1332) in the methamphetamine and 36% (1122/3095) in the marijuana cohorts. The SMRs for all smoking-linked diseases were: alcohol, 3.57 (95% confidence interval [CI] = 3.55 to 3.58); cocaine, 2.40 (95% CI = 2.39 to 2.41); opioid, 4.26 (95% CI = 4.24 to 4.27); marijuana, 3.73 (95% CI = 3.71 to 3.74); and methamphetamine, 2.58 (95% CI = 2.57 to 2.59). The SMRs for almost all of the 19 cause-specific smoking-related outcomes were elevated across cohorts. DISCUSSION AND CONCLUSIONS Given the current findings, addressing tobacco smoking among persons with substance-use disorders should be a critical concern, especially given the heavy smoking-related mortality burden and the currently limited attention devoted to smoking in these populations. [Callaghan RC, Gatley JM, Sykes J, Taylor L. The prominence of smoking-related mortality among individuals with alcohol- or drug-use disorders. Drug Alcohol Rev 2018;37:97-105].

Impacts of Canada’s minimum age for tobacco sales (MATS) laws on youth smoking behaviour, 2000–2014

Background Recently, the US Institute of Medicine has proposed that raising the minimum age for tobacco purchasing/sales to 21 years would likely lead to reductions in smoking behavior among young people. Surprisingly few studies, however, have assessed the potential impacts of minimum-age tobacco restrictions on youth smoking. Objective To estimate the impacts of Canadian minimum age for tobacco sales (MATS) laws on youth smoking behaviour. Design A regression-discontinuity design, using seven merged cycles of the Canadian Community Health Survey, 2000–2014. Participants Survey respondents aged 14–22 years (n=98 320). Exposure Current Canadian MATS laws are 18 years in Alberta, Saskatchewan, Manitoba, Quebec, the Yukon and Northwest Territories, and 19 years of age in the rest of the country. Main outcomes Current, occasional and daily smoking status; smoking frequency and intensity; and average monthly cigarette consumption. Results In comparison to age groups slightly younger than the MATS, those just older had significant and abrupt increases immediately after the MATS in the prevalence of current smokers (absolute increase: 2.71%; 95% CI 0.70% to 4.80%; P=0.009) and daily smokers (absolute increase: 2.43%; 95% CI 0.74% to 4.12%; P=0.005). Average past-month cigarette consumption within age groups increased immediately following the MATS by 18% (95% CI 3% to 39%; P=0.02). There was no evidence of significant increases in smoking intensity for daily or occasional smokers after release from MATS restrictions. Conclusion The study provides relevant evidence supporting the effectiveness of Canadian MATS laws for limiting smoking among tobacco-restricted youth.