JGR, RM, CMB, MC, and DAR conceived of and designed the study. JGR, RM, DT, MIC, PG, and DAR collected the data. JGR, RM, DT, MIC, PG, and DAR analyzed and interpreted the data. JGR, RM, CMB, MC, and DAR participated in drafting the article. JGR, RM, CMB, DT, MIC, PG, MC, and DAR approved the final revised version of the article.
The authors have declared that no competing interests exist.
Alcohol is a contributing cause of unintentional injuries, such as motor vehicle crashes. Prior research on the association between alcohol use and violent injury was limited to survey-based data, and the inclusion of cases from a single trauma centre, without adequate controls. Beyond these limitations was the inability of prior researchers to comprehensively capture most alcohol sales. In Ontario, most alcohol is sold through retail outlets run by the provincial government, and hospitals are financed under a provincial health care system. We assessed the risk of being hospitalized due to assault in association with retail alcohol sales across Ontario.
We performed a population-based case-crossover analysis of all persons aged 13 years and older hospitalized for assault in Ontario from 1 April 2002 to 1 December 2004. On the day prior to each assault case's hospitalization, the volume of alcohol sold at the store in closest proximity to the victim's home was compared to the volume of alcohol sold at the same store 7 d earlier. Conditional logistic regression analysis was used to determine the associated relative risk (RR) of assault per 1,000 l higher daily sales of alcohol. Of the 3,212 persons admitted to hospital for assault, nearly 25% were between the ages of 13 and 20 y, and 83% were male. A total of 1,150 assaults (36%) involved the use of a sharp or blunt weapon, and 1,532 (48%) arose during an unarmed brawl or fight. For every 1,000 l more of alcohol sold per store per day, the relative risk of being hospitalized for assault was 1.13 (95% confidence interval [CI] 1.02–1.26). The risk was accentuated for males (1.18, 95% CI 1.05–1.33), youth aged 13 to 20 y (1.21, 95% CI 0.99–1.46), and those in urban areas (1.19, 95% CI 1.06–1.35).
The risk of being a victim of serious assault increases with alcohol sales, especially among young urban men. Akin to reducing the risk of driving while impaired, consideration should be given to novel methods of preventing alcohol-related violence.
In a population-based case-crossover analysis, Joel Ray and colleagues find that the risk of being a victim of serious assault increases with retail alcohol sales, especially among young urban men.
Alcohol has been produced and consumed around the world since prehistoric times. In the Western world it is now the most commonly consumed psychoactive drug (a substance that changes mood, behavior, and thought processes). The World Health Organization reports that there are 76.3 million persons with alcohol use disorders worldwide. Alcohol consumption is an important factor in unintentional injuries, such as motor vehicle crashes, and in violent criminal behavior. In the United Kingdom, for example, a higher proportion of heavy drinkers than light drinkers cause violent criminal offenses. Other figures suggest that people (in particular, young men) have an increased risk of committing a criminally violent offense within 24 h of drinking alcohol. There is also some evidence that suggests that the victims as well as the perpetrators of assaults have often been drinking recently, possibly because alcohol impairs the victim's ability to judge potentially explosive situations.
The researchers wanted to know more about the relationship between alcohol and intentional violence. The recognition of a clear link between driving when impaired by alcohol and motor vehicle crashes has led many countries to introduce public awareness programs that stigmatize drunk driving. If a clear link between alcohol consumption by the people involved in violent crime could also be established, similar programs might reduce alcohol-related assaults. The researchers tested the hypothesis that the risk of being hospitalized due to a violent assault increases when there are increased alcohol sales in the immediate vicinity of the victim's place of residence.
The researchers did their study in Ontario, Canada for three reasons. First, Ontario is Canada's largest province. Second, the province keeps detailed computerized medical records, including records of people hospitalized from being violently assaulted. Third, most alcohol is sold in government-run shops, and the district has the infrastructure to allow daily alcohol sales to be tracked. The researchers identified more than 3,000 people over the age of 13 y who were hospitalized in the province because of a serious assault during a 32-mo period. They compared the volume of alcohol sold at the liquor store nearest to the victim's home the day before the assault with the volume sold at the same store a week earlier (this type of study is called a “case-crossover” study). For every extra 1,000 l of alcohol sold per store per day (a doubling of alcohol sales), the overall risk of being hospitalized for assault increased by 13%. The risk was highest in three subgroups of people: men (18% increased risk), youths aged 13 to 20 y (21% increased risk), and those living in urban areas (19% increased risk). At peak times of alcohol sales, the risk of assault was 41% higher than at times when alcohol sales were lowest.
These findings indicate that the risk of being seriously assaulted increases with the amount of alcohol sold locally the day before the assault and show that the individuals most at risk are young men living in urban areas. Because the study considers only serious assaults and alcohol sold in shops (i.e., not including alcohol sold in bars), it probably underestimates the association between alcohol and assault. It also does not indicate whether the victim or perpetrator of the assault (or both) had been drinking, and its findings may not apply to countries with different drinking habits. Nevertheless, these findings support the idea that the consumption of alcohol contributes to the occurrence of medical injuries from intentional violence. Increasing the price of alcohol or making alcohol harder to obtain might help to reduce the occurrence of alcohol-related assaults. The researchers suggest that a particularly effective approach may be to stigmatize alcohol-related brawling, analogous to the way that driving under the influence of alcohol has been made socially unacceptable.
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Intentional injury is a widespread cause of death, disability, property damage, demand for emergency medical service, and grief [
Alcohol is the most commonly purchased and consumed psychoactive substance in the Western world [
We wondered whether prior research on the association between alcohol use and violent injury might be biased because of its reliance on survey-based or archival data such as police reports and emergency room visits (where respondents may underestimate their true alcohol consumption), the inclusion of cases from a single trauma centre, and the absence of adequate controls or the high likelihood of between-person confounding (i.e., factors that vary among persons) [
We conducted a retrospective population-based case-crossover study in Ontario, Canada between 1 April 2002 and 1 December 2004 [
Cases were defined as consecutive adult victims of assault aged 13 y and older who were admitted to an Ontario acute care hospital during the study interval. We excluded individuals who were below age 13 y because of the differing nature of assault in paediatric populations. We also excluded individuals who were not residents of Ontario or had no linkable health care file because of database limitations. Cases with more than one hospitalization were counted at the first admission only. Our study did not rely on individual-level consent, and followed safeguards for patient confidentiality at the Institute for Clinical Evaluative Sciences in Ontario. The Ethics Committees of St. Michael's Hospital and the Sunnybrook Health Sciences Centre granted approval for this study.
The Canadian Institute for Health Information (CIHI) Discharge Abstract Database (DAD) captured all hospitalizations in Ontario and up to 25 diagnoses coded by International Classification of Diseases 10th Revision (ICD-10). We identified cases using ICD-10 codes for external causes of morbidity and mortality related to assault. The specific codes were X85 to Y09 (
The CIHI DAD was combined with the Ontario Registered Persons Database to yield basic information about the individual, such as age and sex. The patient's home postal code corresponded to the home residence location at the time of the injury. Income quintile and rural residence were defined according to the individual's home postal code using Statistics Canada census data. Patient length-of-stay was obtained as the difference between the admission date and discharge date, with stays shorter than 24 h coded as 1 d. Discharge status was coded as alive or dead, with no analysis of long-term institutionalization or rehabilitation.
The study exposure was the daily sales of alcohol at the closest LCBO store to the patient on the day before the assault hospitalization. No alcohol can be consumed on the premises of an LCBO store. In Ontario, the sale of alcohol is regulated by provincial statute, with a legal lower limit of 19 y. All spirits, about 85% of total wine, and about 20% of all beer are sold to non-wholesale purchasers by nearly 600 LCBO retail outlets run by the provincial government [
Each LCBO sales outlet has an assigned location and postal code. We used Geographic Information System software (ARC 9.1, Environmental Systems Research Institute) to determine the straight-line distance between each LCBO outlet's postal code and each patient's home postal code [
The case-crossover design compared exposures immediately prior to the injury times to the same exposures at control times. Doing so provided an assessment of the short-term effect of transient exposure on the risk of injury, and minimizes between-person confounding, since a “case” acts as his or her own control [
We excluded the top and bottom 1% of alcohol sales for combined outlets to address extreme outliers, such as early store closures, when sales are abnormally low, or at times of peak sales, such as at Christmas time. The median and interquartile range (IQR) of daily alcohol sales per store were calculated in both litres (l) and 2004 Canadian dollars (Can$), and their 10th and 90th percentile values were used to represent nadir and peak sales [
There were 3,903 youths and adults hospitalized due to assault during the 32-mo study period, equivalent to a rate of four per day. Of these, 15 were excluded because they resided outside Ontario, 419 could not be matched to an LCBO outlet by postal code, and 257 cases had extreme outlier LCBO sales data on the index date, the referent date, or both. This resulted in a study cohort of 3,212 cases. The number of patients was generally steady over time, with a peak between July and October of each year (
The mean age of the cases was 32.5 y, of whom nearly 25% were between the ages of 13 and 20 y, and 83% were male (
Characteristics of Persons Hospitalized for Assault, and Descriptions of the Alcohol Sales Outlets
Among the 491 LCBO outlets closest to an assault case, the median daily volume of alcohol sales per store was 971 l, amounting to Can$8,597 per day (
Case-crossover analysis suggested that increasing alcohol sales was associated with a 13% (95% CI 2%–26%) higher relative risk of being hospitalized for assault for every 1,000 l more of alcohol sold per store per day (
Risk of Assault-Related Hospitalization in Association with Daily Alcohol Sales among 3,212 Cases of Assault
The increased risk of assault was evaluated for the three types of alcohol. On a volume basis, the RR was highest for spirits (1.26, 95% CI 1.02–1.55), and lowest for beer (RR 0.99, 95% CI 0.85–1.10) (
Of all 3,212 assaults, 1,150 (35.8%) were related to the use of a sharp or blunt weapon (
Risk of Hospitalization for Assault, in Association with Daily Sales of All Forms of Alcohol, by Type of Assault
The higher risk of assault associated with alcohol sales was evident for individuals with differing characteristics (
We observed a 13% higher risk of being hospitalized for assault with each additional 1,000 l of alcohol sold per day, equivalent to about a doubling of the usual daily sales. At peak times of alcohol sales, the risk was 41% higher, equivalent to about 1.4 additional assaults per day. About one-third of injuries were due to a sharp or blunt weapon, and were significantly associated with alcohol sales. This suggests that the cognitive impairment caused by alcohol is a factor in intentional injuries [
Our study has several limitations. First, we captured only those cases sufficiently severe to require hospitalization, but not so extensive as to lead to death at the scene. At the other extreme, some injuries may not warrant admission to hospital and are excluded from our study [
Our study also has several strengths. We measured alcohol sales in the index and referent time periods of the same store, and thereby reduced geographic or seasonal variation, an advantage of our case-crossover design [
How well do alcohol sales reflect consumption? Smith et al. compared self-reported alcohol consumption with state-specific per capita sales in 21 states in the US [
Our findings are consistent with other published studies, which often included fewer than 1,000 cases of assault, and were outside of a hospital setting. In the British Crime Survey on alcohol-related violence, about 40% of those committing violent acts were under the influence of alcohol [
US national surveys have found that underage drinkers and adult excessive drinkers consumed nearly 50% of all alcohol [
The direct and indirect costs related to being hospitalized for assault are substantial. A conservative estimate of the daily cost of a hospitalization is Can$1,000 [
These study findings confirm that alcohol-related assault produces serious medical injuries [
While the density of alcohol sales outlets appears to be a major predictor of violent crime [
Clearly, we need rigorous research on how alcohol consumption contributes to assault, in terms of the type, quantity, and rapidity of alcohol consumption, and the degree of intake by the perpetrator and the victim.
confidence interval
International Classification of Diseases 10th Revision
interquartile range
Liquor Control Board of Ontario
relative risk