Low-Level Alcohol Consumption Increases Risk of Injury

Alcohol's burden on society is undisputed. The economic impact alone is staggering. According to the National Institute on Alcohol Abuse and Alcoholism, billions of dollars in earnings are lost each year due to alcoholism and alcohol-related incidents. Billions more are spent on medical costs and public services. Despite all the information about the societal problems due to alcohol, few studies show the impact of short-term exposure to the prevalent drug. New findings by a University of Missouri-Columbia researcher demonstrate that a person's risk of injury increases significantly after only two standard drinks, such as two 12-ounce beers.

"Before our study, it was hard to find the association between risk of injury and short-term exposure to alcohol," said Dan Vinson, associate professor of family and community medicine at MU. "This study shows that just two drinks during a six-hour period more than double the chances that a person will sustain some type of injury."

Vinson's research destroys popular myths about how much alcohol people can safely consume in a given time period. For example, three or four drinks consumed over a six-hour period -- a quantity generally accepted as safe if the drinks are distributed at one or less per hour -- multiplies the risk of injury by five. Five or six drinks in the same time period increase the risk of injury 10-fold. Overall, the study provides strong evidence that short-term, acute exposure to alcohol poses a serious threat of injury.

"We're not talking about alcoholism in this study," Vinson said. "We're talking about common, ordinary behavior."

As predicted before and during the study, Vinson believes the findings provide important data that could influence public policy. The study indicates that the typical person is substantially impaired before reaching a blood-alcohol content (BAC) of 0.08, the current level for being considered legally drunk in Missouri. To illustrate this, a 160-pound man who consumes four drinks in one hour would have a BAC of 0.08 at the end of that hour. A 135-pound woman who consumes three drinks in one hour would have a BAC of 0.08 at the end of that hour.

The study used the case-crossover method, a relatively new study design developed by Malcolm Maclure, one of the co-investigators. The researchers compared patients' drinking consumption in the six hours prior to their injury with their drinking consumption in the same six-hour block of time the day before. The researchers obtained their data from interviews with individuals who were treated for injuries in one of the three emergency rooms in Columbia, Mo. Researchers also compared the subjects to a community-control group and discovered very similar findings.

Vinson hopes his study will spark a public discussion about the implications of low- to moderate-levels of alcohol consumption. He says the information should help family practice physicians answer the common question of how much alcohol may be consumed without endangering one's health. Vinson's study will be published in the May issue of the Journal of Studies on Alcohol.