Nearly 32 million adults in the United States (13 percent of the U.S. population aged 18 and older) consumed more than twice the number of drinks considered binge drinking on at least one occasion, according to a 2013 survey that asked about past-year drinking. This higher level of drinking is associated with increased health and safety risks. A report of the findings is online in the American Journal of Preventive Medicine. The study was conducted by researchers at the National Institute on Alcohol Abuse and Alcoholism (NIAAA), part of the National Institutes of Health.

"This important study reveals that a large number of people in the United States drink at very high levels and underscores the dangers associated with such 'extreme' binge drinking," said NIAAA Director George F. Koob, Ph.D. "Of the nearly 90,000 people who die from alcohol each year, more than half, or 50,000, die from injuries and overdoses associated with high blood alcohol levels."

Binge drinking, defined as having four or more drinks on an occasion for women, or five or more drinks on an occasion for men, can produce blood alcohol levels greater than 0.08 percent, which is the legal limit for driving in the United States. Reaching this level is well known to increase the risk of harms to the drinker and others. However, evidence suggests that many people drink far beyond four or five drinks per occasion, defined as extreme binge drinking. The current study analyzed three levels of past-year binge drinking -- Levels I, II, and III. These levels were defined as four to seven drinks, eight to 11 drinks, and 12 or more drinks on a single occasion for women; and five to nine drinks, 10-14 drinks, and 15 or more drinks on a single occasion for men.

Researchers, led by Ralph Hingson, Sc.D., director of the NIAAA Division of Epidemiology and Prevention Research, analyzed data from two waves of the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC), which is a series of large epidemiologic surveys that examine alcohol use and its co-occurrence with drug use and related psychiatric conditions. In the 2001-2002 and 2012-2013 waves of NESARC, 42,748 and 36,083 U.S. adults, respectively, reported the maximum number of drinks they consumed on any day in the past year.

The researchers found that in the 2012-2013 survey, 39 percent of adult males and 27 percent of adult females reported Level I binge drinking during the previous year. Eleven percent of males reported Level II binge drinking (two times the binge drinking threshold for adult males) at least once in the past year, and 7 percent reported Level III binge drinking (three times the binge threshold) at least once in the past year. Five percent of females reported Level II binge drinking (two times the binge drinking threshold for adult females) at least once in the past year, and 3 percent reported Level III binge drinking (three times the binge threshold) at least once in the past year.

After controlling for age, race, sex, marital status, education, drug use, and smoking, compared to people who did not binge drink, people who drank at the various binge levels were much more likely to experience an alcohol-related emergency department visit; have an alcohol use disorder; be injured because of drinking; be arrested or have legal problems resulting from alcohol use; or be the driver in an alcohol-related traffic crash. Compared to non-binge-drinkers, Level I binge drinkers were 13 times more likely, Level II binge drinkers were 70 times more likely, and Level III binge drinkers were 93 times more likely, to have an alcohol-related emergency department visit.

Comparing data from the 2001-2002 and 2012-2013 NESARC waves, the researchers found that the prevalence of drinking at levels two and three times or more the standard binge thresholds in the past year was significantly higher in the most recent NESARC wave, suggesting that more adults are engaging in extreme binge drinking now than a decade earlier.

"As a society, we are justifiably concerned about extreme binge drinking among underage individuals and college students. This study indicates that other groups in the U.S. population also engage in this harmful behavior and are at increased risk for adverse consequences," says Hingson.

Extreme binge drinking was particularly common among study participants who used other drugs. This is a concern because combining alcohol with other drugs can increase the risk of injuries and overdose deaths.

"Drinking at such high levels can suppress areas of the brain that control basic life-support functions such as breathing and heart rate, thereby increasing one's risk of death," said senior author, Aaron White, Ph.D., Senior Scientific Advisor to the NIAAA Director. "The risk increases further if other sedative drugs, particularly opioids or benzodiazepines, are added to the mix."

The researchers noted that their findings highlight the need to identify interventions to reduce extreme binge drinking and its negative consequences. Additional research is needed to determine how questions about peak alcohol consumption levels can be valuable in screening for alcohol misuse, as well as in assessing gender-specific risk factors and harms for drinking at extreme levels.