More than 20 percent of the world's adult population—one billion people—smoke, while almost 5 percent—240 million—have an alcohol use disorder, according to a new report.
Alcohol's impact in terms of disability is more than three times higher than the impact of illegal drugs, the researchers report in the journal Addiction.
While reliable statistics on illicit drugs are difficult to determine, the researchers estimate about 15 million people worldwide inject illegal drugs such as heroin.
"The most striking thing to emerge is how much more damage is done to society by legal drugs than illegal ones," study co-author Robert West, editor-in-chief of the journal Addiction, said in a journal news release.
The heaviest drinkers reside in Eastern Europe, where an average of 3.7 gallons of alcohol are consumed per person annually, HealthDay reports.
Northern Europeans drink almost as much, while people in Central, Southern and Western Asia drink the least—an average of a half-gallon of alcohol per year.
The study found 30 percent of adults smoke in Eastern Europe and Oceania (the Pacific region that includes Australia and New Zealand). The smoking rate is 20 percent in Western Europe. The rate of injection drug use is highest in North and Central America/Caribbean, and lowest in Northern Europe.