Despite public health campaigns, smoking remains the leading avoidable cause of death worldwide, killing almost six million people a year, mostly in low- and middle-income countries, the World Health Organization said Wednesday.

If current trends hold, the number of deaths blamed on tobacco use will rise to eight million a year in 2030, the WHO said in a briefing unveiled at a conference in Panama.

About 80 percent of tobacco-related deaths forecast for 2030 are expected in low- and middle-income countries, the report added.

“If we do not close ranks and ban tobacco advertising, promotion and sponsorship, adolescents and young adults will continue to be lured into tobacco consumption by an ever-more aggressive tobacco industry,” said WHO Director-General Dr Margaret Chan.

“Every country has the responsibility to protect its population from tobacco-related illness, disability and death.”

Among the dead this year, five million were tobacco users or former users, while more than 600,000 died from second-hand smoke, according to the WHO.

Tobacco use is believed to have caused the deaths of 100 million people in the 20th century.

Barring dramatic change, the tally for this century could soar to one billion people, the WHO warned.

“We know that only complete bans on tobacco advertising, promotion and sponsorship are effective,” Dr. Douglas Bettcher, the Director of the WHO’s Prevention of Noncommunicable Diseases department, told the Panama conference.

“Countries that introduced complete bans together with other tobacco control measures have been able to cut tobacco use significantly within only a few years,” he said.

The report noted that 2.3 billion people from 92 countries benefit from some form of smoking restrictions, more than double the number who did five years ago.

However, that figure still represents just a third of the world’s population, it said.