Government anti-tobacco campaigns should target girls and women because surveys show teenage girls are now smoking almost as much as boys in many nations, officials told an international conference Thursday.

A report released at the 12th World Conference on Tobacco found that the gender gap in tobacco consumption among youths is closing. The report said there were no significant differences between cigarette smoking rates of 13- to 15-year-olds in more than half of the 150 countries surveyed. The results of the survey, the first of its kind, were similar for other tobacco products.

“Programs specific to gender must be developed which emphasize the serious health consequences of tobacco use,” said Charles Warren of the U.S. Centers for Disease Control and Prevention.

The findings indicate tobacco-related deaths would increase significantly if the trend in teenage smoking continues, researchers said. The global survey showed that only in the eastern Mediterranean region were boys still smoking significantly more than girls, while Europe and the Americas had the smallest gender gap in tobacco consumption.

In the United States, 17.7 percent of boys are smokers compared with 17.8 percent of girls. In Europe, 33.9 percent of boys smoke cigarettes regularly, compared with 29 percent for girls.

However, boys still smoke more than girls worldwide, with the survey showing that on average 15 percent of boys smoke regularly compared with 6.6 percent of girls. The increase in young girls' tobacco use was attributed mainly to aggressive marketing aimed at women in which the tobacco industry portrays smoking as fashionable.

“Transnational tobacco companies continue to identify women and girls in developing countries, and particularly in Asia, as a vast untapped market,” the report said. Among adults, the World Health Organization estimates that globally 47 percent of men smoke regularly compared with 12 percent of women.

The report, compiled by the CDC and WHO, was presented at a six-day convention attended by more than 2,000 experts from 115 countries.