U.S. cigarette companies modified their products to induce women smokers by stressing stylishness, taste and perceived health benefits that they knew would appeal to women, a Harvard study of tobacco industry documents claims.

The study could have global health implications as tobacco companies turn to the Third World to increase smoking among women, the study's authors wrote.

While men are smoking less globally, female smoking rates are expected to continue increasing and reach 20 per cent by 2025, driven by the growth of female markets in developing countries.

The paper in the June 2005 issue of the journal Addiction takes a step forward in understanding the role of product design in targeting cigarettes to women. This area had been less well understood than the marketing of appealing attributes such as women's liberation, glamour, success and thinness.

The Harvard study examines documents made public following the 1998 Tobacco Master Settlement Agreement.

"These internal documents reveal that the tobacco industry's targeting of women goes far beyond marketing and advertising," said lead author Carrie Murray Carpenter, a research analyst at the Tobacco Control Research and Training Program at the Harvard School of Public Health.

For more than 20 years, the industry studied gender-based differences in motivational factors, smoking patterns, and product preferences in order to promote smoking among women and girls, the authors wrote.

Even appetite suppressants considered

The research allowed the companies to make cigarettes that exploited the concept of relative saftey through light cigarettes and less sidestream smoke, and conformed to women's taste and odour preferences and the actual way women smoke: with a weaker pull than men.

The documents also show that cigarette makers went so far as to explore the use of appetite suppressants in cigarettes to promote smoking-mediated weight control, the researchers wrote.

"Carpenter and her group reveal that cigarette designs and ingredients were manipulated to make the cigarettes more palatable to women and to complement advertising illusions of smooth, healthy, weight-controlling, stress-reducing smoke," an accompanying editorial in Addiction said.