The big difference between the World Conference on Tobacco Or Health this week in Chicago and other major international conferences was the significant number of delegates from developing countries.

Wandering through the exhibition hall last Sunday, as those with poster presentations assembled their material, was like a roll call at the United Nations. The national dress of Tanzania contrasted with that of Tonga, while around the corner the Sudanese and Swaziland representatives were chatting animatedly in accented English.

Original photographs, interspersed with carefully written text, were the hallmark of these countries' posters. This was in sharp contrast to the computer-generated, laminated and image-filled displays from European, Australasian and American delegates.

Worlds apart maybe, but equally committed in a united drive against the global "tobacco epidemic". At times evangelical to the point of discomfiture, for the most part delegates represented mainstream science, medicine, sociology and the law. That they now represented the establishment was evident throughout the week.

The presence of Dr Gro Harlem Brundt land, director-general of the World Health Organisation, the US Surgeon General, the Canadian Minister for Health and a television link from Vice-President Al Gore, were firm evidence of this.

On several occasions, when they realised I was Irish, delegates spontaneously spoke of the high standing of anti-tobacco activists from the Republic. Watch the likes of Dr Fenton Howell, chairman of ASH, and Dr Bernard McCartan, a dental specialist in Dublin, contribute to the conference, and you see why. This State is clearly seen internationally as one of the most pro-active in the long-running campaign against the tobacco industry.

Tobacco companies were the real villains of this week's show. In her opening address, Dr Brundtland challenged the industry to keep its promise to mend its ways in the future. "Let us see an end to the glamorisation of tobacco use in its promotion through advertisement, sponsorship and free gifts. Let us see you support a strong international convention for tobacco control that enables countries and their people to work together to counter the risks posed by tobacco use."

A hero's welcome was given to Stanley Rosenblatt, the lawyer who achieved the biggest legal defeat yet in the battle against the tobacco industry. Introduced with typical American hoopla as "the greatest trial lawyer of the 20th century", Rosenblatt rallied delegates with a description of the courtroom battles which led to the recent Engle decision in Florida, a $140 billion suit against US tobacco companies.

Rumoured to have cost $11 million to stage, the World Conference on Tobacco Or Health was a joint effort by the American Cancer Society, the World Health Organisation and the Robert Wood Johnson Foundation. This 25-year-old charitable institution has funded $2.6 billion worth of research into healthcare since its inception.

Robert Wood Johnson set up his foundation to support people and organisations dedicated to improving healthcare and public health. One of its current projects is the funding of the National Centre for TobaccoFree Kids, a policy and public education body devoted to preventing nicotine addiction among young people.

Its partnership with basketball, baseball and football was colourfully evident throughout the convention centre.

Where else but in the US would a conference have its own TV station? Truth TV - with an adverting logo of "See Big Tobacco Get Smaller" - is a summer project for young people committed to the fight against tobacco.

The young presenters and producers provided delegates with daily interviews, news and conference updates. Each hotel room's television set was tuned to the station. Delegates could also catch the broadcasts on the shuttle buses between conference venues.

Just before leaving, I asked some of the Irish delegates for their impression of the conference. All were pleased that the effort to attend had been worthwhile.

What were the highlights? Tuesday's plenary session, on the science of addiction, really rallied the delegates. A pumped-up Alan Leshner, director of the US National Institute on Drug Abuse, exhorted the audience to take the scientific facts available and to use them to educate the public and eradicate the scourge of nicotine addiction.

To demonstrate nicotine's effects, he displayed an MRI scan showing the drug's stimulation of dopamine in parts of the brain. "Tobacco rewires the brain. Nicotine stimulates the production of dopamine, and people love that dopamine spike," he said in a dramatic performance.

Delegates left the main conference hall with Leshner's parting message buzzing in their ears: "The science of nicotine addiction is a reality and it needs to be ingrained in the public's perception. We are never going to make progress unless we bridge the great disconnect that exists between perception and reality."

A rallying call for a World Conference on Tobacco Or Health in 2003? ?