The finding, by researchers at a London medical school, provides the first clear proof that going to the Gulf did damage the health of soldiers - even though it has proved impossible to identify any specific illness or any specific cause. The results showed they suffered two to three times more illness than the other groups.
Gulf War Syndrome has been the subject of intense controversy, with veterans' associations on both sides of the Atlantic accusing the military of ignoring the evidence and the plight of sufferers.
More than $115 million (pounds 72m) has been spent researching the syndrome in the United States alone. The latest pounds 1m study, published in two papers in The Lancet, was funded by the US Department of Defense to see if other countries' experience had been the same as America's. Over 50,000 British troops served in the Gulf and the findings are based on a random sample of 3,000.
The symptoms they reported - which ranged from mild fatigue and headaches to severe urinary and sexual problems and double vision - were little different from those reported by soldiers involved in every other war in the past 100 years. It was the scale of those affected that was different - but that could be because so few Allies were killed in the Gulf War there was more opportunity to focus on the problems of the survivors.
Professor Simon Wessely, consultant psychiatrist at King's College Medical School, who led the study with Professor Tony David, said the most likely explanation for the findings was that the experience of war damaged health independent of any injury suffered in fighting. Although this might seem obvious, the carnage of previous wars could have obscured a transparent truth.
One of the strengths of the study was that it compared soldiers in the Gulf, who fought battles with the enemy and were exposed to the threat of chemical and biological weapons, with those in Bosnia, who were involved in skirmishes but did not face the same multiplicity of hazards. A third group were on active service but remained at home.
Professor Wessely added: "The Gulf was more hazardous. Modern warfare is extremely dangerous physically and psychologically to the individual. Although we may not be able to prevent these effects, we should be better prepared to monitor [the soldiers] and care for them afterwards. We have to expect that people involved in modern wars will be at risk from these sorts of illnesses."
Speculation about the causes of illness among Gulf veterans has centred on chemical and biological warfare and the measures, including vaccines, administered to protect soldiers against it.
Although both Bosnian and Gulf soldiers received multiple vaccinations against common infections, only the Gulf group was vaccinated against the biological threats of anthrax and plague - 70 per cent against the first and 35 per cent against the second.
The researchers found those who had the biological vaccines suffered more ill health but the effect was less than that of drinking local water. Those who had multiple vaccines also reported more symptoms, but only in the Gulf. The researchers suggest the explanation could be a mix of immunological and psychological effects.
Flight Lieutenant John Nichol, chairman of the Gulf War Veterans' branch of the Royal British Legion, called for a public inquiry. He said: "We welcome this report. It at last confirms what we have been saying for seven years. It is sad that it has taken an American-funded study to prove their claims were genuine." He added: "Now we need to know why they are ill so that we can help them and ensure this doesn't happen again."
Report on First World War veterans, The Lancet:
"Over 50,000 British, Canadian and American troops returned from battle as changed men. Once-vital young men who left to engage a foreign tyrant began to complain of breathlessness, grinding fatigue, irritability, headache, insomnia, and paraesthesias, rendering 70 per cent of them unfit for further duty."
Report on Gulf War veterans, published in latest issue of The Lancet:
"Veterans... report higher rates of many symptoms and disorders and have a decreased perception of wellbeing... About three times more likely to fulfil criteria for chronic fatigue, post-traumatic stress reaction, or the CDC multi-syndrome criteria."Reuse content