Hundreds of military personnel who served in Operation Desert Storm in 1991 have complained of a variety of chronic health problems ever since, including fatigue, headaches, joint pain and fever.

A UK court recently ruled that the syndrome did exist - and was caused by active service.

Many of those affected believe that the root cause of their problems was exposure to chemical warfare agents during the campaign.

Our findings suggest that veterans who were possibly exposed to very low levels of chemical warfare agents do not differ from other deployed veterans on any health indicator.

Researchers

However, US researchers writing in the American Journal of Preventive Medicine have failed to find the link.

They carried out telephone interviews with 1,779, more than 600 of whom had been deployed in the Khamisiyah area, where there was exposure to chemicals such as the nerve agent sarin.

Another 600 had served in the Gulf, but in an area not thought to be affected by toxic chemicals, and the final 500 had not served in the Gulf.

If the chemical theory were correct, the researchers might expect to see more illness among the group who served in Khamisiyah.

However, there was no difference between the two groups - those deployed in Khamisiyah, and those serving elsewhere in the Gulf.

Smallscale study

The researchers wrote: "Our findings suggest that veterans who were possibly exposed to very low levels of chemical warfare agents do not differ from other deployed veterans on any health indicator."

However, when compared to the group who had never been to the Gulf, the Gulf veterans were more likely to have high blood pressure, heart disease - and to have post-traumatic stress disorder or be hospitalised for depression.

Dr Linda McCauley, from Oregan Health and Science University, said that the relatively small number of veterans involved in the study meant that it might not be completely reliable, and said that far larger numbers of soldiers could potentially have been exposed to low levels of sarin, which might also skew the results.

There are other theories as to why Gulf veterans might be falling ill.

Vaccines given to troops prior to the campaign have also been blamed, although there is little hard data to support this.