‘Gulf War syndrome’ is a phrase coined after the 1991 Gulf War to group together disparate, unexplained health symptoms in Gulf veterans.
This paper examines the many hypotheses that have been put forward about the origins of the concept and gives an overview of the studies that have attempted to explain the lasting health effects associated with Gulf service.
Our review finds that although in the UK there has not yet been evidence of a new Gulf War syndrome as a result of the current conflicts in Iraq and Afghanistan, there is a rise in post-conflict psychiatric disorders now being reported in the USA. We postulate that after conflicts military personnel will always face some form of post-conflict syndrome and the nature of the threats experienced is likely to dictate the form the syndrome might take. We also postulate that media reporting is likely to have influenced and to continue unhelpfully to influence the health of service personnel.
In 1991, a coalition of troops liberated Kuwait from the control of Iraqi forces. The war-fighting phase of the 1991 conflict was short and associated with minimal casualties to Coalition forces. Initially, the conflict was a medical success story, not only in terms of the low number of battle casualties but also the minimal burden of heat-related or infectious diseases, traditionally a major source of both morbidity and mortality for service personnel in operations carried out in testing environments.
However, just a few months after the war, media reports of first an apparent, but never confirmed, cluster of birth defects in the children of some Gulf veterans, and later of unexplained health symptoms in other Gulf veterans began to emerge. These reports began in the USA but gradually spread to nearly all the countries that had taken part in the coalition against Saddam Hussein, with the possible exception of Saudi Arabia. Finally, and it is unclear exactly when or by whom, the term ‘Gulf War syndrome’ (GWS) was coined to group these disparate phenomena together.
The nature and existence of GWS have been and continue to be the subject of heated debates, even though more of the recent attention has switched to the latest conflict in Iraq.
The beginnings of a ‘GWS’
In August 1990, Iraqi forces invaded and occupied Kuwait. The international community responded by convening a coalition military force derived from the USA (697,000 troops committed), the UK (53,500 troops), France (25,000 troops) and over 30 other nations, including Saudi Arabia, Denmark, Canada, and Australia.
After five weeks of intense bombardment of Iraqi positions, the ground war began on 24 February 1991 and lasted only four days. It was a resounding military success, and a triumph for military medical services. Traditionally, offensive operations are associated with large numbers of disease non-battle injury casualties from causes such as heat illness.
However, in the 1991 Gulf War there were no deaths from disease non-battle injuries among US or British troops. Yet death is not the only important, or indeed media-worthy, outcome, as the GWS story showed in a powerful way. The initial reports The first media reports of unusual illnesses occurring in Gulf War veterans began to emerge from the USA towards the end of 1991 (Facing Persian Gulf syndrome. Philadelphia Inquirer, 1993). Initial stories tended to focus on two health concerns: unusual illnesses in previously fit veterans and an increase in birth defects in veterans’ children. Understandably, there was considerable public interest and the media responded by increasing their coverage of the issue. It remains unclear who coined the term ‘GWS’, but considerable media and public pressure led to both the USA, and subsequently, the UK, conducting epidemiological research.
The first studies
The first response was to set up disease registers that enabled Gulf veterans to attend a clinic and undergo a comprehensive health assessment. These began in the USA with the establishment of the Department of Defense and Veterans Affairs Health Examination Registry Program. The UK followed with the Gulf War Veterans Medical Assessment Programme. More than 100,000 veterans attended these programmes, more than 90% of these in the USA.3,4 Case registers such as these are not random samples of the population and caution should be applied before drawing any firm conclusions from the data derived from them.
Given the numbers involved, however, these should have sufficient power to detect any major increase in a well recognized illness or disease or to indicate an emergent condition. Neither of these was identified in studies based on the Gulf War veteran registers, where the largest diagnostic category was ‘medically unexplained symptoms and syndromes’.
Cancer and mortality
The media have claimed that Gulf War veterans suffered an increase in mortality rates. However, comprehensive analyses of the US and UK Gulf cohorts7 have not shown an increase in mortality in both groups, other than a rise in the rate of accidental death (US and UK) or suicide (US only). This observation has often been made in the aftermath of other conflicts and is possibly linked to an increase in risktaking behaviour. Furthermore, no increase was found in cancer rates among UK or Australian veterans of the Gulf War.
The Gulf War health effect
Increased rates of symptom reporting in a Gulf cohort were first picked up by an US Army study looking at reservist personnel in Indiana and then confirmed by the Iowa Persian Gulf Study Group. Incidence of conditions such aschronic fatigue syndrome, depression, and post-traumatic stress disorder (PTSD) were all elevated. All these are based on reported symptoms rather than objective clinical markers.
The UK’s first systematic epidemiological study compared 4246 randomly selected British Gulf War veterans, drawn from all three Services with similar numbers of non-deployed personnel (the so-called ‘Era’ group), and with an active duty control group who had served, some years later, in the Bosnian conflict. The results showed that UK Gulf veterans were 2–3 times more likely to report each and every one of the 50 physical symptoms that were inquired about than either the Era group or the Bosnian group (Figure 1).Furthermore, although perceived health was decreased in the Gulf cohort, physical functioning was only very slightly different and still above expected non-military norms.
These are not isolated findings. A review by Barrett et al. again concluded that Gulf War veterans report 2–3 times the rates of common symptoms compared with their non-deployed colleagues. Other studies have also found that health perception and quality of life are impaired in those who were deployed to the Gulf compared with military personnel who were not. Investigators did find an unexplained twofold increase in rates of seborrhoeic dermatitis, a result that awaits replication.
A large US study performed using multiple methods of data collection has reported 40 cases of amyotrophic lateral sclerosis (ALS). The US government considered this significant enough to declare the disease service-attributable. However, there remains good reason to believe that the excess is the result of an ascertainment bias, in which greater efforts were made to find cases in Gulf veterans than in control individuals, together with an unusually low rate of ALS in those control individuals. An increase in ALS has also been reported in veterans of other wars where there was no suggestion of exposure to organophosphate nerve agents, considered one of the possible causes for GWS. Furthermore, there has not been an increase in mortality owing to neurological disease in Gulf Veterans, which would be expected as ALS is ultimately fatal. ALS is still rare, fortunately, in groups of veterans and cannot explain the overall increase in symptomatology in Gulf veterans.
Is the phrase ‘GWS’ valid?
There is substantial evidence to suggest that there is an identifiable Gulf health effect but that effect does not amount to a discrete disorder or indeed syndrome. To identify a GWS as a unique condition, it would be necessary to show that there was a constellation of symptoms and signs specifically related to service in the Gulf; numerous controlled studies have shown this is not the case. Furthermore, the symptoms experienced by veterans also occur elsewhere, without an association with Gulf deployment.
Most scientists, but not all, share this view. Robert Haley, a US epidemiologist in Dallas, Texas, was the first to present evidence suggestive of a new syndrome and continues to espouse this position. However, his study was based on a single reserve battalion, failed to achieve a satisfactory response rate, but most importantly had no control group.
As others have pointed out on many occasions, this makes it impossible to determine whether the reported constellation of symptoms is indeed unique to Gulf War veterans. Since then he has claimed evidence of first peripheral, and then later on, central nerve damage in Gulf veterans, attributable, in his view, to exposure to a combination of chemical weapons and/or pesticides. However, several expert review panels have not been convinced either by the medical evidence or the suggestion of exposure to chemical weapons. Other studies failed to find evidence of significant damage to the peripheral nervous system in Gulf veterans, making exposure to organophosphate pesticides an unlikely cause of ill health in these people. Well-conducted neuropsychological studies of central nervous system function in Gulf veterans have not shown compelling evidence of damage. A replication of the original neuroimaging study is keenly anticipated but if history is to be a guide, will most likely prove reassuring.
Numerous papers have shown beyond reasonable doubt that there are substantial numbers of veterans labelled with GWS who have identifiable problems; reported prevalence rates range from 20 to 30%. Furthermore, we do not consider that the reporting of symptoms is, in the main, a result of attempts to procure financial rewards. The British War Pension system does not require a formal diagnosis to award compensation, simply an opinion on the level of disability, from whatever cause. In spite of many Gulf Veterans having received monetary recompense for their disabilities, evidence suggests that most Gulf veterans who were ill in 1996 were still unwell in 2001.
Yet whatever the inadequacies of the term, GWS has captured the popular and media imagination and is probably here to stay. Bowing to the inevitable, in 2005 the UK Ministry of Defence accepted the phrase GWS, for the purpose of awarding war pensions, with the caveat that the term was an umbrella term covering the various clinical presentations and outcomes. However, it is noteworthy that not all coalition allies (e.g. the French military) have come to the same view.
What are the proposed causes?
Despite the above, a variety of agents have been alleged to be the ‘cause’ of GWS. In general, most of these claims have not been substantiated. For example, depleted uranium (DU), used in munitions such as tank shells, is often proposed as a possible cause of ill health in Gulf personnel. Those most likely to come into contact with DU would have been personnel working in or around armoured vehicles. But, as already discussed, there is no link between the role an individual veteran fulfilled and reporting of symptoms.
Likewise, those personnel who have been injured with DU fragments, thus indisputably exposed, have not suffered adverse health consequences to date. Evidence from the 2003 Iraq war has also failed to link exposure to DU with health problems in Coalition forces. Another exposure often mentioned relates to the pyridostigmine bromide tablets that were used as a prophylactic against possible effects of exposure to some chemical weapons. However, Canada sent three ships to the Gulf, only two of which used pyridostigmine bromide prophylaxis, yet the rate of illness was the same in personnel from all three ships. Other putative agents include organophosphate pesticides.
These were successfully used to decrease the threat of disease from insect vectors but if handled incorrectly can cause damage to the nervous system. Detailed studies of the peripheral nervous system in both US- and UK-derived samples have failed to find evidence of neuropathy and a large US epidemiological survey of Gulf veterans and their families came to the same conclusion.
Another claim is that ill health has resulted from accidental exposure to organophosphate-based nerve agents, of which the chief culprit was sarin nerve agent that may have been released unnoticed with the destruction of the Iraqi arms dump at Khamisayah. It has also been claimed that there was a deliberate but undetected use of sarin by Iraqi forces but this has little or no military credibility. However, irrespective of whether sarin was released into the environment, expert committees have not been convinced that this could be responsible for the observed ill health, not least given the chemical doses and exposure distances involved.
On the other hand, there is some epidemiological evidence linking the particular pattern of vaccinations given to protect personnel against biological warfare with subsequent ill health. The UK group from King’s College London, for example, reported an association between symptomatic outcomes and receiving multiple vaccinations in general, or specific jabs against chemical and biological weapons (CWBs), such as the anthrax vaccine. However, detailed investigations have failed to confirm that this link is immunologically mediated, and the possibility that problems in record keeping (acknowledged as a major deficiency) and recall bias account for some of this association remains a real one.
Other potential causative agents, including fumes from burning oil wells, have also been investigated but detailed environmental monitoring at the time and subsequent outcome studies have failed to find convincing evidence to support these or other more maverick theories.
We acknowledge that there are some who are convinced that at least one or more of these possible hazards are indeed the cause of ill health in Gulf veterans. Golomb,65 for example, has argued for some years that the combined effect of exposure to acetyl cholinesterase inhibitors, such as nerve agents, pyridostigmine bromide, and pesticides, are indeed directly causal in this context. However, a long series of authoritative and extensive reviews, such as those produced by the prestigious and independent Institute of Medicine in the United States and others, have failed to be convincing through these arguments. No compelling evidence has yet emerged implicating any hazardous substance, acting alone or in combination, in the genesis of ill health in Gulf veterans. We think it is unlikely that this position will change materially.
History has many examples of post-conflict ill health syndromes. From the middle of the nineteenth century, when interpretable medical records and accounts began to be kept, there are clinical descriptions of ex-servicemen with considerable similarities to the Gulf narratives. Their conditions have received many different labels: Soldier’s Heart, later termed Effort syndrome, shell shock, neurasthenia and, more recently, Agent Orange syndrome and PTSD.
Historian Edgar Jones and colleagues conducted a systematic study of UK war pension files from the Boer War, the First and Second World Wars, and ending with clinical files from the Gulf War Medical Assessment Programme. The results showed that post-conflict syndromes with considerable similarities to Gulf War illness have been reported after all the major conflicts involving the British Armed Forces.
The medical literature also contains many other medically unexplained symptoms with similarities to the Gulf War health effect, examples being chronic fatigue syndrome, total allergy syndrome, dental amalgam disease, and sick building syndrome.
Post-conflict syndromes: an emerging health threat?
It seems unlikely that any single cause of the GulfWar health effect will ever be discovered and it is heartening that for whatever reasons our IraqWar veterans do not as yet seem to be experiencing a repeat of GWS. We say ‘as yet’ because no one knows when the Gulf health effect was first detectable, only that it was present at a minimum of five years after the conflict.
The absence of a new ‘unexplained’ syndrome arising after the Iraq war may be a surprise, especially given the legacy of previous conflicts. However, as the term ‘mild traumatic brain injury’ emerges, it may be that the conflicts in Iraq and Afghanistan have still to get their ‘signature’ unexplained syndrome. What is indisputable is the dramatic increase in ‘explained’ syndromes that have arisen in, for example, US soldiers who have served in the Iraq conflict. Simply because PTSD, unlike GWS, has an accepted terminology and a reproducible case definition, it should not follow that it too counts as an ‘unexplained’ syndrome similar to all psychiatric disorders. As numerous critics have pointed out, the assumption that trauma has central importance in the aetiology of PTSD sits uneasily within the general atheoretical nature of psychiatric classification, in which syndromes are defined by symptoms, not aetiology. There is a considerable critical literature on the diagnosis of PTSD, its political as opposed to medical or research origins, and in particular how the assumption that trauma has a central role obscures many other factors that are also of aetiological importance.
The rise, and it is a considerable and dramatic rise, in postconflict psychiatric disorders now being reported from the USA must be seen as evidence that post-conflict syndromes remain a major threat to the health of service personnel. As more and more nations either have already moved or are in the process of moving from large conscript or national service armed forces to smaller, better trained professional services, monitoring their health and their health concerns is becoming an increasing priority.
Perhaps one of the enduring health legacies of the 1991 Gulf War has been the launch of longer term cohort studies of either the entire Armed Forces or large representative samples thereof, a process that has begun in the USA, Canada, the UK, Australia, the Netherlands, and elsewhere. Research and health surveillance are now seen as necessary for monitoring emerging health threats to provide empirical data and also to provide reassurance to service personnel, their families, the public, and the media.