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Health and exposures of United Kingdom Gulf
war veterans.
Part I: The pattern and extent of ill health
N Cherry, F Creed, A Silman, G Dunn, D Baxter, J Smedley, S Taylor, G J Macfarlane
Abstract
Objectives—To assess the health of United
Kingdom Gulf war veterans, to compare
their health to that of similar personnel
not deployed, to describe patterns of ill
health in both groups, and to estimate
their extent.
Methods—Main Gulf (n=4795) and valida-
tion Gulf (n=4793) cohorts were randomly
selected within strata from the population
deployed to the Gulf and a non-Gulf
cohort (n=4790) from those who were not
sent. Seven years after the war subjects
completed a questionnaire about their
health in the past month, including 95
symptom questions and two manikins on
which to shade areas of pain or numbness
and tingling. Responses were subjected to
a principal component analysis with rota-
tion and to a cluster analysis within each
cohort. Mean symptom score was used as
a measure of severity. Areas shaded on the
manikins were coded to indicate wide-
spread pain and possible toxic neu-
ropathy.
Results—A response of 85.5% was
achieved. Those who had been to the Gulf
were more troubled by every symptom
with a mean severity score (3.0) substan-
tially greater than in the non-Gulf cohort
(1.7). Seven factors were extracted ac-
counting for 48% of the variance. The
scores on five factors (labelled psychologi-
cal, peripheral, respiratory, gastro-
intestinal, and concentration) were
significantly worse in those who had been
to the Gulf. Symptoms suggestive of
peripheral neuropathy were found more
often (12.5%) in the Gulf than the non-
Gulf (6.8%) cohorts. Widespread pain was
also found more often (12.2% Gulf; 6.5%
non-Gulf). Those who had been to the
Gulf were found disproportionately
(23.8%) in three clusters with high mean
severity scores; only 9.8% of non-Gulf
respondents were in these clusters. There
was no evidence of an important excess in
the use of alcohol, tobacco, or referral to
hospital specialists by those who had been
to the Gulf. For the same level of reported
ill health those who had been to the Gulf
were less likely to be referred to specialists
than non-Gulf veterans.
Conclusion—7 Years after the war, the
Gulf war veterans were more troubled
about their health than those who had not
been sent, with a substantial subgroup
reporting a pattern of symptoms sugges-
tive of a significant decline in health.
(Occup Environ Med 2001;58:291–298)
Keywords: Gulf war; symptoms; clusters
Follow up studies of random samples of men
and women who served in the Gulf States in
1990–91 have shown—in the United States,
12
Canada,
3
the United Kingdom,
4
and
Denmark
5
—that veterans report considerably
greater ill health than other service personnel.
The syndromes identified in Gulf war veterans
have been determined by the type of instru-
ment used and the interest of the research
team, but have included post-traumatic stress
disorders,
1
chronic fatigue syndrome,
46
fibro-
myalgia,
17
and multiple chemical sensitivity.
6
Although several studies have considered the
possibility of an unusual cluster of symptoms
specific to experience in the Gulf, few study
designs have had the capacity to investigate this
thoroughly, and no novel syndrome has been
identified that has been accepted by the scien-
tific community.
The present report describes the pattern of
symptoms reported by men and women from
the United Kingdom who were sent to the Gulf
and those who were not, and assesses the extent
to which service in the Gulf was associated with
excess ill health.
Methods
The Ministry of Defence (MOD) identified all
men and women deployed to the Gulf or Gulf
states between September 1990 and June
1991. These personnel were stratified by sex,
age (in 5 year groups), service (army, Royal
Navy, Royal Air Force), and rank (commis-
sioned oYcer, other ranks). Each stratum was
then matched with a randomly selected sample
of equal size from the cohort of personnel in
the military forces at 1 January 1991, who were
not deployed to the Gulf but whose health, at
the most recent medical assessment before the
war, would not have prevented that deploy-
ment. The complete study cohorts of Gulf and
non-Gulf personnel were included in a study of
mortality.
8
Because of security risks entailed by
contacting subjects, those serving in the special
forces were excluded from the present study
and thus no conclusion can be drawn about the
eVects of exposure on their health. Three
stratified random samples were then taken, a
total of 14 372 men and women. To examine
the consistency of results two equivalent
cohorts were chosen from those who went to
Occup Environ Med 2001;58:291–298 291
Centre for
Occupational and
Environmental Health,
University of
Manchester, UK
N Cherry
D Baxter
J Smedley
School of Psychiatry
and Behavioural
Science
F Creed
Arthritis Research
Campaign
Epidemiology Unit
A Silman
S Taylor
Biostatistics Unit
G Dunn
Unit of Chronic
Disease Epidemiology
G J Macfarlane
Correspondence to:
Dr N Cherry, Department of
Public Health Sciences,
University of Alberta,
13–103 Clinical Sciences
Building, Edmonton,
Alberta, Canada T6G 2G3
ncherry@ualberta.ca
Accepted 6 February 2001
www.occenvmed.com
the Gulf—a main Gulf and validation Gulf
cohort. A non-Gulf cohort was also selected.
These study cohorts did not overlap with those
in the United Kingdom study already re-
ported
4
; all included here will have been
approached eventually as part of a study of
reproductive eVects, that contact was made
only after collaboration with the present study
had been completed.
All subjects were given a health question-
naire which sought information on current
employment (service or civilian), marital sta-
tus, deployment to other areas of conflict,
attendance at hospital since 1991, and habits
(alcohol, tobacco). They were also asked in
detail about health during the past month,
indicating on an adjacent visual analogue scale,
ranging from “not at all” to “very seriously”,
how much they had been troubled by each of
95 symptoms. The choice of symptoms was
made through review of published reports on
Gulf war illness, discussion with service
personnel who had been in the Gulf, and con-
sideration of illness that might result from
exposures—such as pesticides and smoke from
burning oil wells—known to have occurred.
Subjects were also asked to shade sites of pain
(on one manikin) and numbness or tingling (on
a second) that had been troublesome in the
past month.
Those deployed to the Gulf also completed a
second questionnaire giving details of the dates
they had been deployed at each location and of
exposures that they had experienced while in
that area. They were instructed to complete the
health questionnaire before beginning that on
locations.
Questionnaires were always self completed
but the method of administration diVered
between groups. For those no longer serving
the first approach was by post, with discharge
addresses supplied by the MOD. For those still
serving the approach diVered by service. Most
of the serving personnel were in the army, and
for these, bases were visited in the United
Kingdom, Germany, and Cyprus; subjects
selected for the study were gathered together to
complete the forms in the presence of one of
the research team. Such an approach was inap-
propriate for the navy where service at (or
under) sea eVectively precluded personal visits.
For the air force, where small numbers were
spread over many sites, visits by the research
team to bases were not planned but one large
air force base was included in the site visit to
Cyprus. For army personnel not successfully
encountered at the site visits and for those in
the navy and air force the approach was by post
to the service address supplied by the MOD.
Follow up of untraced subjects and non-
responders took many forms. For those still
serving, telephone contact was made with the
base to ensure that the address was correct and
that the subject was still stationed there. Where
units had moved, the new location was
supplied by the MOD. For those in civilian life
possible new addresses were obtained through
electoral registers, health authorities, and tele-
phone directories. Questionnaires were for-
warded by the Driver and Vehicle Licensing
Authority (DVLA), by some general medical
practitioners, and for a small group of non-
responders who had served in the Gulf, the
medical assessment programme of the MOD.
9
Where a firm address had been established but
the subject had not completed a questionnaire,
a telephone contact or home visit was at-
tempted. Where no other option seemed likely
to succeed, subjects were asked to complete a
shortened form of the questionnaire.
The first site visit was carried out in Decem-
ber 1997, 6.5 years after the end of the Gulf
war. Follow up continued until September
1999.
STATISTICAL METHODS
Responses on each 10 cm visual analogue scale
were allocated, as a symptom score, to 1 of 21
equally spaced segments. The mean symptom
scores overall in both the Gulf and non-Gulf
groups were highly skewed, with most respond-
ents reporting little trouble, but the square root
of the mean score approximated normality and
Table 1 Response by cohort
Gulf
Non-Gulf TotalMain Validation Both
n% n% n% n% n%
Initial cohort 4795 — 4790 — 9585 — 4787 — 14372 —
Died before contact 40 — 40 — 80 — 38 — 118 —
Long questionnaire 4008 84.3 4077 85.8 8085 85.1 3935 82.9 12020 84.3
Short questionnaire 65 1.4 53 1.1 118 1.2 46 1.0 164 1.2
MAP responder 3 0.1 4 0.1 7 0.1 — — 7 0.0
Refusal 61 1.3 55 1.2 116 1.2 67 1.4 183 1.3
No contact 618 13.0 561 11.8 1179 12.4 701 14.8 1880 13.2
Total eligible 4755 100 4750 100 9505 100 4749 100 14254 100
Table 2 Response by subject characteristics*
Gulf Non-Gulf Overall
n% n% n %
Sex:
Male 9288 86.3 4641 83.9 13929 85.5
Female 217 89.9 108 80.6 325 86.8
Age at 1 January 1990:
<20 1381 81.1 688 74.9 2069 79.0
20–4 3312 85.1 1643 80.2 4955 83.5
25–9 2222 86.7 1126 87.2 3348 86.9
30–4 1363 90.2 669 89.4 2032 89.9
>35 1227 91.0 623 91.2 1850 91.0
Rank:
OYcer 1173 90.1 608 90.6 1781 90.3
Others 8332 85.8 4141 82.8 12473 84.8
Service:
Army 6665 86.7 3325 83.9 9990 85.8
Navy 1058 82.4 528 79.2 1586 81.3
Air force 1782 87.7 896 86.2 2678 87.2
*From the database supplied by the Ministry of Defence.
292 Cherry, Creed, Silman, et al
www.occenvmed.com
has been used to test significance. Factor scores
on seven specific dimensions were derived by
principal component analysis (discussed later).
With the technique of cluster analysis (dis-
cussed later) each respondent was allocated to
a group (or cluster) within the same cohort in
which the pattern of 95 symptom scores of
others in the group were as similar as possible
to those of the subject. The size of these
clusters was used to estimate the extent to
which experience in the Gulf had changed pat-
terns of health.
Areas shaded on the manikin to indicate
numbness or tingling were used to define
patterns consistent with toxic neuropathy. Pos-
sible neuropathy was classified as “limited” if
restricted to one or both feet and “extended” if
numbness or tingling were reported in both
feet and at least one hand or lower leg. Areas
shaded to indicate pain (experienced for at
Figure 1 Mean symptom scores in the Gulf and non-Gulf cohorts.
70. Tiredness?
9.007.00 8.006.004.00 5.00
Mean symptom scores
3.002.000.00 1.00
Non-Gulf
Gulf
34. Waking up feeling tired and worn out?
3. Having wind?
26. Headaches?
32. Feeling unhappy and depressed?
35. Losing sleep due to worry?
87. Sudden changes of mood?
20. Feeling irritated for no particular reason?
72. Feeling stiff?
4. Getting up at night to pass water?
45. Having to make notes to help you remember things?
6. Indigestion?
23. Feeling sleepy for most of the day?
56. Feelings of anger which are difficult to control?
55. Having to go back and check that you have done things?
67. Phlegm or sputum (spit from the chest)?
13. Aching all over your body?
43. A poor memory?
24. Sinus problems?
2. Sweating?
54. Head colds?
22. Difficulty concentrating?
85. Heartburn?
36. Having too little energy to start doing things?
59. A sore throat?
44. Itching skin?
45. Ringing sounds in your ears?
5. Stomach pain?
94. Feeling bloated?
37. Coughing?
12. Bleeding gums?
52. A loss of confidence in yourself?
9. Diarrhoea?
25. Wheezing or whistling in your chest?
21. Lack of interest in sex?
68. People telling you that you have a poor memory?
16. Toothache?
76. Cramps or spasms in your muscles?
90. Cold hands or feet?
7. Hot or cold spells?
86. Difficulty in saying what you want to say?
57. Thinking that you were a worthless person?
49. Feeling drunk when you haven't had much to drink?
28. Pain in your chest?
75. Skin rashes?
11. Having a sensation of sand or grit in your eyes?
69. Palpitations (fluttery feelings in the heart)?
89. Your eyes watering?
60. Hair loss?
74. Difficulty in grasping the meaning of what you read?
58. Clumsiness?
29. Poor appetite?
45. A dry mouth?
79. Memory flashbacks?
63. Nightmares?
95. Wishing you were dead and away from it all?
30. Feeling sick?
39. A feeling of heaviness in your chest?
92. Loss of appetite?
88. Loud noises or bright lights?
73. Chest infections?
47. Painful tingling in your hands or feet?
61. Slurring your words?
19. Nervous trouble?
83. Feeling incapable of making decisions about things?
33. Your hands shaking?
64. Ear infections?
80. Shortness of breath when walking with other people of your own age?
10. A loss in weight?
84. Feeling dizzy?
82. Waking up with a light chest?
65. Constipation?
14. Fevers?
50. Loss of sensation in your hands and feet?
71. A flare-up of acne?
91. Tingling under your skin?
8. Waking up with an attack of shortness of breath?
62. Loss of sense of smell?
42. Losing your balance?
41. Feeling too weak to complete what you are doing?
93. Swollen glands?
1. Boils or abscesses?
36. Difficulty in standing up from a chair?
17. Nosebleeds?
81. Feeling unsteady when walking?
66. Hiccups?
31. Vomiting?
51. Difficulty in lifting down an object from just above your head?
53. The smell of perfume or aftershave?
77. The smell of paint, petrol or other chemicals?
78. Double vision?
27. Problems doing up buttons on your clothes?
15. A fear of going outside in open spaces?
40. Fainting?
18. Fits or convulsions?
Health and exposures of UK Gulf war veterans. Part I 293
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least 24 hours in the past month) were used to
define a syndrome of widespread pain present
if there were axial skeletal and contralateral
body pain.
10
Principal component factor analysis
The symptom correlation matrix was analysed,
with the initial extraction method that of prin-
cipal components. The varimax procedure was
used for rotation, producing a set of orthogonal
factor scores, standardised to a mean (SD) of 0
(100). The matrix of weights in the rotated
solutions for each of the three cohorts sepa-
rately were compared by eye in successive
analyses, with the extraction of increasing
numbers of components. Solutions in which
the matrices were judged to be essentially
identical in the main and validation cohorts
were retained. For each such solution the
structure extracted in the Gulf and non-Gulf
cohorts were compared, to explore the possi-
bility of a replicable solution in those who had
served in the Gulf but not present in the non-
Gulf cohort.
Cluster analysis
A k means cluster analysis was used.
11 12
The
non-hierarchical method initially partitioned
the respondents into k clusters (k specified by
the investigator) with each subject reassigned
in turn until an optimal solution was reached in
which the distance between cases in diVerent
clusters was maximised. This analysis was car-
ried out for the three cohorts separately, with
scores from the 95 symptoms. In each case
convergence was reached within 200 iterations.
The solutions for the three cohorts were again
compared by eye, as the number of clusters was
increased sequentially. The solution chosen
was that with the largest number of clusters in
which the pattern of component scores seemed
to be essentially the same in the diVerent
cohorts.
Validation cohort
The study design, with main and validation
cohort selected from those deployed to the
Gulf, permitted replication of analyses. Results
from each of the Gulf cohorts are given where
consistency between cohorts is important in
assessing the weight that should be given to the
interpretation.
Results
One hundred and eighteen members of the
sample died before study contact but of 14 254
surviving, 12 191 (85.5%) completed a ques-
tionnaire (table 1). Of these, 164 were short
questionnaires and seven were completed
through the medical assessment programme;
these have been excluded from the main analy-
ses, the short questionnaires because they did
not complete comparable symptom data, those
completed through the medical assessment
programme because there was no equivalent
system for contacting sick non-Gulf subjects.
The response was higher for those still serv-
ing (5645/6086, 92.8%) than those who had
left the forces (6546/8168, 80.1%). Among the
non-responders a very high proportion could
not be traced to a current address. Although
there were only four in the study for whom no
address of any sort could be found (two absent
without leave from the forces, two thought to
be in Northern Ireland where security decreed
only a minimal follow up) the address supplied
by the MOD for many others proved to be out-
dated. Among subjects who were contacted to
complete the study questionnaire 183 refused
but were asked to confirm whether or not they
were in good health. Of the 47 willing to
provide this minimal information, only one
admitted to being unwell.
In the surviving cohort 2.3% were women,
49.3% aged less than 25 years, and 12.5% were
oYcers. The largest numbers were from the
army (70.1%) with 18.8% from the air force
and 11.1% from the navy. The pattern of
response is shown in table 2. The response rate
was somewhat lower in those who did not go to
the Gulf, particularly in women and those
under 25 years. In both Gulf and non-Gulf
groups there was a marked increase in response
with age. Younger service personnel were more
likely to be on a short term engagement and to
have left the forces without a pension; tracing
in this group was particularly diYcult as there
was no incentive for them to maintain a current
address on MOD records.
SYMPTOMS
A total of 11 914 (99.1%) provided usable
answers to at least 90 of the 95 symptoms and
have been included in the main analysis. The
subject’s mean response to all other symptoms
was assigned where five or less symptoms had
been missed.
The mean score for each symptom is shown
in figure 1 by order of decreasing severity in the
comparison group. It is evident that symptoms
that were rated as particularly troublesome in
the non-Gulf group were also rated in much
the same order in the Gulf group, with feelings
of tiredness being the most troublesome symp-
tom in both groups, and fits or convulsions the
least. A rank correlation between mean scores
for the 95 symptoms in the Gulf and non-Gulf
cohorts exceeded 0.95. On every symptom the
score was higher for those who were deployed.
However this tendency to report greater sever-
ity in the Gulf group was not uniform; for
example Q68 (people telling you that they have
a poor memory) and Q16 (toothache) had very
Table 3 Symptoms on which the mean score for Gulf veterans (n=8014) was at least
twice that for the non-Gulf cohort (n=3900)
Question
number Symptom Ratio Gulf/non-Gulf
68 People telling you that you have a poor memory 2.23
43 A poor memory 2.21
22 DiYculty concentrating 2.16
20 Feeling irritated for no particular reason 2.14
87 Sudden changes of mood 2.12
74 DiYculty grasping the meaning of what you read 2.12
58 Clumsiness 2.09
91 Tingling under your skin 2.07
41 Feeling too weak to complete what you are doing 2.07
56 Feelings of anger that are diYcult to control 2.05
61 Slurring your words 2.04
83 Feeling incapable of making decisions about things 2.02
86 DiYculty in saying what you want to say 2.01
19 Nervous trouble 2.01
294 Cherry, Creed, Silman, et al
www.occenvmed.com
similar mean scores (2.1 for both) in the com-
parison group but in those who had been to the
Gulf memory was seen as much more trouble-
some (with a mean score of 4.8) than toothache
(2.8). The 14 symptoms on which the scores
for the Gulf cohort were at least twice those for
the non-Gulf cohort are shown in table 3.
The diVerence between the two cohorts in
the areas shaded on the manikins suggested
that those who went to the Gulf were more
likely to experience symptoms consistent with
peripheral neuropathy (6.0% limited symp-
toms, 8.5% extended) than the non-Gulf
cohort (4.5% limited, 2.3% extended). The
proportion with widespread pain (12.2%) was
also higher in the Gulf than in the non-Gulf
(6.5%) cohorts.
Mean symptom severity scores were very
similar in the main Gulf cohort (3.1) and vali-
dation cohort (3.0) but significantly lower in
the non-Gulf cohort (1.7) (comparison of
means for Gulf and non-Gulf cohorts;
p<0.001).
In both Gulf and non-Gulf cohorts lower
scores were found in older people (under 25
years 3.3, 25 years or older 2.8), oYcers (2.0,
Table 4 Analysis of principal components with varimax rotation: weights (>0.4) assigned on each of seven factors
Factor*
1234567
3 Having wind 0.541
5 Stomach pain 0.618
6 Indigestion 0.701
8 Waking with an attack of shortness of breath 0.500
9 Diarrhoea 0.510
10 A loss in weight 0.529
19 Nervous trouble 0.571
20 Feeling irritated for no particular reason 0.674
21 Lack of interest in sex 0.485
22 DiYculty concentrating 0.601 0.452
23 Feeling sleepy for most of the day 0.540
25 Wheezing or whistling in your chest 0.685
27 Problems doing up buttons on your clothes 0.457
28 Pain in your chest 0.432
29 Poor appetite 0.599
30 Feeling sick 0.514
31 Vomiting 0.520
32 Feeling unhappy and depressed 0.761
34 Waking up feeling tired and worn out 0.598
35 Losing sleep due to worry 0.640
36 DiYculty in standing up from a chair 0.571
37 Coughing 0.677
38 Having too little energy to start doing things 0.573
39 A feeling of heaviness in your chest 0.635
40 Fainting 0.428
41 Feeling too weak to complete what you are doing 0.441 0.439
42 Losing your balance 0.549
43 A poor memory 0.424 0.683
44 Itching skin 0.572
45 Having to make notes to help you remember things 0.669
47 Painful tingling in your hands or feet 0.463 0.437
50 Loss of sensation in your hands and feet 0.406 0.475
51 DiYculty in lifting down an object from just above your head 0.572
52 A loss of confidence in yourself 0.706
54 Head colds 0.480
55 Having to go back and check that you have done things 0.457 0.589
56 Feelings of anger which are diYcult to control 0.683
57 Thinking that you were a worthless person 0.704
58 Clumsiness 0.442 0.447
59 A sore throat 0.480
61 Slurring your words 0.444
63 Nightmares 0.473
67 Phlegm or sputum (spit from the chest) 0.651
68 People telling you that you have a poor memory 0.657
70 Tiredness 0.566
71 A flare up of acne 0.410
72 Feeling stiV 0.401 0.402
73 Chest infections 0.719
74 DiYculty in grasping the meaning of what you read 0.544
75 Skin rashes 0.570
76 Cramps or spasms in your muscles 0.414
78 Double vision 0.455
79 Memory flashbacks 0.462
80 Shortness of breath when walking with other people of your own age 0.471 0.445
81 Feeling unsteady when walking 0.661
82 Waking up with a tight chest 0.649
83 Feeling incapable of making decisions about things 0.554 0.417
84 Feeling dizzy 0.489
85 Heartburn 0.549
86 DiYculty in saying what you want to say 0.463 0.484
87 Sudden changes of mood 0.697
89 Your eyes watering 0.461
90 Cold hands or feet 0.441
91 Tingling under your skin 0.533 0.417
92 Loss of appetite 0.611
94 Feeling bloated 0.408
95 Wishing you were dead and away from it all 0.639
*Factor 1=psychological; factor 2=peripheral; factor 3=neurological; factor 4=respiratory; factor 5=gastrointestinal; factor 6=concentration; factor 7=appetite.
Health and exposures of UK Gulf war veterans. Part I 295
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other ranks 3.2) and those still serving (2.7, no
longer serving 3.4). Neither marital status at
the time of the Gulf nor sex significantly
aVected symptom scores. DiVerences in sever-
ity score were found between services in both
Gulf and non-Gulf cohorts; in the non-Gulf
cohort those from the army had a mean score
of 2.1, the navy 1.8, and the air force 1.7.
PRINCIPAL COMPONENT ANALYSIS
Principle component analysis (with rotation)
was carried out to explore the structure of
response to the symptom questionnaire. The
analysis was conducted for each of the three
cohorts separately and the results obtained by
extracting diVerent numbers of factors were
examined. The solutions obtained for the main
and validation cohorts were similar when up to
seven components were extracted and rotated
but when more components were extracted the
factors diVered between Gulf cohorts. In each
solution up to seven components the rotated
solutions seemed to be essentially the same for
the non-Gulf as well as the Gulf cohorts. The
analysis was then repeated (table 4) to obtain a
single seven factor solution for all three groups
together. To facilitate interpretation only ques-
tions on which the weight was 0.4 or greater on
any of the first seven factors (accounting for
48% of the variance) are shown in table 4. A
brief label has been given to each factor: (1)
psychological, (2) peripheral, (3) neurological,
(4) respiratory, (5) gastrointestinal, (6) concen-
tration, and (7) appetite. These labels are for
identification only and not necessarily of diag-
nostic significance. Factor 2 was most diYcult
to name in an informative way; peripheral
reflects the skin and neuromuscular complaints
weighted most heavily on this factor.
The mean scores on each of these factors are
shown for the three cohorts in table 5. The
scores for the main and validation Gulf cohorts
were very similar with no significant diVerence
on any dimension. There was, however, a clear
and significant diVerence between the Gulf and
non-Gulf cohorts in six of the seven factors.
Five factors (psychological, peripheral, respira-
tory, gastrointestinal, and concentration) had
higher scores in the Gulf cohorts. One factor
(appetite) was significantly lower than in the
non-Gulf cohort. No diVerence was found for
the neurological factor, which, as seen in table
4, had high weightings not only on peripheral
symptoms but also on symptoms that might
arise from poor functioning of the central
nervous system.
CLUSTER ANALYSIS
To further assess the impact of service in the
Gulf on the health of veterans, a series of clus-
ter analyses was carried out using scores for all
95 symptoms and clustering subjects in each of
the three cohorts separately. The aim was not
to identify a cluster unique to the Gulf
veterans, but to look for common groups of
symptoms.
With six clusters a pattern was found that
could be interpreted by use of the seven factors
from table 4. When each subject was assigned
to one of six clusters, the mean scores for each
factor were as shown in table 6 with the six
clusters arranged in order of decreasing
numbers of subjects and increasing overall
severity (table 7). The scores were standardised
to a mean (SD) of 0 (100); thus from table 6
the mean factor score for psychological ill
health for people in cluster 1 was about 0.5 SD
below the mean in all three cohorts. The clus-
ters formed independently from the main and
validation Gulf cohorts were very similar. The
diVerences between the Gulf and non-Gulf
cohorts were greater, particularly on the
smaller clusters (4–6).
Cluster 1 was essentially composed of those
who were well, with scores appreciably below
the mean on five factors and close to the mean
on the remaining two. The proportion of the
Gulf cohort in this healthy cluster was smaller
(36.4%) than the non-Gulf (48.5%) (table 7).
Those in cluster 2 (accounting for nearly 30%
of each cohort) were also essentially well but
with slightly higher symptom scores and
Table 5 Mean factor scores by cohort
Factor
Cohort Contrasts
Main
(MG)
Validation
(VG)
Non-Gulf
(NG) MG v VG MG+VG v NG
Psychological:
Mean 12.6 12.9 −26.2 p=0.92 p<0.001
SD 108.8 105.2 77.6
Peripheral:
Mean 10.6 10.9 −22.1 p=0.88 p<0.001
SD 110.7 109.6 70.0
Neurological:
Mean −1.2 2.3 −1.1 p=0.16 p=0.39
SD 109.3 112.1 73.2
Respiratory:
Mean 5.9 4.2 −10.3 p=0.47 p<0.001
SD 111.5 108.0 75.0
Gastrointestinal:
Mean 11.8 8.7 −21.0 p=0.18 p<0.001
SD 108.6 104.7 80.8
Concentration:
Mean 10.6 8.4 −20.5 p=0.19 p<0.001
SD 111.5 110.5 67.8
Appetite:
Mean −1.3 −4.5 6.1 p=0.19 p<0.001
SD 114.1 106.2 74.5
n 3969 4045 3900 — —
Table 6 Mean factor scores by cluster and cohort
Factor
Cluster 1 Cluster 2 Cluster 3 Cluster 4 Cluster 5 Cluster 6
MG VG NG MG VG NG MG VG NG MG VG NG MG VG NG MG VG NG
Psychological −49 −49 −52 −3 −1 −50 138 157 41 −12 −7 −13 133 106 204 141 132 132
Peripheral −31 −30 −44 8 4 −8 −7 −8 −15 76 62 59 80 112 −17 122 139 68
Neurological −4 −5 4 −23 −24 −4 −35 −31 −24 −30 −27 −33 37 72 −14 275 306 177
Respiratory −21 −20 −26 −15 −20 −4 −43 −36 −14 95 93 115 74 74 −33 139 105 66
Gastrointestinal −37 −41 −54 18 16 −2 24 10 6 89 100 105 77 59 −23 19 32 58
Concentration −24 −28 −34 9 12 −18 109 85 8 −18 −17 −15 54 55 26 67 81 33
Appetite −8 −6 −4 −18 −16 11 −19 −12 −1 9 −13 20 11 −3 48 167 145 115
MG=main Gulf, VG=validation Gulf, NG=non-Gulf.
296 Cherry, Creed, Silman, et al
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perhaps more peripheral and gastrointestinal
problems. Cluster 3 contained the same
proportions of Gulf and non-Gulf veterans but
the scores for those in the Gulf cohorts were
appreciably higher on the two factors (psycho-
logical and memory or concentration) that
characterise this cluster. In the remaining clus-
ters those who served in the Gulf war were
overrepresented. Thus cluster 4, with high
scores on respiratory and gastrointestinal
problems, accounted for only 4.5% of the non-
Gulf respondents but 11.6% of the Gulf war
veterans. In cluster 5, characterised by high
scores for psychological ill health in all cohorts
but with relatively high scores also for other
factors in the Gulf cohort, the proportions
from the Gulf cohort were again more than
twice as high as in the non-Gulf cohort. Clus-
ter 6, the smallest, contained only 3.1% overall,
but again had higher proportions of those who
went to the Gulf. Those in this cluster had high
symptom scores on all factors with noticeably
higher scores on the factor associated with
neurological symptoms. Together these three
least healthy clusters include 23.8% of the Gulf
but only 9.8% of the non-Gulf cohorts.
HEALTH BEHAVIOURS
The proportion of subjects who had been
referred to hospital by their general practitioner
was high overall with only slightly greater rates
in the main Gulf (52.5%) and validation Gulf
(51.6%) than in the non-Gulf cohort (49.0%)
(diVerence Gulf/non-Gulf p<0.002). The like-
lihood of being referred was strongly related, in
both Gulf and non-Gulf cohorts, to the symp-
tom cluster, with only 40.6% of those in cluster
1 consulting a specialist but 73.3% of those in
cluster 6. It is of note that in the three least
healthy clusters (4–6) Gulf veterans were less
likely (65.9%) than non-Gulf veterans (73.3%)
to be referred by their family physician for spe-
cialist investigation or treatment (p=0.005).
The proportion of current smokers was very
similar in the three cohorts (36.5% main Gulf,
34.4% validation Gulf, and 33.4% non-Gulf).
Only 7.0% of those who went to the Gulf, and
6.7% of those who did not, smoked more than
20 cigarettes a day at the time they were
contacted. The proportions who drank more
than 20 units of alcohol a week were also com-
parable, with 17.9% of Gulf war veterans and
16.6% of the non-Gulf cohort reporting this
amount.
Discussion
The study reported here was set up to investi-
gate whether there was an excess of ill health
among those who went to the Gulf. It is clear
that the veterans were more troubled about
their health than comparable non-deployed
subjects and that these concerns covered a
wide range of symptoms. The use of cluster
analysis, exploiting similarities rather than dif-
ferences between the cohorts, allowed estima-
tion of the size of the group aVected; the
proportion in the three least healthy groups
was 14% more in the Gulf than in the non-Gulf
cohorts, providing an estimate of about 7500
veterans (of 53 462 deployed) with ill health
attributable to the Gulf. Less than half this
number have so far presented to the MOD’s
medical assessment programme.
9
In a recently
published and broadly comparable study from
the United States,
2
the proportions reporting
“functional impairment” (that during the past
2 weeks they had stayed in bed or at home
because of ill health) corresponded quite
closely to the proportions in the three least
healthy clusters in the present study. Among
the United States Gulf veterans 27.8% re-
ported impairment compared with only 14.2%
of non-Gulf veterans.
Interpretation of these data is not easy,
particularly in the absence of objective meas-
ures of the prevalence of conditions—such as
peripheral neuropathy—which might plausably
result from exposures in the Gulf. Previous
studies in the United States have not found an
increase in mortality
13
or hospital admissions of
Gulf War veterans
14 15
and in the present
cohort, those who had been to the Gulf were no
more likely to have died.
8
Although there was
no marked increase in the proportions who had
been referred to specialist physicians, the lower
referral rate for Gulf than non-Gulf veterans in
the three least healthy clusters suggest that, in
the United Kingdom, any increase in morbidity
was being managed largely within primary
care. In the most comparable United States
study,
2
more visits to a clinic during the previ-
ous year were recorded by Gulf (51%) than
non-Gulf (41%) veterans. In the present study
the greater psychological and other concerns in
Gulf war veterans do not seem to be translated
into higher rates of cigarette smoking or drink-
ing of alcohol, which would lead to an excess of
chronic ill health.
Although this lack of an excess in signs of
severe morbidity is reassuring, there is
nevertheless clear evidence, consistent across
the cohorts, that among those who went to the
Gulf there are substantial subgroups who feel
unwell. Such ill health has been reported after
previous conflicts
16
and it may be that this
reflects changes in perception resulting from
disruptions of war rather than specific chemi-
cal, physical, infective, or psychological expo-
sures. The hypothesis that exposures during
deployment contributed to the ill health of
United Kingdom Gulf war veterans is investi-
gated in part II of this paper.
17
We are grateful to Priscilla Appelbe who administered the study,
to Joanne Wren, Melanie Hopwood, Gill Prior, and Vincent
Burke who implemented the follow up, and to Liz Foster and
Tracy Field who cleaned the data. Ministry of Defence staV (in
particular John Graham and Nick Blatchley) identified the study
cohorts who were traced on the NHS Central Register by staV
from the OYce for National Statistics. We also thank everyone
Table 7 Distribution of cohorts by cluster
Cluster Cohort
Number
Mean
severity
Main Gulf Validation Non-Gulf Overall
n% n% n% n %
1 1.0 1448 36.5 1469 36.3 1891 48.5 4808 40.4
2 2.6 1104 27.8 1154 28.5 1161 29.8 3419 28.7
3 4.6 462 11.6 458 11.3 462 11.8 1382 11.6
4 5.0 462 11.6 475 11.7 177 4.5 1114 9.4
5 7.7 333 8.4 339 8.4 145 3.7 817 6.9
6 11.7 160 4.0 150 3.7 64 1.6 374 3.1
Overall 3.1 3969 100.0 4045 100.0 3900 100.0 11914 100.0
Health and exposures of UK Gulf war veterans. Part I 297
www.occenvmed.com
who helped with tracing, particularly Linda Walpole, Amanda
Bale, Bernie Page (from DASA), and Steve McManus.
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Open reviewing
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