5.11
Irritable Bowel Syndrome and other gastrointestinal disorders
5.11.1
Irritable Bowel Syndrome and other gastro-intestinal
disorders at follow up
Irritable Bowel Syndrome measured using Rome III criteria at follow up
Ninety Gulf War veterans (13.3%) and 52 comparison group participants (8.1%) met Rome
III criteria for Irritable Bowel Syndrome (IBS)58 in the three months prior to follow up. The
difference between the two groups was statistically significant with Gulf War veterans at 64%
greater risk of Rome III IBS; RR 1.65, adj RR 1.64, 95% CI 1.18-2.27. Additional analysis
excluding participants who reported that they had Colitis or Crohn’s disease, which might
explain IBS symptoms, caused little change in the difference between the two groups; adj
RR 1.67, 95% CI 1.19-2.38. Among those who met Rome III IBS criteria, 4% of the Gulf War
veterans and 8% of the comparison group participants had constipation; 25% in both groups
had diarrhoea; and 70% and 67% respectively had IBS of mixed type.
Self-reported doctor diagnosed or treated gastro-intestinal disorders at follow up
IBS and other gastrointestinal disorders which were self-reported by respondents to have
been diagnosed, or treated, by a medical doctor since January 2001 are shown in Figure 1.
Figure 1 Self-reported doctor diagnosed or treated gastrointestinal disorders since 2001
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The most prevalent gastro-intestinal disorders were stomach or duodenal ulcers, reported by
5% of the Gulf War veterans and 3.7% of the comparison group. Other gastro-intestinal
disorders were very infrequently reported. Only 6 participants in total (1.7%) reported
doctor-diagnosed, or treated, IBS. There were no statistically significant differences
between the two groups in regard to any of the self-reported doctor-diagnosed gastrointestinal disorders in Figure 1.
5.11.2
Association between Gulf War-deployment characteristics
and Irritable Bowel Syndrome in veterans at follow up
The associations between Gulf War deployment characteristics and the presence of Rome
III IBS at follow up in Gulf War veterans are shown in Table 1.
Table 1 Association between Gulf War-deployment characteristics and Rome III IBS at follow
up in male Gulf War veterans
Gulf War veterans with IBS at follow up
Gulf War exposure
N
n (%)
RR
Adj RR (95% CI)
Age at deployment
< 20
61
7 (11.48)
1.00
1.00
20-24
161
25 (15.53)
1.35
1.74 (0.79-3.83)
25-34
355
48 (13.52)
1.18
2.19 (0.95-5.04)
>=35
98
10 (10.20)
0.89
1.98 (0.70-5.64)
Service branch
Navy
580
77 (13.28)
1.00
1.00
Army
44
6 (13.64)
1.03
1.29 (0.60-2.76)
Air Force
51
7 (13.73)
1.03
1.22 (0.59-2.49)
Officer
144
11 (7.64)
1.00
1.00
Other rank-supervisory
346
45 (13.01)
1.70
1.76 (0.90-3.42)
Other rank - non supervisory
184
34 (18.48)
2.42
3.34 (1.58-7.05)
Rank category
Gulf War veterans with Rome III defined IBS at follow up were significantly more likely to
have been in a non-supervisory rank at the time of the Gulf War deployment, compared to
higher ranks. There was no association between Rome III defined IBS at follow up and age
or service type at deployment.
5.11.3
Key findings
Thirteen percent of Gulf War veterans and 8% of comparison group participants met Rome
III criteria for IBS in the three months prior to follow up. This represented a statistically
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significant 64% increase in risk of IBS amongst Gulf War veterans relative to the comparison
group. Less than one percent of participants in both study groups, however, reported
doctor-diagnosed or treated IBS since 2001. While it is acknowledged that the instrument
used to identify IBS is not a diagnostic instrument, these findings could indicate that study
participants are not reporting symptoms of IBS to medical doctors, or that medical doctors
are not identifying IBS as the condition underlying the reported symptoms or a combination
of both.
There were no statistically significant differences between the groups in regard to any of the
self-reported doctor-diagnosed or treated gastro-intestinal disorders, but numbers were
small. The most frequently reported doctor-diagnosed or treated gastro-intestinal disorder
was stomach/duodenal ulcer which was reported by approximately 4% of all participants and
for which the difference between the two groups was the greatest. Other gastro-intestinal
disorders were very infrequently reported in each group.
Relative to Officers, Gulf War veterans who served with a non-supervisory rank at the time of
the Gulf War were in excess of three times more likely to have met Rome III criteria for IBS.
There was no association between Rome III IBS at follow up and age or service branch at
deployment.
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