Background: There is increasing evidence that hypoxia induces
inflammation in the gastrointestinal tract. The clinical impact of hypoxia
in patients with inflammatory bowel disease (IBD) is so far poorly
investigated.
Aim: We wanted to evaluate if flights and journeys to regions >= 2000
meter above sea level are associated with the occurrence of flares in
IBD patients in the following 4 weeks.
Methods: A questionnaire was completed by inpatients and outpatients
of the IBD clinics of three tertiary referral centers presenting with an IBD
flare. Patients were inquired about their habits in the 4 weeks prior to
the flare. Patients with flares were matched with an IBD group in
remission during the observation period (according to age, gender,
smoking habits, and medication).
Results: A total of 103 IBD patients were included (43 Crohn's disease
(CD), whereof 65% female, 60 ulcerative colitis, whereof 47% female,
mean age 39.3 ± 14.6 years for CD and 43.1 ± 14.2 years for UC).
Fifty-two patients with flares were matched to 51 patients without flare.
Overall, IBD-patients with flares had significantly more frequently a flight
and/or journey to regions >= 2000 meters above sea level in the
observation period compared to the patients in remission (21/52
(40.4%) vs. 8/51 (15.7%), p = 0.005). There was a statistically significant
correlation between the occurrence of a flare and a flight and/or journey
to regions >= 2000 meters above sea level among CD patients with
flares as compared to CD patients in remission (8/21 (38.1%) vs. 2/22
(9.1%), p = 0.024). A trend for more frequent flights and high-altitude
journeys was observed in UC patients with flares (13/31 (41.9%) vs.
6/29 (20.7%), p = 0.077). Mean flight duration was 5.8 ± 4.3 hours. The
groups were controlled for the following factors (always flare group cited
first): age (39.6 ± 13.4 vs. 43.5 ± 14.6, p = 0.102), smoking (16/52 vs.
10/51, p = 0.120), regular sports activities (32/52 vs. 33/51, p = 0.739),
treatment with antibiotics in the 4 weeks before flare (8/52 vs. 7/51,
p = 0.811), NSAID intake (12/52 vs. 7/51, p = 0.221), frequency of
chronic obstructive pulmonary disease (both groups 0) and oxygen
therapy (both groups 0).
Conclusion: IBD patients with a flare had significantly more frequent
flights and/or high-altitude journeys within four weeks prior to the IBD
flare compared to the group that was in remission. We conclude that
flights and stays in high altitude are a risk factor for IBD flares.