Shift work increases the frequency of duodenal ulcer in
H pylori infected workers
A Pietroiusti, A Forlini, A Magrini, A Galante, L Coppeta, G Gemma, E Romeo, A Bergamaschi
............................................................... ............................................................... .
Occup Environ Med 2006;63:773–775. doi: 10.1136/oem.2006.027367
Aim: To evaluate whether shift work is associated with an
increased rate of peptic ulcer in H pylori infected workers.
Methods: During a two year period, consecutive dyspeptic
workers underwent non-invasive evaluation of H pylori status
by means of urea
testing positive were included in the study and divided into
two main categories: day-time workers and shift workers. An
upper gastrointestinal endoscopy was performed in all
workers, and biopsy specimens were taken from the stomach
to confirm the presence of H pylori infection (culture and
Results: A total of 247 day-time workers and 101 shift
workers were included. The prevalence of duodenal ulcer
was significantly higher in shift workers than in day-time
workers (29 of 101 v 23 of 247; OR=3.92, 95% CI 2.13 to
7.21), and persisted after multivariate analysis, taking into
account possible confounding factors (OR=3.96, 95% CI
2.10 to 7.47).
Conclusion: Shift work increases the ulcerogenic potential of
H pylori infection and should be considered a risk factor for
duodenal ulcer in infected shift workers. Treatment of
infection in this high risk group may improve the health of
workers and may reduce the economic impact of peptic
13C breath test or stool testing. Those
on non-standardised assessment of symptoms, and mainly
relying on x ray evaluation.1More important, no study has
evaluated the role of Helicobacter pylori, the main causative
agent of peptic ulcer disease.2On the other hand, the
outcome of H pylori infection is strongly influenced by host
and environmental factors: in fact, although virtually all
peptic ulcers are caused by this organism, only a minority of
infected subjects develop the disease.
In the present study, we examined whether shift workers
infected by H pylori are more prone to develop peptic ulcer
disease in comparison to infected day-time workers.
eptic ulcer disease is considered to be strongly linked to
shift work including night working.1However, most
studies regarding this relationship are outdated, based
During a two year period, a pool of primary care physicians
involved in an educational programme with our Institution3
selected all active workers from at least one year who had
persistent dyspeptic symptoms (i.e. pain or discomfort
centred in the upper abdomen for at least 4 months).
These subjects underwent non-invasive assessment of
H pylori infection with urea
testing; those testing positive were sent to us for further
evaluation. At this time, an occupational physician identified
two groups of dyspeptic workers: day-time workers; and
13C breath test or with stool
workers on either night shifts or rotating shifts that included
at least an average of four nights per month during the last
year. We considered as day-time workers those regularly
working between 6 am and 7 30 pm from at least one year,
who had no past history of shift work including night
working. Night-time work was defined as a shift including at
least 3 hours between midnight and 5 am. Both groups were
considered for upper gastrointestinal endoscopy. Exclusion
criteria for endoscopy were: previous endoscopic evaluation,
regular non-steroidal anti-inflammatory drug intake, con-
sumption of proton pump inhibitors or H2receptor antago-
nists during the month before endoscopy, previous x ray
diagnosis of peptic ulcer, and antibiotic intake after non-
invasive diagnosis of H pylori infection. A standard upper
gastrointestinal endoscopy was performed. The endoscopist
was unaware of whether the patient was a shift worker or a
day-time worker. During endoscopy, three biopsy specimens
were taken from the gastric antrum, and three from the
gastric body. At each site, two biopsy specimens were utilised
for histological assessment of inflammation and of H pylori
infection, and one was utilised for culture and urease testing.
Patients were considered infected if culture and/or urease
testing plus histology tested positive. Details on the perfor-
mance of histology and culture have been given elsewhere.4
Data are expressed as mean ¡ standard deviation.
Univariate analysis and multiple logistic regression, including
factors possibly affecting the risk of peptic ulcer were used to
estimate the odds ratios (ORs) and 95% confidence intervals
(CIs) for peptic ulcer associated with shift work. All analyses
were performed with SPSS release 13 software.
Overall, 941 workers were considered; 395 of them tested
negative at the non-invasive testing for H pylori infection, and
were therefore excluded from the study. Among the remain-
ing 546 workers, 303 were classified as day-time workers, and
132 as shift workers with a job schedule including at least
four nights per month. The remaining 111 workers with a
different job schedule were excluded. Eighty one patients did
not perform endoscopy because they did not meet the
inclusion criteria (39 patients among day-time workers and
28 among shift workers) or because they refused the
procedure (13 patients among day-time workers and two
among shift workers). Thus, endoscopy was performed in 251
day-time workers and 102 shift workers. After endoscopy,
four additional day-time workers and one shift worker were
excluded, since they were H pylori negative at invasive testing.
Thus, our final analysis included 247 day-time workers and
101 shift workers.
The two groups were similar with respect to age
(39.13¡9.88 v 40.54¡10.20 years), prevalence of male sex
(66.3% v 57.9%), and familial history of peptic ulcer disease
(19.8% v 17%), whereas active smokers were more frequently
detected among shift workers than among day-time workers
(38% v 25.9%; OR 1.72, 95% CI 1.05 to 2.82; p=0.04).
The prevalence of duodenal ulcer was higher in shift
workers than in day-time workers (29/101, 28.7% v 23/247,
9.3%; OR 3.92, 95% CI 2.13 to 7.21; p , 0.0001) and persisted
after multivariate analysis, taking into account possible
confounders: OR 3.96, 95% CI 2.10 to 7.47 (table 1).
No significant difference in the prevalence of duodenal
ulcer was observed between smokers and non-smokers (day-
time workers: 7.8% v 9.8%, OR 0.77, 95% CI 0.28 to 2.11,
p=0.63; shift workers: 34.2% v 25.3%, OR 1.52, 95% CI 0.69
to 3.64, p=0.34).
Gastric ulcer was diagnosed in 4/101 shift workers (3.9%) v
3/247 day-time workers (1.2%) (p=0.11).
In both groups, we did not detect any significant
association in the prevalence of peptic ulcer with a particular
job; furthermore, the difference between shift workers and
day-time workers was present within the same job (table 2).
Finally, the prevalence of peptic ulcer among shift workers
was higher in those working for at least seven nights per
month during the last year (10/21, 47.6%) in comparison to
other shift workers (18/80, 22.5%) (OR 3.13, 95% CI 1.14 to
We examined a population of H pylori infected dyspeptic
workers, and found that the prevalence of duodenal ulcer
was strongly increased in shift workers in comparison to day-
time workers; furthermore, a positive relationship between
the number of nights worked per month and the risk of
peptic ulcer was detected. This finding may have relevant
implications in occupational medicine, since it identifies
H pylori positive dyspeptic shift workers as a high risk group
for peptic ulcer disease. Because this disorder is an important
cause of absence from work,5strategies aimed at its
prevention in high risk groups may have relevant clinical
and economic implications. Further support to this consid-
eration is given by the fact that the prevalence of H pylori
infection is probably increased in shift workers.6
We feel that treatment of infection is a better strategy for
preventing peptic ulcer disease in shift workers. In fact,
H pylori eradication is relatively easy, requiring a one week
course of antibiotic therapy, and recurrences are rare after
successful treatment. This approach does not necessarily
require changes in work schedule, since in spite of the
persistence of any co-factor, the development of peptic ulcer
is practically impossible in the absence of H pylori infection.
Thus, we recommend screening procedures for H pylori
infection for dyspeptic shift workers. According to current
guidelines, infection in subjects less than 45 years old,
without alarming symptoms, can be confidently eradicated
without further invasive diagnostic procedures.7In this
context, occupational physicians may play a major role for
the application of this preventive strategy in shift workers.
The usefulness of this approach in day-time workers is much
less certain, because dyspeptic symptoms disappear after
eradication only if they are induced by a duodenal ulcer;8
given the relatively low rate of duodenal ulcer in this group,
the impact of screening and eradication is probably negligible
in an economic perspective.
Previous studies on the relationship between peptic ulcer and
shift work did not control for H pylori infection:1this fact
reduces the reliability of these data, since the disease is strongly
linked to infection; thus, differences in the prevalence of
infection between cases and controls may result in spurious
associations. Furthermore, effective preventive measures can-
not be taken without knowing H pylori status.
According to the accepted model of H pylori related ulcer,
the organism first colonises the gastric antrum, inducing the
so-called antrum predominant gastritis. This kind of gastritis
increases acid output, which induces a gastric metaplasia in
the duodenum; the presence of gastric mucosa in the
duodenum allows colonisation of the organism, and the
subsequent development of duodenal ulcer.9Shift work may
interact with this pathophysiological model. Indeed, long
term stress and nocturnal sleep deprivation, typically
associated with shift work,10may increases gastric acid
secretion,11and reduce mucosal defence.12
The study has some limitations. In fact, we cannot exclude
the possibility that uncontrolled factors increasing the rate of
duodenal ulcer, such as genetic predisposition or associated
diseases, may have affected our findings. Furthermore, shift
workers are largely a self selected population and therefore
inherent differences unrelated to shift work itself may be
In conclusion, this study supports the findings of previous
studies that have reported a higher rate of duodenal ulcer in
shift compared to day workers, and confirms that these
results are not only due to the differential rates of H pylori
infection in these two groups of workers. H pylori eradication,
by reducing the risk of peptic ulcer in shift workers, may also
have relevant economic consequences.
A Pietroiusti, A Galante, Department of Internal Medicine, Tor Vergata
University, Rome, Italy
A Forlini, Department of Surgery, Tor Vergata University, Rome, Italy
A Magrini, L Coppeta, G Gemma, E Romeo, A Bergamaschi,
Department of Biopathology–Occupational Medicine, Tor Vergata
University, Rome, Italy
Competing interests: none
Correspondence to: Dr A Pietroiusti, Department of Internal Medicine,
Tor Vergata University, Via Montpellier 1, 00161 Roma, Italia;
Accepted 19 May 2006
ulcer in day-time workers and shift workers after
adjustment for possible confounding factors
Odds ratio for the development of duodenal
Prevalence of duodenal ulcer
*ORs are adjusted with each other.
different types of work in day-time workers and in shift
Prevalence of duodenal ulcer according to
774Pietroiusti, Forlini, Magrini, et al
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