|
|
||||||||
Guest Access | Sign In via User Name/Password |
|||||||||
* From the Department of Lung Medicine (Drs. T. Gislason, Björnsson, and D. Gislason), Vifilsstadir Hospital, Gardabaer, Iceland; the Department of Medical Sciences, Respiratory Medicine, and Allergology (Drs. Janson and Boman), Akademiska Sjukhuset, Uppsala, Sweden; the Department of Respiratory Medicine (Dr. Vermeire), University of Antwerp, Antwerp, Belgium; and the Asthma and Allergy Research Center (Dr. Plaschke), Sahlgrenska Hospital, Göteborg, Sweden.
Correspondence to: Thorarinn Gislason, MD, Department of Lung Medicine, Vifilsstadir Hospital, 210 Gardabaer, Iceland
| Abstract |
|---|
|
|
|---|
Design: Cross-sectional international population survey.
Participants: Participants consisted of 2,661 subjects (age range, 20 to 48 years) from three countries (Iceland, Belgium, and Sweden), of whom 2,202 were randomly selected from the general population and 459 were added because of reported asthma.
Measurements: The investigation included a structured interview, spirometry, methacholine challenge, peak flow diary, skin-prick tests, and a questionnaire on sleep disturbances.
Results: In the random population sample, 101 subjects (4.6%) reported GER, which was defined as the occurrence of heartburn or belching after going to bed at least once per week. Subjects with nocturnal GER more often were overweight and had symptoms of sleep-disordered breathing than participants not reporting GER. Participants with GER were more likely to report wheezing (adjusted odds ratio [OR], 2.5), breathlessness at rest (adjusted OR, 2.8), and nocturnal breathlessness (adjusted OR, 2.9), and they had increased peak flow variability compared to the subjects without GER. Physician-diagnosed current asthma was reported by 9% of subjects with GER compared to 4% of those not reporting GER (p < 0.05). Subjects with the combination of asthma and GER had a higher prevalence of nocturnal cough, morning phlegm, sleep-related symptoms, and higher peak flow variability than subjects with asthma alone.
Conclusion: The occurrence of GER after bedtime is strongly associated with both asthma and respiratory symptoms, as well as symptoms of obstructive sleep apnea syndrome. The partial narrowing or occlusion of the upper airway during sleep, followed by an increase in intrathoracic pressure, might predispose the patient to nocturnal GER and, consequently, to respiratory symptoms.
Key Words: asthma epidemiology gastroesophageal reflux sleep snoring.
| Introduction |
|---|
|
|
|---|
The majority of studies in this field have concentrated on highly selected populations at secondary or tertiary referral hospitals. There are few epidemiologic studies of the general population, and little is known about a possible association between respiratory symptoms and GER in an unselected random population. Between 1990 and 1993, an epidemiologic investigation into the prevalence of asthma and allergy, the European Community Respiratory Health Survey (ECRHS), was conducted in different centers throughout the world.8 In four of the participating centers (Reykjavik, Iceland; Uppsala and Göteborg, Sweden; and Antwerp, Belgium), a questionnaire relating to sleep disturbances was added to the second part of the ECRHS study.9 10 11 We have previously reported that GER is associated with an increased prevalence of sleep disturbances as well as with symptoms related to obstructive sleep apnea.9 10 In accordance with the results of other studies,12 13 14 we also found that the quality of sleep often was decreased in subjects with asthma.11
The aim of the present investigation was to estimate the possible association between reported symptoms of GER after bedtime, sleep-disordered breathing, respiratory symptoms, and asthma.
| Materials and Methods |
|---|
|
|
|---|
Populations
In the ECRHS, a random sample of persons in the age range of 20
to 44 years was selected using the population register at each center
(Table 1
).9
10
11
In brief, a postal questionnaire was sent to 3,600
subjects each in Reykjavik, Uppsala, and Göteborg and to
8,029 subjects in Antwerp. The response rates to the questionnaire were
81%, 87%, 80%, and 75%, respectively.
|
A structured interview was conducted among all participants to include measurements of lung function and allergy testing. A sleep questionnaire also was administered to all participants (see below), and the number of participants is noted in Table 1 . The informed consent of all participants was obtained, and the study was approved by all the local ethics committees.
The screening questionnaire and the questionnaire used in the structured interview were based on the International Union Against Tuberculosis and Lung Disease questionnaire.15 In the interview, the patients answered questions relating to respiratory symptoms, respiratory disorders, medication, and environmental factors.
The following asthma-related symptoms were used in this analysis: (1) wheezing or whistling in the chest; (2) being awakened by a feeling of tightness in the chest; (3) having had an attack of shortness of breath that came during the day when at rest; (4) having had an attack of shortness of breath followingstrenuous activity; and (5) having been awakened by an attack of shortness of breath. The recall period was 12 months for all these symptoms. Asthma was defined as having ever reported an occurrence of asthma in which the diagnosis had been confirmed by a doctor and also having had at least one asthma-related symptom in the preceding 12 months.11
The following cough-related symptoms were used in this analysis: (1) being awakened by an attack of coughing in the last 12 months (nocturnal cough); (2) usually coughing in the morning in the winter (morning cough); and (3) usually bringing up phlegm from the chest in the morning in the winter (morning phlegm).
Lung Function and Bronchial Hyperresponsiveness
FEV1 was measured using a computerized
dry-rolling seal spirometer system (Spiro Medics system 2130;
SensorMedics; Anaheim, CA) [Table 1
]. The predicted values were
calculated for each patient.16
Methacholine challenge was performed using a dosimeter (Mefar;
Brescia, Italy).17
Patients with a decrease in
FEV1 of > 20% accompanying an accumulated
methacholine dose of
2 mg were defined as having bronchial
hyperresponsiveness (BHR).
All the participants in Uppsala and Göteborg, a random sample of 25% of the participants in Reykjavik, and all of those with symptoms indicating asthma were asked to record peak expiratory flow (PEF) [ie, the best of three measurements] twice daily during 1 week with a flowmeter (Mini-Wright Peak Flow Meter; Clement Clarke; London, UK). The number of patients who managed to record PEF measurements twice a day on at least 4 of 7 days was 155 in Reykjavik, 552 in Uppsala, and 533 in Göteborg (Table 1) . PEF variability was calculated by dividing the difference between the highest and lowest daily PEF readings by the daily mean PEF value.18
Allergy Testing
Skin-prick tests (Phazet; Pharmacia Diagnostics;
Uppsala, Sweden) were conducted on 2,144 individuals. Those with a
positive result (ie, a mean weal diameter of
3 mm) to at
least one of the following allergens were defined as having atopy:
birch; timothy grass; Dermatophagoides pteronyssinus; cat;
dog; Cladosporium herbarum; or Alternaria
alternata.19
Sleep Questionnaire
After completing the interview and examination, all the subjects
were asked to fill out a separate questionnaire addressing their
quality of sleep during the last few months. The questionnaire was a
slightly modified version of a questionnaire used in previous Swedish
and Icelandic studies.20
21
The questionnaire, which has
been described in detail previously,10
comprised 14
multiple-choice questions in which the subjects were asked to estimate
the frequency of different symptoms on the following 5-point scale: 1,
never; 2, less than once a week; 3, 1 to 2 nights a week; 4, 3 to 5
nights a week; and 5, almost nightly/daily. The question about GER was
"Do you have heartburn or belching when you have gone to bed?" The
questionnaire was translated and then back-translated from Swedish to
Dutch to enable its use in Antwerp. The numbers of subjects in the
random and symptomatic samples who completed the sleep
questionnaire were 2,202 and 459, respectively (Table
2
). Those subjects who reported GER 1 to 2 nights per week
(3 points) or more often are in this article referred to as reporting
nocturnal GER.
Statistical Analysis
The relationships among nocturnal GER, respiratory symptoms, and
symptoms of sleep-disordered breathing were estimated in the randomly
selected population. The symptomatic subjects were included in the
comparison of asthmatic subjects with or without reported GER. The
variation in the prevalence of symptoms and subjects with and without
nocturnal GER was studied using the
2 test
and unpaired t test. When the analysis was limited to
subjects with asthma, Fishers Exact Test was used instead of the
2 test. In these analyses, PEF variability was
log-transformed to achieve normal distribution. Logistic regression was
used when calculating the effect of nocturnal GER on symptoms and
asthma while adjusting for possible confounders. A p value < 0.05 was
regarded as statistically significant. A statistical software package
(StatView, version 5.0; SAS Institute Inc; Cary, NC) was used for all
calculations.
| Results |
|---|
|
|
|---|
|
|
When the random and symptomatic samples were combined, a total of 276 subjects with asthma were identified. Subjects with the combination of nocturnal GER and asthma had a significantly higher BMI and a higher prevalence of several sleep-related symptoms (Table 4 ). Subjects with the combination of both asthma and nocturnal GER had a higher prevalence of nocturnal cough and morning phlegm and an increased peak flow variability than did subjects with asthma alone. No significant differences were found in the prevalence of atopy, BHR, or mean FEV1 between these two groups of asthmatic subjects (Table 5 ).
|
|
| Discussion |
|---|
|
|
|---|
There are several methodologic issues that should be discussed in this investigation. The main one is that our definition of nocturnal GER is based on self-reported symptoms; it is well-known that the association between reported GER and objective measurements, such as 24-h esophageal pH monitoring, is weak.4 Having in mind how very prevalent symptoms of GER are,24 our rather strict criterion for the inclusion of GER symptoms at least once per week has probably resulted in a study population that represents the part of the general population that is more severely affected. A second issue is that in this study the use of three different languages carries the possibility of a translation bias. The questionnaire used in this study is based on the basic Nordic sleep questionnaire.25 The main change in that questionnaire, compared to many earlier sleep questionnaires, was the introduction of a 5-point scale to indicate how many nights or days per week the symptoms occurred. This was done in order to facilitate comparisons when the questionnaire was used in different countries. As we have reported from our previous analysis of the randomly selected sample, the variation in the prevalence of sleep disturbances between the two Swedish centers was of the same magnitude as that between the Swedish and the non-Swedish centers.9 10 Therefore, we do not think that translation bias was a major problem in this study. A validation study26 of the ECRHS interview-led questionnaire also showed good internal consistency, suggesting that the experience of reporting symptoms is not affected by cross-cultural differences.
The definition of asthma used in this study was based on self-reported physician-diagnosed asthma. This definition has been suggested as optimal for epidemiologic studies as it has a high specificity for clinical asthma.27 In order to exclude subjects who had asthma only in childhood, we included only individuals who reported having had asthma-related symptoms in the preceding 12 months. As we have not included adults over the age of 44 years, we have probably avoided most of the problems of separating asthma from COPD. Theophylline is known to cause GER28 and might be a confounding factor in our study. However, as only five of the asthmatic subjects reporting GER had undergone theophylline therapy, the power to detect a significant relationship between the use of theophylline and GER was low in this study.
The clear association between GER and asthma shown in the present investigation and in several previous studies1 2 3 4 gives rise to the question of how patients who have both these diseases should be managed. The inclusion of a 3-month trial of a high-dose proton pump inhibitor in the management of adult asthma patients if GER symptoms are present has been recommended.29 Investigations evaluating the effect of antireflux therapy in patients with asthma and GER have shown a subjective improvement but no effect on lung function.6 The strong association between symptoms of sleep-related breathing disturbances and reported GER after bedtime in our study also indicates that asthmatic subjects with nocturnal GER and daytime sleepiness or other symptoms related to sleep-disordered breathing should be referred for sleep studies, including the monitoring of esophageal pH. In asthmatic subjects with sleep-disordered breathing, a treatment trial with continuous positive airway pressure (CPAP) should be considered. Among the outcome variables of such a CPAP study, both respiratory symptoms and symptoms of sleep-related breathing disturbances should be included. Although previous studies30 31 have not involved the possible role of nocturnal GER, there have been reports32 on improved asthma control after CPAP therapy and also on the presence of less BHR among snoring and OSAS patients after receiving CPAP therapy for 2 to 3 months. Even if a patient is only undergoing a 24-h monitoring of esophageal pH and the results reveal a sleep-related reflux, such a finding warrants at least basic questions about symptoms of sleep-disordered breathing.
We conclude that GER reported to occur after bedtime is strongly associated with a high prevalence of both asthma and respiratory symptoms, as well as symptoms of OSAS. The partial narrowing or occlusion of the upper airway during sleep, followed by more negative swings in intrathoracic pressure, might predispose the patient to nocturnal GER and, consequently, to respiratory symptoms.
| Acknowledgements |
|---|
| Footnotes |
|---|
The Icelandic part of this study was supported financially by the Icelandic Research Council. The Swedish part of this study was supported by the Swedish Heart and Lung Foundation, the Swedish Medical Research Council, and the Swedish Association Against Asthma and Allergy. The Belgian part of this study was
supported by the Belgian Science Policy Office and the National Fund for Scientific Research.
Received for publication December 20, 2000. Accepted for publication June 28, 2001.
| References |
|---|
|
|
|---|
This article has been cited by other articles:
![]() |
T. O. Kiljander, S. M. Harding, S. K. Field, M. R. Stein, H. S. Nelson, J. Ekelund, M. Illueca, O. Beckman, and M. B. Sostek Effects of Esomeprazole 40 mg Twice Daily on Asthma: A Randomized Placebo-controlled Trial Am. J. Respir. Crit. Care Med., May 15, 2006; 173(10): 1091 - 1097. [Abstract] [Full Text] [PDF] |
||||
![]() |
I S Olafsdottir, T Gislason, B Thjodleifsson, I Olafsson, D Gislason, R Jogi, and C Janson C reactive protein levels are increased in non-allergic but not allergic asthma: a multicentre epidemiological study Thorax, June 1, 2005; 60(6): 451 - 454. [Abstract] [Full Text] [PDF] |
||||
![]() |
W. C. Orr Heartburn: Another Danger in the Night? Chest, May 1, 2005; 127(5): 1486 - 1488. [Full Text] [PDF] |
||||
![]() |
R. Fass, S. F. Quan, G. T. O'Connor, A. Ervin, and C. Iber Predictors of Heartburn During Sleep in a Large Prospective Cohort Study Chest, May 1, 2005; 127(5): 1658 - 1666. [Abstract] [Full Text] [PDF] |
||||
![]() |
L. G. Sulit, A. Storfer-Isser, C. L. Rosen, H. L. Kirchner, and S. Redline Associations of Obesity, Sleep-disordered Breathing, and Wheezing in Children Am. J. Respir. Crit. Care Med., March 15, 2005; 171(6): 659 - 664. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. M. Sharma Managing weighty issues on lean evidence: the challenges of bariatric medicine Can. Med. Assoc. J., January 4, 2005; 172(1): 30 - 31. [Full Text] [PDF] |
||||
![]() |
M.I. Gunnbjornsdottir, E. Omenaas, T. Gislason, E. Norrman, A-C. Olin, R. Jogi, E.J. Jensen, E. Lindberg, E. Bjornsson, K. Franklin, et al. Obesity and nocturnal gastro-oesophageal reflux are related to onset of asthma and respiratory symptoms Eur. Respir. J., July 1, 2004; 24(1): 116 - 121. [Abstract] [Full Text] [PDF] |
||||
![]() |
C. Casanova, J.S. Baudet, M. del Valle Velasco, J.M. Martin, A. Aguirre-Jaime, J. Pablo de Torres, and B.R. Celli Increased gastro-oesophageal reflux disease in patients with severe COPD Eur. Respir. J., June 1, 2004; 23(6): 841 - 845. [Abstract] [Full Text] [PDF] |
||||
![]() |
C F Everett, J A Kastelik, S A Mulrennan, A H Morice, L Heaney, and B Johnston Predictors of therapy resistant asthma * Authors' reply Thorax, March 1, 2004; 59(3): 270 - 271. [Full Text] [PDF] |
||||
![]() |
W. J. Calhoun Nocturnal Asthma Chest, March 1, 2003; 123(2007): 399S - 405S. [Abstract] [Full Text] [PDF] |
||||
![]() |
S. Teramoto, H. Kume, Y. Ouchi, C. Janson, and T. Gislason Nocturnal Gastroesophageal Reflux: Symptom of Obstructive Sleep Apnea Syndrome in Association With Impaired Swallowing Chest, December 1, 2002; 122(6): 2266 - 2267. [Full Text] [PDF] |
||||
![]() |
S. Teramoto, H. Kume, Y. Ouchi, and B. Mokhlesi Altered Swallowing Physiology and Aspiration in COPD Chest, September 1, 2002; 122(3): 1104 - 1105. [Full Text] [PDF] |
||||
![]() |
S. K. Field and W. W. Flemons Is the Relationship Between Obstructive Sleep Apnea and Gastroesophageal Reflux Clinically Important? Chest, June 1, 2002; 121(6): 1730 - 1733. [Full Text] [PDF] |
||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |