Study objective: To estimate the possible association
between reported symptoms of gastroesophageal reflux (GER) after
bedtime, sleep-disordered breathing, respiratory symptoms, and asthma.
Design: Cross-sectional international population
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.