Abstract
Introduction: Nocturnal gastroesophageal reflux (nGER) is associated with respiratory diseases. It is however unclear how nGER subjects should be identified. Our aim was to validate a method to define nGER in a general population sample.
Methods: Among 450 Icelandic participants in the European Community Respiratory Health Survey III (ECRHS III, see www.ecrhs.org), 48 subjects reporting any symptoms of nGER as well as age and gender paired controls (n=42) were studied further by questionnaires, laryngeal fiberscopy and exhaled breath condensate (EBC). A subgroup underwent 24 hours esophageal pH impedance (24h MII-pH) measurements. Symptoms of nGER were further assessed with a modified version of the Reflux Disease Questionnaire (RDQ), where symptoms were divided into daytime and nocturnal.
Results: Those reporting nGER symptoms (58% nocturnal heartburn, 96% nocturnal regurgitation) at least once in the previous month (hereafter nGER group) had on average more daytime than nocturnal gastroesophageal reflux symptoms (p=0.02). Of the 16 nGER group subjects that underwent 24h MII-pH, altogether 11 had a positive measurement. The nGER group had significantly more often signs of laryngopharyngeal reflux (35% vs 10%, p=0.02), even if only looking at those with mild nGER symptoms. Pepsin was more commonly found in EBC in the nGER group (67% vs 45%, p=0.04).
Conclusions: Subjects with nGER symptoms at least once a month on a modified RDQ have a high level of positive 24h MII-pH measurements. Even those with mild symptoms have signs of airway involvement. This definition of nGER identifies a representable group for studies on nGER and respiratory diseases at least in general population samples.
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