Measuring Duodeno-Gastric and Duodeno-Gastro-Esophageal Reflux in Clinical Practice: The Role of Age

creased acid exposure with age [9, 10]. In the present issue of Digestion , Bollschweiler et al. [11] compared normal values for DGR and DGER exposure in younger and older asymptomatic volunteers . The authors found that older volunteers ( 1 40 years old) had higher DGER exposure compared to younger volunteers, but they reported no differences in DGR exposure. Comparison of studies investigating DGR in the literature is hampered by the use of different positions of the probe (antrum vs. fundus), the use of different cut-offs for bilirubin absorbance, and the use of different dietary interventions to avoid food impaction artifacts [6–8]. Bollschweiler et al. [11] studied DGR exposure 10 cm distal to the LES in subjects on a white diet, and comparing DGR values at different cut-offs, they found no agerelated differences. When assessing esophageal bilirubin exposure, the authors found signifi cantly higher DGER values in older volunteers. In the absence of a difference in gastric exposure, these fi ndings suggest that age-related changes in esophageal motility or in competence of the esophagogastric junction underlie the higher DGER exposure in older subjects. Peristalsis is the only clearance mechanism for DGER [12], but decreases in peristaltic function with age in asymptomatic subjects are subtle and probably of minimal impact [13]. The incidence of hiatal hernia clearly increases with age, and this is potentially an important contributor to higher levels of duodenal content The pathological role of acid refl ux to the esophagus in gastro-esophageal refl ux disease (GERD) is well established: typical symptoms of heartburn are mimicked by esophageal acid perfusion [1] , esophageal pH monitoring is used to quantify GERD [2] and acid-suppressive drugs are the cornerstone of medical treatment [3] . There is now an increasing body of evidence that duodeno-gastroesophageal refl ux (DGER) is also involved in the pathophysiology of GERD. The occurrence of erosive esophagitis in patients with achlorhydria and after total gastrectomy [4, 5] argues in favor of a role for refl ux of duodenal content in the pathogenesis of erosive esophagitis. The use of prolonged fi beroptic monitoring of bilirubin concentration (Bilitec ® ) has allowed quantifying refl ux of duodenal content to the stomach and the esophagus. Bilitec ® studies have shown that DGER is more common in patients with severe esophagitis and Barrett’s esophagus than in patients without or with minor esophagitis [6, 7]. It is clear that duodeno-gastric refl ux (DGR) is a prerequisite for DGER to occur, and a recent study has shown that DGR is a physiological phenomenon in the postprandial period and occurs sporadically in the interdigestive state [8] . In order to study the role of acid refl ux, DGR and DGER in disease, knowledge of the normal range of gastric and esophageal exposure is required. Studies on the infl uence age on esophageal pH monitoring showed confl icting results, although there is a clear tendency for inPublished online: March 16, 2005