Date Published: January 20, 2017
Publisher: Public Library of Science
Author(s): Hiroshi Kishikawa, Kayoko Kimura, Asako Ito, Kyoko Arahata, Sakiko Takarabe, Shogo Kaida, Takanori Kanai, Soichiro Miura, Jiro Nishida, Gernot Sellge.
Several clinical factors; overweight, male gender and increasing age, have been implicated as the etiology of hiatal hernia. Esophageal shortening due to acid perfusion in the lower esophagus has been suggested as the etiological mechanism. However, little is known about the correlation between gastric acidity and sliding hiatus hernia formation. This study examined whether increased gastric acid secretion is associated with an endoscopic diagnosis of hiatal hernia.
A total of 286 consecutive asymptomatic patients (64 were diagnosed as having a hiatal hernia) who underwent upper gastrointestinal endoscopy were studied. Clinical findings including fasting gastric juice pH as an indicator of acid secretion, age, sex, body mass index, and Helicobacter pylori infection status determined by both Helicobacter pylori serology and pepsinogen status, were evaluated to identify predictors in subjects with hiatal hernia.
Male gender, obesity with a body mass index >25, and fasting gastric juice pH were significantly different between subjects with and without hiatal hernia. The cut-off point of fasting gastric juice pH determined by receiver operating curve analysis was 2.1. Multivariate regression analyses using these variables, and age, which is known to be associated with hiatal hernia, revealed that increased gastric acid secretion with fasting gastric juice pH <2.1 (OR = 2.60, 95% CI: 1.38–4.90) was independently associated with hiatal hernia. Moreover, previously reported risk factors including male gender (OR = 2.32, 95% CI: 1.23–4.35), body mass index >25 (OR = 3.49, 95% CI: 1.77–6.91) and age >65 years (OR = 1.86, 95% CI: 1.00–3.45), were also significantly associated with hiatal hernia.
This study suggests that increased gastric acid secretion independently induces the development of hiatal hernia in humans. These results are in accordance with the previously reported hypothesis that high gastric acid itself induces hiatal hernia development.
Hiatal hernia is a herniation of the gastric cardia through the esophageal hiatus of the diaphragm. It is differentiated into four types (types I-IV), of which type I (sliding hiatal hernia), characterized by both widening of the muscular hiatal aperture of the diaphragm and laxity of the phreno-esophageal membrane, accounts for 95% of cases . The association between sliding hiatal hernia and gastroesophageal reflux disease (GERD) has long been recognized because of the high prevalence of their coexistence . Hiatal hernia reduces lower esophageal sphincter tone, which results in a loss of the pinchcock effect of prevention of gastric acid reflux, and also acts as an acid reservoir that allows ready access of gastric juice into the esophagus, thus contributing to prolonged esophageal acid exposure leading to GERD [3, 4].
In the present study, there was a significant positive association between endoscopic hiatal hernia development and high gastric acid secretion. Several reported risk factors for hiatal hernia, such as male sex, obesity, and increasing age, were also shown to be predictors of hiatal hernia in the present study [7, 20]. Several previous studies indicated that acid injury of the esophageal mucosa causes longitudinal muscle contraction and esophageal shortening, which induces the development of hiatal hernia [8, 9]. However, to date, it has not been clarified whether high gastric acid secretion, which causes increased acid exposure to the lower esophagus, is associated with hiatal hernia in humans. Thus, this is the first clinical study suggesting that high acid secretion itself may induce hiatal hernia development in humans, based on a direct evaluation of the association between acid secretory function and endoscopic findings of hiatal hernia in over 400 subjects.