Among females older than 50 years, saliva secretion is significantly lower in non-erosive reflux disease patients than in healthy controls.

Background: Saliva secretion is significantly lower in patients with non-erosive reflux disease (NERD) than in healthy controls (HC). A previous study on HC showed that saliva secretion was lower in females than in males. Saliva secretion may be lower in female patients with NERD than in male patients. Therefore, the present study investigated sex differences in saliva secretion in patients with NERD.

Methods: Subjects older than 50 years were included in the present study and consisted of 20 male patients with NERD, 19 male HC, 25 female patients with NERD, and 23 female HC. Saliva secretion was assessed as follows: each patient chewed sugar-free gum for 3 min prior to endoscopy, and the amount and pH of saliva before and after acid loading as an index of the acid-buffering capacity were measured.

Results: In males, no significant differences were observed in the amount of stimulated saliva secretion or salivary pH between NERD patients and HC. However, the acid-buffering capacity (NERD: 6.1 [5.9-6.5], HC: 6.4 [6.2-6.6]) was significantly lower in NERD patients than in HC. In females, the amount of stimulated saliva secretion (NERD: 2.6 [2.0-4.1], HC: 5.8 [3.7-7.5]), salivary pH (NERD: 7.0 [6.8-7.2], HC: 7.2 [7.0-7.2]), and the acid-buffering capacity (NERD: 5.8 [5.4-6.2], HC: 6.2 [6.0-6.5]) were significantly lower in NERD patients than in HC.

Conclusion: Among females older than 50 years, saliva secretion was significantly lower in NERD patients than in HC. This reduction in saliva secretion may contribute to the pathophysiology of NERD in females.