Intragastric pH and serum cortisol levels in shift workers, with special reference to eating and working patterns

Objective: The prevalence of peptic ulcers is increased in shift workers. The aim of this study was to describe the patterns of gastric pH, food intake and cortisol levels (a measure of biological diurnal rhythmicity) during changing shifts. Design and methods: Gastric pH was studied during changing shifts (morning, afternoon and night) by means of 24-h intragastric pH recordings in 12 shift workers, 16 healthy controls and 15 patients with active duodenal ulcer disease. In the shift workers, serum cortisol levels were measured before and after each working period. Normal life style was allowed. An «eat/drink» diary was kept. Results: No significant differences in median pH were seen between either the different shifts or groups of subjects. The percentage time pH < 3 in shift workers was between that observed in controls and duodenal ulcer patients, and was higher during sleep than in the active period in all groups, though more pronounced in controls