Effects of aging and gastritis on gastric acid and pepsin secretion in humans: a prospective study.

Recent studies suggesting that gastric secretion does not decrease with aging included few elderly individuals and measured only acid secretion. The aims of this study were to measure gastric acid and pepsin output in 206 health Americans (age range, 18-98 years) and to compare secretion rates with gastric histology. Immediately after basal and pentagastrin-stimulated acid and pepsin outputs were measured, oxyntic biopsy samples were obtained. Gastric acid and pepsin output rates were similar in young (age range, 18-34 years) and middle-aged (age range, 35-64 years) groups. Stimulated acid output was reduced approximately 30% in the elderly (age range, 65-98 years). However, after adjustment for histology, Helicobacter pylori infection, and other variables, age had no independent effect on acid output. The decline in acid secretion in the elderly was primarily related to a higher prevalence of chronic atrophic gastritis and a lower prevalence of smoking. Pepsin output was reduced by approximately 40% in the elderly. After adjustment for other variables, age remained a robust predictor of reduced pepsin output. Although advancing age has no independent effect on gastric acid secretion, it is associated with reduced pepsin output independent of atrophic gastritis, H. pylori infection, and smoking.