Context: Early studies suggested that gastric acidity declines as people age. However, sequelae of achlorhydria are uncommon in older people, making this conventional wisdom unlikely.
Objective: To ascertain the prevalence of basal gastric acidity and atrophic gastritis (indicated by serum pepsinogen ratio) in older adults.
Design: Cross-sectional study in a volunteer sample.
Setting: Retirement communities in suburbs of Kansas City, Mo.
Subjects: A total of 248 white male and female volunteers aged 65 years or older living independently.
Main outcome measures: Presence of basal unstimulated gastric acid was evaluated noninvasively by having subjects swallow quininium resin. Gastric acid with a pH lower than 3.5 releases quinine, which is then absorbed and excreted into urine. Atrophic gastritis was defined as a ratio of serum pepsinogen I/pepsinogen II of less than 2.9.
Results: Basal unstimulated gastric content was acidic (pH <3.5) in 208 (84%) of 248 elderly subjects. On retesting 66 subjects (35 normals and 31 hyposecretors), 28 (80%) of 35 had pH less than 3.5 both times, and 22 (71%) of 31 had pH of 3.5 or higher twice; in the remaining 16 subjects, low vs high gastric pH changed between tests. Weighted population prevalence estimates in this sample were 67% for consistent acid secretion, 22% for intermittent secretion, and 11% for consistent gastric pH higher than 3.5. Whereas 14 (67%) of 21 consistent hyposecretors had serum pepsinogen ratios of less than 2.9, indicating atrophic gastritis, only 2 (5%) of 44 consistent or intermittent secretors of acid had ratios in this range (P<.001).
Conclusions: In contrast to what is commonly stated, nearly 90% of elderly people in this study were able to acidify gastric contents, even in the basal, unstimulated state. Of those who were consistent hyposecretors of acid, most had serum markers of atrophic gastritis.