Hypersecretion of gastric acid in a representative Finnish family sample.

To evaluate the family behaviour of acid secretion and particularly of 'hypersecretion', we have examined by pentagastrin test and direct vision gastric biopsy 342 subjects with a normal mucosa or superficial gastritis of the body mucosa, collected from a large family sample of the Finnish population. Acid output (AO) was expressed in terms of fat-free body weight (FFB), which eliminates the sex factor found by other expressions of AO. Subjects with values above 1.0 mmol/h/FFB were considered 'hypersecretors' (14 subjects, or 4% of the whole sample). They differed from the whole sample with regard to a high prevalence of signs of duodenal ulcer disease, of high serum pepsinogen, and of blood group O and lack of gastric antibodies and of high serum gastrin levels. The Fisher distribution test showed a significant family aggregation of AO values. In addition, at low AO levels there were subgroups with distinct gaps between them. This finding suggests the effect of genetic variation rather than of a common family environment. The occurrence of higher AO values in sibs but not in children of 'hypersecretors' seems to rule out the possibility of a dominant Mendelian inheritance. These present results are considered to be best compatible with a multigenetic mode of inheritance of gastric hypersecretion.