Geographical Variations in the Morphology of the Small Intestinal Mucosa in Apparently Healthy Individuals

Macroscopic and microscopic photographs of seven jejunal biopsies illustrating the range of morphological changes found in southern Indian control subjects were circulated, together with a questionaire, to observers in different parts of the world. There was general agreement among the observers regarding the ‘normality’ of the biopsy showing the least changes and the abnormality of the two showing the most marked changes, but considerable disagreement over those intermediate between these two extremes. Opinion regarding the prevalence of the different biopsy appearances in control subjects varied significantly between temperate and tropical areas. A hierarchy of abnormality has been drawn up ranking countries in decreasing order of prevalence of the two most abnormal biopsies. Possible factors in the pathogenesis of the morphological changes in the jejunal mucosa in the tropics are discussed.