Gastric cell phenotypes and intestinal metaplasia in Polynesian and non-Polynesian residents of New Zealand.

Previous studies have indicated that the frequency of different cell phenotypes as well as of the mucosal extension of intestinal metaplasia (IM) in the gastric mucosa varies in different geographic regions (Scandinavia, Japan, Mexico, Hawaii, and mainland U.S.A.). These variations appear to be influenced by environmental factors but not by the race of the individuals. In the present work, 241 gastrectomy specimens from the two main racial groups in New Zealand, indigenous Pacific Island Polynesians (mainly Maoris) and non-Polynesian settlers (mainly of European ancestry), were examined. The occurrence of histologic changes known to be influenced by the environment such as intramucosal gastric cysts, intestinal metaplasia (IM), ciliated metaplastic cells, and cells with large vacuoles were recorded. The mucosal extension of IM was classified into low IM (having one to five areas with IM in at least one of the sections) and high IM (having one area with IM in all microscopic fields in at least one of the sections or occupying entire fields in one or more sections). Polynesians with adenocarcinomas and peptic ulcers were younger than non-Polynesians. The gastric mucosa in younger Polynesians harboring an intestinal type carcinoma or a peptic ulcer differed from that of non-Polynesians; Polynesians more often had intramucosal cysts, high IM scores, or ciliated metaplastic cells at a younger age than non-Polynesians. These results suggest that the gastric mucosa of Polynesians may be exposed to environmental factors (ulcerogenic or carcinogenic) at an earlier age than the gastric mucosa of non-Polynesians in New Zealand.