Ethnic variation in the incidence of stomach cancer in Illinois, 1986- 1988

Abstract

Wide ethnic and geographic variation in stomach cancer incidence has been reported in Eastern and Western countries. Stomach cancer is reported to be the most common malignant neoplasm in Asia, specifically, China, Japan, and Korea. In contrast, stomach cancer incidence in the United States among Caucasians is low and among blacks, moderate to low. Only one other study has directly compared the rates of stomach cancer in the three ethnic groups (i.e., white, African American, and immigrant Korean) living in the same region. The authors extend their investigation by comparing the incidence rate of stomach cancer among the same three ethnic groups in the state of Illinois from 1986 to 1988. In this study, the incidence of stomach cancer was observed to be lowest in whites, intermediate in African Americans, and highest in immigrant Koreans. The overall 3-year cumulative incidence rate from 1986 to 1988 was 62.6/100,000 (95% confidence interval (CI) 38.6-86.7), 28.2/100,000 (95% CI 25.7-31), and 22.5/100,000 (95% CI 21.5-23.5) for immigrant Koreans, African Americans, and whites, respectively. The 3-year age-adjusted cumulative incidence rate for immigrant Koreans (172/100,000) was approximately four- and eightfold higher than for African Americans (41/100,000) and whites (21/100,000). The incidence of stomach cancer increased as a function of age in both sexes. Although a higher rate was observed in males than in females, these rates were four- and eightfold higher in African Americans and immigrant Koreans, when compared with their white counterparts in both sexes. Despite a substantial reduction of stomach cancer incidence in the United States and other Western countries, it remains the most frequent malignancy in native and immigrant Koreans. The high rate of stomach cancer in immigrant Koreans compared with African Americans and white populations residing in Illinois indicates either a drastically disproportionate undercount of immigrant Koreans in the 1990 census or a profound genetic-environmental interaction.