Ethnic variations in the occurrence of colonic neoplasms

With the exception of African Americans and Hispanics, few studies have dealt with the influence of other types of ethnicity on the prevalence of colon polyps and colorectal cancer. The present study was undertaken to compare the ethnic and socioeconomic distributions of colonic neoplasms among different ethnic groups in the United States.

A total of 813,057 patients, who underwent colonoscopy during 2008-2014, were recruited from an electronic database of histopathology reports (Miraca Life Sciences) for a cross-sectional study. Using multivariate logistic regression analyses, the presence of hyperplastic polyps, serrated adenomas, tubular adenomas, or adenocarcinomas each served as separate outcome variables. Patient ethnicity was determined using a name-based computer algorithm. Demographic (age, sex, ethnicity) and a variety of socioeconomic risk factors (associated with patients' ZIP code) served as predictor variables.

About 50% of the study population harbored adenomatous polyps, 25% hyperplastic polyps, 8% serrated adenomas, and 1.4% adenocarcinomas. Tubular adenomas and adenocarcinomas showed similar ethnic distributions, being slightly more common among Hispanics and East Asians. All four types of colonic neoplasm were relatively rare among patients of Asian-Indian descent and relatively common among patients of Japanese descent. Except for Japanese patients, serrated adenomas tended to be less prevalent among East Asians. In general, markers of high socioeconomic status showed a tendency to be negatively associated with the presence of tubular adenoma and adenocarcinoma, but positively with the presence of serrated adenoma.

Ethnicity and socioeconomic factors affect different histology types of polyps differently. Genetic as well as environmental factors interact in the development of colorectal cancer and its precursor lesions.