Racial and ethnic differences in the risk of premalignant colorectal neoplasia have not been extensively studied.


To measure adenoma prevalence among asymptomatic white, black and Hispanic patients undergoing screening colonoscopy.


In this cross sectional cohort study, data from individuals ≥50 years undergoing first-time colonoscopy since 2006 at a single tertiary-care medical centre were obtained from the electronic medical record. Adenoma prevalence among whites, blacks and Hispanics was calculated; multivariate Poisson and logistic regression were used to identify factors independently associated with adenoma rates and the presence of advanced adenomas.


We identified 5075 eligible subjects: 3542 (70%) whites, 942 (18%) Hispanics and 591 (12%) blacks. The mean age was 62.2 years with 58% women. At least one adenoma was detected in 19%, 22% and 26% of whites, Hispanics and blacks respectively (Hispanics vs. whites P = 0.09; blacks vs. whites P = 0.0001). Isolated proximal adenomas were present in 9% of whites, 11% of Hispanics (P = 0.03) and 11% of blacks (P = 0.03). In multivariate analyses, a higher rate of adenomas was present in Hispanics (RR: 1.37, 95% CI: 1.20–1.57) and blacks (RR: 1.76, 95% CI: 1.52–2.04) than whites. Hispanics and blacks also had an increased risk of advanced adenomas compared to whites (ORHispanics: 2.25, 95% CI: 1.62–3.11; ORblacks: 1.91, 95% CI: 1.27–2.86).


Adenoma prevalence was higher in blacks and Hispanics than in whites. Both groups were at greater risk of having proximal adenomas in the absence of any distal pathology than whites, where these lesions would have only been detected by colonoscopy. Efforts to promote screening are necessary among diverse, under-represented populations.