Risk of colorectal adenomas in a multiethnic Asian patient population: race does not matter

Ethnic differences have been reported for colorectal polyps and large bowel cancer; although the supporting data is weak and insufficient to draw firm conclusions.

We undertook this study to determine whether such racial disparity in colorectal adenomas exists in an ethnically mixed non-migrant population. The prevalence, histology and distribution of colonic polyps were documented as well as other known risk factors for colorectal malignancy.

In this prospective cross-sectional study, 311 consecutive referred and self-referred multiracial patients attending for colonoscopy over a 41-month period in a private endoscopy center were recruited. The mean age of the study population was 51.8 +/- 14 years (range 16-91). The male to female ratio was 1.1 and an ethnic breakdown as follows: 87 Malays, 115 Chinese and 109 Indians.

Sixty-three adenomas were recorded in 36 patients: six Malays, 19 Chinese and 11 Indians. Of these adenomas, 59 were polypoid, three flat and one depressed. The majority of adenomas 42/63 (67%) were distal to the splenic flexure as were all (10/10) the Duke's A carcinomas and 6/8 (75%) of the advanced cancers. Patients with adenoma(s) compared with those without (controls) were significantly older (P = 0.005), more likely to have a family history of colorectal cancer (P = 0.005), and showed a trend towards significance for ethnic group (P = 0.09) on univariate analysis. Using logistic regression analysis, only family history (P = 0.05) and age > or = 50 years (P = 0.011) were found to be significantly associated with adenomas.

Risk factors for colonic adenoma(s) in our cohort of symptomatic multiethnic patients attending for colonoscopy do not seem to differ from those reported elsewhere and, in particular, race does not appear to be a factor.