Selenium and colorectal adenoma: results of a pooled analysis.

Study answer

What this study found

Higher baseline blood selenium was associated with lower odds of adenoma recurrence in the pooled analyses. Highest versus lowest quartile OR = 0.66 (95% CI 0.50–0.87); P-trend = 0.006. For large adenomas, OR = 0.57 (95% CI 0.34–0.95). Linear decrease in odds with increasing selenium beyond ~100 ng/mL. The inverse association supports prior findings that higher selenium status may reduce colorectal neoplasia risk; more research is needed to determine optimal selenium dose and chemical form for cancer prevention.

Study & population

Participants: adults who recently had a colorectal adenoma removed during colonoscopy.

Intervention

Wheat Bran Fiber Trial: high-fiber cereal supplement vs low-fiber supplement for 3 years; Polyp Prevention Trial: vitamin C, vitamin E, and beta-carotene supplementation for 4 years; Polyp Prevention Study: low-fat, high-fiber diet containing fruits and vegetables vs normal diet for 4 years

Key limitation

Differences in trial designs and sampling across the three trials; selenium was measured with different assays across laboratories; potential misclassification of recurrences due to year-1 colonoscopy as a 'clean-out'; participants were volunteers with prior adenomas, limiting generalizability; inability to determine…

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Original abstract