Low serum β-carotene is associated with the incidence of colorectal adenoma

Antioxidant vitamin status has been associated with colorectal cancer in many but not all epidemiological studies; few studies have examined the association of antioxidant vitamins with colorectal adenoma. The present case-control study was conducted to investigate the association of serum carotenoids and tocopherols with colorectal adenoma and cancer and to further examine whether such associations differ by colon subsites. Subjects were recruited from patients undergoing a colonoscopy up to the ileocecal junction. Serum concentrations of 5 carotenoids and 2 tocopherols were compared among 67 patients with colorectal adenoma, 31 patients with colorectal cancer, and 34 controls. Serum β-carotene was inversely associated with the risk of colorectal adenoma. Compared with controls, colorectal adenoma cases had significantly lower mean concentration of serum β-carotene (P = .04). Colorectal adenoma and cancer cases had slightly lower mean concentration of serum lycopene (P = .10). Serum β-carotene concentration in patients with proximal colon adenoma was much lower than that of controls (P = .03). Serum lycopene concentration in patient with proximal and distal colorectal adenoma was lower in comparison with that of controls, but they were not significant (P = .06). In conclusion, these findings suggest that serum β-carotene may be inversley related to the risk of colorectal adenoma; and this association is more pronounced in proximal colon adenomas.