Systemic markers of oxidative status and colorectal adenomatous polyps.

PURPOSE

Oxidative damage has been implicated in carcinogenesis. We hypothesized that elevated systemic oxidative status would be associated with later occurrence of colorectal adenomatous polyps, a precursor of colorectal cancer.

METHODS

We examined the prospective association between four systemic markers of oxidative status and colorectal adenomatous polyps within a nondiabetic subcohort of the Insulin Resistance Atherosclerosis Study (n = 425). Urine samples were collected from 1992 to 1994 and colorectal adenomas prevalence were assessed in 2002 to 2004. Oxidative status markers were assessed, which included four F(2)-isoprostanes (F(2)-IsoPs) from the classes III and IV: iPF2α-III, 2,3-dinor-iPF2α-III (a metabolite of iPF2α-III), iPF2α-VI, and 8,12-iso-iPF2α-VI. All biomarkers were quantified using liquid chromatography-tandem mass spectrometry. Prospective associations were assessed using multivariate logistic regression analysis.

RESULTS

The adjusted odds ratio (OR) (95% confidence interval [CI]) for occurrence of colorectal adenomatous polyps and scaled to 1 SD of F(2)-IsoP distribution were 1.16 (95% CI, 0.88-1.50), 0.88 (95% CI, 0.63-1.17), 1.04 (95% CI, 0.80-1.34), and 1.16 (95% CI, 0.90-1.48) for iPF2α-III, iPF2α-VI, 8,12-iso-iPF2α-VI, and 2,3-dinor-iPF2α-III, respectively.

CONCLUSIONS

The lack of association between F(2)-IsoPs and adenomatous polyps does not support the hypothesis that elevated oxidative status is associated with colorectal adenomatous polyp occurrence during a 10-year period of follow-up.