| Abstrakt: |
Objective: The aim of this study was to determine whether intestinal colonization with enterococci that produce extracellular superoxide (...), a free radical implicated in the development of colorectal cancer, is associated with these lesions or their precursors. Methods: A prospective case-cohort study was performed by isolating enterococci from stools of consecutive patients undergoing colonoscopy who had no prior history of colonoscopy or colorectal cancer. A food frequency questionnaire was also administered to control for dietary factors known to affect the risk for these lesions. Results: Among 159 evaluable participants were 77 with no pre-cancerous or cancerous pathology, 61 with adenomas < 2 cm, 10 with adenomas ≥2 cm, and ii with cancer. Regression analyses found no associations for those subjects with adenomas of any size or with cancer and colonization with ...-producing enterococci, any nutrient, or age. For those patients with large adenomas ≥2 cm or cancer, however, significant associations were noted for age (OR 1.94 per decade, 95% CI 1.2-3.5), β-carotene (OR 0.44 per 500µg/1000 kcal/day, 95% CI 0.2-0.8), vitamin A (OR 3.20 per 500 µg/1000 kcal/day, 95% CI 1.2-8.9), and vitamin E (OR 0.09 per 10 mg/ 1000 kcal/day, 95% CI 0.006-0.9), but not colonization with ...-producing enterococci. Second stools collected I yr later, however, often contained dissimilar enterocoecal flora, undermining an important study assumption. Conclusions: Significant associations were found for those with large adenomas or cancer (but not small adenomas), with age, and with foods enriched for vitamin A, vitamin E, and β-carotene. An association between colonization with ...-producing enterococci and colorectal adenomas or cancer, however, could not be ascertained, possibly because intestinal enterococcal flora changes over time, leaving a potentially cohesive hypothesis of colon cancer and risk factors as yet unanswered. [ABSTRACT FROM AUTHOR] |
