RELATIONSHIP OF AGING AND TOBACCO USE WITH THE DEVELOPMENT OF ABERRANT CRYPT FOCI IN A PREDOMINATELY AFRICAN-AMERICAN POPULATION

Authors: MOXON, DARRAN - UNIVERSITY OF ILLINOIS; RAZA, MAMOON - UNIVERSITY OF ILLINOIS; KENNEY, RICHARD - UNIVERSITY OF ILLINOIS; EWING, RONALD - UNIVERSITY OF ILLINOIS; AROZULLAH, AHSAN - UNIVERSITY OF ILLINOIS; MASON, JOEL - TUFTS-HNRCA; CARROLL, ROBERT - UNIVERSITY OF ILLINOIS

Submitted to: Clinical Gastroenterology and Hepatology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/27/2004
Publication Date: 3/1/2005
Citation: Moxon, D., Raza, M., Kenney, R., Ewing, R., Arozullah, A., Mason, J., Carroll, R.E. 2005. Relationship of aging and tobacco use with the development of aberrant crypt foci in a predominately African-American population. Clinical Gastroenterology and Hepatology. 3(3):271-8.

Interpretive Summary: Elder age, tobacco smoking, and insufficient dietary folate are each thought to be risk factors for cancer of the large bowel but the interrelationships of these three factors are unknown. Microscopic alterations in the lining of the large bowel, called aberrant crypt foci (ACF) are thought to be precursors of cancer and can be seen through a magnifying colonoscope. We therefore hypothesized that age, smoking, and low folate intake would be related to the prevalence of ACF in the large bowels of humans undergoing colonscopy. Eighty three subjects completed questionnaires concerning alcohol, dietary habits, and tobacco use. ACF in the latter portion of the large bowel were counted using magnification colonoscopy (mag 35X). Folate concentrations in biopsies taken from the rectum were determined. ACF number increased with age. Additionally, ACF were more prevalent and contained more precancerous features with increasing tobacco intake. Reduced colonic folate was associated with lower dietary folate intake but did not correlate with ACF number, nor did higher colonic folate concentrations convey a protective effect for ACF formation with age or tobacco use. Increasing age and tobacco use are independently linked to the presence of ACF of the large bowel. Depleted folate stores were not associated with prevalence of ACF and might therefore not be linked to promoting the process of cancer at this stage of cancer development.

Technical Abstract: In clinical studies, diminished folate availability appears to increase the risk for colorectal neoplasms. Additionally, alcohol and tobacco use are associated with an increased risk for colon cancer, but the early pathologic events by which these agents promote neoplastic transformation are not well understood. Aberrant crypt foci (ACF) are potential precursors of adenoma and cancer, and can be visualized by magnification endoscopy. We hypothesized that folate depletion is linked to ACF formation and therefore studied the association between tissue folate, dietary habits, and ACF number in patients undergoing screening colonoscopy. Eighty-three patients, undergoing screening colonoscopy at an urban Veterans Affairs and university hospital, completed a questionnaire concerning alcohol, nonsteroidal anti-inflammatory drugs (NSAIDs), and tobacco use. Folate intake was calculated from food frequency questionnaires. Rectal ACFs were scored using magnification chromoendoscopy by methylene blue staining. Folate concentrations in rectal biopsy specimens were determined by microtiter bioassay. Results showed that ACF number increased with age and with increasing tobacco intake. Decreased colonic folate level was associated with increased homocysteine levels and lower dietary folate intake but did not correlate with ACF number. We concluded that increasing age and tobacco use were linked independently to the presence of colonic ACF in this predominately African-American population. Folate, alcohol, and acetylsalicylic acid (ASA) use did not influence the prevalence of these lesions.