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ASSOCIATION BETWEEN URINARY MUTAGENICITY AND RISK OF COLORECTAL ADENOMAS IN A CLINIC-BASED CASE-CONTROL STUDY
Citation:
Peters, U., D M. DeMarini, R. Sinha, L R. Brooks, S H. Warren, N. Chatterjee, AND N. Rothman. ASSOCIATION BETWEEN URINARY MUTAGENICITY AND RISK OF COLORECTAL ADENOMAS IN A CLINIC-BASED CASE-CONTROL STUDY. Presented at American Association for Cancer Research, San Francisco, CA, 4/6-10/2002.
Description:
ASSOCIATION BETWEEN URINARY MUTAGENICITY AND RISK OF COLORECTAL ADENOMAS IN A CLINIC-BASED CASE-CONTROL STUDY
Humans are exposed to a variety of mutagens from diet, smoking, or occupation. To explore if exposure to mutagens was related to the risk of colorectal adenomas incidence, we measured urine mutagenicity in a case-control study of colorectal adenomas. An overnight urine sample was provided by 163 subjects with histologically confirmed colorectal adenomas and 161 controls with no evidence of adenomas by sigmoidoscopy. Mutagenicity was measured in strain YG 1024 of Salmonella in the presence of S9 fraction after extracting urine with l8/methanol before acid hydrolysis (free mutagenicity = unmetabolized mutagens) and after acid hydrolysis (total mutagenicity = unmetabolized + cleaved mutagens). The association between urinary mutagenicity and colorectal adenoma risk was analyzed in logistic regression models. The lOth and 90th percentiles for free and total mutagenic activity were 0; 16,800 and 17,000; 249,100 revertants/overnight, respectively. The risk of colorectal adenoma was increased by 140% comparing ~he highest quintile to the lowest quintile of free mutagenicity [ odds ratio (OR) 2.4, 95% confidence interval (CI) 1.1-4.9). Excluding current smokers (20 cases and 5 controls) from the analysis resulted in an odds ratio for free mutagenicity of2.0 (95% CI: 0.9-4.5 comparing Sth vs. 1st quintile ), indicating that mutagenicity from sources besides tobacco, such as the diet, may be associated witl1 risk of colorectal adenomas. In contrast, total urinary mutagenicity was not associated with colorectal adenoma risk (OR 0.7, 95%CI 0.3-1.4 comparing highest quintile to the lowest quintile ). These results suggest that free urine mutagenic activity is associated with increased risk of colorectal adenomas and is consistent with a previous report from this study linking dietary mutagenic and heterocyclic aromatic amine intake assessed by questionnaire and risk of this tumor.
[Abstract does not necessarily represent the policy of the U.S. EPA.]