Colorectal Cancer
Copyright ©The Author(s) 2003. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Jan 15, 2003; 9(1): 99-103
Published online Jan 15, 2003. doi: 10.3748/wjg.v9.i1.99
Nested case-control study on the risk factors of colorectal cancer
Kun Chen, Jian Cai, Xi-Yong Liu, Xi-Yuan Ma, Kai-Yan Yao, Shu Zheng
Kun Chen, Jian Cai, Department of Epidemiology, Zhejiang University School of Public Health, Hangzhou 310006, Zhejiang Province, China
Xi-Yong Liu, Shu Zheng, Cancer Institute of Zhejiang University, Hangzhou 310009, Zhejiang Province, China
Xi-Yuan Ma, Kai-Yan Yao, Institute of Cancer Research and Prevention, Jiashan 314000, Zhejiang Province, China
Author contributions: All authors contributed equally to the work.
Supported by the National Natural Science Foundation of China, No. 30170828
Correspondence to: Kun Chen, Department of Epidemiology, Zhejiang University School of Public Health, 353 Yan-an Road, Hangzhou 310006, Zhejiang Province, China. ck@zjuem.zju.edu.cn
Telephone: +86-571-87217190
Received: April 29, 2002
Revised: May 23, 2002
Accepted: June 8, 2002
Published online: January 15, 2003
Abstract

AIM: To investigate the risk factors of colon cancer and rectal cancer.

METHODS: A nested case-control study was conducted in a cohort of 64693 subjects who participated in a colorectal cancer screening program from 1989 to 1998 in Jiashan county, Zhejiang, China. 196 cases of colorectal cancer were detected from 1990 to 1998 as the case group and 980 non-colorectal cancer subjects, matched with factors of age, gender, resident location, were randomly selected from the 64693 cohort as controls. By using univariate analysis and mutivariate conditional logistic regression analysis, the odds ratio (OR) and its 95% confidence interval (95%CI) were calculated between colorectal cancer and personal habits, dietary factors, as well as intestinal related symptoms.

RESULTS: The mutivariate analysis results showed that after matched with age, sex and resident location, mucous blood stool history and mixed sources of drinking water were closely associated with colon cancer and rectal cancer, OR values for the mucous blood stool history were 3.508 (95%CI: 1.370-8.985) and 2.139 (95%CI: 1.040-4.402) respectively; for the mixed drinking water sources, 2.387 (95%CI: 1.243-4.587) and 1.951 (95%CI: 1.086-3.506) respectively. All reached the significant level with a P-value less than 0.05.

CONCLUSION: The study suggested that mucous blood stool history and mixed sources of drinking water were the risk factors of colon cancer and rectal cancer. There was no any significant association between dietary habits and the incidence of colorectal cancer.

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