Basic Research
Copyright ©The Author(s) 2005. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Aug 21, 2005; 11(31): 4794-4799
Published online Aug 21, 2005. doi: 10.3748/wjg.v11.i31.4794
Vitamin D receptor gene Tru9I polymorphism and risk for incidental sporadic colorectal adenomas
You-Ling Gong, Da-Wen Xie, Zong-Lin Deng, Roberd M Bostick, Xi-Jiang Miao, Jin-Hui Zhang, Zhi-Hong Gong
You-Ling Gong, Tumor Center, West China Hospital, Sichuan University, Chengdu 610041, Sichuan Province, China
You-Ling Gong, Da-Wen Xie, Zong-Lin Deng, Jin-Hui Zhang, Zhi-Hong Gong, Department of Epidemiology and Biostatistics, School of Public Health and South Carolina Cancer Center, University of South Carolina, Columbia, SC 29203, USA
Roberd M Bostick, Department of Epidemiology, Rollins School of Public Health, Emory University, Atlanta, GA 30322, USA
Xi-Jiang Miao, Department of Computer Science and Engineering, University of South Carolina, Columbia, SC 29203, USA
Author contributions: All authors contributed equally to the work.
Supported by the Public Health Service grants, No. R01CA-51932 to RMB (National Cancer Institute), and Center for Colon Cancer Research grant, No. RR017698 to FGB from National Institutes of Health, Department of Health and Human Services
Correspondence to: Dr. Da-Wen Xie, University of South Carolina, 14 Richland Medical Park, Suite 500, Columbia, SC 29203, USA. dawen.xie@palmettohealth.org
Telephone: +01-803-434-3707 Fax: +01-803-434-3795
Received: December 3, 2004
Revised: January 1, 2005
Accepted: January 5, 2005
Published online: August 21, 2005
Abstract

AIM: Recent laboratory and epidemiological studies suggest that vitamin D is a potential agent for colorectal cancer prevention. Its function is partially mediated by the vitamin D receptor (VDR). The aim of this study was to investigate whether a novel G (allele ‘U’)>A (allele ‘u’) polymorphism (Tru9I) in the VDR intron 8 region is associated with risk for colorectal adenoma in a colonoscopy-based case-control study.

METHODS: Genotyping for a total of 391 subjects was carried out through PCR and restriction fragment length polymorphism.

RESULTS: The frequencies of ‘U’ and ‘u’ alleles were 89.3% and 10.7%, respectively. The ‘Uu’ and ‘uu’ genotypes were associated with decreased risk for adenoma (OR, 0.71; 95%CI, 0.40-1.25). The inverse association was more pronounced for multiple adenomas and adenomas that were larger had moderate or greater dysplasia, or were sessile: the odds ratios (ORs) were, 0.51 (95%CI, 0.21-1.24), 0.37 (95%CI, 0.11-1.28), 0.68 (95%CI, 0.33-1.41), and 0.36 (95%CI, 0.13-0.97) respectively. In joint/combined analyses, inverse associations were more obvious among those who had at least one ‘u’ allele and also were younger (OR, 0.60; 95%CI, 0.26-1.37), women (OR, 0.38; 95%CI, 0.17-0.88), did not smoke (OR, 0.39; 95%CI, 0.13-1.23), or took NSAID (OR, 0.38; 95%CI, 0.12-1.25), but no evidence existed for interactions with calcium or vitamin D intake.

CONCLUSION: Our findings suggest that the VDR Tru9I polymorphism may be associated with lower risk for colorectal adenoma, particularly in interaction with various risk factors, but not with calcium or vitamin D.

Keywords: Case-control study; Colorectal adenoma; Colorectal neoplasia; Vitamin D receptor; Genetic polymorphism