Vitamin D receptor gene Tru9I polymorphism and risk for incidental sporadic colorectal adenomas.
OBJECTIVE
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.


CONCLUSIONS
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.
Gong
You-Ling
YL
Tumor Center, West China Hospital, Sichuan University, Chengdu 610041, Sichuan Province, China.
Xie
Da-Wen
DW
Deng
Zong-Lin
ZL
Bostick
Roberd M
RM
Miao
Xi-Jiang
XJ
Zhang
Jin-Hui
JH
Gong
Zhi-Hong
ZH
D000236:Adenoma / Q000453:epidemiology / Q000235:genetics*; D000428:Alcohol Drinking; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000009:adverse effects; D015179:Colorectal Neoplasms / Q000453:epidemiology / Q000235:genetics*; D005260:Female; D005787:Gene Frequency; D005838:Genotype; D006801:Humans; D008297:Male; D008875:Middle Aged; D011110:Polymorphism, Genetic; D018167:Receptors, Calcitriol / Q000235:genetics*; D012307:Risk Factors; D012907:Smoking
D000894:Anti-Inflammatory Agents, Non-Steroidal; D018167:Receptors, Calcitriol